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Cleanup of Sewage Lakes: Case Studies in Jeddah and Riyadh. Presentation to National Water Company Forum Day 7 December 2011. Agenda. Ba ckgro und Jeddah Sewage Lake Drivers and project overview Recommended plan Clean-up Completion Al- Nazeem Sewage Lake (Riyadh) Project overview

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Cleanup of Sewage Lakes:Case Studies in Jeddah and Riyadh

Presentation to

National Water Company

Forum Day

7 December 2011


Agenda
Agenda

  • Background

  • Jeddah Sewage Lake

    • Drivers and project overview

    • Recommended plan

    • Clean-up Completion

  • Al-Nazeem Sewage Lake (Riyadh)

    • Project overview

    • Sediment management

    • Clean-up status

  • Project’s Benefits


Wastewater infrastructure has not kept pace with growth demands in saudi arabia
Wastewater Infrastructure has not kept pace with Growth Demands in Saudi Arabia

  • Septage issues in nearly all Cities

    • ~50 % of population served by central collection systems

    • Country-wide issue that is independent of city size


Sewage lakes are common in middle east and saudi arabia
Sewage Lakes are Common in Middle East and Saudi Arabia Demands in Saudi Arabia

  • No inventory available for sewage lakes

  • Jeddah

    • Only 6 percent of municipal planning area is currently sewered

    • ~140,000 m3/day hauled by tanker trucks

  • Riyadh

    • ~50 percent of population on central collection system

  • Wastewater pumped from cesspits and trucked to sewage lake

    • Air pollution from trucks

    • Significant energyinvestment in trucking


Agenda1
Agenda Demands in Saudi Arabia

  • Background

  • Jeddah Sewage Lake

    • Drivers and project overview

    • Recommended plan

    • Clean-up Completion

  • Al-Nazeem Sewage Lake (Riyadh)

    • Project overview

    • Sediment management

    • Clean-up status

  • Project’s Benefits


Jeddah sewage lake created in mid 1990s
Jeddah Sewage Lake Created in Mid- 1990s Demands in Saudi Arabia

Received1500to 2000 tanker trucks/day

Up to 50,000 m3/day of sewage

Lake grew to 2.8 km2 in surface area



Project required rapid response
Project Required Rapid Response with the Sewage Lake

July 25, 2010

October 2, 2010

  • May 2010

    • Custodian of the Two Holy Mosques King Abdullah bin Abdulaziz issued a royal decree ordering that the hazardous Sewage Lake be emptied within 1 year

    • NWC took responsibility for the project

  • June 2010

    • NWC hires Lake Contractor

  • July 2010

    • Water evacuation efforts initiated

    • Planning consultant hired

  • October 2010

    • Lake Evacuation completed

  • November 2010 to July 2011

    • Sediment clean-up


Planning to evaluate environmental effects and alternatives for jeddah sewage lake
Planning to Evaluate Environmental Effects and Alternatives for Jeddah Sewage Lake

  • Flood Management

    • Removal of the Sewage Lake Dam

  • Water Management

    • Evacuation of the Lake

    • Water Use and Agricultural

      Activities

  • Sediment Management

    • Characterization

    • Treatment/Management

      alternatives

  • Regulatory Requirements

  • Mitigation Needs

  • Recommended Plan

  • Plan Supervision


Lake sediment volume update
Lake Sediment Volume Update for Jeddah Sewage Lake

  • Additional sediment depth sampling points

    • 125 measurements

  • Sediment depths

    • Main Lake – <0.5 m

    • West Lake - <1.2 m

  • Sediment volume

    • Main Lake

      • 300,670 m3

    • West Lake

      • 84,724 m3

  • Total Volume = 385,000 m3


Lake sediment characteristics
Lake Sediment Characteristics for Jeddah Sewage Lake

Characteristics of silty clay

~ 3-5 cm thick


Main lake sediment characteristics
Main Lake Sediment Characteristics for Jeddah Sewage Lake


Lake characterization for main lake and secondary lake
Lake Characterization for Main Lake and Secondary Lake for Jeddah Sewage Lake

  • Main Lake Data

    • Data indicated meeting KSA criteria for agricultural use of sludge and US EPA “Exceptional Criteria”

    • A few sites with elevated petroleum hydrocarbons

  • Secondary Lake

    • Showed sediments also met KSA and EPA Criteria

    • Did show general contamination by petroleum hydrocarbons


Sewage lake ecological features
Sewage Lake - Ecological Features for Jeddah Sewage Lake

Open Water and Wetlands Ecosystem

Planted Forest

Upland Ecosystem


Sediment management recommended plan
Sediment Management Recommended Plan for Jeddah Sewage Lake

  • Continued drying of sediments

    • Use mineral material as a drying agent

    • Sample new areas as can be accessed

  • Mix thinner sediments in place

    • When sufficiently dry

  • Excavate thicker sediments

    • Spread in upper areas of the Main lake with thin deposits

  • Mix sediments that have been spread

  • Conduct “Site Release Sampling Plan”

