Wastewater Treatment Technologies

NAWQAM National Water Quality and Availability Management

PFRA

NWRC

Prairie Farm Rehabilitation Administration

National Water Research Center

Agriculture & Agri-Food Canada

DRAINAGE WATER REUSE AND PILOT SCHEMES Component 3000

DRAINAGE WASTEWATER TREATMENT TECHNOLOGIES AND APPROACHES

Report No. DR-TE-0209-007-fbFN

September 2002

The working team is composed of the following staff DRI Prof. Dr. Shaden Abdel Gawad Dr. Essam Khalifa Eng. Ahmed Ali Rashed

DRI Director Asst Component Manager Asst. Researcher

EPADP Eng. Nabil Fawzi Eng. FouaD Moussa Ramadan

EPADP Chairman Component Coordinator

NAWQAM Project Management‫آ‬ Dr. Jacques Millette Dr. Sameh Sakr

CEA-CTL Technical Advisor

Table of Contents Acknowledgements --------------------------------------------------------------------------------------- 4 1. Introduction ---------------------------------------------------------------------------------------------- 5 2. Wastewater Treatment ------------------------------------------------------------------------------- 7 3. Physical/Mechanical Treatment Systems ------------------------------------------------------- 8 3.1 Mechanical Wastewater Treatment in Egypt: ---------------------------------------------- 9 4. Aquatic Treatment Technologies ---------------------------------------------------------------- 11 4.1 Facultative Lagoons ---------------------------------------------------------------------------- 11 4.2 Constructed Wetlands ------------------------------------------------------------------------- 12 4.3 Aquaculture Systems -------------------------------------------------------------------------- 14 4.4 Sand Filter Systems ---------------------------------------------------------------------------- 14 5. Terrestrial Treatment Technologies ------------------------------------------------------------- 15 5.1 Grass Filter Strips, Tillage Modification, and Buffer Zones as Agricultural Wastewater Treatment Alternatives ------------------------------------------------------------- 16 5.2 Operation and Maintenance of Aquatic Treatment Systems ------------------------ 20 5.3 Level of Involvement --------------------------------------------------------------------------- 20 6. Low Cost Aquatic Treatment Alternatives for Wastewater in Egypt -------------------- 21 6.1 Domestic Wastewater Treatment (Gravel Bed Hydroponics Wetlands-Subsurface Wetland, Ismailia) -------------------------------------------------------------------- 21 6.2 Industrial Wastewater Treatment Project at 10th of Ramadan City ---------------- 22 6.3 A Passive Wetland Water Quality Management System Incorporating ----------- 22 6.4 Full Scale Subsurface Flow Wastewater Treatment Wetland of Samaha Village, Dakahlia ------------------------------------------------------------------------------------------------ 24 6.5 Lake Manzala Engineered Wetland for Treatment of Bahr El Baqar Drain ------ 27 7. Costs of Construction, Operation & Maintenance of Treatment Systems ------------ 47 7.1 Comparisons of Effectiveness of the Technology -------------------------------------- 50 7.2 Suitability ------------------------------------------------------------------------------------------ 51 8. Conclusions and Recommendations ----------------------------------------------------------- 54 9. References -------------------------------------------------------------------------------------------- 55

List of Tables Table 1. Wastewater Treatment Plant technology Case of Operation (Abdel Gawad, 1998) ------------------------------------------------------------------------------------------------- 11 Table 2. Typical Design Features of Treatment Level ----------------------------------------- 11 Table 3. Typical Design Features for Constructed Wetlands -------------------------------- 12 Table 4. Site Constraints for Land Application Technologies -------------------------------- 15 Table 5. Mean Treatment Performance of GBH Beds with Phragmites at Abu Attwa, Egypt ------------------------------------------------------------------------------------------------- 22 Table 6. Stage of Wastewater Treatment --------------------------------------------------------- 30 Table 7. Selected Heavy Metals Water and Sediment. --------------------------------------- 37 Table 8. Preliminary Design Assumptions for influent Water Quality (TVA, 1999) ----- 39 Table 9. Drain Water Inflow Characteristics ------------------------------------------------------ 39 Table 10. Potential Removal of Heavy Metals by the Treatment System ---------------- 40 Table 11. Characteristics of the Project Site (TVA, 1999) ------------------------------------ 41 Table 12. Approximate Intake Pumping Conditions -------------------------------------------- 42 Drainage Wastewater Treatment Technologies and Approaches Eng. Ahmed Ali Rashed September 2002

