operating and maintenance manual - sewage treatment plant

OPERATING &

MAINTENANCE MANUAL

PLANT : SEWAGE TREATMENT PLANT TRICKLING FILTER PLAN

CLIENT : XXX

CONTRACT : XXX VWS REF. : XXX

DATE : OCTOBER 2010

REV DATE BY COMMENTS

0 12/07/2010 AL Preliminary 1 11/10/2010 AL Draft copy issued internally for comments

C792_DEIA_AppendixE1_OMPlan.doc of 34

RESTRICTIONS & COPY RIGHTS

• The use of this document including all data, details and drawings is restricted to that of

XXX and the client’s trained operators. • Veolia Water Systems (Pty) Ltd disallows the reproduction of this document or its

contents to be divulged without written permission. • This manual must be clearly understood before plant installation, start-up and

operation can commence. • This document has been written with the intention to provide all the required

information to the operating staff, in order for competent operation and maintenance of the plant.

• This plant should be operated and serviced by trained persons only.


TABLE OF CONTENTS

1 TECHNICAL DATA........................................................................................................... 5 1.1 BACKGROUND ......................................................................................................... 5 1.2 SUMMARISED TECHNICAL DESCRIPTION ........................................................... 5 1.3 RAW AND FINAL WATER QUALITY AND FLOW .................................................... 6

2 TREATMENT PLANT ....................................................................................................... 7 2.1 TREATMENT PLANT OVERVIEW ............................................................................ 7 2.2 EQUIPMENT DETAILS ............................................................................................. 7

2.2.1 Diversion sump .................................................................................................. 7 2.2.2 Control valve sump ............................................................................................ 8 2.2.3 Float valve sump with flow control ...................................................................... 8 2.2.4 Collection sump .................................................................................................. 8 2.2.5 Screening facility - Inlet box with manual rake screen ........................................ 8 2.2.6 Flow equalisation and anaerobic digestion – Septic tank modules .................... 9 2.2.7 Anoxic Zone – Recycle sump ............................................................................. 9 2.2.8 Trickling filter towers with collection basins ...................................................... 10 2.2.9 Secondary Clarifier ........................................................................................... 12 2.2.10 Disinfection – Chlorine contact channel ........................................................... 12 2.2.11 Final Water Discharge ...................................................................................... 13 2.2.12 Valves .............................................................................................................. 13 2.2.13 Instruments ...................................................................................................... 13

2.3 SOLID WASTE REMOVAL ..................................................................................... 13 2.4 OPERATING PARAMETERS & PROCEDURES .................................................... 14

2.4.1 Influent flow ...................................................................................................... 14 2.4.2 Chlorine Dosing (Treated effluent) ................................................................... 14 2.4.3 Plant Start-Up ................................................................................................... 14 2.4.4 Normal Operation ............................................................................................. 14 2.4.5 Plant Shutdown ................................................................................................ 15 2.4.6 Maintenance ..................................................................................................... 15 2.4.7 Septic Tank Inspection ..................................................................................... 16

3 CONTROL PHILOSOPHY .............................................................................................. 18 3.1 PLANT INLET FEED PUMPS ................................................................................. 18 3.2 TRICKLING FILTER FEED PUMPS ........................................................................ 18 3.3 SECONDARY SETTLER DESLUDGE .................................................................... 18 3.4 DOSING CONTROL ................................................................................................ 18 3.5 FINAL WATER DISCHARGE PUMPS .................................................................... 19 3.6 CONTROL PANEL MCC1000 ................................................................................. 19 3.7 ALARM CONDITIONS ............................................................................................ 20 3.8 HMI PARAMETER SETTING .................................................................................. 20 3.9 HMI PASSWORD .................................................................................................... 20 3.10 CONTROL PANEL MCC2000 ................................................................................. 21

4 ELECTRICAL CONTROL ............................................................................................... 22 5 RECOMMENDED SPARES ........................................................................................... 23 6 DRAWINGS, DIAGRAMS, TABLES, SCHEDULES & PROCEDURES .......................... 24

6.1 Pump Schedule ....................................................................................................... 24 6.2 Valve Schedule ....................................................................................................... 24 6.3 Instrument Schedule ............................................................................................... 24


6.4 Plant General Layout Drawings ............................................................................... 24 6.5 Process & Instrument Diagrams .............................................................................. 24 6.6 Electrical Diagrams & Panel Drawings .................................................................... 24 6.7 Civil Drawings.......................................................................................................... 24

7 SUPPLIER DOCUMENTS .............................................................................................. 25 7.1 Chemicals – Data Sheets & MSDS ......................................................................... 25 7.2 Collection Sump – Grundfos pumping station ......................................................... 25 7.3 Instruments ............................................................................................................. 25 7.3.1 Flow measuring system – Endress + Hauser Promag ......................................... 25 7.3.2 Flow transmitter – Endress + Hauser Prosonic .................................................... 25 7.3.3 Level switches – Grundfos ................................................................................... 25 7.3.4 Level switches – ITT Flygt ................................................................................... 25 7.3.5 Pressure indicators – WIKA ................................................................................. 25 7.4 Lifting Equipment..................................................................................................... 25 7.5 Manhole covers – Coalition Trading polymer covers ............................................... 25 7.6 Media – Trickling filter packing ................................................................................ 25 7.7 Nozzles – Trickling filter .......................................................................................... 25 7.8 Pumps ..................................................................................................................... 25 7.8.1 Collection sump – Grundfos ................................................................................ 25 7.8.2 Dosing pumps – Grundfos Alldos ........................................................................ 25 7.8.3 Effluent sump – Sakuragawa ............................................................................... 25 7.8.4 Recycle sump – Grundfos ................................................................................... 25 7.9 Tanks – Chemical dosing ........................................................................................ 25 7.10 Valves ..................................................................................................................... 25 7.10.1 Valve actuators – Noah ....................................................................................... 25 7.10.2 Float valve – Vosa ............................................................................................... 25 7.10.3 Gate valves – Pleix-Quip ..................................................................................... 25 7.10.4 PVC valves .......................................................................................................... 25

