water authority of fiji fabrication & installation … · water authority of fiji | fabrication...
TRANSCRIPT
WATER AUTHORITY OF FIJI
FABRICATION & INSTALLATION OF GREASE TRAPS AND UNDERGROUND
GREASE INTERCEPTORS
2017
Clean Water and Sanitation for a Better Life
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
HANDBOOK
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 1
ACKNOWLEDGEMENTThis handbook is an important tool for people and businesses in the plumbing industry. This serves a great need for the restaurant industry where it is manda-tory to have grease traps or grease interceptors. The success and final outcome of this handbook required guidance and assistance from many people. We acknowledge and express our sincere gratitude towards the following people who have greatly assisted in compiling this handbook.
• Fiji National University, especially Mr Luke Diloi who is also the President for Fiji Institute of Plumbing and Mr Salabogi Mavoa who is the Associate Dean for College of Engineering, Science and Technology
• Town and City Councils • GHD Capacity Building Consultancy.• Sydney Water Corporation, Australia.• Planning and Design Team of Water Authority of Fiji • All the participants who took part in the Fabrication and Installation of
grease trap consultation workshop for contributing bright ideas towards the handbook.
We would like to give our special acknowledgement to the Water Authority of Fiji’s management team for making it possible to publish this handbook.
2
TABLE OF CONTENTS
Pages Acknowledgment 1 Preface 2 1.Background 2.Objectives
3
3.Designs
4
3.3 Designs 3.3.1 Under sink grease trap design
5 - 9
3.3.2 Guidelines 3.3.2.1 Under Sink Grease Trap
10 – 13
Table -Dimensions for Underground Grease Interceptors
18 -19
4.1 FOG Management
20 -24
14 - 17
26-27
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
4.2 Minimum Pretreatment Requirement for Food Proccesses
3.3.3 Underground Grease Interceptor
3.3.4 Guidelines3.3.4.1 Underground Grease Interceptor4.Appendices4.1 FOG Management 25
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
PREFACE
Grease traps and grease interceptors are devices designed to separate the Fats, Oil and Grease (FOG) and solids prior to discharge into a wastewater disposal system. It protects the wastewater system from blockages due to FOG and solid waste from food preparation areas. Through various inspections, workshops and presentations, it was found by WAF that there was poor or improper grease trap and grease intercep-tor designs and installations. The majority of the small restaurant owners were not aware of grease trap designs, its purpose, the size required or even the maintenance. Many restaurants had grease traps or grease interceptors but were not maintaining them, while others had undersized designs or poor pipework. This handbook details the designs of the passive grease trap and grease interceptors. It informs the user on the fabrication, materials, sizing and manufacturing. It also outlines the installation process that includes; positioning, venting and piping. This handbook also includes; the frequency of clean outs, responsibility for clean outs and disposal, clean out methods and disposal methods of FOG. These designs are a mandatory guideline for new Grease trap designs and are accept-able if it is inspected by Water Authority of Fiji technician and is found to be function-ing and maintained properly.……………………………………………………………………………………………………………………………………….........Prepared By: Assisted By: _______________ & ________________ _______________________Andrew Kirkwood Hillary Fisher Komal DeviGHD Consultant Graduate Engineer Team Leader Liquid Trade Waste Water Authority of Fiji Water Authority of Fiji
Reviewed By: Checked By:
_______________________ ________________________Rahul Sharma Danilo de AsaGraduate Engineer Senior Engineer Water Authority of Fiji Water Authority of Fiji
Recommended for Approval By Approved By
________________________ _________________________Seru Soderberg Opetaia Ravai Acting GM Planning and Design Chief Executive O�cer Water Authority of Fiji Water Authority of Fiji
1. BACKGROUND
Proper management of Fats, Oils and Grease (FOG) produced by the discharge from kitchens and food preparation areas is a problem for the Food Industry and for the Water Authority of Fiji's Wastewater Operations. The solids and FOG should not be discharged in waste water or sewer lines as it causes blockages which is an issue for WAF's sewer reticulation system and the treatment plants that eventually receive the discharge.
Grease Traps and Interceptors are designed to separate the FOG and solids from the grey water in discharge from kitchens and food preparation areas. The traps use the physical principal that fats, oils and grease are lighter than water and will rise to the top of a water surface and heavy debris will fall to the bottom of the trap when the mixture is allowed to settle for a period of time in quiet conditions. The longer the wastewater stays in the trap, the better the separation.
However, as the amount of retained grease and solids increases, the working capacity of the trap decreases, retention time decreases and physical separation decreases, resulting in the pass through of solids, fats, oils and grease. To prevent this, grease traps and interceptors have to be regularly maintained by removing both the top grease layer and the settled solids at the base of the trap.
There are two ways to remove the grease layer and settled solids. Either by a. manually removing it or b. through pump outs Option (b) is the approved method especially for the larger grease traps or under-ground grease interceptors. Pump outs must be done several times over a specified period (usually daily for small grease traps and quarterly for the larger ones) depend-ing on the requirements of the Trade Waste Policy and local government regulations.
