Odour Assessment of Marafiq’s Wastewater Facilities in Jubail

Industrial City KSAIndustrial City, KSAK. Z. Subaie1, M. W. Ponsonby1, T. A. Bahamdan1,

2 2 2 3C. Hubble2, A Carrèire2, Dr. A. Davies2 & A.R. Ather3

1 Marafiq, 2 RWDI Air Inc., 3 Haif Company Est.

MarafiqMarafiq• Provides a total integrated power & water solution to

industrial commercial & residential customers in theindustrial, commercial & residential customers in the industrial cities of Jubail & Yanbu

• Operations in Jubail & Yanbu include power generation, transmission & distribution, seawater cooling for i d t i t d li ti f t bl tindustries, seawater desalination for potable water production, & sanitary & industrial wastewater treatment

2

Wastewater FacilitiesIndustrial Wastewater Treatment Plant

Capacity – 60 000 m3/d

Sanitary Wastewater Treatment PlantCapacity 72 000 m3/dCapacity – 72 000 m3/d

3

Wastewater FacilitiesWastewater Pump & Lift StationsWastewater Pump & Lift Stations

– 57 pump stations & 216 lift stations– 620 kilometres of pipelines– 620 kilometres of pipelines– Odour control systems on pump stations

4

ObjectivesM d i i f b th l t d• Measure odourous emissions from both plants and establish emission rates

• Develop an odour emissions inventory identifyingDevelop an odour emissions inventory identifying major emission sources from each plant

• Model the odour impacts of emissions from each plant on the surrounding area

• Provide recommendations for mitigating emissions M d l h d i f i i i i• Model the odour impacts of mitigation scenarios to estimate the degree of odour reduction

5

What is an Odour Unit?O (O )• One odour unit (OU) represents the concentration at which 50% of the population can just detect the odour

• No published criteria for odour• No published criteria for odour– typically 1 OU/m3 (over a 10 minute average)

considered acceptablep• An odour unit is not representative of a concentration of

a specific chemical but instead is a measure of the d f i todours from a mixture– IWTP odour producing compounds primarily VOCs

SWTP odour producing compounds primarily reduced– SWTP odour producing compounds primarily reduced sulphur compounds

6

Source Sampling– Samples for area sources i e lagoons & aeration– Samples for area sources i.e. lagoons & aeration

tanks, collected using a flux chamber – A lung sampler was used to sample scrubbers andA lung sampler was used to sample scrubbers and

stacks– Sampling locations selected to capture most p g p

significant sources– Sampled operations represent the majority of

emissions from each facility– Sample results represent emissions at one point

in time while actual emissions would vary based on material input to the facilities

7

Flux Chamber

• The fluxThe flux chamber loweredonto water surface• nitrogen used to purge air from the chamberat sweep rate • Sample of gas taken from chamber after t bili ti fstabilization of

the gases

8

Lung Sampler•The odour sample

g pSampling Line

V Li

•The odour sample bag is placed in lung sampler with sampling line Vacuum Line

P

Lung sampler Lung sampler schematicschematic

sampling line attached•Vacuum pump empties lung sampler Pumpschematicschematicempties lung sampler•Odourous air drawn by vacuum to fill

l b Tedlar Bagsample bag

Rigid, Leak Proof Container

9

Odour Emissions for IWTP

491 345

600,000

491,345

400,000

500,000

/s)

300,000

,

on R

ate

(OU

/

200,000Emis

sio

18,904 20,560 16,89039,090

11,473

83,249

14,47914,480

100,000

0Pump

Station 18Pump

Station 1Pump

Station 2Lagoons Primary

TanksAeration

TanksSecondaryClarifiers

ActivatedSludge

Thickening

SludgeFiltration

House

10

Odour Emissions for SWTP3,000,000

2,567,8772,500,000

1,500,000

2,000,000

Rat

e (O

U/s

)

1,000,000Emis

sion

120,61113 2931 984 2 916 22 3081 996 7 561

500,000

13,2931,984 2,916 22,3081,996 7,5610

Pump Station# P4

EmergencyLagoons

Grit Removal PrimarySedimentation

Aeration Tanks SecondarySettlement

Tanks

Grit HouseScrubber @

DAF

DAF Scrubber

11

Dispersion ModellingAERMOD the USEPA preferred dispersion model• AERMOD, the USEPA preferred dispersion model, was used for modelling odour emissions

