After full operation of secondary treatment at the East and West treatment plants, the future production of sludge from these plants and from Amriya and Agamy secondary treatment plants in addition to the rest 14 secondary treatment plants all around Alexandria is expected to exceed than 1200 m3/d by 2015 thus the capacity if the sludge disposal site should exceed. Therefore, the future sewage sludge management represents a critical environmental issue in Alexandria, this management includes sludge dewatering, handling, transportation cost to the disposal sites and the final product marketing. As the capacity of Alexandria sludge disposal system will be limited by the increase in sludge production and the current management system, there is an immediate need to investigate ways to establish a future management system and to demonstrate successful operations at higher sludge producing rates. Currently, Site 9N the sole disposal site in Alexandria include a composting plant established when the site was initially developed as a dedicated disposal area for sludge. Consequently, land spreading of the sludge on the dedicated disposal area has ceased and all of the current production of raw sludge is now being composted using the turned windrow technique. The present study aims to evaluate the current efficiency of the sludge management system and adopt a future vision for the Alexandria sludge system and recommend modifications to protect public health and environment.

1. A VISION FOR FUTURE SLUDGE MANAGEMENT
IN ALEXANDRIA
Dr. Helaly Abdel Hady Helaly (1)
Chem. Hussein Mohamed Abdou Elashqar (2)
Dr. Samaa Maher Abdel Aziz (3)
(1) “General Manager of Industrial wastewater, Sludge and Reuse Sector, Alexandria Sanitary
Drainage Company”.
(2) " Manager of Landfill Composting Facilities (site 9N)".
(3) “Manager of Industrial Wastewater Studies and Research Department”.
Keywords: sludge production, Alexandria, future, wastewater quantities, sludge
dewatering, sludge handling, sludge treatment, compost marketing.
ABSTRACT
After full operation of secondary treatment at the East and West treatment
plants, the future production of sludge from these plants and from Amriya and Agamy
secondary treatment plants in addition to the rest 14 secondary treatment plants all
around Alexandria is expected to exceed than 1200 m3/d by 2015 thus the capacity of
the sludge disposal site should exceed. Therefore, the future sewage sludge
management represents a critical environmental issue in Alexandria, this management
includes sludge dewatering, handling, transportation cost to the disposal sites and the
final product marketing.
As the capacity of Alexandria sludge disposal system will be limited by the
increase in sludge production and the current management system, there is an
immediate need to investigate ways to establish a future management system and to
demonstrate successful operations at higher sludge producing rates.
Currently, Site 9N the sole disposal site in Alexandria include a composting
plant established when the site was initially developed as a dedicated disposal area for
sludge. Consequently, land spreading of the sludge on the dedicated disposal area has
ceased and all of the current production of raw sludge is now being composted using
the turned windrow technique.
The present study aims to evaluate the current efficiency of the sludge
management system and adopt a future vision for the Alexandria sludge system and
recommend modifications to protect public health and environment.

2. Introduction
Alexandria is the second largest main city in Egypt. It is the primary port home
for 40% of Egypt industrial base. In 1998, Alexandria population was 3.5 million and
it is estimated to reach 8 millions by year the 2030. Alexandria has attracted
considerable attention towards developing its basic structure and overcome some of
the problems facing its utilities.
In the late seventies, sanitary drainage activities covered only 40% of the total
inhabited area of the city. Even that the sewers were often worn out by time and
unable to handle the flows they receive. The problems of streak flowing have existed
due to the inability of pump stations and treatment plants to receive flows exceeding
,
their capacities. The city s wastewater treatment facilities which are expected to serve
a population of about 4 million were not operated well and the collection system was
aging and limited in coverage. These conditions lead to frequent and unavoidable
operational failures which posed a direct threat to the public health, constrain
industrial development, and impacted the daily lives of the residents of the city.
Alexandria has two large primary treatment plants (East Treatment Plant (ETP)
and West Treatment Plant (WTP). The confined capacities of 607,000 and 400,000
m3/d were respectively, sludge processing and disposal facilities (600 tons/day),
collection system of large interceptors, tunnel collectors, pump stations, and
establishing a site for disposing the generated scum, grit, and sludge. The
implementation of wastewater project in the city of Alexandria resulted in large
quantities of sludge being produced (400 tons /day) average.
Future production of sludge from East and West treatment plants, Amriya and
Agamy will become more than double the current production. As a result, sludge
disposal site capacity has to exceed approximately 700 m3/d. This production level
expected around year 2010 with only primary treatment at East and west treatment
plants.
The installation of a secondary treatment at the East and West treatment plants
will result in the capacity of sludge site being exceeded when these units start full
operation. The key features of site 9N include the composting system and the
supporting facilities and equipment. Approximately 100 % of the dewatered sludge