2. OBJECTIVE Upgrade the current Grease Trap design used by the Restaurant Industry in Fiji and ensure the final designs and guidelines is a standard for installing new units for businesses and residents.
2
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 5
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
4
3
3. DESIGNS
3.3 DESIGNS
3.3.1 UNDER SINK GREASE TRAP DESIGN
Please refer to the Drawings on the next page
STANDARD DESIGNWAF has developed standard designs for:1. An Under the sink Grease trap2. An Underground Grease Interceptor
Businesses with seating of between 1 - 69 seats will need to install an underground grease interceptor with a volume of 1000 liters minimum. This interceptor can be fabricated to fit above or below ground.
The under sink grease traps are ONLY for Co�ee lounges and Snack Bars. It will have a total volume of 200 liters.
This document includes guidelines on the Fabrication, Installation and Maintenance for each design. It is the minimum requirements and can be used as a guideline for Manufacturers that wish to produce the traps in bulk for distribution.
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 7
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
6
3
100500
300
900
225225 50
500
5050400
45050
350 150
150 50 300
Scale: 1:5
Elevation
PlanS
cale: 1:5
25
Ratu M
ara Road, N
asinu, Suva
G.P
.O. B
ox 1272S
uvaR
epublic of The Fiji IslandsP
+679 334 6777F
+679 334 3284W
ww
w.w
aterauthorityoffiji.com
PR
OJE
CT
SU
B P
RO
JEC
T
DR
AW
ING
TITLEP
RO
JEC
T№
SH
EE
T№
AM
EN
D
GR
EA
SE
TRA
P D
ES
IGN
2LIQ
UID
TRA
DE
WA
STE
GR
EA
SE
TRA
P D
ES
IGN
W00/00/00
0200
AP
PR
OV
ED
BY
:S
CA
LE:
1:5D
ATE
:A
UG
'16
TEA
M LE
AD
ER
DR
AFTIN
GR
.KA
RA
VA
KI
PR
OJE
CT M
AN
AG
ER
:
DR
AW
N B
Y:
SU
RV
EY
ED
BY
:
T.FILIPE
EN
GIN
EE
R P
LAN
NIN
G &
DE
SIG
N
S.S
OD
ER
BE
RG
A/G
EN
ER
AL M
AN
AG
ER
PLA
NN
ING
& D
ES
IGN
490
789
476 13
485
284
20
484
Scal
e: 1
:5Plan
Scal
e: 1
:5Elev
ation
3mm
thic
kbu
tt w
eld
3mm
thic
k by
pass
SS
20×5
mm
Fla
t Pla
te 3
mm
thic
k bu
tt w
eld
to th
e SS
Tra
y20
×5m
m F
lat P
late
3m
m th
ick
butt
wel
d to
the
SS T
ray
Rat
u M
ara
Roa
d, N
asin
u, S
uva
G.P
.O. B
ox 1
272
Suva
Rep
ublic
of
The
Fiji
Isla
nds
P+6
79 3
34 6
777
F+6
79 3
34 3
284
Ww
ww
.wat
erau
thor
ityof
fiji.c
om
PRO
JEC
T
SUB
PRO
JEC
T
DR
AWIN
G T
ITLE
PRO
JEC
T№
SHEE
T№
AMEN
D
GR
EASE
TR
AP 2
TR
AY D
ETAI
LS 1
GR
EASE
TR
AP D
ESIG
N
W00
/00/
00
0300
APPR
OVE
D B
Y:SC
ALE:
AS S
HO
WN
DAT
E:
TEAM
LEA
DER
DR
AFTI
NG
R.K
ARAV
AKI
PRO
JEC
T M
ANAG
ER:
DR
AWN
BY:
SUR
VEYE
D B
Y:
T.FI
LIPE
ENG
INEE
R P
LAN
NIN
G &
DES
IGN
S.SO
DER
BER
GA/
GEN
ERAL
MAN
AGER
PLA
NN
ING
& D
ESIG
NAU
G '1
6LI
QU
ID T
RAD
EWAS
TE
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 9
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
8
3
906
506
23
303200
50 20
50200
50303
303
243
906
Plan
Scale: 1:4Elevation
5050
303
243
Scale: 1:4
Detail A
Detail C
Detail B
Detail D
Ratu M
ara Road, N
asinu, SuvaG
.P.O. Box 1272
SuvaR
epublic of The Fiji IslandsP
+679 334 6777F
+679 334 3284W
ww
w.w
aterauthorityoffiji.com
PRO
JECT
SUB PR
OJEC
T
DR
AWIN
G TITLE
PRO
JECT№
SHEET№
AMEN
D
GR
EASE TRAP 2 LID
DETAILS 1
LIQU
ID TR
ADEW
ASTE
GR
EASE TRAP D
ESIGN
W00/00/00
0300
APPRO
VED BY:
SCALE:
1:4D
ATE:
TEAM LEAD
ER D
RAFTIN
GR
.KARAVAKI
PRO
JECT M
ANAG
ER:
DR
AWN
BY:
SUR
VEYED BY:
T.FILIPEEN
GIN
EER PLAN
NIN
G & D
ESIGN
S.SOD
ERBER
GA/G
ENER
AL MAN
AGER
PLANN
ING
& DESIG
NJU
LY '16
Sca
le: 1
:1D
etai
l A
1030
10
5 510
50
20
2 3-
5mm
Pop
rivet
s2
3-5m
m P
opriv
ets
50
1030
10
3-5m
m P
op ri
vets
Sca
le: 1
:1D
etai
l B
50
1030
10
3-5m
m P
op ri
vets
Sca
le: 1
:1D
etai
l D
Sca
le: 1
