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wwt flow

wastewater plant processing stage

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wwt flow

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  1. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements 2.PLANT REQUIREMENTS 2.1.GENERAL Consideration of Regulations is mandatory and the DB Contractor is fully responsible to stick to the regulation. The DB Contractor is expected to Design and Build an environmental friendly Wastewater Treatment Plant and sewer line that serves the wastewater treatment and disposal considering that the plant does not cause any potential hazard to the public health, safety, and welfare; does not contaminate any drinking water or potential drinking water supply, or the waters of ponds, lakes, streams …etc, and; does not cause nuisances such as odor, noise, unsightly appearance or other such forms of public impact. The wastewater treatment plant site area is shown on the layout drawing and all the treatment units and internal facilities shall be constructed with in this proposed area limits as per the approved final design by the Engineer. The DB Contractors shall as a minimum consider the below listed considerations for the design and build of the WWTP. •Special considerations with respect to ease of construction and facilities planning and organization; •Considerations of accessibility for day to day operation and maintenance including vehicular access for operation and maintenance to the plant sites which demand vehicle access as per the approval of the Engineer; •The DB Contractor is expected to visit the site and incorporate in the scope of the project work all associated civil and site works including access roads, crossing structures, internal road to each unit, retaining structures, flood protection, landscaping, Compound Lighting, Storm water drainage and water supply system; •Reflect the prevailing 21st century contemporary architectural designs to the Treatment Plant additional facilities; •Respect shall be paid to its surrounding context; •Sensitivity with respect to quality, durability and aesthetics; •Consideration to the ascertainment of usage efficiency, maintenance ease and durability/sustainability, as well as lifecycle cost shall be planned. While introducing Page 47 of 135

  2. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements advanced devices and systems that are energy efficient, resource and environmental friendly, ensure it is adaptable to future changes and are easy to renew or upgrade; •Consideration of both the lighting and other modern facility so as to reduce the inconvenience in use of the plant, to the maximum extent possible; •Consideration of advanced technology and Material that is able to reduce the surrounding noise pollution, technology that provides for a comfortable working and user environment, and other advanced options can be proposed by the contractor and will be considered; •An electronic security system with a complete control room shall be introduced throughout the plant infrastructure including its vicinity; •Main entrance areas should provide a light, attractive and welcoming approach to the plant using high quality materials with hardwearing low maintenance floors (hard, easily cleaned, vandal resistant finishes with an attractive ambience) and attractive & durable wall finishes, ceilings including entrance areas shall be the best quality feature types with effect lighting incorporated as an integral part of the design; •Landscape features including specific hardscape materials, vegetation and compound lighting fixture shall be incorporated; •Building faced and mass visibility of the buildings shall be experienced with a well- designed and articulated use of lighting technology; •Electrical, Plumbing, Wastewater and HVAC utility areas shall be sufficient in scale to enable easy and safe access to equipment for inspection and maintenance and to facilitate the removal/replacement of components, lockable access and restricted to authorized persons only, IT and server rooms must be lockable, provide emergency lighting, and ventilated to provide a safe working environment; •Adequate waste disposal facilities and suited to the purpose and size of the development should be provided, the location should be in a lockable area resistant to vermin attack and should contain a separate space for the storage of recyclable materials, care shall be given to the location and design of waste disposal facilities for any solid waste; Page 48 of 135