3. and all the grit received from the treatment plants are disposed and incorporated into
composting plant located in the site which is about 140 feddan.
As the capacity of Alexandria sludge disposal site is limited by current
operation system, there is immediate need to investigate ways to increase site capacity
and to demonstrate successful operations at higher sludge producing rates.
The present study aims to evaluate the current efficiencies of the ASDCO
sludge disposal system with emphasis on site 9N as the main disposal facility and
recommend modifications to expand its capacity and life time than planned, to protect
public health and environment.
The quality and quantities of sludge produced at a municipal treatment facility are
controlled by the composition of the incoming wastewater and the required treatment.
The sludge characteristics, in turn, affect the alternatives available for
treatment, beneficial use and disposal. Different sludge treatment processes will yield
different types and volumes of sludge which can effect the beneficial use/disposal
options available. The proposed beneficial use / ultimate disposal of the sludge solids
dictate the extent to which the sludge must be treated prior to disposal. Various
alternatives for sludge treatment and disposal are presented in Figure (1), Table (1).
Figure (1): Sludge Disposal Alternatives

4. Table (1): Sludge treatment processes and their functions
Unit Processes
Function
Thickening
gravity, flotation, belt thickeners
Water Removal
Volume Reduction
Blending
Biological Stabilization
Aerobic Digestion
Anaerobic Digestion
Composting
Pathogenic Destruction
Volume and Weight Reduction
Odor Control
Putrescibility Control
Gas production (methane)
(Anaerobic Digestion)
Conditioning
Chemicals, heat, fly ash
Improve Dewatering rate
Improve Solids capture
Improve compactability
Belt Filters
Water Removal
Solids capture
Change to Damp Cake
Volume and Weight reduction
Dewatering
Vacuum Filter
Belt Filter press
Filter press
Centrifuge
Water Removal
Solids capture
Change to Damp Cake
Reduces Fuel Requirements for
Incineration/Drying
Drying Beds
Heat Drying
Water removal
Incineration
Destruction of solids
Water removal
Conversion
Sterilization
Final Disposal
irrigation and croplands
Energy
Land reclamation and Landfill
ocean disposal (Banned in USA)
Incineration
Wet oxidation