:1D
etai
l C
1030
10
5 510
50
20
2 3-
5mm
Pop
rivet
s2
3-5m
m P
opriv
ets
Rat
u M
ara
Roa
d, N
asin
u, S
uva
G.P
.O. B
ox 1
272
Suv
aR
epub
lic o
f Th
e Fi
ji Is
land
sP
+679
334
677
7F
+679
334
328
4W
ww
w.w
ater
auth
ority
offij
i.com
PR
OJE
CT
SU
B P
RO
JEC
T
DR
AW
ING
TIT
LEP
RO
JEC
T№
SH
EE
T№
AM
EN
D
GR
EA
SE
TR
AP
2 L
ID D
ETA
ILS
2
GR
EA
SE
TR
AP
DE
SIG
N
W00
/00/
00
0400
AP
PR
OV
ED
BY
:S
CA
LE:
1:1
DA
TE:
TEA
M L
EA
DE
R D
RA
FTIN
GR
.KA
RA
VA
KI
PR
OJE
CT
MA
NA
GE
R:
DR
AW
N B
Y:
SU
RV
EY
ED
BY
:
T.FI
LIP
EE
NG
INE
ER
PLA
NN
ING
& D
ES
IGN
S.S
OD
ER
BE
RG
A/G
EN
ER
AL
MA
NA
GE
R P
LAN
NIN
G &
DE
SIG
NJU
LY '1
6LI
QU
ID T
RA
DE
WA
STE
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 11
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
10
3
3.3.2 GUIDELINES
3.3.2.1 Under Sink Grease Trap
A. FABRICATION:
a) Total Volume The Under sink Grease Trap shall have a total volume of 200 Litres with
a working capacity of 150 Litres and shall ONLY be used for Snack Bars and Co�ee Lounges.
b) SizingThe scaled version of the design will use a ratio of surface area to volume.
E.g. The trap is 0.9m x 0.5m x 0.5m and has a:
Surface Area = 2 x [(L x W) + (L x H) + (W x H)] = 2 x [(0.9 x 0.5) + (0.9 x 0.5) + (0.5 x 0.5)] = 2.3 m2,
Total Volume = L x W x H =0.9 x 0.5x 0.5 = 0.225 m3,
And therefore a surface area to volume ratio of
SA: V = 2.3m2:0.225m3 = 2.3:0.225 = 10.22:1 = 10.22/1 = 10.22 ≈ 10
The ratio must be reduced until the volume (V) is 1.
For situations where the FOG to separated exceeds the working capacity of 150 Litres and is less than 700 Litres, the design for the 1000 litre underground grease interceptor MUST be used.
c) Materials The grease trap must be made from a material that does not corrode and
is suitable for in kitchen use. (i.e. Materials specified for food equipment such as food grade Stainless
Steel Type 316 or HDPE).
If alternative materials wish to be used to fabricate the traps then approval must first be obtained from WAF.
d) Manufacturing• The First baffle shall extend from at least 50mm above the water level to
within 50mm of the inside floor of the trap. • The Second baffle shall extend from the inside floor of the trap to within
100mm of the top of the trap. • The Inlet shall be at least 50mm from the top on the inside of the trap
and the outlet pipe at least 150mm from the inside base of the trap.
e) Alternative Designs Any alternative designs for a under the sink grease trap that a business
may wish to use for their food preparation areas must first be approved by the WAF.
B. INSTALLATION:
a) Positioning the Grease Trap• Grease traps shall be placed as close as practical to the fixture(s) being
served. • It shall be located where it is easily accessible at all times for inspection,
cleaning, and removal of accumulated grease. • It can be placed outdoors if there is a limited amount of space inside the
food preparation area.
b) Piping• All Pipe works must be completed by a licensed plumber.• There shall be no piping inside the Grease trap. • Inlet and outlet piping must be as per the regulations set out by the Fiji National Building Codes and the WAF Grease Trap Design Standards and Guidelines.
c) Venting• No Venting required
d) Access to the Trap• Access to the grease trap shall be through the lid.• Lids can be either left as it is on the trap or clamped down. • For areas in which the trap may be encountered by the public, the trap
lid must be securely fastened to prevent tampering.
e) Certificate of Compliance • A certificate of compliance must be provided by the licensed plumber-
safter the installation of the trap.