  3. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •A fully furnished operators, administration, control rooms sufficient enough to perform the plant operation and maintenance; fully furnished two residential units 2 Bed Room (each unit shall have a minimum area of 100 m2 with living & dining, kitchen, store, two bed rooms, common toilet facilities) for the plant operators. •Minimum office and residential units clear internal rooms, Lobbies, Corridors etc. height (floor finish – ceiling) shall not be less than 3.5 m unless HVAC system is provided where the height can be reduced to 3.0 m. The DB Contractor shall consider the minimum clear height available in his Structural, Mechanical, Electrical and other special system designs depth and crossings, so as to attain the clear room height not less than 3.5m. •The WWTP process mechanical components include the equipment required for treating the liquid treatment process, using a three stages conventional activated sludge with biological nutrient removal technology (CAS-A20 with a pre-anoxic tank) and solid streams treatment process using aerobic stabilisation with mechanical dewatering. •A sewer pipe route to convey the sewage from the waste water lift pumping station and other sources to the treatment plant as proposed on the layout and as approved by the Engineer. •The DB contractor is expected to make a site visit, check the topography of the site, review and confirm the proposed layout, and design the plant based on the national and international standards and codes to meet the project intended purpose as per the design parameters and technical specifications provided in the employer’s requirement. The proposed location of the waste water pumping station is indicated on the layout, but the DB Contractor can survey, design and propose an acceptable location depending on the final output of the design. Furthermore, the location of the final manhole of sewage at the plant inlet, the invert level and the top level is also shown on the layout. •The DB Contractor shall prepare a detail engineering design of the plant as per the design parameters and technical specifications provided in this employer requirement, Page 49 of 135

  4. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements supply and install materials well-known having an energy efficient brand with the highest quality standard of the latest technology possible to operate in automatic mode, which is appropriate to the conditions for use, and also provide with additional essential equipment for O&M which can serve for five years after commissioning. •The Contractor shall on completion of works supply the Employer with a complete set of Manuals, Operation and Maintenance Documents, “As Built Drawings”, and other necessary documents both in soft and hard copies. 2.2.WW TREATMENT PLANT FACILITIES The WWTP chosen by the Employer is for the liquid treatment process, a three stages activated sludge technology with biological nutrient removal, and for the solid stream treatment process, aerobic stabilisation with mechanical dewatering, aiming to treat the wastewater as per the Employer’s requirement (to be operated by the Employer’s staff after 24 months of operation, maintenance and on job training by the DB contractor) and to: •discharge treated effluent for disposal to the nearby lowest natural drainage (assuring that the treated effluent quality meets the criteria, and suitable and safe for reuse and disposal), •provide solid stream treatment to dispose bio-solids safely for end-use for fertiliser in agriculture, land fill or other eco-friendly options, •have two parallel process trains flow in the design, so that one train can be taken off line for maintenance without disrupting the treatment process. The DB Contractor shall design and submit to the Engineer for approval detail engineering design as per the national and international standards including layout, process mechanical, civil, structural, building mechanical, electrical, instrumentation and controls to make the project feasible and attainable. The plant has to be designed and the treated water shall be sampled and studied from laboratory considering the quality of water to be disposed to the nearby lowest natural drainage or going to be reused by locals, animals, and fauna growth. The Contractor shall Page 50 of 135

  5. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements make a detail topography survey of the site and the design shall be within the layout territory for the erection of the wastewater treatment plant. The treatment plant shall be constructed inside the compound at the site indicated on the attached layout drawing, and it has closeness proximity to the catchment where the treated effluent will be drained and accessible by the population. Hence, the WWTP has to be designed with well proven international techniques comprising noise level, odour level and efficiency of the treatment plant. The Contractor shall also carry out detail geotechnical investigation and submit the final designs before implementation based on the investigation report. The Contractor shall construct and operate safely avoiding any significant disturbance or damage to the people and the fauna and flora, to the environment and the neighbourhood, implementing a comprehensive monitoring scheme. The Detail Engineering Design, Manufacture, Supply, Install, Test, Commission and Operation of the Waste Treatment plant and Sewer line service project, as a minimum shall comprise the following treatment steps and units to attain the project purpose. •Oil and Grease Separator, for waste from main Kitchen, •Pumping station with solids separation system : dry well installation, smaller free ball passage, •Sewage system sewer lines and manholes, •Lift Pumping Station: dry well installation, •Pre-treatment: oInlet chamber / equalization Tank, oSelf-cleaning screens with manually operating bypass stainless-steel screens (coarse and fine screens), oAerated vortex grit and grease removal system, oDistribution Chamber, oPrimary sludge pumping station: dry well installation, Page 51 of 135