8 COMMISSIONING & HANDOVER ................................................................................. 26 8.1 Installation & Commissioning Checklist ................................................................... 26 8.2 Installation Parameters ............................................................................................ 26 8.3 Commissioning Parameters .................................................................................... 26 8.4 Normal Operating Parameters ................................................................................ 26 8.5 Operator Training Register ...................................................................................... 26 8.6 Commissioning Certificate ....................................................................................... 26 8.7 Handover Certificate ................................................................................................ 26


1 TECHNICAL DATA 1.1 BACKGROUND

VWS Envig is a total solutions water and wastewater treatment company, offering a full range of activities from turnkey contracting for small and large projects, to specialised services and speciality chemicals for the industrial and municipal markets. These activities are all undertaken from the company's offices in South Africa, Botswana and Namibia. VWS Envig specialises in the design, construction, commissioning and operation of water and wastewater treatment plants and offers a full range of operational contracts including technical assistance, complete outsourcing, and financing of projects. VWS Envig is recognised worldwide for its water treatment expertise. VWS Envig was contracted to design a sewage treatment plant for XXX in XXX to alleviate the pressure on the overloaded oxidation ponds currently in use. VWS designed the plant in conjunction with Aqua Services and Engineering our Namibian sister company. VWS constructed all steel work and provided all process and mechanical equipment including the design guidelines of the civil structures for the sewage treatment plant. VWS also constructed the steel work for the treated effluent sump including supply of pumps and piping within the contract battery limits. Guidelines were given to the civil engineer for design of the diversion sump, float valve sump and effluent sump.

1.2 SUMMARISED TECHNICAL DESCRIPTION

The Sewage Treatment Plant was designed to cater for extensive daily fluctuations, as well as to allow future extensions to the plant to double the capacity at a later stage by adding similar modules as exist now. Trickling filter technology was chosen because it constitutes simple but extremely versatile technology, does not require skilled operators and produces a final effluent of high quality that can be discharged back into the environment or re-used as irrigation water for gardening or to grow selective crops. Major treatment components in this plant include rough screening, anaerobic digestion in a septic tank, carbon removal and nitrification in a trickling filter, sludge removal by means of a secondary clarifier, and disinfection in a chlorine contact tank. The final effluent is stored in a reservoir for recirculation to the process plant or irrigation purposes.

Warning: Untreated sludge should not be discharged directly into stream, rivers or dams due to the possibility of presence of diseases, worms, etc.

http://www.vwsenvig.co.za/en/expertise/services-consumables-chemicals/services-maintenance/

http://www.vwsenvig.co.za/en/expertise/services-consumables-chemicals/chemicals/

http://www.vwsenvig.co.za/en/expertise/services-consumables-chemicals/chemicals/

http://www.vwsenvig.co.za/en/markets/industry/

http://www.vwsenvig.co.za/en/markets/municipalities/

http://www.vwsenvig.co.za/en/expertise/design-build/

http://www.vwsenvig.co.za/en/expertise/operations/

http://www.vwsenvig.co.za/en/markets/municipalities/Potable_Water/

http://www.vwsenvig.co.za/en/markets/municipalities/Mun_Wastewater_Sewage/


1.3 RAW AND FINAL WATER QUALITY AND FLOW

Final (treated) water quality: After treatment, the final effluent will have a quality equal or better than specified in the South African Water Resources Management Act, 2004 (Act No 24 of 2004). [Final effluent will comply with the General Standards as laid out in the Government Gazette Regulation R553 of 5 April 1962, in Section 21(1) and 21(2) of the Water Act (Act No 54 of 1956).] In line with common practice in South Africa, the plant has been designed to produce final effluent to comply with the RSA General Standard for Discharge as published in Table 3.2 of Gazette No. 20526 of 8 October 1999 as shown below. Substance/Parameter RSA Standard Faecal Coliforms (per 100 ml) 1,000 Chemical Oxygen Demand (mg/l) 75* after removal of algae pH 5.5 - 9.5 Ammonia (ionised and un-ionised) as Nitrogen (mg/l) 3 Suspended Solids (mg/l) 25 BOD 20 The parameters can not be guaranteed due to these being dependant on the effluent supply content. Further treatment processes might have to be added dependant on the supply effluent analysis.

Plant capacity XXX m3/d (max) Maximum no. of people XXX PE Flow rates:

Average dry weather flow (ADWF) XXX m3/h Peak hydraulic flow (PWWF) XXX m3/h

Inflow water quality (average): Chemical Oxygen Demand (COD) 800 mg/l Biological Oxygen Demand (BOD) 400 mg/l Ammonia Nitrogen NH4-N 49 mg/l


2 TREATMENT PLANT 2.1 TREATMENT PLANT OVERVIEW

A complete treatment based on new generation trickling filter technology, was provided. The plant includes all unit processes and treatment components required to accomplish rough screening before entering the septic tank, primary treatment, carbon removal and nitrification, solids removal (secondary settling) and disinfection (chlorination). Raw sewage from the inlet pipe to the oxidation ponds is diverted from a sump above the trickling filter plant. From the diversion sump it flows through a float valve sump which is equipped with a flow control valve and float valve which will shut the flow to the trickling filter plant to prevent overflow during power outages. From the float valve sump raw sewage flows into the final collection sump TK-1000 fitted with duty/standby pumps pumping the raw sewage to the trickling filter sewage treatment plant where it discharges into an inlet box CT-1100 before flow is diverted equally into the septic tank modules CT-1200 & CT-1201. The following section describes the process and equipment that is provided. Please also refer to the included process and instrumentation diagram. An effluent treatment plant to serve a mining community with shift workers must cater for extreme fluctuations in flow (and load) throughout the year. This requires great flexibility if a biological treatment plant is employed. New generation trickling filter technology in conjunction with a septic tank to serve as buffer tank was considered to be the most appropriate technology for this application. Trickling filters employ fixed film technology, which can accommodate considerable fluctuations in flow and load (biological), incorporate simple technology and require no process control. The trickling filter design incorporates continuous recirculation through and wetting of the media, even during times of low or no inflow. This ensures that the bioculture is kept alive during times of low or no inflow. The sludge settled in the secondary clarifier CT-1600 of the trickling filter system is recycled back to the primary treatment tank (septic tank) CT-1200 & CT-1201 and the recycle stream is variable. Latter is achieved by an adjustable timer, which is set to switch the sludge recycle flow on/off on a time basis. Also, part of the mixed liquor (outflow from the trickling filter) is recycled. For biological treatment the following unit processes are as follows:

