sewage sludge management in egypt_mohamed ghazy

Institut of Sanitary and Environmental EngineeringTechnische Universität Braunschweig, Germany

Msc. Eng. Mohamed GhazyMsc. Eng. Mohamed Ghazy

E-Mail: [email protected]

Institute of Institute of SanitarySanitary and and EnvironmentalEnvironmental Engineering EngineeringTechnische Universität Braunschweig, GermanyTechnische Universität Braunschweig, Germany

Prof. Dr.-Ing. N. Dichtl Prof. Dr.-Ing. N. Dichtl

Sewage Sludge Management in Egypt:Sewage Sludge Management in Egypt:

Current Status and Perspectives Towards a Current Status and Perspectives Towards a

Sustainable Agricultural UseSustainable Agricultural Use

DAAD International Workshop for Water, Wastewater and the Environment-Urgent Issues for Sustainability (26th October – 3rd November 2009), Braunschweig, Germany.


PopulationPopulation: Tripled during the last 50 years.

80 million, year 2008, Annual growth rate 1.75 % More than 13 million tourists/year+

IntroductionIntroduction

ClimateClimate: : A desert climate, hot and dry most

of the year.

With the rapidly growing population and

industrial development, the wastewater and

sewage sludge generation has been also

increased.

The Egyptian sanitation sector is facing

many difficulties to manage this wastewater

and sewage sludge, Which require huge

investments currently are above the

presently available national resources.CapitalCapital: Cairo

CairoCairo

Current population 17 million, producing

more than 5 million m3/day of wastewater.

AreaArea: 1 million km2

Only 5% occupied by population along the

Nile Valley and Delta.


Wastewater Services Coverage in Wastewater Services Coverage in EgyptEgypt

Rural (4700 villages)

57%

Urban (217 cities)

43%

Cover60%

Not cover40%

Urban Areas

About 60 % are covered by wastewater collection

and treatment facilities, and planning to cover

100 % with 2020.

Urban AreasUrban Areas

Cover15%

Not cover85%

Rural Areas

Only 15 % are covered by wastewater collection

and treatment facilities.

The other using Septic tank or disposal the

wastewater direct to water bodies.

Rural AreasRural Areas

It is required more than 100 Billion US$ to cover 100 % of Rural and Urban

areas


Wastewater Treatment Plants in Wastewater Treatment Plants in EgyptEgypt

Systems of Wastewater Treatment Systems of Wastewater Treatment

Capacities of WWTPsCapacities of WWTPs Total No of WWTPs: 303, Total Treatment Capacity: 12 million m3/day

More than 78 % of WWTPs is relatively small (< 30x103 m3/day) representing 22 % of total treatment capacity.

Scales of WWTPs, and amount of sludge generation in Egypt, year 2008_

Activated Sludge Systems:

Conventional Activated Sludge Conventional Activated Sludge SystemsSystems

Oxidation DitchOxidation Ditch Systems Systems

Mainly conventional and oxidation ditch

systems and representing about 63 % of the

total WWTPs capacity and treating about 7.5

million m3/day.

Representing about 12 % of WWTPs No. and 2.25

% of Treatment capacity (0.3 million m3/day). Preliminary Preliminary TreatmentTreatment

InfluentInfluent

Excess sludgeTo sludge treatment facilities

EffluentEffluent

Oxidation Oxidation PondsPonds

Preliminary Preliminary TreatmentTreatment

InfluentInfluent

Excess sludgeTo sludge treatment facilities

EffluentEffluent

Oxidation Oxidation PondsPonds

Oxidation Pond SystemsOxidation Pond Systems

Oxidation Pond Systems:


The Applied The Applied Scenarios Scenarios for Sludge Treatment for Sludge Treatment and Disposal and Disposal in in EgyptEgypt

Type of WWTPsType of WWTPs

Oxidation Ponds

Conventional Activated Sludge

Trickling Filter

Agricultural ReuseGravity Thickener

The thickened sludge solids concentration:4-6% DS

Natural Dewatering

The solids concentration after drying beds is 40-60

%.