  6. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •Preliminary Treatment: oPrimary Clarification Tanks, oDistribution Chamber, •Secondary Treatment: Bioreactors for aerobic biological oxidation, nitrification and de- nitrification, phosphorous removal, oPre Anoxic Tank, oAnaerobic Tank, oAnoxic Tank (De-Nitrification Tank), oAeration Tank (Nitrification Tank) with one spare aerator and agitator for emergency, oFinal Clarifier, •Tertiary Treatment: Chlorine disinfection and de-chlorination; oChlorination Chamber, oDe-chlorination Chamber, •Sludge Treatment & Disposal mechanisms: oSludge re-circulation pumping station, oSludge discharge pumping station, oPrimary Sludge Gravity Thickener, oPrimary Sludge Stabilization Tank with one spare aerator and agitator for emergency, oBiological Sludge Gravity Thickener, oAerobic sludge stabilization (digester), oAerated Sludge Mixing & balancing tank, oSludge Dewatering Building : Belt Filter Press with dewatering facility, oSludge container: movable type having a total capacity to hold one week sludge production, oSludge transporting truck (to be provided by the Employer) oSludge drying bed: made of concrete having a capacity to hold one month sludge produced during emergency occasions. Page 52 of 135

  7. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •Ancillary Structures: oThe architectural designs and the detail engineering designs of all the building blocks within the WWTP shall be designed as per the National and International codes and standards. The roofing structure of the buildings shall be with a water tight concrete roofing having proper roof drainage, aesthetically designed parapets with marble coping, and sufficient outlets. oOperation and control block including sufficient size control room for operators, fully furnished with all the required furniture’s, computers, and all data system with full accessories for data handling and processing, oLaboratory block fully furnished with all required furniture’s and laboratory equipment’s with their spare parts, so as to monitor the regular operation of the treatment plant, oChemical building and chemical storage, fully furnished to store chemicals and spare parts separately, oPower house, oGuard House; oHigh quality security boundary fencing with security gate; oDischarge to the catchment / continuous discharge to the catchment: outfall structures to the nearby natural drainage lines which will be approved by the consultant and concerned regulatory body; oLandscaping, plantation of grasses and approved decorative plants, internal road with in the premises of the treatment plant to and from each unit and block; oHeavy road allowing easy access to all the facilities, and allowing the rotation on the site of trucks carrying deliveries and or transporting dried sludge; oHighlighted / marked and shaded parking lots for visitors and operators, oAccess road from the nearby compound road to the treatment plant, oEmergency drying bed, oSludge storage shade; Page 53 of 135

  8. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •Sewer Network and Appurtenances; •Standby Generator; •Factory Inspection at Manufacturers site for five (5) professionals from the Employer and the Engineer. The DB Contractor shall provide a plant bypass system in order to pass the total flow from the inlet of the WWTP directly to the outlet bypassing all the treatment units depending on the final approved design. The Contractor shall also supply and fix all fixture and equipment's according to the detail specifications, layout drawings and approval by the engineer and the Contractor shall supply only equipment with high reputation and recognized brands and referenced in the WWTP industry or profession, where the final choice of suppliers and brands is subject to the approval of the Engineer and/or the Employer. 2.3.WWTP TEST PROCEDURES AND CERTIFICATES The Contractor shall arrange factory inspection / factory acceptance testing for all mechanical, electrical, and instrumentation & control equipment’s, pipes and fittings supplied from abroad at the place of manufacturing prior to shipment. The manufacturing and shipping of the equipment’s may be carried out in several batches, the Contractor shall arrange factory inspection for each shipment or as many as the number of shipments. The factory inspection and testing shall be witnessed by both the Engineer and the Employer. The Contractor shall arrange for a minimum of five people to attend the inspection and testing of the equipment’s in each factory inspection visit. The contractor shall cover all the factory inspection/testing /visit costs. The Contractor shall obtain from the suppliers and/or manufacturer’s representative test certificates and submit three copies of certificates to the Engineer, on delivery and prior to incorporation into the works for Materials, Plant and other items to be incorporated into the Permanent Works. Such certificates are required to certify, that the materials, plant and equipment have been tested, inspected and quality control during production is in accordance Page 54 of 135