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Table 13. Preliminary Design Parameters for Sedimentation Basin and Flow Distribution Channel ----------------------------------------------------------------------------- 42 Table 14. Preliminary Design for the Wetland Treatment System -------------------------- 43 Table 15. Estimated Effluent Concentration and Removal Efficiency --------------------- 44 Table 16. Preliminary Design Parameters for the Reciprocating Treatment System -- 45 Table 17. Preliminary Design Parameters for the Hatchery Ponds ------------------------ 45 Table 18. Preliminary Design Parameters for the Fingerling Ponds ----------------------- 46 Table 19. Preliminary Design Parameters for Sludge Drying Beds ------------------------ 46 Table 20. Comparative Advantages and Disadvantages of Wetland Scheme ---------- 47 Table 21. Comparason of the cost for different treatment methods (Abdel Gawad;1998) -------------------------------------------------------------------------------------- 47 Table 22. Comparison of Costs of Construction & Operation & Maintenance of Conventional Municipal Wastewater Treatment Technologies from Local Bids & Tenders --------------------------------------------------------------------------------------------- 48 Table 23. Comparative Performance of Sewage Treatment Systems -------------------- 51 Table 24. Advantages and Disadvantages of Conventional and Non-Conventional Wastewater Treatment Technologies ------------------------------------------------------- 52

List of Figures

Figure 1: Summary of Wastewater Treatment Technologies. ........................................ 8 Figure 2 Grass Filter Strips and Buffer Zones (Hammer, 1993) ................................... 17 Figure 3 Plan and Section in Grass Filter Buffer Zone Strip (Higgins et al. 1993) ....... 19 Figure 4 Profile View of a Passive Wetland Treatment System for Treatment ............ 23 Village Sanitation Drainage .......................................................................................... 23 Figure 5. Alternative 1: Engineered Wetlands within the Lake or Drain ....................... 31 Figure 6. Alternative 2: Engineered Wetland Parallel to the Drain ............................... 32 Figure 7 Lake Manzala UNDP Project Area ................................................................. 36 Figure 8 Schematic Diagram for the Constructed Wetland Project Components ........ 38 Figure 9 Comparative Capital Cost of Wastewater Treatment Technologies .............. 49 Figure 10 Comparative Operations and Maintenance Cost of Wastewater Treatment 49 Technologies ................................................................................................................ 49 Figure 11 Land Requirement & Local Component (Adopted from Abdel Gawad, 1998) ............................................................................................................................. 50

Drainage Wastewater Treatment Technologies and Approaches Eng. Ahmed Ali Rashed September 2002

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Acknowledgements I would like to take this opportunity to thank the many individuals who helped to make this report possible through their diligent efforts. Special tribute goes to Dr. Mona El Kady, Dr. Shaden Abdel Gawad, Dr. Hossam Fahmy, Eng. Mostafa Nada, Eng. Mohamed Fathy, Dr. Jacques Millette, Dr. Chandra Madramootoo, Dr. Henry Murkin, Dr. Diaa El Deen Al Qoussy and Dr. Essam Khalifa I am also grateful to the DRI Staff, EPADP Staff, NAWQAM Project, MWRI Staff and CIDA for providing the necessary data in comprehensible form and for their tireless efforts and timely support.


