Sewage Sludge Management In Egypt_mohamed Ghazy

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

Sewage Sludge Management in Egypt: Current Status and Perspectives Towards a Sustainable Agricultural Use Msc. Eng. Mohamed Ghazy E-Mail: [email protected]

Institute of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany Prof. Dr.-Ing. N. Dichtl

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Introduction Population:

Tripled during the last 50

years.

+

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

Capital : available Cairo national resources. presently

 Current population 17 million, producing more than 5 million m3/day of wastewater.

Area:

1 million km2

 Only 5% occupied by population along the Nile Valley and Delta.

Climate: A desert climate, hot and dry most of the year. Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Cairo

Wastewater Services Coverage in Egypt Urban Areas



Urban (217 cities)

About 60 % are covered by wastewater collection and treatment facilities, and planning to cover

43%

100 % with 2020.

Rural Areas



Only 15 % are covered by wastewater collection

57%

and treatment facilities.



Rural (4700 villages)

The other using Septic tank or disposal the wastewater direct to water bodies.

Cover 15% Not cover 40%

Urban Areas

Cover 60%

Not cover 85%

Rural Areas

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

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Wastewater Treatment Plants in Egypt Capacities 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_

Systems of Wastewater Treatment



Activated Sludge Systems: Mainly conventional and oxidation ditch Conventional Activated Sludge Systems

systems and representing about 63 % of the total WWTPs capacity and treating about 7.5 million m3/day.

 Oxidation Pond Systems:

Oxidation Ditch Systems

Representing about 12 % of WWTPs No. and 2.25 % of Treatment capacity (0.3 million m3/day).

Pr eliminary re Tre reatment

Oxidation Ponds

Influent

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

To sludge treatment facilities

Effluent Excess sludge

Oxidation Pond Systems

The Applied Scenarios for Sludge Treatment and Disposal in Egypt Type of WWTPs

Conventional Activated Sludge

Gravity Thickener

Natural Dewatering

Drying Area

Agricultural Reuse

Oxidation Ponds

Trickling Filter

 

The thickened sludge solids concentration:4-6% DS The solids concentration after drying beds is 40-60 %.

 

Primary Treatment Stabilisation Pond

The dewatering time is usually 25 days in summer Storage period of 1.5 to 6 months according to the and 40 days in winter. weather and available stacking area before using in

UASB

agriculture



It is noted that, this scenario of sludge treatment does not contain facilities for stabilization processes. Moreover, the quality of the produced sludge in

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

most of the WWTPs doesn’t fit the Egyptian or international standards, especially pathogens limits.

Recently Applied Scenarios: Anaerobic digestion (Al Gabel Asfer WWTP- Cairo) Al Gabel Asfer WWTP Current capacity:1.8 million m3/day, Total area: 630 hectares First stage: stage Started operation: October 1998 Capacity: 1.2 million m3/day (actual), Cover : 12 million capita Second stage: Started operation: 2004 Capacity:0.5 million m3/day, Cover : 2.5 million capita Future Stage: Will start operation: 2020 Capacity:1.5 million m3/day (Total capacity 3 million m3/day).

Sludge Treatment Scenario

Second stage m3/day 103*54 0

First stage m3/day 103*12 00

Future extens ion 1500 x10 3 m 3da y

Sludge treatm ent facility

It will be the largest WWTP in the World Gravity thickening Mechanical dewatering Phase I: 16 Thickeners with volume of 3,200 Phase I: 30 belt filter press units with a capacity of 23 m3/hr m3 each Phase II: 3 with volume of 2,500 m3 Phase II: 12 units with a capacity of 21 m3/hr each 3 Thickened sludge: 12,500 m /day, Conc. 4 % Solid concentration : 23-30 % ; Polymers dose: 4 kg/ton DS DS digestion Anaerobic Drying area Stacking area: 54 hectares Primary digesters 3 Solid concentration : 40-60 % Then it transferred to use in Phase I: 20 digesters with volume of 11,000 m agriculture 3 Phase II: 8 with volume of 10,000 m Retention time: 20 days Secondary digesters Phase I: 10 digesters with volume of 7,500 m3 Phase II: 2 with volume of 9,000 m3 Retention time: 7 days