5. Location and capacity (current and planned) of all WWTPs:
Alexandria has 18 wastewater treatment plants, ranging from 3,000 m3/day
to 607,000 m3/day. Total capacity is about 1.4 MCM/day, of which 1.3 MCM/day is
concentrated in 4 large treatment plants. About 1 MCM/day is currently upgraded to
secondary. 0.3 MCM is already secondary. Planned capacity increase is 0.55
MCM/day.
The East Treatment plant is currently a primary treatment plant under
upgrading to secondary activated sludge treatment and discharges to Dayer El-Matar
drain to Lake Maryout. Abis Villages 6 secondary treatment plants; The 10th Abis TP
discharges to El Amlak drain, Nasriya TP to Dayer El Matar drain, Abis 1st and 2nd
TPs to Mansheya Drain, Abis 3rd TP to Mansheya 3 drain and Abis 4th to Mansheya 4
drain.
The West Treatment plant (primary under upgrading to secondary Activated
sludge treatment) discharges directly to Lake Maryout. The Km 26 secondary
activated sludge treatment plant does not discharge its effluent but it is reused by Alex
West Tourist Compound adjacent to the treatment plant.
Iskan Moubarak secondary TP discharges to Amriya drain, while Khorshid
& Zawayda TP and El Maamoura TP are secondary treatment plants and discharge to
Amiaa Drain. El Hannovile secondary treatment plant (Ard El Hesh) discharges near
El Dekhila Harbour. El Seiouf secondary treatment plant disharges to El Qalaa Drain.
El Agamy Km 21 Treatment plant will discharge to West Noubariya drain.
And El Amriya secondary treatment plant will discharge to Noubariya canal. While el
Noubaria secondary treatment plant discharges to El-Shagaa drain.
New Borg El-Arab secondary Aerated lagoon treatment plant discharges to
its surrounding forest area which is considered reused. It is proposed to discharge the
rest unreused effluent to the West Noubaria Drain.
Sludge generation (location, quantity, quality), processing and disposal.

6. The sludge from both ETP and WTP is mechanically dewatered at the WTP.
The liquid primary sludge is pumped from the ETP to the WTP where it is co-settled
with sewage and the sludge is dewatered by the belt press to about 30% dry solids (ds).
Sludge production is currently about 450 m3/d, equivalent to about 50,000 tonnes dry
solids (tds per year). This will increase when the WWTPs are extended (currently under
development) and secondary treatment is installed (planned for 2010), reaching about
80,000 tds by 2015. Table (2) shows the current and future sludge production in
Alexandria.
The generated amount of sludge from the East Treatment plant that resulted from
clarifiers is about 3000-4000 m3/d , solid concentration 2-3%, it is diluted to 1-2% then
pumped through middle zone tunnel (12 km length, 5 m depth), to WTP, then
dewatered by mechanical dewatering facility.
Table (2) : Current and Future sludge production in Alexandria main
treatment plants (m3/d)
Year
ETP/WTP
Current
2009
2010
2015
2020
2025
450
669
724
724
759
759
Amriya
TP
169/109
169/109
169/109
169/109
445/285
Hannoville
TP
352
364
376
388
400
Total
450
1,190/1,130
1,257/ 1,197
1,269 / 1,209
1,316 / 1,256
1,604 / 1,444
The amount of sludge generated from the West treatment plant is also about
3000-4000 m3/d with solid concentration of 3-5% , then to the mechanical dewatering
facility, The produced sludge is 8704 Ton/month; Used polymer 6927 kg
polymer/month; Polymer cost 182873 L.E/month.; Dewatering efficiency 27.9%.
The generated sludge from El-Hannoville TP and Iskan Moubarak TP is
dewatered by centrifugation, with solid concentration of 25-30%, transported to 9N.
The Mex/Dekhila/Agamy WWTP is initially expected to produce 200 m3/d of
20% ds, increasing to 400 m3/d by 2025. This will be a conventional primary
sedimentation and activated sludge plant. The total quantity of sludge that will be
produced by Alexandria will be about 1,200 m3/d by 2015, equivalent to about
150,000 tds/y.

7. The produced composted sludge has an average of 34 % Organic matter, 3%
Total Nitrogen, 175 mg/kg available phosphorus. The heavy metals contents of the
compost are within the required limits of Egyptian regulations.
Sludge Treatment and Disposal system:
Site 9N is located 35 km west of Alexandria. The site receives sludge cake
from the MDF and grit, scum and screenings removed from the ETP and WTP. Grit,
sand and screenings generated from the ETP and WTP are transported to site 9N by
dump trucks. Currently, the total quantities transported of sludge are 83212 m3/year,
of sand is 7973 m3/year and of screenings is 1749 m3/year, and from Industrial solid
waste 3338.85 m3/year according to values of year 2008/2009.
At Site 9N, a composting plant is established when the site was initially
developed as a dedicated disposal area for the sludge. Consequently, land spreading of
the sludge on the dedicated disposal area has ceased and all of the current production
of raw sludge is now being composted using the turned windrow technique as shown
in Figure (2).
Figure (2) : Composting Processes of Dewatered Sludge.
Mature compost is used as a bulking agent to improve the aeration of the
composting process and is mixed on a 1:1 volume basis with the fresh dewatered raw