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1. Introduction Over 85 percent of Egypt‘s water resources are utilized for agriculture. Although improvements to canal and field irrigation systems will result in some overall water savings, agriculture will in the future be forced to continue utilizing increased amounts of low quality water. The emphasis on increased reuse of drainage water for irrigation is essential as Egypt expands its agricultural land base to meet the food supply requirements of a rapidly growing population. In the most downstream part of the Nile and horizontal expansion areas, there is potential to greatly increase the reuse of drainage water for irrigation. About 12 billion cubic meters of surplus irrigation water are collected in drains each year, but only an approximate 5 billion cubic meters are currently being reused. Surplus irrigation water represents a valuable resource. The Government of Egypt is embarking on an initiative to reuse the drainage water from the El-Salam Canal to irrigate approximately 600,000 feddans of new lands in the north-eastern Delta and northern Sinai Peninsula. But this endeavor is not without negative consequences. Soil and crop productivity as well as animal and human health could be adversely affected as a result of reusing such low quality water. Moreover, the environmental limitations of this water resource must be determined and considered in order to develop a sustainable wastewater reuse and agricultural strategies for the region. Another important consideration is that the soils of the region are heavily salinized, so leaching, reclamation and cropping strategies under conditions of low quality water use must also be taken into account. The National Water Quality and Availability Management Project (NAWQAM) is undertaken by the Governments of Egypt and Canada to maximize utilization of reused drainage water in reclamation activities and to increase national income. The project consists of four components: national water quality monitoring, water availability management, drainage water reuse and pilot schemes, and information management communication. The primary objective of the drainage water reuse component is to determine how to best reuse drainage from the El-Salam Canal for irrigation in an environmentally safe manner. The overall objective of the Drainage Water Reuse and Pilot Schemes component (Component 3000 of the NAWQAM project) is to determine how to reuse drainage/waste water from the El-Salam Canal in a way that is safe for the environment and human health. Environmental monitoring, reclamation and agricultural reuse of mixed low quality water, in addition to crop management strategies, technology development and transfer, and training form the basis of this component. For successful program delivery, a broad-based training element with an emphasis on water quality and environmental management is planned by the project team. Given its current population growth rate and its need for national food security, Egypt is forced to develop new lands for agricultural production. Coupled with the expansion of the agricultural land base is the need to provide adequate irrigation water supply. This poses a serious challenge because the country has a finite irrigation water supply from the Nile. Egypt is concerned about water scarcity because of increased competition for water from all sectors of the economy. The country has therefore embarked on a water conservation program, which includes an Irrigation Improvement Project. Additionally, drainage water—which flows out of the Delta and is lost to the Mediterranean Sea—needs to be captured and reused for irrigation. Moreover, further land and water developments in Egypt face several environmental challenges. Two such challenges are: 

How to safely reuse low quality drainage water in an environmentally safe manner.


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

How to undertake intensive agriculture in regions close to unique ecosystems. This is especially the case with the El-Salam Canal project, which is in close proximity to Lake Manzala and surrounding wetlands.

Two specific sub-activities of the NAWQAM component 3000 have been identified as part of the activity focused on environmental protection strategies. These are:  

Development of an environmental management plan for drainage water reuse in the study area with a comprehensive review of wetlands in the area. Evaluation of engineered wetlands to treat drainage water in the project region.

This report is submitted according to the NAWQAM work plan 2001-2002 (Report No. PR-IN-0006-007-FN, WBS 3550), and is prepared and reviewed by the Drainage Research Institute. The primary objective of this report is to assess the applicability of using wetlands for drainage water treatment, and to identify other appropriate options for drainage water treatment. Accordingly, the study includes the following specific objectives:  Assess the applicability and suitability of constructed wetlands as a wastewater treatment option.  Summarize the procedure of selecting the Lake Manzala constructed wetland as a wastewater treatment alternative.  Explore the feasibility and effectiveness of various treatment technologies for low quality drainage water treatment.  Review available information and data on the environmental evaluation of the drainage water reuse projects and appropriate options for low-cost treatment.  Review available information and data on ongoing similar wastewater treatment approaches in the El-Salam Canal area. Another objective of this report is to explore technologies for low-quality drainage water treatment, so that reuse does not lead to detrimental environmental and human health impacts, and so that pollution abatement measures are taken. This would include items such as:   

