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
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Wastewater FacilitiesIndustrial Wastewater Treatment Plant
Capacity – 60 000 m3/d
Sanitary Wastewater Treatment PlantCapacity 72 000 m3/dCapacity – 72 000 m3/d
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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Discrete and Grid Receptors IWTPIWTP #8 – primary source
of industrial odoursNumbered points are discretediscrete
receptors
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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
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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
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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
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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
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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
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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
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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
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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
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Acknowledgements• Marafiq management for their support • RWDI/ Haif project team
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Thank you24
Thank you