• Flow equalisation / smoothening and anaerobic digestion in septic tank (CT-1200 & CT-1201);

• Anoxic treatment with nitrate rich recycle in a recycle sump (CT-1300); • Aerobic/attached growth treatment for carbonaceous material removal and nitrification in

trickling filters (TF-1400 & TF-1401). • Solids removal in a secondary clarifier (CT-1600)

2.2 EQUIPMENT DETAILS

2.2.1 Diversion sump

Qty : 1 in main sewage line feeding oxidation ponds Purpose : To divert raw sewage from the main line to the new plant Ancillaries : Proposed 1 off screen


2.2.2 Control valve sump

Qty : 1 in newly diverted sewage line feeding trickling plant Purpose : To control inflow to new STP, shut off flow based on rising level in

time of power outages and reopen if level has dropped after power reconnection

Ancillaries : 1 off 150NB gate valve for flow control

2.2.3 Float valve sump with flow control Qty : 1 in newly diverted sewage line feeding trickling plant Purpose : To control inflow to new STP, shut off flow based on rising level in

time of power outages and reopen if level has dropped after power reconnection

Ancillaries : 1 off 150NB equilibrium float valve 2.2.4 Collection sump

Prefabricated pump sump Qty. : 1 Tag No. : TK-1000 Make / M.O.C. : Grundfos PUST 10.25.D.A.SS.DPSE 1000 X 2500 Selected pump duty point : 15 m3/hr at 17.5 mWG Capacity : 1.8 m3 Ancillary items : The PUST tank comes pre-mounted with all necessary accessories and valves as supplied by Grundfos. Pumps in sump : 2 off (duty/standby) PC1000 & PC1001 Pump make and model : Grundfos SLV 65.65.30.2.50D

2.2.5 Screening facility - Inlet box with manual rake screen

The inlet box is fitted with a bar screen (manual screen) and drip tray. Access for an operator with a wheelbarrow is provided next to the inlet box. Once per day, the operator has to rake trapped matter (screenings) with the rake onto the drip tray and leave this to dewater until the next day. The (semi-dry) screenings from the previous day should be discarded at a suitable waste disposal site or incinerated. Qty. : 1 Split box with inlet to each of two septic tank compartments VWS Tag No. : CT-1100 Make / M.O.C. : Concrete structure Capacity : 2.4 m3 each x 2 compartments Flow control : Manually adjusted stainless steel penstocks PS-1100 & PS-1101 Screening : MS-1100 & MS-1101 manually cleaned with rake and drip dry system


2.2.6 Flow equalisation and anaerobic digestion – Septic tank modules After screening the effluent enters a twin module, three-compartment septic tanks (CT-1200 & CT-1201). Solids and sludge settle out and are digested in the first compartment of this tank, while the second and third compartment mainly contains grey water. Anaerobic conditions in this tank ensure BOD removals of at least 35 % to 50 %. Additionally, aerobic sludge from the secondary settler is recycled to the inlet box, to be further digested in the septic tank. This reduces the overall sludge volume produced in the biological system. The design parameters of the septic tank are as follows: Type : Three-compartment, horizontal flow Capacity : 180 m³ x 2 modules = 360 m3 Retention time (based on ADWF)

: 36 h

Occasionally, the sludge accumulated in the septic tank must be removed. The amount of sludge accumulated in especially the first compartment of each train of the septic tank has to be assessed at least every six months. This is further described in Section 2.4.7 of this manual. When approx. 400 to 500 mm of sludge has accumulated on the bottom of the first compartment of the septic tank, desludging is required. Only the sludge and scum in the first compartment needs to be removed by pumping it out. To remove this sludge, the operator can use his own desludge pump or he may use one of the trickling filter feed pumps which is on standby for this purpose. The effluent from the septic tank is discharged into the recycle sump (CT-1300).

2.2.7 Anoxic Zone – Recycle sump In the recycle sump (CT1300), oxygen deficient effluent from both septic tanks is mixed with aerated, nitrate-rich effluent that is recycled from the sumps of the trickling filter (CT-1500 & CT-1501). The recycle sump is sized to ensure anoxic conditions are maintained inside this tank, and is fitted with three open impeller submersible pumps (2 on duty (one for each module), 1 common standby, cyclic operation) as follows: Tag Number : PC1300 / PC1301 / PC1302 Make and Model : Grundfos SLV 65.65.30.2.50D Type : Submersible, open impeller Selected duty point : 29 m³/h at 12 mWG Motor : 3.0 kW, 380-415 V During times of no inflow to the plant, there will be no discharge from the septic tank into this sump. The pumps will then continue recirculating water from the trickling filter basin through the recycle sump back to the filter media, ensuring that the biomass on the media is kept wet (and alive). The pumps are fitted with a run dry protection level switch (LS1300 LL). If the period of non-inflow to the plant is very long, it can be expected that water will be lost through evaporation and the level in this sump will drop. To then prevent the pump(s) from running dry, they will be switched off (trip) at low low-level. Should the plant receive inflow again, the level in the sump will rise and the level switch (LS1300 L) will switch the pump(s) on automatically. The recycle flow is reduced as the level in the pump sump rises due to closing of the electrically actuated return valves (XV1501, XV1502, XV1503 & XV1504) by high level switch (LS1300 H) and more effluent is discharged to the clarifier. This also ensures that no operator will be required to switch the plant on or off.