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

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



East WWTP

Capacity: 600x103 m3/day (actual) Start of operating: 1990 (prim. treatment) Amount of sludge: 3000-4000 m3/day, conc. 2-3 %



West WWTP

300

% ge lud c. 2-3 s f o n o t y, c ou n Am m3 /da 0 00 0 -4

Capacity: 360x103 m3/day (actual). Start of operation: 1993 (prim. treatment) Amount of sludge: 3,100-4,000 m3/day, conc. 3.5-6%



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

No. 2, Capacity 900 m3 Retention time: 7-9hr Blower capacity: 800 m3

Destination of Disposal (9 N) site at distance 45 km

Sludge Treatment Scenario

(9 N Site)

WWTPs, Alexandria

Primary Treatment

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Mechanical Dewatering

Composting

Agricultural Reuse

(9 N) site – Alexandria (9N) site: Start of operating: 1997 Site area: 1.5 Km2 Ground water depth: 60 m Distance from nearest residential area: 6 km

Composting Process Windrow formation

No. of windrows: 60 Dimension of each: (250 m, 3.5 m, 1.5 m) Bulking agent: recycle compost, Bulking ratio: 1:1.5 Moisture content : (40 to 50%)

Dump the raw dry sludge

Active composting stage

Composting time: 2 months Mixing and aeration: 3 times/day (3 days), Every 15 days Operating temperature: 55-65 °C

Curing stage

Cover the raw sludge by old compo Mixing with bulking agent

Curing time: 1 month Moisture content : 10-25%

Capacity of Produced Compost Year 2005 2006 2008

Reciving sludge Produced compost (m3/year)

(m3/year)

82000 109000 129000

29000 39000 46000

Stabilization stage Mentoring and temperature control

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Curing stage

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

Drying beds

No of thickeners : 8 Diam: 25 m,depth: (46.5m) Amount of thickened sludge 5000 m3/day, Conc. 5-6 % 50

Total area: 210 hectares No of Beds: 96 Dim. 125 x 64 x 2 m Drying time: (25-40 days) Amount of dry sludge 450 m3/day (220 tons/day), Conc. 35-50 %

. iam d n ai em orc mm km f 2 :3 nce a t s Di

3

AL Berka WWTP Treatment Capacity: 600 x 103 m3/day(design) 4.0 million capita Amount of sludge 5700 m3/day,Conc. 2 %

Al Berka compost project

Sludge treatment scenario in Al Berka WWTP Al Berka&Shobera WWTPs

Al Berka (pilot project) 30 %

Drying beds Composting

Shobera WWTP 70 % Gravity Thickener Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Agricultural Reuse

Treatment Capacity: 600 x 103 m3/day 3.0 million capita Amount of sludge 4700 m3/day,Conc.3%

AL Berka pilot project- Cairo Al Berka Pilot Compost Project Started operating: 2007

Rice straw shredding

Investment costs: 3.5 million US$ Raw sludge: 140 m3/day, Site area: 2.6 Ha Capacity of compost: 25,000 tons/year Windrow formation

Composting Process Windrow formation

Cover the raw sludge by rice straw

No. 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%)

Active composting stage

Mixing with bulking agent

Aeration and temperature control

Composting time: 2 months Mixing and aeration: 3 times (first), Every 15 days Operating temperature: 55-65 °C

Curing stage

Stabilization stage

Curing time: 1-2 month Moisture content : 10-30%

Municipal 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 Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Curing stage

Screening and bagging stage

Sewage Sludge Production in Egypt According 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

According to theoretical calculation 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/m of treated sewage. Estimation the reliable amount of produced dry sludge 3