  9. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements with the requirements of the Contract and shall contain the results of all tests carried out. The Contractor shall provide adequate means of identifying the materials, plant and equipment delivered to the Site against the corresponding test certificates. The Contractor shall prepare and submit test procedures as per the manufacturers manual for review and approval by the Engineer one month before the plant is ready for testing and commissioning. Tests shall be performed in accordance with agreed and approved procedures at the presence of the Engineer and plant operators. 2.4.WWTP OPERATION & MAINTENANCE The DB Contractor shall provide full operation and maintenance service of the constructed facilities for a period of two years, keeping all the facilities of the plant clean, safe and secured. The scope of the service during this period includes but not limited to: •Carry out all Operation and Maintenance service of the plant as per the Operation and Maintenance Manuals: oassigning sufficient number of skilled professionals for the service, ostoring sufficient quantities of all consumables, spare parts, tools, instruments (meters) required for O & M of the Plant, with their guidelines and Instruction manuals, so as to ensure a non-stop operations, otraining of the employer’s staff on job providing detailed schedule and manual of all O & M activities after all the procedures, schedules, and documentations are reviewed and approved by the Engineer, odocumenting the labor hour’s expended, electrical power consumed and other consumables consumed, problems faced and rectified, ominimizing power consumption during operation, maintaining and providing alternative arrangements of electrical and other equipment which may be affected during power failures, orecording of treated & untreated wastewater at outlet and inlet of the facilities , at all locations approved and recommended by the Engineer as per the Page 55 of 135

  10. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements standard, based on continuous flow measurements, regular calibration, cleaning, maintenance and replacement of measuring devices; oanalysing & testing of the collected influent and effluent samples on a regular basis to determine the quality of wastewater and performance of the treatment plant; osupplying consumables, chemicals, laboratory reagents, lubricants, diesel fuel and any other materials that are required for the operation and maintenance of the plant. •Design, supply and provide all consumables required for the start-up and commissioning of the plant till full start-up. •Perform all activities required for the operation and maintenance of the plant in full compliance with all applicable rules, regulations, laws, codes, effluent quality requirements including for operation personnel, spares, tools and tackles, routine maintenance, screenings and grit collection, sludge collection and disposal of the residual matter obtained after processing and treatment of the wastewater such as sludge, grit, waste screens etc. and the effluent in a manner which is compliant to all applicable environmental laws and rules. •The Operation and Maintenance service includes all Electrical, Mechanical and Civil facilities but not limited to mechanical components, instrumentation system, electrical systems, road works, landscaping, civil and structural, and all utility and ancillary buildings for the period of two years from the Provisional Acceptance date. •The Contractor shall operate the WWTP and sewer line on a continuous, uninterrupted 24-hour per day, 7-day per week basis. •The Contractor shall not intentionally reduce the level of wastewater treatment capable of being achieved by the WWTP in an effort to reduce its operating and maintenance expenses. •The Contractor shall at all times operate and maintain the Works in accordance with the approved Environmental Management Plan and approved Contractor’s Documents. Page 56 of 135

  11. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •The Contractor shall ensure that the minimum dry weather and peak flow design capacity is made available at all times during Operation & Maintenance Service Period. •Based on annual Performance Evaluation result, the Employer has the right to act contractually if the result of the evaluation is not satisfactory during the O&M period. •The contractor shall provide vehicle for transportation of operators during O & M period. •Copies of all approved plans and manuals shall be retained at the Site at all times and available for inspection by the Employer. •Contractor’s Operation and Maintenance Manuals shall include sufficient detail to operate, maintain, dismantle, reassemble, adjust and repair the Plant and Works and all requirements requested by the Engineer. •The Contractor shall prepare an emergency response plan to manage emergencies of the plant. •The Contractor shall develop a wastewater quality testing plan. The methods and frequencies of sampling and testing in the Wastewater Quality Testing Plan shall comply with the requirements of the regulatory authorities, and with the methods and frequencies specified in this Employer’s Requirement. •The Contractor shall develop written health and safety procedures covering all aspects of the operation and maintenance of the Works. •The Contractor shall develop a quality assurance manual in accordance with the requirements of EN ISO 9001. The quality assurance system shall be ISO approved and certified. •The Contractor shall submit to the Engineer for approval, a staffing plan one month before the date of commencement of the Operation & Maintenance Service. The Contractor shall promptly inform the Engineer in writing of any changes to its staffing or organizational arrangements. The Contractor shall also ensure that its staff has expertise and experience consistent with the requirements specified in this Employer’s requirement. Page 57 of 135