C. MAINTENANCE:
a) Frequency of Clean Outs• These 200 litre grease traps should be cleaned out on a daily basis. • Traps with a Volume greater than 200 litres and less than 500 litres must
be cleaned every second or third day.• Businesses must keep a record of the clean outs done. If pump outs are
done, then the receipts for the pump out chargers must be kept as this is proof of frequent cleaning.
b) Responsibility for Clean Outs and DisposalIt is the responsibility of the Liquid Trade Waste Permit Holders to ensure that the clean out of the Grease traps are done on a regular basis and disposed of prop-erly.
It is NOT the responsibility of WAF or the relevant authorities to do this. However, it is WAFs and other authorities’ responsibility to monitor the businesses and residents to ensure that this is done regularly and properly.
c) Clean Out Methods
Clean out of the grease traps can be done manually or through pump outs.
For manual removal:• First scrape the top layer of FOG off the surface on the inside of the trap
and place in a sealed plastic bag. Continue this until all the FOG on the surface is removed.
• Using the handles of the perforated tray, gently lift the tray up and hold to allow for the effluent water to drain through it.
• Once drained remove the tray and place contents into a sealed plastic bag.
• Scrape the inside of the trap to remove FOG that is stuck to its inside surface and place into the sealed plastic bag.
• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only make
the solidified FOG soluble and harder to remove.
For Pump outs:• Remove lid from the top of the trap.• Place suction hose into the trap.• Begin pump out of the trap.
• Scrape the inside of the trap to remove FOG that is stuck to its inside surface.
• Continue pump out until all FOG is removed• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only make
the solidified FOG soluble and harder to remove.
d) Disposal of FOGIf businesses incorporate the under the sink grease trap with an underground grease interceptor, then the removed FOG from the smaller units can be put into the underground interceptor and pumped out when the underground interceptor needs to be cleaned. The removed FOG can then be taken to the Sewerage Treat-ment Plant for disposal.
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
3.3.2 GUIDELINES
3.3.2.1 Under Sink Grease Trap
A. FABRICATION:
a) Total Volume The Under sink Grease Trap shall have a total volume of 200 Litres with
a working capacity of 150 Litres and shall ONLY be used for Snack Bars and Co�ee Lounges.
b) SizingThe scaled version of the design will use a ratio of surface area to volume.
E.g. The trap is 0.9m x 0.5m x 0.5m and has a:
Surface Area = 2 x [(L x W) + (L x H) + (W x H)] = 2 x [(0.9 x 0.5) + (0.9 x 0.5) + (0.5 x 0.5)] = 2.3 m2,
Total Volume = L x W x H =0.9 x 0.5x 0.5 = 0.225 m3,
And therefore a surface area to volume ratio of
SA: V = 2.3m2:0.225m3 = 2.3:0.225 = 10.22:1 = 10.22/1 = 10.22 ≈ 10
The ratio must be reduced until the volume (V) is 1.
For situations where the FOG to separated exceeds the working capacity of 150 Litres and is less than 700 Litres, the design for the 1000 litre underground grease interceptor MUST be used.
c) Materials The grease trap must be made from a material that does not corrode and
is suitable for in kitchen use. (i.e. Materials specified for food equipment such as food grade Stainless
Steel Type 316 or HDPE).
If alternative materials wish to be used to fabricate the traps then approval must first be obtained from WAF.
d) Manufacturing• The First baffle shall extend from at least 50mm above the water level to
within 50mm of the inside floor of the trap. • The Second baffle shall extend from the inside floor of the trap to within
100mm of the top of the trap. • The Inlet shall be at least 50mm from the top on the inside of the trap
and the outlet pipe at least 150mm from the inside base of the trap.
e) Alternative Designs Any alternative designs for a under the sink grease trap that a business
may wish to use for their food preparation areas must first be approved by the WAF.
B. INSTALLATION:
a) Positioning the Grease Trap• Grease traps shall be placed as close as practical to the fixture(s) being
served. • It shall be located where it is easily accessible at all times for inspection,
cleaning, and removal of accumulated grease. • It can be placed outdoors if there is a limited amount of space inside the
food preparation area.
b) Piping• All Pipe works must be completed by a licensed plumber.• There shall be no piping inside the Grease trap. • Inlet and outlet piping must be as per the regulations set out by the Fiji National Building Codes and the WAF Grease Trap Design Standards and Guidelines.
c) Venting• No Venting required
d) Access to the Trap• Access to the grease trap shall be through the lid.• Lids can be either left as it is on the trap or clamped down. • For areas in which the trap may be encountered by the public, the trap
lid must be securely fastened to prevent tampering.
e) Certificate of Compliance • A certificate of compliance must be provided by the licensed plumber-
safter the installation of the trap.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 13
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
12
3
C. MAINTENANCE:
a) Frequency of Clean Outs• These 200 litre grease traps should be cleaned out on a daily basis. • Traps with a Volume greater than 200 litres and less than 500 litres must
be cleaned every second or third day.• Businesses must keep a record of the clean outs done. If pump outs are
done, then the receipts for the pump out chargers must be kept as this is proof of frequent cleaning.
b) Responsibility for Clean Outs and DisposalIt is the responsibility of the Liquid Trade Waste Permit Holders to ensure that the clean out of the Grease traps are done on a regular basis and disposed of prop-erly.