An access platform is provided for manual valve operation and for maintenance purposes on the pumps, valves and level switches within the recycle sump. Pumps in sump See detailed pump section / pump schedule

2.2.8 Trickling filter towers with collection basins The trickling filter system (TF1400 & TF1401) consists of a bed of highly permeable medium, which serves as a platform for micro-organisms to attach to and grow on, to form a biological film. The wastewater is sprayed over and percolates through the media. Organic material in the wastewater is absorbed by micro-organisms growing as a biological film on the media. In the outer portion of the film, aerobic organisms degrade organic material, whereas anaerobic organisms exist deeper into the biological film, i.e. near the surface of the media. The new generation trickling filter is provided with a bed of approximately 80 m³ per module (inside dimension of each module 2.975 m x 4.4 m x 6 m high) plastic (UV protected PVC) packing medium as shown in Figure 1 & 2.

Figure 1. Trickling Filter Media (Packing)

Figure 2. Packing after glueing into blocks


Water (effluent) from the trickling filter feed sump (recycle sump CT-1300) is distributed (not necessarily evenly) and sprayed over the top surface of the media using a simple system of open, non-clogging nozzles positioned on a 100mm OD uPVC header. The water then percolates through the media. The orifice sizes of the nozzles have been set to Ø 18mm. The uPVC header is equipped with flushing valves on the ends of each leg. After checking / cleaning the nozzles once a week, these valves need to be opened to clear any sludge that accumulated in the pipes. The reason for an aerobic and anaerobic layer being established is an increase in the thickness of the microbial layer, causing the diffused oxygen to be consumed before it can penetrate the full depth of the microbial layer. Therefore, oxygen only reaches the outer layer of micro organisms resulting in aerobic conditions, whereas deeper into the biological film no oxygen is available resulting in anaerobic conditions. Figure 3 demonstrates this principle.

Figure 3. Biological activity on trickling filter media

Water that has passed through the trickling filter is collected in the trickling filter basins (CT 1500 & CT-1501) and then flows to a static settler. Biological solids that have become detached from the packing media must be removed before the effluent is disinfected and can be finally discharged. Removal of the biomass is achieved in a conventional, secondary settling tank. The design parameters of the trickling filter are as follows: Tag Number : TF-1400 & TF-1401 Type : Modern, plastic media packing (UV stabilised PVC) Design Flow (ADWF) : 240 m³/d Design Load : 192 kg/d COD + 11.7 kg/d NH4-N A simple system of non-clogging, open nozzles will be used to distribute the water from the recycle sump over the top of the media. The wastewater is sprayed over and percolates through the media. Organic material in the wastewater is absorbed by the micro-organisms growing as a biological film on the media and ammonia nitrogen is converted to nitrites and nitrates. The water, after percolating through the media, is collected in the trickling filter basin (CT-1500 & CT-1501), where part of the nitrate-rich water is recycled back into the recycle sump and part overflows into the secondary clarifier (CT-1600). The trickling filter basins are each fitted with 45° V-Notch weirs to control the level in the system.


2.2.9 Secondary Clarifier Treated effluent from the trickling filter is discharged into the settling tank (CT-1600), where the suspended solids settle out and clear water is drawn off via a draw-off pipe at the top of the clarifier. The sludge is collected in the bottom cone of the clarifier and pressed through a 63mm discharge pipe by means of hydrostatic pressure. The sludge is allowed to periodically drain back into the feed pipe of the inlet screen by opening a sludge discharge valve (XV1601). The sludge recycling frequency can be changed by modifying the opening and closing duration of this actuator. These levels are however set by the process engineer during commissioning and should not be changed by the operator. Biological solids that have become detached from the packing media have to be removed before the effluent is disinfected and can be finally discharged. The hydraulics of the plant will ensure that water from the trickling filter basin will only overflow into the secondary settling tank if there is inflow into the plant. The clarifier design parameters are as follows: Tag Number : CT-1600 Type : Square tapering sides – casted concrete structure Surface Area : 3.5 m x 3.5 m = 12.25 m2 Draw off system : 90mm OD uPVC pipe system with inverted draw off holes Stilling well : Stainless steel structure & internals Design Flows (Hydraulic): ADWF : 240 m³/d PWWF : 15 m³/h The clarifier is be fitted with a centre mixing/stilling well, clarified water draw off piping, and sludge removal pipe.

2.2.10 Disinfection – Chlorine contact channel Clarified water from the settling tank is discharged into the chlorine contact tank (CT-1700). This tank is sized for an effective contact time in excess of the required 20 min at PF. The contact channel is fitted with fibre cement boards channelling the effluent in such a way that it makes six direction changes before discharge to ensure effective mixing of chlorine and effluent. The effluent is disinfected utilising calcium hypochlorite / sodium hypochlorite in the form of dissolved granules or liquid. Dosing pump PD1800 is injecting chlorine at 2-4 ppm through an injection valve located at the inlet of the contact channel. The chlorine contact tank is fitted with a 45° V-Notch weir at the outlet. This is being utilised to measure the flow at any specific time through the plant by a Endress + Hauser Prosonic flow transmitter. The level reading is transmitted to the controller and converted to flow rate indicated on the in field display unit. Dosing Ancillaries: Chemical dosing tank – Sodium Hypochlorite (HYDREX 8023) / Calcium Hypochlorite Qty. : 1 Tag No. : TK-1800 Make / M.O.C. : Sinvac TE0070 - Polyethylene Dimensions : Ø 385 x 615 mm Capacity : 70 Litre


Dosing pump (Chlorine) Qty : 1 Tag No : PD1800 Make : Grundfos Alldos Model : DMI 208-1.0-10 Duty : 0.22 lph @ 10 bar Power : 0.011 kW @ 220-240 VAC, 50 Hz, 1~