8. sludge, delivered daily to Site 9N. Specialized windrow turners are used for mixing
the materials and for process (temperature, moisture) control in the windrows. Some
mixing and turning is also done by mechanical shovel. A 30-day period is allowed for
the active composting phase in windrows, following which the compost is removed to
a curing and stockpile area where it is allowed to mature for several weeks, but the
compost may be stored for many months before sale and use.
Based on these assumptions, 1 m3 of dewatered sludge is converted into 0.4
m3 of matured compost. Therefore, at the current sludge production level, compost
production is likely to be about 66,000 m3/y, rising to 184,000 m3/y by 2015, and
234,000 m3/y by 2025, based on the estimated increases in sludge production
Assessment of the current Mechanical Dewatering Facility (MDF) conditions:
1- Hydrogen sulfide problems, which resulted from the septic condition of sludge at
the equalization tanks and different location of sludge dewatering operations, thus
affecting life time of the MDF components.
2- Produced quantities of dewatered sludge (30%) of the designed value.
3- Reduction in sludge dewatering production results in accumulation of the sludge in
the end effluent channel of the WTP, affecting primary treatment operation efficiency.
According to ASCDO committee (no. 931 dated 30/11/2008) recommended the
following to improve MDF performance:
1- Starting rehabilitation of current belt press components.
2- Keep the safe level of H2S concentration.
3- Repairing and operating the blowers to ensure continuous mixing of liquid sludge
in equalization tanks, homogenizing SS concentration and prevents septic
conditions.
4- operating MDF hydrogen sulfide control unit.
5- Rehabilitation of computer systems.
It is a must to increase the efficiency of mechanical dewatering operations to
guarantee dewatering all sludge from primary treatment plants.
Control of odor emissions from the current wastewater treatment plants by
taking appropriate operating measures is not implemented to mitigate any
noncompliance.

9. Assessment of Sludge/Solids Disposal Facility (9N)
Composting significantly reduces the volume of sludge. During the
composting process, there is a substantial loss of water during composting (reducing
from 70% to 10% moisture content) but the density of the product will become less
than that of the sludge because of its open texture (reducing from 1 to 0.7 m3/t). The
amount of dry solids will also be reduced through the mineralization of organic matter
(20% loss assumed). The volume of the compost will be increased by using matured
added to facilitate the composting process, but this is in effect internal relying within
Site 9N and so does not influence the net volume of compost produced for marketing.
The assessment indicated that the thermophilic composting temperatures of 55–65ºC
are evolved during composting. The temperature of the compost is stable within this
range for up to two months and is relatively insensitive to the frequency of turning.
The compost windrows do not require many turnings to maintain efficient processing,
which is desirable for moisture retention since high moisture loss is likely to limit
microbiological activity.
Sludge Handling, Treatment and Disposal
The goal of any wastewater residual solids disposal system is to dispose of
solids in a cost-effective manner that protects the public health and the environment.
Sludge disposal has historically been a major challenge in the wastewater
treatment field. Approximately half of the operation and maintenance costs for a
typical wastewater treatment operation are incurred in the sludge disposal processes.
Current means of disposal in use in the U.S. include incineration, landfilling, ocean
disposal and land spreading. All of these means have drawbacks; they are either too
costly to operate or they may create a potential threat to the public health and
environment. Therefore, an economical sludge disposal process that ensures
protection of public health and the environment must be developed.