  12. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Section V: Employer’s Requirements •The Contractor shall prepare and implement a staff training plan for the training of the Contractor’s operations and maintenance staff, Employer’s and Engineer’s supervisory staff. The Staff Training Plan shall be submitted to the Engineer for comment and approval. The quality and effectiveness of the Contractor’s training programs shall form part of the performance evaluation of the Contractor’s performance. •The Contractor’s training program shall include Standard Operating and Maintenance Procedures, On-Site / On-Job Training and final Certification of plant operators by a recognized third party after the completion of both the in class and on-site training, •All standard spare parts and special tools shall be provided as recommended in the manufacturer's instruction manuals for each component of the equipment. •Prior to completion of the Operation & Maintenance Service period, the Contractor shall allow the trainee Employer’s staff to operate the WWTP and sewer lines for a minimum of 1 month under his supervision. Page 58 of 135

  13. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 3.PLANT DESIGN CRITERIAS 3.1.GENERAL The Design of the plant by the DB Contractor shall be made to meet the target effluent quality by taking into consideration of influent quality, temperature, and variation of influent load of the hour, day, month and season. The plant shall also be designed having two process line considering the suspension of individual operational line for inspection, repair, cleaning, rehabilitation, and replacement. The Layout and the structure shall suit the neighbouring environment of WWTP, especially for the university community and surrounding residences, by considering emission of odour, noise, air pollution, and landscape disturbance. If necessary, cover of clarifiers and greenery along the boundary of WWTP site shall be designed. The Layout shall be designed to include space for rehabilitation of civil and architectural works including temporary works and rehabilitation works. Layout shall include roads around facility so that machines and electrical would be brought in for installation. When clarifiers are rehabilitated, they cannot accept wastewater. Therefore, bypass channel or shut off gate shall be designed. Layout should be designed to place machinery and electronics at easily replaceable positions as they are shorter in useful life than civil and architectural works. Layout and structure shall be designed to incorporate future upgrade plan to any future advanced treatment plant type. 3.2.TECHNOLOGY SELECTION AND DESIGN The Plant type selected by the Employer for Design, Construction, Manufacturing, Installing and Operation of the waste water is for the liquid stream treatment process a three stages conventional activated sludge with biological nutrient removal technology (CAS-A20 with a pre- anoxic tank) and for the solid stream treatment process aerobic stabilisation. Therefore, the DB Contractor shall design and build only this technology, based on actual site data of the detail topographic survey for an optimized and efficient design solution and arrangements with in the context of the selected treatment technology that meets the Technical Requirements specified for the plant capacity in this employer requirement. Page 59 of 135

  14. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 3.3.PLANT CAPACITY 3.3.1.GENERAL The DB Contractor shall design and build the Treatment Plant to fulfil the minimum specified capacity requirements specified in this Employer’s requirement, and shall ensure that such capacity is available throughout the Operation & Maintenance Service Period. The Contractor shall plan, design, construct, operate and maintain the Works as necessary to meet the standards specified here below. The Employer may, subject to any conditions that (in its sole discretion) it may deem appropriate, agree to a temporary and limited relaxation of such standards to the limit it doesn’t affect the plant performance and capacity. 3.3.2.WASTEWATER INFLUENT FLOWS The plant shall be designed to give the planned service for the below listed projected wastewater influent flows. Table 1. Projected Influent Flows Description Unit 2025 2030 Total Average Daily Flow (m3/day) 1500 2000 Peak Daily Flow (m3/day) 1875 2500 3.3.3.DESIGN FLOWS The average design flow in the Wastewater Treatment Facility is forecasted to be 2000 m3/d as a daily capacity, and design flows can be projected from the average design estimated flow rate to a growth of about 125% peak flow rate assuming that the per capita wastewater generation rates remain the same throughout the plant life time. Design flows are summarized in Table 2 below: Table 2. Design flows values No Item Unit Minimum Capacity m3/d 1 Average daily flow rate 2000.00 m3/d 2 Daily peak flow 2500.00 m3/hr 3 Average flow 83.3 m3/hr 4 Peak flow 104.16 3.4.INFLUENT QUALITY AND EFFLUENT STANDARD Page 60 of 135