The dewatering time is usually 25 days in summer

and 40 days in winter.

Drying Area

Storage period of 1.5 to 6 months according to the

weather and available stacking area before using in

agriculture

Stabilisation Pond

Primary Treatment

UASB

It is noted that, this scenario of sludge treatment does not contain facilities

for stabilization processes. Moreover, the quality of the produced sludge in

most of the WWTPs doesn’t fit the Egyptian or international standards,

especially pathogens limits.


Recently Applied Recently Applied Scenarios: Scenarios: Anaerobic digestionAnaerobic digestion (Al Gabel Asfer WWTP- Cairo)(Al Gabel Asfer WWTP- Cairo)

GravityGravity thickeningthickening

Phase I: 16 Thickeners with volume of 3,200 m3

Phase II: 3 with volume of 2,500 m3

Thickened sludge: 12,500 m3/day, Conc. 4 % DS

Mechanical dewateringMechanical dewatering

Phase I: 30 belt filter press units with a capacity of 23 m3/hr each

Phase II: 12 units with a capacity of 21 m3/hr each

Solid concentration : 23-30 % ; Polymers dose: 4 kg/ton DS Drying areaDrying area

Stacking area: 54 hectares

Solid concentration : 40-60 % Then it transferred to use in agriculture

Al Gabel Asfer WWTPAl Gabel Asfer WWTPCurrent capacity:1.8 million m3/day, Total area: 630

hectares

First stageFirst stage: Started operation: October 1998

Capacity: 1.2 million m3/day (actual), Cover : 12 million capita

Second stage:Second stage: Started operation: 2004

Capacity:0.5 million m3/day, Cover : 2.5 million capita

Future Stage: Future Stage: Will start operation: 2020

Capacity:1.5 million m3/day (Total capacity 3 million

m3/day).

It will be the largest WWTP in the World

First stage1200*103 m3/day

Second stageSecond stage540540**101033 mm33/day/day

Sludge treatment facility

Future extension 1500 x103 m3day

Sludge Treatment ScenarioSludge Treatment Scenario

Anaerobic digestionAnaerobic digestion

Primary digesters

Phase I: 20 digesters with volume of 11,000 m3


Retention time: 20 days Secondary digesters Phase I: 10 digesters with volume of 7,500 m3


Retention time: 7 days


Amount of sludge

3000-4000 m3 /day, conc. 2-3 %

No. 2, Capacity 900 m3

Retention time: 7-9hr

Blower capacity: 800 m3/hr

Mechanical Dewatering SiteAmount of produced sludge:

(400 tons/day, conc. 25-30%)

No of Machines: 12 Belt filter Presses

Belt width: 2 m, Capacity:700-900 m3/day

Destination of Disposal (9 N) site at distance 45 kmSludge Treatment ScenarioSludge Treatment Scenario

Mechanical Dewatering

Agricultural ReuseCompostingPrimary Treatment

WWTPs, Alexandria (9 N Site)

Recently Applied Recently Applied Scenarios: Scenarios: Windrow compostingWindrow composting (9 N site – Alexandria)(9 N site – Alexandria)

WWTPs in AlexandriaWWTPs in Alexandria

West WWTPCapacity: 360x103 m3/day (actual).

Start of operation: 1993 (prim. treatment)

Amount of sludge: 3,100-4,000 m3/day, conc. 3.5-6%

East WWTPCapacity: 600x103 m3/day (actual)

Start of operating: 1990 (prim. treatment)

Amount of sludge: 3000-4000 m3/day, conc. 2-3 %

Others: 6 WWTPs, (Sec. treatment) Total treatment capacity107 x103 m3/day.