Current Egyptian techniques and legislation for improving water quality Pilot techniques to reduce negative impacts of drainage water reuse Assessment of water quality treatment needs

Summary of the Report Contents: A brief description of the wastewater treatment technologies explored is presented in Section 2. Mechanical treatment technologies and their component facilities are presented in Section 3. The aquatic treatment technologies assessed, including treatment lagoons, stabilization ponds, and constructed wetlands are presented in Section 4. The operation and maintenance issues related to these treatment technologies are also discussed. Section 4 contains information about Grass Filter Strips and Buffer Zones as Agricultural Wastewater Treatment Alternatives in some foreign countries that have similar climatic conditions.


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Wetlands capture surface runoff from croplands and the treatment of various types of wastewaters. In addition to the aforementioned topics, some details of the wetland functions and values in the treatment processes are discussed. Examples of low-cost treatment alternatives for wastewater treatment in Egypt are presented in Section 4. The first model is the use of Gravel Bed Hydroponics (GBH) reed beds, for wastewater treatment in Ismailia, Egypt. The second model is the passive wetland water quality management system incorporating the existing drainage canals in Fayoum. Detailed descriptions with treatment techniques are presented. A practical application model of the GBH reed beds is presented in the case of municipal wastewater treatment of a big village in the Nile Delta, Egypt. Detailed descriptions of the Lake Manzala engineered constructed wetlands are presented in Section 5. The process of selecting the Lake Manzala constructed wetland as a wastewater treatment alternative is discussed. Descriptions of the different components of the wetlands as well as design parameters are also presented. Cost comparisons between the different treatment technologies in other countries are discussed in Section 6. These comparisons include construction costs as well as operation and maintenance costs. Some information is included about treatment costs of municipal wastewater in both mechanical and wetland treatment systems.

2. Wastewater Treatment Relatively simple wastewater treatment technologies can be designed to provide lowcost sanitation and environmental protection while providing additional benefits from the reuse of water. These technologies make use of natural aquatic and terrestrial systems. These systems may be classified into three principal types, as given below and shown in Figure 1. Mechanical treatment systems use natural processes within a constructed environment; they tend to be used when suitable lands are unavailable for the implementation of natural system technologies. Aquatic systems are represented by lagoons; facultative, aerated, and Hydrograph Controlled Release (HCR) lagoons are variations of this technology. Lagoon-based treatment systems can be supplemented by additional pre- or post-treatments using constructed wetlands, aquacultural production systems, and/or sand filtration. They are used to treat a variety of wastewaters and function under a wide range of weather conditions. Terrestrial systems make use of the nutrients contained in wastewaters. Plant growth and soil adsorption convert biologically available nutrients into less-available forms of biomass, which is then harvested for a variety of uses, including methane gas production, alcohol production, or cattle feed supplements.


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Figure 1: Summary of Wastewater Treatment Technologies. Source: Ernesto Pérez, P.E., Technology Transfer Chief, Water Management Division, USEPA Region IV, Atlanta, Georgia.

The following sections describe each of the systems in detail.