2.2.11 Final Water Discharge Disinfected water from the chlorine contact channel (CT-1700) discharges into the final water reservoir / effluent sump (CT-1900) by gravitational flow from where it is be pumped away to the evaporation pond or diverted to the tailings dam through an 80NB pipe line. The effluent sump civil structure as per Sirston consultants drawing numbers 3035-S01 Rev E, 3035-S13 Rev A, 3035-S14 Rev A & 3035-S15 Rev A is fitted with an access platform leading to a duty / standby pump set with the following detail: Qty. : 2 (duty/standby) Tag No. : PC1900 / PC1901 Make / M.O.C. : Sakuragawa U-2153AW Selected pump duty point : 30 m3/hr at 65 mWG Ancillary items : Endress + Hauser Promag flow meter on outlet. Refer to schedules and supplier’s documentation provided

2.2.12 Valves Refer to valve schedule 2.2.13 Instruments

Refer to instrument schedule

2.3 SOLID WASTE REMOVAL

Sludge stabilisation and digestion takes place in the septic tank. This tank is bi-annually inspected. If the sludge at the bottom of the first compartment of the septic tank has accumulated to a height of ca 400 to 500 mm the sludge has to be removed by pumping it into the adjacent sludge drying beds. A separate sludge pump can be used for this, or alternatively one of the trickling filter feed pumps can be used to manually remove this sludge from the tank.


2.4 OPERATING PARAMETERS & PROCEDURES

2.4.1 Influent flow

Flow rate : ADWF 240 m3

Peak design flow : 15 m3/hr Supply pressure : Gravity flow from oxidation pond diversion sump then pumped by

collection sump pumps at 15 m3/hr at approximately 1.8 bar into trickling filter sewage plant.

2.4.2 Chlorine Dosing (Treated effluent)

Guidelines: Chemical : Sodium Hypochlorite 12% (HYDREX 8023) Tank make up (dilution) : 15 Litre sodium hypo + 50 Litre purified water Total make up : 65 Litre Tank capacity : 70 Litre Dosage : 2 mg/l free chlorine Dosing pump stroke setting : 69% - Refer to Dosing pump selection sheet

Caution: Inhaling chlorine fumes may cause serious lung damage. Avoid direct skin contact with liquid chlorine solution. Use of correct PPE is recommended.

2.4.3 Plant Start-Up

Initial start-up

The anaerobic micro-organisms (in the septic tank) take about 5 months to mature / fully develop the aerobic micro-organisms take about 8 to 12 weeks. If there is an anaerobic pond close by, it will accelerate the process drastically by filling some of the sludge into the septic tank - 3 m3 to 5 m3 will do a lot to accelerate the process! The above is also true for any other biological sewage treatment process, even pond systems. The treated effluent will not be to standard upon initial start-up due to deficiency of microorganisms, because the microbial cultures need time to establish, the clarifier outflow should also still look a bit murky, because it will not have the bioflocs yet - that will only form once a proper biomass is established and latter is slouched off by the water trickling through. The following steps need to be followed to start the plant after a shutdown:

• Check all pipework is in good condition; • Check that all valves (isolating and non-return valves) are functional; • Ensure all manual isolating valves are fully open; • Ensure the chlorine dosing tank contains the correct amount and concentration of chemical; • Switch on the electricity and all electrical equipment; • Check nozzles on top of trickling filter. Water must spray out of each nozzle and the

complete surface area must be covered (not necessarily evenly). • Select all valves & pumps to AUTO. • Press F1 to accept all alarm messages.

2.4.4 Normal Operation

No adjustments or special operational procedures other than routine operation and maintenance, as described under Section 2.4.6, are required.


2.4.5 Plant Shutdown

The following steps need to be followed to stop the plant:

• Select all valves to SHUT, wait for the SHUT lamps to illuminate. • Select all pumps to OFF. • Desludge all tanks where aerobic sludge can accumulate (clarifier and recycle sump); • Switch off all power at the control board; • Keep water in all structures at all times. Groundwater may lift empty structures! • Remove and clean all mechanical equipment; • For long shutdowns, take out all submersible pumps, clean with potable water and store in a

suitable store room.

2.4.6 Maintenance

This plant requires very little maintenance. However, the following routine maintenance is necessary:

Daily

• Remove all objects accumulated on the bar screen of the inlet box. Use a rake to remove

these and discard into waste bin; • Check that the chlorine dosing tank still contains sufficient chemical – replace when almost

empty; • Check free chlorine concentration of the final effluent at the outlet of the chlorine contact

tank. It should be at least in the range of 0,5 to 1,0 mg/l. Adjust if not within this range; • Check all indicating lights on the electrical panel. If any pump/motor has tripped, a red light

as well as the general alarm (strobe) light will come on; • Check pump operation.

Weekly

• When operating in low-flow mode, check nozzles of trickling filter weekly and clean if

necessary. If a nozzle does not spray water, it is clogged. Manually clean nozzle with a piece of wire. Use extreme care and put on safety gloves when working with effluent;

• Remove collected grit and sand in inlet box and behind the inlet screen. Open screen to gain access to grit and sand collected behind it.

Monthly

• Dispose of contents in waste bin to a suitable landfill site. Cover with at least 800 mm soil. Or

incinerate if possible; • Check nozzles of trickling filter. If a nozzle does not spray water, it is clogged. Manually

clean nozzle with a piece of wire. Use extreme care and put on safety gloves when working with effluent;

• Check functionality of all manual valves by opening and closing each valve – replace if necessary.


Bi-Annually

• Check sludge and scum accumulation in septic tank (see method below – Section 2.4.7). Empty sludge into sludge drying bed and allow to thoroughly dry.

Annually

• Clean settling tank pipework; • Inspect and maintain feed pumps as per manufacturer’s manual; • Check sludge and scum accumulation in septic tank (see method below – Section 2.4.7).

Empty sludge into sludge drying bed and allow to thoroughly dry; • Check all pipework and valves for leaks. Paint, repair or replace if necessary.