It is NOT the responsibility of WAF or the relevant authorities to do this. However, it is WAFs and other authorities’ responsibility to monitor the businesses and residents to ensure that this is done regularly and properly.
c) Clean Out Methods
Clean out of the grease traps can be done manually or through pump outs.
For manual removal:• First scrape the top layer of FOG off the surface on the inside of the trap
and place in a sealed plastic bag. Continue this until all the FOG on the surface is removed.
• Using the handles of the perforated tray, gently lift the tray up and hold to allow for the effluent water to drain through it.
• Once drained remove the tray and place contents into a sealed plastic bag.
• Scrape the inside of the trap to remove FOG that is stuck to its inside surface and place into the sealed plastic bag.
• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only make
the solidified FOG soluble and harder to remove.
For Pump outs:• Remove lid from the top of the trap.• Place suction hose into the trap.• Begin pump out of the trap.
• Scrape the inside of the trap to remove FOG that is stuck to its inside surface.
• Continue pump out until all FOG is removed• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only make
the solidified FOG soluble and harder to remove.
d) Disposal of FOGIf businesses incorporate the under the sink grease trap with an underground grease interceptor, then the removed FOG from the smaller units can be put into the underground interceptor and pumped out when the underground interceptor needs to be cleaned. The removed FOG can then be taken to the Sewerage Treat-ment Plant for disposal.
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
3.3.3 UNDERGROUND GREASE INTERCEPTOR
Please refer to the Drawings on the next page
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 15
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
14
3
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
Plan
Scal
e: 1
:10
D D
B
A
DL
LD
inle
tou
tlet
Stee
l Mes
h wi
reRe
fer t
o Ta
b 3.
2
DL
DL
A
JI
K
IJ
K
F
G
Ratu
Mar
a Ro
ad, N
asin
u, S
uva
G.P
.O. B
ox 1
272
Suva
Repu
blic
of T
he F
iji Is
land
sP
+679
334
677
7F
+679
334
328
4W
www.
wate
raut
horit
yoffi
ji.com
PRO
JECT
SUB
PRO
JECT
DRAW
ING
TIT
LEPR
OJE
CT№
SHEE
T№
AMEN
D
UNDE
RGRO
UND
GRE
ASE
INTE
RCEP
TOR-
PLAN
LIQ
UID
TRAD
EWAS
TE
GRE
ASE
TRAP
DES
IGN
APPR
OVE
D BY
:SC
ALE:
1:15
DATE
:AU
G '1
6
TEAM
LEA
DER
DRAF
TING
R.KA
RAVA
KI
PRO
JECT
MAN
AGER
:
DRAW
N BY
:
SURV
EYED
BY:
T.FI
LIPE
ENG
INEE
R PL
ANNI
NG &
DES
IGN
S.SO
DERB
ERG
A/G
ENER
AL M
ANAG
ER P
LANN
ING
& D
ESIG
N
C:\U
sers
\Pub
lic\P
ictur
es\S
ampl
e Pi
ctur
es\L
OG
O.p
ng
W00
/00/
00
0100
NOTE
S:So
il St
abili
zatio
n:
Soil a
roun
d tra
p to
be
com
pact
ed to
95%
inte
nsity
.
Conc
rete
blin
ding
of 5
0mm
ben
eath
the
base
of t
he s
truct
ure.
Da
mp
Proo
f Cou
rse
unde
rnea
th th
est
ruct
ure
to p
reve
nt w
ater
see
page
.
Vent
(Ø=1
00m
m)
Insp
ectio
n Po
int
(Ø=1
00m
m)
Insp
ectio
nPo
int
(Ø=1
00m
m)
Vent
(Ø=1
00m
m)
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 17
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
16
3
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
E2 E1
DD
DL
DL
C
A
GE2
ElevationS
cale: 1:15
inletoutlet
N1 N2
M1M2
JI
K
LIDLID
LID
WL
R
Steel M
esh wire
Refer to Tab 3.2
O2
O1 F
P
Q
B
End ElevationS
cale: 1:15
(Ø=100m
m)
Ratu M
ara Road, N
asinu, Suva
G.P
.O. B
ox 1272S
uvaR
epublic of The Fiji IslandsP
+679 334 6777F
+679 334 3284W
ww
w.w
aterauthorityoffiji.com
PR
OJE
CT
SU
B P
RO
JEC
T
DR
AW
ING
TITLEP
RO
JEC
T№
SH
EE
T№
AM
EN
D
UN
DE
RG
RO
UN
D G
RE
AS
EIN
TER
CE
PTO
R-E
LEV
ATIO
NS
LIQU
ID TR
AD
EW
AS
TE
GR
EA
SE
TRA
P D
ES
IGN
AP
PR
OV
ED
BY
:S
CA
LE:
1:15D
ATE
:A
UG
'16
TEA
M LE
AD
ER
DR
AFTIN
GR
.KA
RA
VA
KI
SE
NIO
R E
NG
INE
ER
:
DR
AW
N B
Y:
DE
SIG
NE
D B
Y:
T.FILIPE
EN
GIN
EE
R P
LAN
NIN
G &
DE
SIG
N
S.S
OD
ER
BE
RG
A/G
EN
ER
AL M
AN
AG
ER
PLA
NN
ING
& D
ES
IGN
C:\U
sers\Public\P
ictures\Sam
ple Pictures\LO
GO
.png
W00/00/00
0200
NO
TES:Soil Stabilization:
Soil around trap to be com
pacted to95%
intensity.