• The model used three years of hourly weather data• The model used three years of hourly weather data (i.e. wind speed & direction, temperature, humidity, etc.) from Jubail Industrial City gathered by the ) y g yRoyal Commission (from 2001 to 2003 inclusive)

• Maximum concentrations are based on worst-case meteorological conditions over the 3 modeled years

• One hour concentrations were converted to 10 minute averages

12

Dispersion Modeling• 20 x 20 km grid with receptors at 500m intervals• 1.8 x 1.8 km grid with receptors at 100m intervals

surrounding the facilities• 10 discrete receptors chosen based on impact on

id ti l & i d t i lresidential & industrial areas• IWTP and SWTP were modeled separately as the

odours from the plants are caused by differentodours from the plants are caused by different chemical groups i.e. VOC for IWTP & TRS for SWTP

13

Discrete and Grid Receptors IWTPIWTP #8 – primary source

of industrial odoursNumbered points are discretediscrete

receptors

14

IWTP Baseline ResultsDiscrete receptor

identifier (R1) & odour concentration at receptor

(12 OU/m3)

Results plotted are maximum concentrations

based on orst case(12 OU/m ) based on worst-case meteorological

conditions over the 3 modeled years

15

SWTP Baseline ResultsDiscrete receptor

identifier (R1) & odour concentration at receptor

(12 OU/m3)

Results plotted are maximum concentrations

based on worst-case (12 OU/m ) meteorological conditions over the 3

modeled years

16

Mitigation ScenariosIWTP Mitigation

1. Reduce number of aerated lagoons in operation & increase aerator depth& increase aerator depth

2. Re-commission existing odour control equipment at the IWTP pumping stations

3 C bi ti f S i 1 d 23. Combination of Scenarios 1 and 2SWTP Mitigation

1 Re-commission oxygen injection system prior to1. Re-commission oxygen injection system prior to primary settling tanks at the SWTP

2. Operate grit removal and screen house extraction t d d t l i t t thsystem and odour control equipment at the

SWTP in addition to the above scenario

17

Mitigation Scenarios - IWTP

100

Baseline Scenario 1 Scenario 2 Scenario 3

8090

100O

U/m

3)

506070

trat

ion

(O

304050

Con

cent

1020

Odo

ur C

0 1 2 3 4 5 6 7 8 9 10

Discrete Receptors

18

Mitigation Scenarios - SWTP

3000

Baseline Scenario 1 Scenario 2

2500

3000O

U/m

3)

1500

2000

trat

ion

(O

1000

1500

Con

cent

0

500

Odo

ur C

01 2 3 4 5 6 7 8 9 10

Discrete Receptors

19

Conclusions• In general the SWTP causes higher odour

concentrations than the IWTP• Implementation of mitigation for the IWTP would• Implementation of mitigation for the IWTP would

achieve odour reduction of approximately 50% at discrete receptorsp

• Implementation of mitigation for the SWTP would achieve odour reduction of approximately 90% at discrete receptorsdiscrete receptors

• As mitigations will not reduce odours enough, additional projects have been identified to reduceadditional projects have been identified to reduce odour causing chemicals in the wastewater

• A list of proposed action plans follows

20

Action Plans• Rehabilitation of HVAC & Odour Control Systems on

Support Industries Pump Stations• Re-commissioning of Ozone Systems at pump stationsg y p p• Installation of Odour Control Systems on 32 Lift Stations

in Community Area• Reduce number of aerated lagoons & submerge aerators• Reduce number of aerated lagoons & submerge aerators• Re-commission oxygen injection before PST’s at SWTP

#9 to remove H2S• Re-commission odour control system at SWTP #9• Implementation of IWW Violation Procedure to improve

control of wastewater dischargescontrol of wastewater discharges• Installation of On-line Analyzers in IWW Network to

monitor & control wastewater discharges

21

Action Plans (continued)• Re-commissioning of Odour Scrubbers in IWW Network

to reduce VOC emissions from pump stations• Audit of Oxygen Injection Systems in SWW Network to• Audit of Oxygen Injection Systems in SWW Network to

identify need for additional OCS• Perform Odour Survey after Installation of 32 Odour

Control Systems to identify• Investigation of NutriOx as alternate odour control

technology to oxygen injectiontechnology to oxygen injection• Detailed VOC Sampling & Analysis

22

Acknowledgements• Marafiq management for their support • RWDI/ Haif project team

23

Thank you24

Thank you