10. Table (3) : Expected Sludge Production from different wastewater treatment plants
Area
Treatment
plant
Amount of sludge produce ton/day (25% solids)
2012
2013
2014
2015
228
234
294
324
324
648
El Hannovile
60
60
60
60
60
60
Iskan Moubarak
18
25.2
25.2
25.2
25.2
25.2
Km 26
4.8
12
12
12
12
12
Km 21
180
192
204
216
216
216
Amrya
0
0
108
120
144
144
King Mariot
0
0
36
48
60
60
Abo talat
0
0
12
12
12
12
Borg Elarab (old)
52.8
52.8
52.8
52.8
52.8
52.8
Borg Elarab (new)
0
0
84
96
108
138
East TP
330
330
720
720
720
720
Elsiouf
West
2011
West TP
East
2010
8.4
8.4
8.4
8.4
8.4
8.4
Elmammoura
2.4
8.4
24
30
36
42
Khorshid
18
48
54
54
54
54
Abis (6TP)
21.6
21.6
21.6
21.6
21.6
21.6
Daily total
924
992.4
1716
1800
1854
2214
Monthly total
27723
29775
51483
54003
55623
66423
Annual total
337295
362261
626375
657035
676745
808145

11. Suggested scenario for Sludge management in Alexandria
This scenario aims to manage the sludge production in the near future 2015. All
Alexandria wastewater treatment plants will be in operation, so the sludge
management will depend on collection of all sludge produced from the new small
treatment plants and large treatment plants. Then, the dewatered sludge will be
transported to treatment sites by large vehicles in order to be treated and disposed.
Figure (3): Flow diagram of the sludge treatment by using windrow
composting
Figure (4) : Unloading of Sludge.
Figure (5) : Covering of dewatered sludge with composted sludge.

12. Figure (6): Turning of windrows with composting machine.
The steps of the plan could be as follows:
1- Sludge handling
a- The sludge produced from East wastewater treatment plants
The East Treatment plant is a central plant located east of Alexandria which will
produce around 720 ton/day dewatered sludge. The dewatered sludge produced from
all small treatment plants in the east of Alexandria will be collected there. The small
secondary treatment plants are:
•
Maamoura T.P. will produce around 42 ton/day of sludge.
•
Khorshid and Zawieda T.P will produce around 54 ton/day.
•
EL seiouf T.P. will produce around 8.5 ton/day of sludge.
•
The Abis treatment plants (six treatment plants) will produce around
21.5 ton/day of sludge.
b- Sludge produced from Amyria and Agami wastewater treatment plants
The sludge produced from Iskan Moubarak T.P. (will be around 25 ton/day) and will
be transported to Amyria T.P. which will produce around 144 ton/day. All sludge
produced from both treatment plants will be transported to site 9N.
c- The Km 21 treatment plant which will produce around 216 ton/day of sludge will
be the collection point of sludge produced from both Hannoville T.P. and Km 26 T.P.
•
Hannoville T.P. will produce around 60 ton/day of sludge.
•
Km 26 T.P. will produce around 12 ton/day of sludge.
d- The sludge produced from West wastewater treatment plants
The sludge produced from the West treatment plant will be around 648 ton/day which
will be transported directly to site 9N.

13. 2- Sludge treatment system
Composting area of site 9N is 140 feddans which has been used for sludge
composting as shown on Figure (7).
Figure (7) : Location of Site 9N and the proposed extension area.
Site 9N is the most suitable location for composting operation, where it is downwind
of the near houses and can easily be managed as a composting area. The composting
area contains 180 windrows of 250 length, 1.5m height and 4m width. The distance
between each two windrows is 5 m. For building a windrow, 35 – 40 trucks
containing 20 m3 of sludge cake are required (700 m3 – 800 m3), construction of one
windrow takes from 2-3 days. The spoil material storage area is utilized for
emergency use. For adopting windrow composting method to treat non stabilized
primary sludge the windrows are covered after each turning with a 5 cm layer of
matured compost to minimize the flies' attraction, especially during first week of
composting period. Also, ten centimeters matured compost is used during
construction at the bottom to prevent septic condition at the lower layer of the
windrows.
The expected total quantity of dewatered sludge produced in Alexandria will be
around 2000 ton/day. This quantity will be sent to site 9N for treatment and disposal.
Currently Site 9N has two areas for sludge composting, south and north composting
areas 30 hectares each. In addition to a storage area of about 15 hectares. The total