Concrete blinding of 50m
m beneath
the base of the structure.
Dam
p Proof C
ourse underneath thestructure to prevent w
ater seepage.
D.D
EA
SA
R.S
HA
RM
A
H.FIS
HE
R
Vent (H
) (Ø=100m
m)
Inspection Point
(Ø=100m
m)
Vent (H
) (Ø=100m
m)
Inspection Point
(Ø=100m
m)
Vent
(Ø=100m
m)
Vent
(Ø=100m
m)
Inspection Point
Plan
Scal
e: 1
:10
B
A
D
F
inle
tou
tlet
LID
CO
VER
LID
CO
VER
LID
CO
VER
D
G
Rat
u M
ara
Roa
d, N
asin
u, S
uva
G.P
.O. B
ox 1
272
Suva
Rep
ublic
of
The
Fiji
Isla
nds
P+6
79 3
34 6
777
F+6
79 3
34 3
284
Ww
ww
.wat
erau
thor
ityof
fiji.c
om
PRO
JEC
T
SUB
PRO
JEC
T
DR
AWIN
G T
ITLE
PRO
JEC
T№
SHEE
T№
AMEN
D
UN
DER
GR
OU
ND
GR
EASE
INTE
RC
EPTO
R-E
LEVA
TIO
NS
LIQ
UID
TR
ADEW
ASTE
GR
EASE
TR
AP D
ESIG
N
APPR
OVE
D B
Y:SC
ALE:
1:15
DAT
E:AU
G '1
6
TEAM
LEA
DER
DR
AFTI
NG
R.K
ARAV
AKI
PRO
JEC
T M
ANAG
ER:
DR
AWN
BY:
SUR
VEYE
D B
Y:
T.FI
LIPE
ENG
INEE
R P
LAN
NIN
G &
DES
IGN
S.SO
DER
BER
GA/
GEN
ERAL
MAN
AGER
PLA
NN
ING
& D
ESIG
N
C:\U
sers
\Pub
lic\P
ictu
res\
Sam
ple
Pict
ures
\LO
GO
.png
W00
/00/
00
NO
TES:
Soil
Stab
iliza
tion:
So
il ar
ound
trap
to b
e co
mpa
cted
to95
% in
tens
ity.
C
oncr
ete
blin
ding
of 5
0mm
ben
eath
the
base
of t
he s
truct
ure.
D
amp
Proo
f Cou
rse
unde
rnea
th th
est
ruct
ure
to p
reve
nt w
ater
see
page
.
0300
Vent
(Ø=1
00m
m)
Vent
(Ø=1
00m
m)
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 19
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
18
3
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
Tabl
e 3.
2 (c
ontin
ued)
Type
I (
mm
) J
(mm
) K
(mm
) L
(mm
)
M1
/ M2
(mm
) N
1 / N
2 (m
m)
O1
/ O2
(mm
) P
(m
m)
Q (m
m)
WL
(mm
)
1 25
0 35
0 30
0 50
65
0 /
100
550
/ 20
0 10
0 /
100
200
250
550
- 600
2 30
0 45
0 35
0 10
0 70
0 /
200
600
/ 30
0 15
0 /
150
200
250
800
- 850
3 35
0 70
0 45
0 10
0 75
0 /
200
650
/ 30
0 15
0 /
150
200
250
750
- 800
4 35
0 70
0 45
0 10
0 90
0 /
200
800
/ 30
0 15
0 /
150
200
250
900
- 950
5 35
0 70
0 45
0 10
0 10
50 /
200
950
/ 30
0 15
0 /
150
20
0 25
0 10
50 -
1100
Table 3.2 - Dimensions for
Underground Grease Interceptors (1000 - 5000 Liters)
Type
Total Volum
e (Litres)
Dimension
on Grease Interceptor
A (mm
) B (m
m)
C (mm
) D (m
m)
E2 / E1 (m
m)
F (mm
) G (m
m)
H (mm
) Rebar Type
Rebar Thickness
(mm
)
Concrete Strength
(MPa)
1 1000
Inside 1000
800 750
100 100 / 50
100 100
100 665
mesh
5.3 25
Outside 1200
1000 900
2 2000
Inside 1300
1000 900
100 100 / 100
100 100
100 F81
mesh
8 25
Outside 1500
1200 1100
3 3000
Inside 1700
1000 950
150 150 / 100
100 100
100 F81
Mesh
8 32
Outside 2000
1300 1200
4 4000
Inside 1700
1200 1100
150 150 / 100
100 100
100 F81
Mesh
8 32
Outside 2000
1500 1350
5 5000
Inside 1700
1400 1250
150 150 / 100
100 100
100 F81
Mesh
8 32
Outside 2000
1700 1500
Note
: Soi
l Sta
biliz
atio
n •
Soil
arou
nd t
he G
reas
e In
terc
epto
r is
to
be c
ompa
cted
to
95%
Den
sity
.•
Con
cret
e bi
ndin
g of
50
mm
ben
eath
the
bas
e of
the
Gre
ase
Inte
rcep
tor.