    • Verification of site safety

  • Excavate sediment material littered with trash from former conveyance channel and dispose at a land fill


On site mixing of organic sediments
On-Site Mixing of Organic Sediments for Jeddah Sewage Lake

Stratified Sediment Before Mixing

Topsoil Condition After Mixing

Organic Sediment

<50% Organic Matter

~0.75 g/cc

Mixed Topsoil

<25% Organic Matter

~1.0 g/cc

20 cm

30 cm

Tillage

Mineral Soil

<1% Organic Matter

~1.5 g/cc

10 cm

Subsoil

Subsoil


On site mixing of organic sedimen ts
On-Site Mixing of Organic Sedimen for Jeddah Sewage Lakets

Stratified Sediment Before Mixing

Topsoil Condition After Mixing

Tillage


Jeddah sewage lake cleanup status
Jeddah Sewage Lake Cleanup Status for Jeddah Sewage Lake

29 March 2011

  • October 2010

    • Lake Evacuation completed

  • November - December

    • Sediment drying and mixing activities

    • Additional sediment characterization

  • December-February 2011

    • Completion of report documentation

    • Additional rainfall events partially refilling the lake to ~2m depth

  • March – August 2011

    • Pumping to evaporation ponds

    • Continued sediment drying and mixing activities

    • Completed site release sampling


Site release sampling completed
Site Release Sampling Completed for Jeddah Sewage Lake

  • Lake evacuation

    • Delayed because of availability of pumps

    • Started in March 2011

    • Completed in May 2011

  • Sampling grid

    • Final grid included 205 cells

    • Thick vegetation along margins prevented sampling of infrequently flooded areas


Summary of results
Summary of Results for Jeddah Sewage Lake

  • Total Organic Carbon – low levels indicating sediments are stable

  • Metals –maximum values <12% of criteria

  • Microbiological

    • Fecal Coliform – Maximum value of 24 MPN/g versus standard of 1000 MPN/g

    • Parasite eggs – None detected

  • Petroleum Hydrocarbons

    • Only 3 sites showed some values exceeding levels of 2000 mg/kg for Total Petroleum Hydrocarbons

    • Additional mixing and re-sampling significantly reduced levels

      Cleanup plan was executed and site release sampling demonstrated site was safe for turnover back to the municipality




Agenda2
Agenda Grazing

  • Background

  • Jeddah Sewage Lake

    • Drivers and project overview

    • Recommended plan

    • Clean-up Completion

  • Al-Nazeem Sewage Lake (Riyadh)

    • Project overview

    • Sediment management

    • Clean-up status

  • Project’s Benefits


Background on al nazeem lake
Background on Al-Nazeem Lake Grazing

  • Lake has been used for approximately 20 years

  • Received

    • 1000 to 1500 trucks per day

    • ~20,000 to 30,000 m3/day

  • Mixture of Domestic and Industrial Waste

    • Domestic waste eliminated in January 2011

    • Industrial waste eliminated in Mid-May 2011


Lake cleanup focus
Lake Cleanup Focus Grazing

  • Lake area is ~3.5 km2

  • When cleanup began in June/July 2011 – very little water remained

  • Cleanup focus

    • Sludge characterization

    • Sludge drying

    • Sludge treatment

  • Lake are divided into 4 zone with 39 separate lakes



Char acterization results provided clear direction for cleanup
Char Onsite Disposalacterization Results Provided Clear Direction for Cleanup

  • Characterization focus

    • Metals

    • Microbiological indicators

    • Petroleum hydrocarbon fractions

    • Volatile and Semi-volatile compounds

  • Results

    • Zones 3 & 4 – no results exceed criteria

    • Zones 1 & 2

      • Metals and hydrocarbon issues at several locations



Project clean up is nearing completion
Project Clean-up is Nearing Completion sludge

Clean-up has involved excavation, mixing and combining with clean sand

Lake contractor is conducting verification sampling

Upon completion – site release sampling will be conducted by an independent laboratory


Agenda3
Agenda sludge

  • Background

  • Jeddah Sewage Lake

    • Drivers and project overview

    • Recommended plan

    • Clean-up Completion

  • Al-Nazeem Sewage Lake (Riyadh)

    • Project overview

    • Sediment management

    • Clean-up status

  • Project’s Benefits


Sewage lake clean up projects address public health and aesthetic issues
Sewage Lake Clean-up Projects Address Public Health and Aesthetic Issues

NWC Efforts have eliminated two long standing health hazards

Detailed investigations have led to environmentally sensitive solutions

Jeddah Lake project recognized with GLOBAL WATER INTELLIGENCE Reuse Project of the Year (reuse of sludge to enhance soils)


Cleanup of Sewage Lakes: Aesthetic IssuesCase Studies in Jeddah and Riyadh

Presentation to

National Water Company

Focus Day

7 December 2011


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