  15. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 3.4.1.INFLUENT QUALITY The table below is for the average waste water quality for the design purpose of the plant. However, the DB Contractor shall collect samples, analyse and confirm the Influent Quality before bid submission and at the design stage. The conceptual design criteria to be considered is summarized in table 3 below: Table 3. Design Criteria of the wastewater No Parameter Unit WWT concentration at inlet 1 Biological Oxygen Demand (BOD5) mg/l 300 - 500 2 Chemical Oxygen Demand (COD) mg/l 800 - 1000 3 Total Suspended Solid (TSS) mg/l 200 - 400 4 Total Phosphorus (TP) mg/l 10-30 5 Total Nitrogen (TKN/TN) mg/l 50-70 7 PH 6-9 3.4.2.OUTLET EFFLUENT DISCHARGE STANDARD The wastewater treatment plant shall be designed to meet the below listed effluent quality throughout the project life time. Therefore the minimum effluent discharge standard shall be attained and the treated effluent shall be pumped to concrete reservoir to be constructed by the DB contractor including the pumps required, and the remaining shall be discharged into the nearby water body or forest area in downstream of the outlet that would be decided by the governmental regulatory body. The Effluent wastewater quality to be discharged to the concrete reservoir, or nearby water Body or forest shall as a minimum fulfil the below listed quality parameters and the plant shall meet the standards at all times of the plant operation. Table -4 water quality outlet / effluent discharge standard No Item Unit Max Concentration of limit BOD5 COD 1 2 mg/l mg/l < 30 < 50 3 TSS TP TN Ammonia (NH4-N) Nitrate (NO3-N) mg/l mg/l mg/l < 10 < 2 < 15 4 5 6 mg/l < 2 7 mg/l < 10 8 Total Coliform < 100 Page 61 of 135

  16. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 9 PH 7-8 3.5.SLUDGE MANAGMENT •The sludge shall be suitable for agricultural purpose as a manure, and the Contractor shall manage the sludge both mechanically as a sludge cake and also for emergency purpose on the sludge drying bed. •The sludge from the plant shall meet an acceptable pathogenic class and vector attraction based on the Ethiopian and International standards. •The dewatered sludge shall have a minimum solid concentration of 20%. •The sludge should also be suitable for land application. 3.6.SMELL AND NOISE CONTROL SYSTEM 3.6.1.ODOR CONTROL SYSTEM The DB contractor shall provide an odour control system at all potential sources of odour to the standards approved by the Engineer. Furthermore the Contractor shall implement an odour monitoring equipment as part of the O & M of the works, which shall be made available at all times at the treatment plant to carry out this task. The concentration of H2S (Hydrogen Sulphide), Methyl mercaptan, Butyl mercaptan and any other related concentrations shall be controlled to an acceptable standard range both in boundary of the site, at the outlet and within the site. The odor control system shall be capable of achieving the maximum possible acceptable level of concentrations, intensity and hedonic tone at the boundary of the site as determined by measuring with olfactometers taken in the gas stream discharge to atmosphere. 3.6.2.NOISE CONTROL The DB Contractor shall measure noise levels at specific locations and the intervals specified in the Employer Requirements during the O&M of the Works. The Equipment or Machinery to be installed for the plant shall emit a noise within an acceptable national and international standard, to be approved by the Engineer. However if there is any noisy machinery or equipment that emits loud noise, it needs to be installed inside a building for additional noise reduction. 3.7.WASTEWATER DESIGN TEMPERATURE Page 62 of 135