3. Physical/Mechanical Treatment Systems Mechanical systems utilize a combination of physical, biological, and chemical processes to achieve the treatment objectives. Using essentially natural processes within an artificial environment, mechanical treatment technologies employ a series of tanks, along with pumps, blowers, screens, grinders, and other mechanical components to treat wastewaters. Various types of instrumentation control the flow of wastewater in the system. Sequencing Batch Reactors (SBR), oxidation ditches, and extended aeration systems are all variations of the activated-sludge process, which is a suspended-growth system. The Trickling Filter Solids Contact Process (TF-SCP), by contrast, is an attached-growth system. These treatment systems are effective where land is at a premium (Reed, 1988). Kadlec and Knight (1996) defined the primary, secondary and tertiary treatment processes. Primary treatment consists of screening, grit removal, and primary sedimentation. Primary sedimentation is used to initially reduce the high concentration of TSS present in row wastewater and for the removal of floatable materials. Primary sedimentation may be enhanced by pre-aeration to promote flocculation (aggregation of smaller particles into larger particles called flocks) or through chemical coagulation with ion salts, alum, or lime. Secondary treatment consists of the removal of additional wastewater solids and dissolved organic matter through microbial uptake and growth. It is essentially a biological process in which bacteria and fungi are encouraged to grow in lagoons, mixed tanks, or lagoons on fixed surfaces. Tertiary (advanced or polishing) treatment is a process in which the concentration of BOD and TSS can be reduced below the typical secondary treatment level and nutrients (primarily nitrogen and phosphorus) are transformed or removed from the wastewater Drainage Wastewater Treatment Technologies and Approaches Eng. Ahmed Ali Rashed September 2002

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stream. Nitrification, denitrification and phosphorus removal are three forms of tertiary treatment. 3.1 Mechanical Wastewater Treatment in Egypt: Different wastewater methods are used in Egypt to treat wastewater. Activated sludge and the extended aeration are the most conventional methods of secondary treatment used in Egypt. Oxidation ponds and oxidation ditches are sometimes used. However, wetlands have in fact been used in Egypt as a wastewater treatment method on an experimental scale as seen in Abu Attwa, Ismailia, and on an operational scale as can be observed in Samaha Dakahlia. Constructed wetlands can be used to demonstrate this low-cost technology method for treating municipal wastewater, agricultural drainage water, and industrial wastewater. Abdel Gawad (1998) reported five major systems of treating wastewater in rural areas in Egypt, presented in the sub-sections below: 3.1.1. Stabilization (Oxidation) Ponds: Flow enters a manually cleaned bar screen to two anaerobic ponds that are operated in parallel. Flow then proceeds to maturation ponds, which operate in series; flow passes from one to the next, with effluent passing through a flow-measuring V-notch weir before discharging to the drain (Abdel Gawad, 1998). No mechanical equipment is used at this type of a facility. Sludge must be removed from the anaerobic ponds (once every two years) by taking the pond off-line (bypassing it) and daring it; the sludge is then allowed to dry for ‗ease of handling‘ and is removed and disposed of off-site. 3.1.2. Stabilization Ponds with Aerated Facultative Cell: Flow enters the aerated stabilization pond facility from the pump station and passes through the manually cleaned bar screens to two anaerobic ponds that are operated in parallel. Flow then proceeds to a series of four ponds, the first of which is aerated (facultative). After leaving the first pond, flow enters the maturation pond, and then proceeds through two ―polishing‖ ponds in sequence. Effluent discharges to a drain canal through a flow-measuring V-notch weir. Mechanical equipment consists of four floating surface aspirating aerators in the aerated pond. Sludge must be removed from the anaerobic ponds once every two years by taking the pond off-line (bypassing it). The sludge is then allowed to dry for ease of handling and is removed from the pond and disposed of off-site. The majority of wastewater treatment plants in medium-sized cities apply this treatment technique. 3.1.3. Submerged Fixed Film Reactor (SFFR): Flow enters the facility from a pump station and passes through a manually cleaned bar screen to two anaerobic tanks operated in parallel. Flow then proceeds to a lagoon with a set of internal baffle walls that establish a serpentine flow pattern. The inlet portion of the lagoon contains the submerged fixed film reactor, while the effluent end of the lagoon contains a recycle pump and a parallel plate separator. The recycle pump discharges through an aspirating venturi into the submerged fixed film reactor. Exiting the lagoon, flow proceeds by gravity over a small circular weir, which leads to a chlorine contact chamber for final discharge to a drain through a flow-measuring Vnotch weir. Drainage Wastewater Treatment Technologies and Approaches Eng. Ahmed Ali Rashed September 2002

