Zero Energy Compact Unit (ZECU) for Sewage
Treatment in Small Communities in Egypt
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Dr. Tarek Ismail Sabry
Professor, Public Works Department, Faculty of Engineering
Ain Shams University
Dr. Ahmed S. El-Gendy
Associate Professor, Dept. of Construction and Architectural Engineering,
The American University in Cairo
Dr. F. A. El-Gohary
Emeritus Professor, National
Research Center (NRC),
Introduction and Problem Definition
• Substantial efforts and resources have been directed by the Government of Egypt to improving access, reliability and quality of water services both in urban and rural areas.
• Priority to expansion of water supply and sanitation services coverage is in urban areas than in rural areas.
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Introduction and Problem Definition
3
Rural sanitation: a remaining challenge
Egypt suffers from low coverage of appropriate
sanitation systems in rural areas.
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Introduction and Problem Definition
• The updated number of small communities in
rural Egypt which suffer from lack of sanitation
services include about 3,170 villages and
26,542 hamlets (Ezba or Naga)
• This is approximately about 50 million capita
that do not have access to proper sanitation
services.
Cesspits effluents infiltrate through the soil and cause serious
contamination of ground water and the nearby canals and drains.
(Health and Environmental risk)
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Introduction and Problem Definition
The degradation of
environmental
quality and health is
severe due to the
uncontrolled
disposal of the
untreated sewage.
Introduction and Problem Definition
• Conventional Centralized sewage treatment has high cost of construction, operation and maintenance
• In addition, it requires skilled labor
and large footprint.
• Decentralized onsite compacted
low cost treatment models are the solution to serve small communities in Egypt.
• Onsite treatment help in improving the water quality of drains and canals and other water bodies.
• Therefore, new configurations employing the best practices of sanitation technology for wastewater treatment in rural areas of Egypt are highly needed.
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• Upflow Septic tank followed by anaerobic Baffled Reactor
(USBR) as a new concept of low cost technology employing
two stages anaerobic treatment for sewage treatment
proved to be able to efficiently treat wastewater (Sabry
and Sung, 2004).
• This technology is also easy to implement and operate.
Therefore, it would be more convenient for the conditions
of rural areas in Egypt.
Introduction and Problem Definition
System Development and State
of the Art
System Development and State of the Art
Using Upflow Septic Baffled Reactor (USBR)
Low cost new technology suitable for tackling rural sanitation
problems.
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Wastewater Treatment system at
El-Arab Village, Ismailia
Governorate (200 Capita)
2005
Project Cost 100,000 L.E.
Wastewater Treatment system at
Abo-Halifa, Ismailia Governorate
(100 Capita)
2005
Project Cost 100,000 L.E.
Wastewater Treatment system at
Aabdel-Kareem Issa Village, El-
Fayoum Governorate (2000
Capita)
2006
Project Cost 305,000 L.E.
Wastewater Treatment system
at Juhaina Factory, El-Ras
City – KSA (250 Capita)
2009
Project Cost 310,000 Saudi
Riyals
Technical and financial comparison among different treatment technologies
Treatment system
Removal efficiency %
Land Area
m2 / m3/ day
Construction Cost
L.E* /m3
Running Cost
L.E* /m3
Nuisance (fly, smell)
Operation Complex
BOD5 pathogenic Bacteria
Activated sludge
75-95 60-90 2.4 2400-4000 250 low high
Oxidation ditches
75-95 60-90 6 1700 137 low high
Trickling filters
65-85 60-90 3.6 1600 55 low to
medium
medium
Aerated ponds
80-95 60-90 19.2 1500- 1600 66 low medium
Oxidation ponds
80-95 99-99.9 24 1200-2500 27 medium to high
low
USBR 80- 85 undetected 1- 1.4 1500 25 low low
Best performed technology
Activated Sludge
Oxidation Ponds
USBR USBR USBR Activated sludge
USBR
* LE= Egyptian Pound, $ Dollar= 5.3 LE Pounds according to the currency value at October 2008.
However, the USBR system in its current shape, still
occupies a relatively large area of land.
Bearing to the fact that land availability in a major part of
the inhabited rural areas in Egypt (for example, the Nile
Delta) is limited and expensive, the use of the USBR for
sewage treatment in these areas might be not quite
appropriate.
Therefore, a new treatment system with a smaller
footprint and a similar concept of the USBR has been
constructed and tested (Sabry et al., 2011).
This treatment system is a compact system. It consists
of an up-flow anaerobic reactor and down-flow
anaerobic packed-bed baffled reactor followed by a
passive aeration, aerobic biological filter, and sand
filter for improving the effluent quality of the two-
stage anaerobic system at different operating
conditions.