 The dry sludge production rate  

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

from the activated sludge systems in Egypt is considered at Type of WWTPs 0.22 kg/m3 The production rates from the others WWTP types are assumed at 0.05-0.22 kg/m3 according to Activated Sludge the literatures The estimated amount of produced dry sludge from Egyptian's WWTPs are about 2.4 x103 tons/day. Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Oxidation Ditch Trickling Filter Extended Aeration Oxidation Ponds Aerated Lagoon Primary Treatment Others* Total

No of WWTPs

97 47 9 17 35 4 22 72 303

Sludge production rate(kg/m3)

0.225 0.225 0.22 0.1 0.05 0.1 0.15 0.2

Capacity of treated wastewater 103 m3/day 6,703 833 291 170 266 197 2,021 1,372 11,853

Estimated dry sewage sludge (50 % DS) Amount (tons/day)

Volume (m3/day)

1,508 187 64 17 13 20 303 274 2,387

2,793 347 119 31 25 36 561 508 4,421

Sewage Sludge Agronomic Value Nutrients content

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

The agronomic value of sewage sludge depends on its nutrients

Field study, 2008 AFESD, 2007 content, trace elements and organic IIP, 2002 NOPWASD, 2000 matter content Sewage sludge monetary valueMETAP, 1999 Average

 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. 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



Total organic mater (OM) % 57 61 No data 61 45 56

Total nitrogen (TKN) % 3.16 3.13 2.4 4.11 1.7 2.90

Total Phosphorus (P) % 1.13 0.65 0.55 1.6 0.8 0.95

Potassium (K) % 0.28 0.19 0.3 0,55 0.3 0.32

The monetary values for the relevant resources in dry sludge Egyptianmarket USAMarket Resourses price price (US$/kg) (US$/kg) Nitrogen(N) 0.76 1.61 Phosphorus (P) 2.23 4.91 Potassium(K) 0.43 0.94 Organic matter 0.015 0.044

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)

matter can be estimated according to the market price of the generated The price of dry sewage sludge in the international and Egyptian market electricity during the anaerobic Amount of relevant Monterey value digestion stabilization. resources Egyptian market USA market Average The theoretical price of 3 3 3 Resources content % K g/ton kg/m US$/ton US$/m US$/ton US$/m sewage sludge according to N itrogen (N ) 2.9 29 15.7 22.0 11.9 46.7 25.2 its resources price in 0.95 9.5 5.1 21.2 11.4 46.6 25.2 Egyptian market is 28 US$/m3 Phosphorus (P) Potassium (K ) 0.32 3.2 1.7 1.4 0.7 3.0 1.6 or 53 US$/ton. Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

O rganic matter Total

56

560

302.4

8.4 53

4.5 28.5

24.64 121

13.3 65.3

Options of beneficial uses of sewage sludge Organic Fertilizer

1. Agriculture Reuse

2. Energy recovery

Heat Generation

3. Construction materials

Cement Industrial

Soil Conditioner

Electricity Generation

Construction Materials

4. Phosphorus recovery

Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Phosphors

Potential uses of sewage sludge in

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.

Delta

1000

m2/Capita

900 800 700 600 500

950

Nile valley

400 300

500

200

380

100 0

1960

1996

2017

Year 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 Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Beneficial use of sewage sludge in Egypt (Potential demand of sewage sludge in agriculture) Expansion of reclamation desert 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)

Soil conditions of the reclaimed land



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 Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

South valley development project

Beneficial use of sewage sludge in Egypt (Sewage sludge market ) Potential market demand



The recommended application rate of dry sewage sludge in Egypt: 8 - 20 m3 DS/acre/year for arable crops.



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.



The current dry sludge production represent only less than 5 % of the actual demand of the target market (the reclaimed desert land only).

Sewage sludge market price

   

The current sale price of dry sludge in Egyptian market ranges from 1.5-11 3 US$/m . of the other organic fertilizer are about 17 US$/m3. This price

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 Institut of Sanitary and Environmental Engineering

3 16 US$/m . Braunschweig, Germany Technische Universität

Conclusion 

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.



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). Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany

Thank you

? Institut of Sanitary and Environmental Engineering Technische Universität Braunschweig, Germany