2.4.7 Septic Tank Inspection

The scum and sludge accumulations in a septic tank should be measured every six months to a once a year. A useful tool for measuring the thickness of the scum is a rod graduated in centimetres to which a disc or square flap is attached as shown in Figure 4. If this rod is pushed through the scum mat, moved sideways to a place where the scum is undisturbed, and then pulled up gently, the bottom of the scum layer can easily be felt. In the same way the bottom of the outlet device can be located. The top of the sludge layer can be determined by slowly lowering this tool into the tank. The increase in resistance encountered when the sludge layer is reached can usually be felt quite easily, especially after a little experience. Whenever the distance between the scum layer and the outlet device is 150 mm or less, the tank should be cleaned. A second (better) method of determining the extent of sludge accumulation is to push a rod wrapped in white towelling, down to the bottom of the tank and rotating it a few times. On withdrawal, the towelling will be blackened to the depth of the sludge. For this method the scum should be broken away from the surface, in order to ensure free withdrawal of the towelling. When the distance between the top of the sludge layer and the bottom of the outlet device is less than 150 mm, the tank should be cleaned. Before sludge and scum can be effectively removed by pumping, they must be intimately mixed with the liquid by stirring with a wooden rod or the tool described above if it is made sufficiently sturdy. Alternatively, the pump used for desludging can be inserted into the sludge and switched on to turn around the sludge without connecting it up to the flexible hose. This mixture will form a less viscous mass, which will flow more easily than undisturbed sludge or scum. When septic tanks are cleaned, they should not be washed or disinfected. In order for the digesting process to continue when the tank is put into use again, a small quantity of sludge must be retained to serve as a starter. VWS recommends using a separate submersible pump to empty the septic tank sludge as it is not practical on large plants to remove the recycle sump standby pump for this purpose.


Figure 4. Measuring Sludge and Scum in the Septic Tank

When handling sludge, operators should wear overalls and boots at all times and direct contact with the sludge should be avoided to prevent infection with worms or diseases.

For safety reasons, any person that is required to open or inspect the septic tank, that person is required to wear a life jacket prior to and during opening of any hatch. It is recommended to install a rope ladder on the inside of each chamber to assist in case of accidental falling into the tank.


3 CONTROL PHILOSOPHY 3.1 PLANT INLET FEED PUMPS

Two pumps PC1000/1001 (duty/standby) are situated in the collection sump. These pumps are controlled automatically by level switches. Effluent level falling below switch LS1000LL stops the duty pump, effluent level rising above switch LS1000L starts the duty pump. This is a normal condition and does not alarm. Pump duty is swapped each pump start. If the duty pump trips or fails to start then the standby automatically takes over duty. Effluent level rising above switch LS1000H will issue an alarm.

3.2 TRICKLING FILTER FEED PUMPS

Three submersible pumps (2 duty/1 standby) transfer the effluent from the septic tank to the top of the trickling filters. Sufficient sump level is maintained to allow these pumps to run continuously. Sump level falling below switch LS1300LL stops the duty pumps, effluent level rising above switch LS1300L starts the duty pumps. An alarm is issued at low level. Pump duty is swapped every eight hours. If a duty pump trips or fails to start then the standby automatically takes over duty. Sump level falling below switch LS1300L opens the recycle valves to maintain the minimum sump level. Sump level rising above switch LS1300H shuts the recycle valves to allow normal treatment to continue. Sump level rising above switch LS1300HH will issue an alarm.

3.3 SECONDARY SETTLER DESLUDGE The secondary settler is fitted with a draw-off pipe to remove accumulated sludge from the bottom of the settler and transfer it to the septic tank. The flow in this pipe is regulated periodically by means of an electric actuator valve. Note that this valve maintains its current position at power failure. If power is lost while the valve is open then it must be manually shut by the operator. During normal operation this valve should be set to open for a few minutes every hour. The shut period (minutes) and open period (seconds) are set on the hmi screen on the mcc control panel.

3.4 DOSING CONTROL The dosing pump is permanently powered on. Dosing rate is controlled by using the pulse (frequency) output from flow transmitter FIT1701 as the stroke input of the dosing pump.


3.5 FINAL WATER DISCHARGE PUMPS

Two pumps PC1900/1901 (duty/standby) are situated in the treated effluent sump. These pumps are controlled automatically by level switches. Treated effluent level falling below switch LS1900LL stops the duty pump, effluent level rising above switch LS1900L starts the duty pump. This is a normal condition and does not alarm. Pump duty is swapped each pump start. If the duty pump trips or fails to start then the standby automatically takes over duty. Treated effluent level rising above switch LS1900H will issue an alarm.

3.6 CONTROL PANEL MCC1000

Automated operation of the pumps and dosing is by PLC in control panel MCC1000. Operator interaction is via the hmi, selector switches and lamps mounted on the mcc. The plant is designed to run continuously, all pumps and valves should be selected to auto. EMERGENCY STOP: Pressing this button stops all equipment immediately. Twist the button to release. 400VAC/230VAC HEALTHY: The mcc control panel has a voltage window comparator which will shutdown all controls if any phase deviates by more than 5%. There is a start up delay of about ten minutes after power up, wait for the healthy lamp before the plant will start. PUMPS: OFF – The pump will not run. AUTO – The pump will run as required by the plc. TEST – The pump will run regardless of conditions or interlocks. This should only be used for maintenance purposes and never to operate the plant. While selected to OFF or TEST position, a trip/fault alarm is active and HEALTHY lamp is off. VALVES: AUTO – The valve will open as required by the plc. SHUT – The valve is forced shut, plc is ignored. OPEN – The valve is forced open, plc is ignored. An OPEN or SHUT lamp lights up when the valve has reached the respective position. This can take a few seconds while the actuator is moving.