Mixing with bulking agent

Stabilization stage

Active composting stageActive composting stageComposting time: 2 monthsMixing and aeration: 3 times/day (3 days), Every 15

daysOperating temperature: 55-65 °C

Mentoring and temperature control

Curing stage

Curing stageCuring stageCuring time: 1 monthMoisture content : 10-25%

Composting ProcessComposting Process

Start of operating: 1997

Site area: 1.5 Km2

Ground water depth: 60 m

Distance from nearest residential area: 6 km

(9N) site(9N) site::

Windrow formationWindrow formationNo. of windrows: 60Dimension of each: (250 m, 3.5 m, 1.5 m)Bulking agent: recycle compost, Bulking ratio: 1:1.5Moisture content : (40 to 50%) Dump the raw dry sludge

Cover the raw sludge by old compost

Capacity of Produced CompostCapacity of Produced Compost

YearReciving sludge Produced compost

2005 82000 290002006 109000 390002008 129000 46000

(m3/year) (m3/year)

(9 N) site – (9 N) site – AlexandriaAlexandria


Gravity thickenersNo of thickeners : 8Diam: 25 m,depth: (4-6.5m)Amount of thickened sludge5000 m3/day, Conc. 5-6 %

Shobera WWTPTreatment Capacity: 600 x 103 m3/day 3.0 million capitaAmount of sludge4700 m3/day,Conc.3%

AL Berka WWTPTreatment Capacity:

600 x 103 m3/day(design)

4.0 million capitaAmount of sludge5700 m3/day,Conc. 2 %

Drying beds Total area: 210 hectaresNo of Beds: 96Dim. 125 x 64 x 2 mDrying time: (25-40 days)Amount of dry sludge450 m3/day (220 tons/day), Conc. 35-50 %

2 force main diam. 350

mm

Distance: 3 km

Al Berka compost project

Recently Applied Recently Applied Scenarios: Scenarios: Windrow compostingWindrow composting (AL Berka pilot project-Cairo)(AL Berka pilot project-Cairo)

Sludge treatment scenario in Al Berka Sludge treatment scenario in Al Berka WWTP WWTP

Gravity Thickener

Al Berka&Shobera WWTPs

Drying beds

Al Berka

Composting

(pilot project)

Agricultural Reuse70 %

30 %


Composting ProcessComposting Process

Al Berka Pilot Compost Al Berka Pilot Compost ProjectProjectStarted operating: 2007

Investment costs: 3.5 million US$

Raw sludge: 140 m3/day, Site area: 2.6 Ha

Capacity of compost: 25,000 tons/year

Windrow formationWindrow formationNo. of windrows: 26, Dimension of each: (100 m, 3 m, 1.5 m)

Bulking agent: recycle compost and rice straw

Bulking ratio: 4 parts raw sludge (25% DS):1 old compost (60%

DS):1 shredded rice straw (85% DS),

Moisture content : (40 to 50%)

Cover the raw sludge by rice straw

Rice straw shredding

Windrow formation

Mixing with bulking agent

Active composting stageActive composting stageComposting time: 2 months

Mixing and aeration: 3 times (first), Every 15 days

Operating temperature: 55-65 °C

Aeration and temperature control

Stabilization stage Curing stageCuring stageCuring time: 1-2 monthMoisture content : 10-30%

Curing stage

Screening and bagging stage

Municipal Future PlanningMunicipal Future Planning

The project may be expanded to a full-scale project to produce a compost of 250,000 tons/year from the dried sewage sludge accumulated from Al Berka, Shobera and Al Gabel Asfer WWTPs

AL Berka pilot project- AL Berka pilot project- CairoCairo


Sewage Sludge Production Sewage Sludge Production in in EgyptEgypt

Based on Egyptian BOD and TSS concentrations and taking the effect of Temp. from (10-30 °C) and sludge age (5-20 days)

German standards (ATV A 131E ): The production rate ranged from 0.20 to 0.28 kg/m3 of treated sewage.

Metcalf & Eddy (2003): It ranged from 0.11 to 0.21 kg/m3 of treated sewage.