14. capacity of sludge treatment at site 9N is about 150,000 tons, which is equal to sludge
produced from Alexandria treatment plants during 75 days. The sludge treatment
process takes three months (two months fermentation period and one month curing
period) which indicates that the composting area at site 9N is not enough to receive
the sludge in the nearest future (2015), therefore it is important to find another new
composting site with an area of about 200 feddans. The site suggested is the extension
of site 9N to the west direction which has a large unused desert area surrounded by
agriculture fields Figure (7). The suggested new site should be designed as the
follows:
1- Composting field 120 feddan serviced with ground and surface water
protection system.
2- Storage area about 40 feddan which must be beside the composting area.
3- Site utilities about 40 feddan which include the following:
-
Administrative buildings
-
Maintenance work shop.
-
Temporary storing area for equipments.
-
Equipment washing area.
-
Roads and trees surrounding the site area. (as shown in Figures (8,9))
North Composting area
South Composting area
Figure (8): Suggested new site design.

15. Figure (9): Suggested new site after extension.
3- The sludge produced from Borg El -Arab wastewater treatment plants
The sludge produced from Borg El-Arab treatment plants -about 200 tons/day- will
need to be treated in situ, and so we need to establish two sites for sludge treatment in
Borg El-Arab city. The area of each sludge treatment site should be about 70 feddans,
60% of the proposed site should be used for sludge treatment, 20% for sludge storage
and 20% for traffic building and equipments. The suspected new site design is as the
follow as shown in Figure (10).
1- Composting field 42 feddan serviced with ground and surface water protection
system.
2- Storage area about 14 feddan which must be beside the composting area.
3- Site utilities about 14 feddan which include the following:
-
Administrative buildings
-
Maintenance work shop.
-
Temporary storing area for equipments.
-
Equipment washing area.
-
Roads and trees surrounding all site.

16. Figure (10): Suggested new sludge treatment site for Borg ElArab.
The sludge management system of Borg El Arab city will depend on the characteristic
of each dewatered sludge batches. As a result of laboratory chemical analyses, batches
characterized with high contents of hazardous industrial waste must be collected and
transferred to site 9N for sanitary landfill. The batches satisfy with the Egyptian
criteria for sludge reuse especially in terms of heavy metals will loaded into windrow
composting area.
References:
1- Integrated Urban Water Management (IUWM), CEDARE/SWITCH project
(2010), "New Strategies for Wastewater Management and Reuse in
Alexandria in 2037"
2- Malina Joseph F.,. Sludge Handling, Treatment and Disposal Processes.
Workshop on Domestic wastewater treatment and sludge Disposal
processes. The American University in Cairo. 17-20 April 1995..

17. 3- Sludge Handling and Conditioning, Operations Manual. U. S. EPA,
Washington, (1978).
4- Wastewater Research Group (WRC), Alexandria Effluent and sludge
Reuse Study . Alexandria, ARE., January 2000.
5- Wastewater Research Group (WRC), Alexandria Effluent and sludge
Reuse Study . Alexandria, Final Report March 2001.
6- Egyptian Code ECP 501-2005, (2005). “Egyptian standards for use of
treated wastewater in agriculture". World Academy of Science, Engineering
and Technology 57 2009.
7. Master plan of Alexandria wastewater system 2007)
8. M. Ghazy, T. Dockhorn, and N. Dichtl, Sewage Sludge Management in Egypt:
Current "Status and Perspectives towards a Sustainable Agricultural Use, World
Academy of Science, Engineering and Technology 57 2009.