3.7 ALARM CONDITIONS Every new alarm activates the audible strobe beacon mounted at the mcc room. Press the CANCEL button below the hmi screen to silence the beacon. On the hmi scroll up/down using the arrow buttons to display all active messages, alarm messages are display before status messages. Alarm messages are latched, the message is only removed from display after the fault condition has been corrected AND function button F1 is pressed to accept the alarm. Interlocks remain in force until the relevant message has been cleared. ALARM MESSAGES: TK1000 level high Effluent sump level is high. CT1300 low stopped Trickle filter sump level is low, transfer pumps stopped. CT1300 level high Trickle filter sump level is high. PC#### trip/fault Pump mcc tripped or field isolator activated. PC#### run fail Pump has failed to run after plc start issued. XV#### fault Electric actuated valve has failed to open/shut.

3.8 HMI PARAMETER SETTING Sludge purge sequence times are set at the hmi. To display these settings use the down/up arrow button to move to the desired setting, positioned on the top display line of the hmi. Press ENTER to update the value field, use the up/down arrow to increase/decrease the value and press ENTER to accept. Press ESC to exit all field value updates, the cursor moves to the left of the display and up/down arrow buttons scroll up/down the display again. • SLUDGE SHUT ### min - Set the wait time between sludge purge cycles in minutes. • SLUDGE OPEN ### sec - Set the sludge valve open period per cycle in seconds. NOTE: The wait timer is accumulated on running hours.

3.9 HMI PASSWORD The HMI has no password restriction.


3.10 CONTROL PANEL MCC2000

Automated operation of the final water discharge pumps is by PLC in control panel MCC2000. Operator interaction is via the selector switches and lamps mounted on the mcc. The pumps are designed to run according to level control, both pumps should be selected to auto. PUMPS: OFF – The pump will not run. AUTO – The pump will run as required by the plc. TEST – The pump will run regardless of conditions or interlocks. This should only be used for maintenance purposes and never to operate the plant. While selected to OFF or TEST position, a trip alarm is active and HEALTHY lamp is off. LAMPS: SUMP LEVEL LOW – The duty pump will not run. This is a normal condition. SUMP LEVEL HIGH – Final water sump level is too high, this is an alarm condition. DRIVE TRIPPED – MCC tripped or field isolator activated, this is an alarm condition. ALARM CANCEL: Press the button to silence the audible alarm.


4 ELECTRICAL CONTROL

Refer to EC&I document C10-1436-06-11 for panel schematics.


5 RECOMMENDED SPARES

The following spare holding is recommended to minimise long period shutdown in the event of failure: All spares can be obtained from VWS Envig. Please refer to Engineering Schedules for detail on items.

Item Qty Description

1 1 ea Submersible pump Grundfos SLV65.65.30.2.50D

2 1 ea Submersible pump Sakuragawa U-2153AW

3 1 ea Dosing pump – Alldos DMI 208 1,0-10 and service kit + installation set DN4 suitable for Cl2

4 2 ea Level switch – ITT Flygt ENM-10 (13 m)

5 2 ea Pressure indicator – Wika, 63 mm, 0-1000 kPa, glycerine, back entry ¼” BSPT

6 1 ea Endress + Hauser Prosonic Flow transmitter Prosonic S FDU90

7 1 ea Endress + Hauser Promag 10W80 with local display

8 1 ea PVC non return valve DN65

9 1 ea PVC ball valve DN65

10 1 ea Pleix-Quip butterfly valve 80NB

11 2 ea Noah Electrical valve actuator SA-005

12 6 ea Trickling filter distribution nozzles orifice sized down to diameter 18mm

Electrical Spares – Refer to Electrical Bill of Quantities on drawings Section 6


6 DRAWINGS, DIAGRAMS, TABLES, SCHEDULES & PROCEDURES

6.1 Pump Schedule 6.2 Valve Schedule

6.3 Instrument Schedule

6.4 Plant General Layout Drawings

6.5 Process & Instrument Diagrams

6.6 Electrical Diagrams & Panel Drawings

6.7 Civil Drawings


7 SUPPLIER DOCUMENTS 7.1 Chemicals – Data Sheets & MSDS 7.2 Collection Sump – Grundfos pumping station 7.3 Instruments

7.3.1 Flow measuring system – Endress + Hauser Promag 7.3.2 Flow transmitter – Endress + Hauser Prosonic 7.3.3 Level switches – Grundfos 7.3.4 Level switches – ITT Flygt 7.3.5 Pressure indicators – WIKA

7.4 Lifting Equipment 7.5 Manhole covers – Coalition Trading polymer covers 7.6 Media – Trickling filter packing 7.7 Nozzles – Trickling filter 7.8 Pumps

7.8.1 Collection sump – Grundfos 7.8.2 Dosing pumps – Grundfos Alldos 7.8.3 Effluent sump – Sakuragawa 7.8.4 Recycle sump – Grundfos

7.9 Tanks – Chemical dosing 7.10 Valves

7.10.1 Valve actuators – Noah 7.10.2 Float valve – Vosa 7.10.3 Gate valves – Pleix-Quip 7.10.4 PVC valves


8 COMMISSIONING & HANDOVER

The following checklists are to be completed by VWS and one copy issued to Client or Client’s representative (receipt signed for)

8.1 Installation & Commissioning Checklist 8.2 Installation Parameters

8.3 Commissioning Parameters

8.4 Normal Operating Parameters 8.5 Operator Training Register 8.6 Commissioning Certificate

8.7 Handover Certificate

Reference documents: General Layout C10-1436-00-01 Process & Instrumentation Diagrams C10-1436-01-01 & C10-1436-01-02 Electrical Panel Diagrams C10-1436-06-11 Operating & Maintenance Manual C10-1436 O&M


Section 8.1 Doc. No. : C101436 INSTALLATION & COMMISSIONING CHECKLIST Sheet: 1 / 1 Date :

No. Description Comments Done

1 All equipment mounted securely Yes

2 All mechanical & process connections done and checked Yes

3 All electrical and control instrumentation connections done and checked Yes

4 Chemical dosing tank positioned and dosing line connected and tested Yes

5 All installation measurements taken and recorded Yes

6 All panel tests performed Yes

7 All spares and chemical supply handed to client Yes

For VWS Envig: ______________ ________________ ___________________ Name Title Signature