According to According to theoretical calculationtheoretical calculation

According to the NOPWASD and HCWW dataAccording to the NOPWASD and HCWW data

The total current capacity of treated sewage: 12 million m3/day.The dry sludge production was estimated to 5.8x103 tons/day The sludge production rate: 0.48 kg/m3 of treated sewage (which seems relatively high compared to many

other typical values: USA (0.2-0.3 kg/m3 ); Metcalf & Eddy (0.18 -0.27 kg/m3 ); China was 0.21 kg/m3

Estimation the reliable amount of produced dry sludgeEstimation the reliable amount of produced dry sludge

The dry sludge production rate from the activated sludge systems in Egypt is considered at 0.22 kg/m3

The production rates from the others WWTP types are assumed at 0.05-0.22 kg/m3 according to the literatures

The estimated dry sludge produced from all WWTPs in Egypt, 2008

Activated Sludge 97 0.225 6,703 1,508 2,793Oxidation Ditch 47 0.225 833 187 347Trickling Filter 9 0.22 291 64 119Extended Aeration 17 0.1 170 17 31Oxidation Ponds 35 0.05 266 13 25Aerated Lagoon 4 0.1 197 20 36Primary Treatment 22 0.15 2,021 303 561Others* 72 0.2 1,372 274 508Total 303 11,853 2,387 4,421

Estimated dry sewage sludge

(50 % DS)

Capacity of treated

wastewater 103 m3/day

Type of WWTPsNo of WWTPsSludge

production rate(kg/m3)

Amount (tons/day)

Volume (m3/day)

The estimated amount of produced dry sludge from Egyptian's WWTPs are about 2.4 x103 tons/day.


Sewage Sludge Agronomic Value Sewage Sludge Agronomic Value

Sewage sludge monetary valueSewage sludge monetary value

Theoretically, the monetary values of the resources contained in sewage sludge can be evaluated according to the current price of these relevant resources in the commercial market.

Egyptian market price

USA Market price

(US$/kg) (US$/kg)Nitrogen (N) 0.76 1.61

Phosphorus (P) 2.23 4.91Potassium (K) 0.43 0.94Organic matter 0.015 0.044

Resourses

The monetary values for the relevant resources in dry sludge

Assume: The average retail price of electricity in USA, 2008 was 10.13 Cent/kWh and in Egypt 3.4 Cent/kWh and the exchange rate used in 2008 was US$ = 5.76 LE (Egyptian pound)

The economic values of the N, P and K resources can be calculated according to the market prices of these elements in the commercial inorganic fertilizers.

The monetary values of the organic matter can be estimated according to the market price of the generated electricity during the anaerobic digestion stabilization.

Nutrients contentNutrients content

The agronomic value of sewage

sludge depends on its nutrients

content, trace elements and organic

matter content

Concentration of nutrient resources in the dried sludge in Egypt’s WWTPs

Field study, 2008 57 3.16 1.13 0.28AFESD, 2007 61 3.13 0.65 0.19IIP, 2002 No data 2.4 0.55 0.3NOPWASD, 2000 61 4.11 1.6 0,55METAP, 1999 45 1.7 0.8 0.3

Average 56 2.90 0.95 0.32

Potassium (K) %

ReferenceTotal organic mater (OM)

%

Total nitrogen (TKN) %

Total Phosphorus

(P) %

The price of dry sewage sludge in the international and Egyptian market

Kg/ton kg/m3 US$/ton US$/m3 US$/ton US$/m3

Nitrogen (N) 2.9 29 15.7 22.0 11.9 46.7 25.2Phosphorus (P) 0.95 9.5 5.1 21.2 11.4 46.6 25.2Potassium (K) 0.32 3.2 1.7 1.4 0.7 3.0 1.6Organic matter 56 560 302.4 8.4 4.5 24.64 13.3

Total 53 28.5 121 65.3

ResourcesAverage

content %

Amount of relevant resources

Monterey valueEgyptian market USA market The theoretical price of

sewage sludge according to its resources price in Egyptian market is 28 US$/m3

or 53 US$/ton.