Pilot-Scale (Zenien WWTP in Giza Governorate)
Flow rate = 0.5 m3/d
The USBR has been developed and renamed as Zero
Energy Compact Unit (ZECU)
Pilot-Scale Process Diagram
Flow rate = 9.0 m3/d
Full-Scale (ZECU)
(Zawyet El-Karatzah in El-Fayoum Governorate)
Aerial Photos for the Location of the Full-Scale Setup at Zawyat El-Karatsah
WWTP in El-Fayyoum Governorate - Egypt
Perforated
Trays
Biological Filter
Sedimentation
Tank next to
Slow Sand
Filter
Tower contains
the three
reactors of the
anaerobic
stage
Different Treatment Units of the Full-Scale System after being assembled and
installed at Zawyat El-Karatsah WWTP
Inlets and Outlets of the Full-Scale System
Force main of the
raw sewage (from
the submersible
pump)
Influent of the
Full-Scale (at the
First Reactor in
the two modules)
Cones for gas
collection from the
First Reactor in each
module
Final Effluent of
each Module
Ladder for
Inspection and
System
Maintenance
Effluent of the
Anaerobic Stage
Effluent of the Anaerobic Stage and the Perforated Trays
Effluent of the Anaerobic Stage trickling through the Perforated Trays
(During Testing of the System)
Effluent of the
Anaerobic Stage
Perforated Trays
Perforated
Trays
Trickled
Wastewater
Aerobic Biological Filter packed with Sponge
Vents for
aeration of the
Biological
Filter
Sponge
Media
Perforated
Trays
Aerobic Biological Filter with Air Vents on its Side Wall
Air Vents
Air Vents
Points of Strength
Existence of “KNOW HOW”
Existence of successful projects
Passive system
Low cost treatment
Locally manufactured
Small foot-print area
Simple in operation
No need for skilled labors
Little maintenance
Provide effluents that comply with the limits regarding disposal in agricultural drains or Effluent Reuse in irrigation
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Results and Data Analysis
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Results and Data Analysis (cont’d)
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Results and Data Analysis (cont’d)
Parameter Raw Effluent of the
anaerobic stages Final Effluent
Temperature, oC (20 + 3)
pH (7.1 + 0.1) (7.4 + 0.1) (7.5 + 0.1)
COD – Total, mg/L 300 – 475 (389) 128 – 453 (275) 24 – 98 (58)
COD – Soluble, mg/L 89 – 126 (106) 48 – 142 (87) 18 – 63 (33)
BOD, mg/L 174 – 294 (222) 90 – 255 (152) 12 – 49 (28)
TSS, mg/L 110 – 310 (217) 69 – 324 (177) 6 – 40 (20)
VSS, mg/L 39 – 160 (93) 25 – 195 (79) 3 – 21 (10)
At optimum hydraulic loading rate of the biological filter (1.64 m3/m2/d) – Summary of system performance [range and (average)]
Results and Data Analysis (cont’d)
Parameter
Effluent, range and (typical or average) concentrations - mg/l
Onsite wastewater treatment systems (septic tank)
Bradley et al.
(2002)
Converse and
Converse (1999)
USEPA
(2002) Current System
BOD 150 – 250 (180) 32 – 548 (192) 46 – 156 (93.5) 12 – 49 (28)
TSS 40 – 140 (80) 14 – 626 (87) 6 – 40 (20)
Comparison of Onsite Wastewater Treatment Systems (OWTS) and the Current System Effluent Quality (at optimum hydraulic loading rate of the biological filter)
Results and Data Analysis (cont’d)
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Conclusions
The use of passive aeration after the anaerobic phases of
the treatment increases the dissolved oxygen contents of
the anaerobic effluent by 6 folds to reach an average
concentration of 5.22 mg/L.
The added oxygen activates the aerobic attached-growth
microorganisms which play the main role of wastewater
treatment in the biological filter system.
Among the tested hydraulic loading rates of 1.09, 1.64
and 3.27 m3/m2.d, the highest removal efficiencies of
CODTotal, CODsoluble, BOD5, TSS and VSS from
wastewater were obtained at the hydraulic loading rate of
1.64 m3/m2.d.
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Conclusions
At optimum hydraulic loading rate, average overall
removal efficiencies of 85%, 88%, 91% and 89% can be
achieved for CODTotal , BOD5, TSS and VSS, respectively.
Overall, the integration of anaerobic and aerobic phases of
the treatment can provide effluents with quality
acceptable for disposal in agricultural drains according to
Law 48 for the Year 1982 with respect to CODTotal, BOD5
and TSS.
SELECTED PUBLICATION: El-Gendy, A. S., T.I.M. Sabry, and F. A. El-Gohary (2012). The Use of AN Aerobic Biological
Filter for Improving the Effluent Quality of A Two-Stage Anaerobic System. Sixteenth International Water Technology Conference, IWTC 16 2012, Istanbul, Turkey, May 17-21.
Sabry, T.I.M., A. S. El-Gendy and F. A. El-Gohary (2011). An Integrated Anaerobic – Aerobic System for Wastewater Treatment In Rural Areas. IWA Conference 2011 Small Sustainable Solutions for Water, Venice, April 18-22.
Sabry, T.I.M. (2010): Evaluation of decentralized treatment of sewage employing Upflow Septic Tank/Baffled Reactor (USBR) in developing countries.
Journal of Hazardous Materials, ELSEVIER, 174 (2010) 500–505 Ghobrial, F. H., Sabry, T.I.M., Wahb, I, S, and Osman M. (2008). Establishing Design Criteria
for the Up Flow Septic Tank / Baffled Reactor (USBR) Use in Rural Egypt. Scientific newsletter, Faculty of engineering, El Azhar University. Vol. 30, No. 3, October 2008, pp. 1123- 1133.
Sabry, T.I.M. (2007): Application of the UASB inoculated with flocculent and granular sludge in treating sewage at different hydraulic shock loads. Bioresource Technology, ELSEVIER, 99 (2008) 4073–4077.
Sabry, T.I.M. (2007), "دراسة فنية واقتصادية"استخدام تكنولوجيا جديدة منخفضة التكاليف في معالجة مياه الصرف الصحي
.2007ديسمبر 5-2المؤتمر الهندسي السعودي السابع بجامعة الملك سعود في الفترة بين - Sabry, T.I.M., and Sung, S. (2007): Demonstration of The Modified Septic Tank (USBR) for
Rural Wastewater Treatment in Egypt European Water and Wastewater Management Conference, Aqua Enviro, Newcastle, England, 24th – 26th September 2007.
Acknowledgements
• The current research is funded by the Science
and Technology Development Fund, STDF,
Egypt, Grant No 940.
Thank you