Section 8.2 Doc. No. : C101436 INSTALLATION PARAMETERS Sheet: 1 / 1 Date :

No. Description Value Comment

1 Float valve sump

1.1 Float shut off height 580 mm from floor

2 Collection sump

2.1 LS1000LL height 450 mm from floor

2.2 LS1000L height 1000 mm from floor

2.3 LS1000H height 1880 mm from floor

3 Recycle sump


3.2 LS1300L height 1180 mm from floor 3.3 LS1300H height 1650 mm from floor 3.4 LS1300HH height 2560 mm from floor 4 Trickling filter

4.1 TF1400 V-Notch crest to floor 510 mm

4.2 TF1401 V-Notch crest to floor 510 mm

5 Chlorine contact tank

5.1 CT1700 V-Notch crest to floor 1633 mm

5.2 CT1700 V-Notch crest to FIT1700 membrane 477 mm

5.3 FIT1700 probe to V-Notch plate 1000 mm

6 Effluent sump


6.2 LS1900L height 1150 mm from floor

6.3 LS1900H height 3330 mm from floor



Section 8.3 Doc. No. : C101436 COMMISSIONING PARAMETERS Sheet: 1 / 1 Date :

No. Description Value Comment

1 Trickling filter

1.1 Spray Nozzle orifice diameter 18 mm

1.2 Nozzle spray diameter 1450 mm

2 Chlorine dosing

2.1 Chlorine make-up dilution 0.5 kg HTH per 10 l water

2.2 PD1800 pump setting 80 %

3 Chlorine Contact Tank

3.1 CaCl2 concentration 2.5 mg/l

3.2 Max flow rate during commissioning 15.69 m3/h

4 Effluent sump

4.1 Max flow rate to evaporation pond during cold commissioning 56 m3/h @ 2 bar

5 Recycle sump 5.1 Pump pressure 1 bar

6 Collection sump

6.1 Pump pressure 0.6 bar



Section 8.4 Doc. No. : C101436 NORMAL OPERATING PARAMETERS Sheet: 1 / 1 Date :

No. Description Design Actual Unit

1 Collection sump PC1000/1001 4.2 l/s @ 15 mWG flow rate not recorded pressure 6 m WG

2 Recycle sump PC1300/1301/1302 7.8 l/s @ 17 mWG flow rate not recorded pressure 10 m WG

3 Dosing pump setting 69 % 80 %

4 Effluent sump PC1900/1901 30 m3/hr @ 65 mWG 56 m3/hr @ 20 mWG

5

6

7

8

9

10

11

12

13

14

15

16

17

18

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Section 8.5 Doc. No. : C101436 OPERATOR TRAINING REGISTER Sheet: 1 / 1 Date :

No. Name Title Signature

1 Signed copy attached

2

3

4

5

6

7

8

9

10

Training has been given to the above persons in respect of:

• Operation of plant • Mixing and safe handling of chemicals • Cleaning Procedure & general maintenance of plant

For VWS ______________ ________________ ___________________ Name Title Signature


8.6 COMMISSIONING CERTIFICATE

CLIENT : XXX DESCRIPTION : WASTE WATER TREATMENT PLANT XXX m3/DAY TRICKLING FILTER STP CONTRACT NO : XXX VWS REF. No. : XXX This certificate is the final Commissioning Certificate and precedes the final Contract Handover Notification and Acceptance. The attached sheets cover the mechanical/electrical equipment acceptance and may include certain items awaiting finalisation for reasons noted. All operating parameters have been set and tested; performance and sampling reports are attached where possible with available testing instrumentation. All relevant staff members have been trained, the training register is attached. The following documents are issued with this certificate: C101436 O&M Updated Operating & Maintenance Document (Final copy to be couriered) C101436 Installation & Commissioning Checklist C101436 Operating Parameters C101436 Operators Training Register Please sign one copy and return to the VWS Commissioning Technician to acknowledge receipt of this certificate and all accompanying documents as listed above. Issued By (for VWS) __________________ ________________________ __________________ Signature Full name Date Received By Client __________________ ________________________ __________________ Signature Full name Date


HANDOVER

For handover the following requirements must be satisfied: 1 Installation & Commissioning Checklist C101436 must be complete. 2 Any outstanding snag-list items must be clearly described on Checklist, including the action

plan and time period as agreed by VWS and Client. 3 Commissioning Operating Parameters C101436 must be complete. 4 Operating and maintenance training must be complete and register C101436 signed by all

attendees. 5 Two copies of Updated Operating & Maintenance documents issued. 6 Commissioning Certificate is issued.


8.7 CONTRACT HANDOVER ACCEPTANCE CERTIFICATE CLIENT : XXX DESCRIPTION : WASTE WATER TREATMENT PLANT XXX m3/DAY TRICKLING FILTER STP CONTRACT NO : XXX VWS REF. No. : ES10-1436 Attention : Project Manager XXX Dear Sir/s, We have pleasure in confirming that the above upgraded equipment has been checked and tested by our commissioning engineer. We will look upon the date of _____/_____/ 20_____ as the hand over date. This letter serves to confirm that the contract is complete and we are confident that all items and equipment are functioning properly, and in accordance with our specification. This handover may be signed subject to minor outstanding items to be corrected within a time period as agreed between yourself and Veolia Water Systems. All outstanding items are to be clearly identified in writing as well as the agreed course of correction / resolution and time period. Please sign both copies of this certificate and return one copy to the Veolia Water Systems commissioning engineer. If you are not completely satisfied, please advise Veolia Water Systems, in writing within 7 days. If, within 30 days, no correspondence or signed copy is received, Veolia Water Systems will assume acceptance and the guarantee period will start from the handover date. Assuring you of our best attention at all times. For Veolia Water Systems __________________ ________________________ __________________ Signature Full name Date For Client __________________ ________________________ __________________ Signature Full name Date

operating and maintenance manual - sewage treatment plant

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