• D
amp
proo
f cou
rse
unde
rnea
th t
he G
reas
e In
terc
epto
r to
pre
vent
see
page
.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 21
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
20
3
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
5
3
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 23
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
22
3
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 25
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
24
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
4. APPENDICES
4.1 FOG MANAGEMENT
CHECKLIST FOR MANAGING FAT, OILS AND GREASE IN THE KITCHEN
DO's DON'Ts
Wipe and scrape plates, pots, pans and utensils before washing it in the sink (place all these food scrapings into the rubbish bin) × Do not pour Cooking Oil, Fat or
Grease down the sinks
Collect Waste Oil in a suitable secure container. ×
Do not pour Waste Oil, Fat or Grease down the drains
Use sink strainers in sink holes and empty solid contents from the strainer into the rubbish bin. ×
Do not put food scrapings into the sink. Put it into the rubbish bin.
Regularly clean out and maintain grease traps. ×
Do not sweep waste into floor drains. Collect and place it in the rubbish bin.
Get a licensed waste management company to collect and dispose of FOG from grease traps ×
Do not pour boiling hot water down the sink to dissolve fat and grease.
3.3.4 GUIDELINES
3.3.4.1 Underground Grease Interceptor
A. FABRICATION:
a) Total Volume The underground grease interceptor shall have minimum total volume of
1000 litres. Larger interceptors, that have a volume greater than 1000 litres and up
to 5000 litres, can use the dimensions provided in Table 3.2.
b) SizingFor situations where the volume of FOG to be separated exceeds the working capacity of the 1000 litre grease interceptor and is less than that of the 5000 litre grease interceptor:
• A larger sized grease interceptor can be used. For further specifications please refer to the dimensions provided in Table 3.2 to suit the require-ments of the situation
Or• Two or more grease interceptors can be installed in series to cater for the
load.
c) MaterialsThe Interceptor will be made of concrete and be either precast or constructed from the ground up.
Other materials can be used but these must be approved by WAF before it can be manufactured or built.
d) ManufacturingThe first baffle shall extend from the cover above the water level and down to be at least 100mm away from the inside floor of the interceptor and be spaced 250mm away from the inlet.
The second baffle shall extend from the inside floor of the interceptor and up to be at least 200mm away from the cover above and be spaced 300mm away from the outlet.
The vent shall be positioned at opposite sides of the interceptor and be at least 50mm above the water level.(Refer to INSTALLATION part(c) Vents for minimum Vent size)The above mentioned specifications is for the 1000 litre underground grease interceptor. Refer to Table 3.2 for specifications for larger Grease Interceptors.
e) Alternative DesignsAny alternative designs for underground Grease Interceptors that a business wishes to use on their property must first be approved by the WAF.
B. INSTALLATION:a) Positioning of the Underground Grease Interceptor The underground grease interceptor shall be placed as close as practi-
cal to the fixture(s) being served.
It shall be located where it is easily accessible at all times for inspection, clean-ing, and removal of accumulated grease.
It can be installed indoors or outdoors.
In situations where the interceptor is placed outdoors:• Ensure that it is as close as possible to the building.
• Ensure that it can withstand the external loads being placed on it (vehicles and people).
• If it is buried and the top of the interceptor is level with the ground then all piping for vents and inspection points must not disrupt other utility connections, hinder vehicles or people.
• A protective wall must be erected around it at least 200mm above the ground level to prevent water run o�s from seeping into the intercep-tor.
• It must be at least 200mm above the ground level to prevent water run o�s from seeping into it (if they grease interceptor will not be.
In situations where the interceptor is placed indoors:• Ensure that it can withstand the external loads being placed on it
(vehicles or people).
• A protective wall must be erected around it at least 200mm above the ground level to prevent water runo� from seeping into the interceptor (If the top of the interceptor is level with the ground).
• If it is partially buried then it must be at least 200mm above the ground level to prevent water run o�s from seeping into its compart-ments.
• If it is placed in an area with limited space then ensure that it has gas tight lids and proper venting.
b) PipingThere shall be no piping inside the underground grease interceptor. All pipe works must be completed by a licensed plumber.