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Mechanical equipment consists of one SFFR unit recycle pump, two undersized pumps for removing settled solids from the anaerobic tanks, a hypo chlorite day tank, small feed pump, and a stand-by generator. Once every six to twelve months, sludge pumped from the anaerobic tanks is discharged to a sludge drying bed, and disposal of sludge is off-site. This technique was applied on a very few sites in Egypt since it was imported and directly applied as a package. One example is at Al Ebrashia village, Damietta Governorate north-eastern Nile Delta. 3.1.4. Extended Aeration (Oxidation Ditch) Flow enters the facility from the pump station force main and passes through a bar screen to the oxidation ditches. Flow then proceeds to the clarifiers, where sludge is settled. Clarifier effluent is discharged to the chlorine contact chamber and then to the receiving drain. Sludge from the clarifiers is continuously pumped back to the oxidation ditches as return sludge. A portion of this sludge is removed each day as waste sludge to the thickener tank. From the sludge thickener, concentrated solids are sent to the sludge drying beds, where dried sludge is removed and disposed of off-site. Filtrate from the sludge daring beds and supernatants from the sludge thickener are returned to the aeration basins for additional treatment. Mechanical equipment consists of aspirating aerators, clarifier and thickener drives, chlorine dilution water pumps, a chlorinator, and a stand-by generator. 3.1.5. Extended Aeration (Package Plant) Flow enters the package extended aeration facility from the pump station force main through a mechanically cleaned bar screen and proceeds through a scum-grit removal taken into the aeration basins. Flow then proceeds to the clarifiers, where sludge is settled. Clarifier effluents are discharged to the chlorine contact chamber and then to the receiving drain through a flow-measuring (ultrasonic-type) partial flume. Sludge from the clarifiers is continuously pumped back to the aeration basins as return sludge. A portion of this sludge is removed each day as waste sludge to the sludge holding tanks. From the sludge holding tanks, concentrated solids are sent to the sludge drying beds. Dried sludge is removed and disposed of off-site. Filtrate from the sludge drying beds and suppurate from the sludge holding tanks are returned to the basins for additional treatment. Mechanical equipment consists of a mechanically cleaned bar screen, grit pump, surface aerator, clarifier driver, chlorine dilution water system, and chlorinator, and stand-by power generators. Abdel Gawad (1998) classified the mechanical wastewater treatment technology to assess the applicability of each technique. Each operation is scored in terms of the degree of difficulty in its construction, operation and maintenance through the use of different existing facilities. These figures are presented in Table 1.


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Table 1. Wastewater Treatment Plant technology Case of Operation (Abdel Gawad, 1998) Wastewater Treatment Technology Ext. Aer. System (package plant) Ext. Aer. (Oxid-Dich) SFFR Aerated Stab. Pond Stabilization Pond (Oxidation)

Mech. Equip

Elect. & Instr.

Specia l Tolls

Proces s Control

Staff Trainin g

On-site Lab Testing

Stead Flow

Overall Level Difficulty

5

5

5

5

5

5

5

35

5

3

5

5

5

5

33

2

2

4

2

2

3

3

18

2

2

2

2

1

3

2

14

0

0

0

1

1

3

2

7

4. Aquatic Treatment Technologies Typical design parameters of aquatic treatment technologies are summarized in Table 2. This method includes an oxidation pond, fluculative pond, aerated pond, storage pond and root zone treatment and Hyacinth ponds. Table 2. Typical Design Features of Treatment Level Technology

Treatment goal

Oxidation pond Facultative pond Aerated pond Storage pond, HCR pond

Secondary Secondary Secondary, polishing Secondary, storage, polishing Secondary

Root zone Treatment, Hyacinth pond

Detention Time (days)

Depth (m)

10-40 25-180 7-20

0.9-1.4 1.4-2.3 1.8-5.5

Organic Loading (kg/ha/day) 33-100 18-45 41-163

100-200

2.7-4.6

18-45

30-50