Options of beneficial uses of sewage sludge Options of beneficial uses of sewage sludge

1. Agriculture Reuse 1. Agriculture Reuse Soil ConditionerOrganic Fertilizer

Cement Industrial Construction Materials3. Construction materials3. Construction materials

4. Phosphorus recovery4. Phosphorus recovery

Phosphors

2. Energy recovery2. Energy recovery Electricity GenerationHeat Generation


Potential uses of sewage sludge inPotential uses of sewage sludge in

Egypt Egypt

Egypt is an arid country, the dessert represents more than 95% of the total area.

Only 5 % of Egypt area occupied by overpopulation in the limited strip of the Nile valley and Delta.

Nile valley

Delta

950

500380

0

100

200

300

400

500

600

700

800

900

1000

1960 1996 2017

Year

m2 /

Ca

pit

a

Change of the cultivated land per capita in Egypt

The sharp decline of the per capita cultivated land will also reduce the per capita crop production.

An important issue for Egyptian agricultural policy is to redistribute the population over a larger area


Expansion of reclamation desert Expansion of reclamation desert land land Over the last 30 years, More than 3.3 million acres have

been reclaimed and that will be increased in the future.

About 170,000 acres are reclaiming yearly (the

South Valley Development Project about 1 million acres

until 2020)

South South valley development development projectproject

Soil conditions of the reclaimed Soil conditions of the reclaimed landland Often saline, mild to moderately alkaline (pH 7.7 -

8.2).

Micronutrient elements shortage are common,

particularly manganese, iron and zinc, which are

required for plant growth and are present in sludge.

Calcareous soils limit crop uptake of heavy metals

and potential toxicity.

Extensive sunshine exposure, high temperature,

and dry conditions, Which provide unfavorable

conditions for survival of microbial pathogens

Beneficial use of sewage sludge in Beneficial use of sewage sludge in EgyptEgypt (Potential demand of sewage sludge in agriculture)(Potential demand of sewage sludge in agriculture)


Beneficial use of sewage sludge in Beneficial use of sewage sludge in EgyptEgypt (Sewage sludge market )(Sewage sludge market )

Sewage sludge market price Sewage sludge market price

The current sale price of dry sludge in Egyptian market ranges from 1.5-11

US$/m3. This price of the other organic fertilizer are about 17 US$/m3.

The target price of treated dry sewage sludge is estimated by 12 US$/m3.

This price has still a proper competition margin up to 5 US$/m3 less than other

organic fertilizers and less than the estimated theoretical price of sewage sludge by

16 US$/m3 .

Potential market demand Potential market demand

The recommended application rate of dry sewage sludge in Egypt: 8 - 20 m3

DS/acre/year for arable crops.

The current dry sludge production represent only less than 5 % of the actual

demand of the target market (the reclaimed desert land only).

The target market: New reclaimed desert land, which can be considered more

preferably for sludge application, hence the supply of sludge more practical,

safe and any input of organic matter will improve the soil properties.


ConclusionConclusion

The use of sewage sludge in agriculture in Egypt may offer the most sustainable and

beneficial use of sewage sludge under Egyptian conditions. Also, it may offer the

most economical route for sludge disposal because the Egyptian farmers are

prepared to pay for any source of organic fertilizers.

The treated sewage sludge has a good potential demand in the Egyptian market. The

target price of municipalities is estimated at 12 US$/m3 of dry sludge (it will provide a

yearly income about 19 million US$, which represents more than 30 % of the

operation and maintenance costs of all Egyptian WWTPs).

The sewage sludge production is continuously increasing in Egypt. Therefore, the

main currently pressing needs are to find/develop more efficient and more

sustainable technologies to allow a safe and suitable reuse of sewage sludge in

agriculture. Recently, the application of the anaerobic digestion technology for sludge

stabilization and power generation in Al Gabelb Asfer WWTP and the windrow

composting processes in (9N) site and Al Berka WWTP have achieved good results.

There is a growing interest in using such technologies on large scale in the future.


Thank youThank you

??

sewage sludge management in egypt_mohamed ghazy

Documents

m3day of wastewater

m3day total capacity

total treatment capacity

scenario of sludge treatment

stage m3day

stage capacity

total wwtps capacity

produced sludge