The inlet pipe will be submerged and therefore the water level inside the trap will be determined by the level of the outlet pipe.
The piping will be completed according to the WAF Fabrication & installation of Grease Traps and Underground Grease interceptors’ guidelines.
Inspection points must be included on the inlet pipe before the interceptor and on the outlet pipe after the interceptor
The inspection points must be a minimum of 100mm in diameter and should be teed o� from the inlet and outlet pipes to at least 200mm above the ground level.
c) VentingAll Underground Grease Interceptors must have:• Two vents, a minimum of 100mm in diameter, open to the atmosphere
to allow for cross ventilation.• An induct vent, at low or high level directly off the interceptor at the
inlet compartment. • An educt vent, at a high level also directly off the interceptor at the
outlet compartment.• The educt Vent diverted to at least 2 meters above the highest point of
the building (where necessary).• Exterior flaps on the openings of the induct and educt vents.
Plumbers must ensure that the vents are installed properly so that siphoning does not occur within the chambers of the interceptor.
d) Access to the InterceptorAccess to the Grease interceptor shall be though one of three lids above the:• Inlet compartment• Separation compartment and • Outlet compartment.
e) Certificate of Compliance A certificate of compliance must be provided by the licensed plumbers after the installation of the trap.
C. MAINTENANCE:a) Frequency of Clean OutsThe interceptor should be cleaned on a fortnightly basis through pump outs.
Grease interceptors with a volume greater than 1000 litres and less than 3000 litres must be cleaned out at least every month.
If business owner(s) wish to pump out their underground grease interceptors more frequently (such as weekly) they are allowed to do so.
b) Responsibility for Clean outs and DisposalsIt is the responsibility of the Trade Waste Permit Holders to ensure that the clean outs of the Grease traps/interceptors are done on a regular basis and disposed of properly.
It is NOT the responsibility of WAF or the relevant authorities to clean out the traps/interceptors. However, it is WAFs and other authorities’ responsibility to monitor the businesses or residents to ensure that this is done regularly and properly.
c) Clean out Methodsa) Clean out of Underground grease interceptors can be done through pump outs.
For Pump outs:• Remove lid from the top of the interceptor.• Place suction hose into the compartment.• Begin pump out.• Scrape the inside of the compartment to remove FOG that is stuck to
its inside surface.• Continue pump out until all FOG is removed.• DO NOT use degreasers to clean out the grease trap.• DO NOT use hot water to clean out the grease trap as this will only
make the solidified FOG soluble and harder to remove.
d) Disposal of FOGFOG that is removed through pump outs can be disposed by the bailing trucks.
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors 27
Water Authority of Fiji | Fabrication & Installation of Grease Traps and Underground Grease Interceptors
26
4.2 MINIMUM PRETREATMENT REQUIREMENTS FOR FOOD PROCESSES
Commercial process
Seats/beds
Minimum pre- treatment
in floor and in sink bucket traps
Supermarket with chicken cooker
1500 L yes
BBQ wholesale (chicken) 1500 L yes
BBQ wholesale (pork, duck)
2000 L yes
BBQ restaurant 2000 L yes
Hotel/motel kitchen 1-69 1000 L yes
Hotel/motel kitchen 70-199 1500 L yes
Hotel/motel kitchen 200-399 2000 L yes
Hotel/motel kitchen 400-599 3000 L yes
Hotel/motel kitchen 600-799 4000 L yes
Hotel/motel kitchen 800-1000 5000 L yes
Butchers – retail (no cooking)
1000 L yes
Fish (fresh outlet) no cooking
Large basket trap with fixed screen and removable basket
yes
Chicken (fresh retail) no cooking
1000 L yes
Bakery retail –hot bread - cakes
No grease trap yes
Bakery retail – pies – sausage rolls
1000 L
Commercial process Seats/beds
Minimum pre-treatment
in floor and in sink bucket traps
Cafeteria, canteen (and school hot meals)
1000 L yes
Take-away, including food court shops
1000 L yes
Snack bar – co�ee lounge Under sink yes
Restaurant
1-69
1000 L
yes
Restaurant
70-199
1500 L
yes
Restaurant
200-399
2000 L
yes
Restaurant
400-599
3000 L
yes
Restaurant
600-799
4000 L
yes
Restaurant 800-1000 5000 L yes
Kitchen – hospital, nursing home
1-69
1000 L
yes
Kitchen – hospital, nursing home
70-199
1500 L
yes
Kitchen – hospital, nursing home
200-399
2000 L
yes
Kitchen – hospital, nursing home
400-599
3000 L
yes
Kitchen – hospital, nursing home
600-799
4000 L
yes
Kitchen – hospital, nursing home
800-1000
5000 L
yes
McDonalds
1500 L – 3000 L
yes Pizza Hut Restaurant 1000 L yes
Function centre
1-69
1000 L
yes
Function centre
70-199
1500 L
yes
Function centre
200-399
2000 L
yes
Function centre
400-599
3000 L
yes
Function centre
600-799
4000 L
yes
Function centre
800-1000
5000 L
yes