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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

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Cleanup of sewage lakes case studies in jeddah and riyadh

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

  • 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

  • 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

Received1500to 2000 tanker trucks/day

Up to 50,000 m3/day of sewage

Lake grew to 2.8 km2 in surface area


25 november 2009 flood highlighted major concerns associated with the sewage lake

25 November 2009 flood highlighted major concerns associated with the Sewage Lake


Project required rapid response

Project Required Rapid Response

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

  • 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

Characteristics of silty clay

~ 3-5 cm thick


Main lake sediment characteristics

Main Lake Sediment Characteristics


Lake characterization for main lake and secondary lake

Lake Characterization for Main Lake and Secondary 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

Open Water and Wetlands Ecosystem

Planted Forest

Upland Ecosystem


Sediment management recommended plan

Sediment Management Recommended Plan

  • 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

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 Sediments

Stratified Sediment Before Mixing

Topsoil Condition After Mixing

Tillage


Jeddah sewage lake cleanup status

Jeddah Sewage Lake Cleanup Status

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

  • 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

  • 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


Sediment mixing completed throughout the lake areas

Sediment mixing completed throughout the lake areas


Upper portion of former lake area being used for camel grazing

Upper Portion of Former Lake Area being used for Camel Grazing


Agenda2

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


Background on al nazeem lake

Background on Al-Nazeem Lake

  • 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

  • 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


Cleanup plan for sediments focused on characterization and onsite disposal

Cleanup Plan for Sediments focused on Characterization and Onsite Disposal


Char acterization results provided clear direction for cleanup

Characterization 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


Initial work focused on facilitating drainage and drying of sludge

Initial work focused on facilitating drainage and drying of sludge


Project clean up is nearing completion

Project Clean-up is Nearing Completion

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

  • 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 case studies in jeddah and riyadh

Cleanup of Sewage Lakes:Case Studies in Jeddah and Riyadh

Presentation to

National Water Company

Focus Day

7 December 2011


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