  17. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements Wastewater design temperatures to be considered shall be based on the plant area monthly average temperature metrological data for winter and summer. 3.8.MONITORING AND TESTING STANDARDS Unless the period of testing is relaxed by the Employer at the time of the plant maintenance and operation period, the testing periods shall be as follows: •BOD5, TSS, and TP : on a weekly basis, •COD, Ammonia (NH4-N), Nitrate (NO3-N), Total Coliform, PH: on a daily basis. Page 63 of 135

  18. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 4.PLANT PROCESS 4.1WASTE WATER PUMPING STATION Due to topography of the campus premises, partially raw waste water from the university blocks drains to the indicated collection chamber at the pumping station by gravity sewage collection system and the waste collected shall be pumped to the inlet channel where it is passedthroughcoarse screen and fine screen to remove any particles. The sump shall be then provided with two lifting pumps, one duty and one standby, capable of pumping the waste (refer the drawing for the pump capacity or information needed to calculate the pump capacity). Peak factor of 2.0 shall be considered to design the lift station pumps. The remaining wastewater shall also be connected to the inlet channel using gravity sewage collection system, where it is again passed through coarse screen and fine screen to remove any coarse and fine particles. The DB contractor shall design and construct sewer lines to collect the waste water from the septic tanks or nearest manholes to the collection chamber for pumping. The design and construction of collection tank at the pumping station shall be as per the pump manufacturer’s instruction. 4.1.PRELIMINARY TREATMENT 4.2.1.GENERAL The raw wastewater shall be treated for the removal of heavy solid material, grit and grease at the preliminary stage of the treatment process. The preliminary treatment facilities shall have the capacity for the treatment of the maximum wastewater flow coming to the plant. The plant, equipment and infrastructure required at the preliminary stage of treatment shall be designed and build considering the potential to produce odour and it shall be covered as much as possible or controlled in some other way subject to the approval of the Engineer. 4.2.2.SCREENING Larger inorganic solid material shall be removed by way of screening, so that only material of 5mm or less in size is passed through to the next stage of treatment. This material shall be removed using automatically operated self-cleaning wastewater screens, proven for this specific application. The velocity through the screen shall not exceed 1.2 m/h at full flow. Page 64 of 135

  19. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements The screening installation shall have a design, which avoids sedimentation of solids before the screens due to low wastewater velocity. Each screen shall be: •Provided with automatic cleaning system to prevent blocking; •Capable of being lifted and removed for inspection, maintenance and repair; All lifting equipment shall be provided to ensure that the screens can be removed easily when required; Page 65 of 135

  20. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements •Provided with serviced penstocks for closing each line. A penstock shall be installed before and after each screen; •Controlled by means of a label transmitted installed upstream of the screen; •Provided with an automatic release system; •Provided with a ventilated cover to avoid emission of foul air. Foul air from each screen shall be ducted via an odor control system. The collected screenings shall be washed to minimize the organic content and pass through compression device to achieve a minimum dry solids content of 30 %. The resulting wastewater stream shall be returned to the wastewater stream. Washed compacted screenings shall be transferred to a suitable reception container prior to final disposal. An emergency bypass, for bypassing the fine screens, in an emergency, in the event of failure of the latter, due to power failure etc shall be installed. The emergency bypass shall be equipped with a coarse screen for manual cleaning. The coarse screen shall have a maximum bar screening of 10mm. Therefore, the Contractor shall provide enough standby capacity to enable continuous screening to take place at maximum wastewater flow during maintenance and in the event of breakdown. For this purpose bar screen channel shall be provided with manual coarse screen with 10 mm opening and screw screen of 5 mm opening. There shall also be a by pass channel provided to screw screen so that in case of any maintenance of screw screen manual screen can be used. The DB contractor shall propose the design and installation of all civil, and electromechanical works required for coarse and fine screening of the plant for approval by the Engineer, with the latest available technology to the plant standard, and manually operating screens shall also be provided. 4.2.3.GRIT & GREASE REMOVAL The DB Contractor shall design, manufacture, supply, install and construct the required civil and other related infrastructures to remove debris, gravel, grit, fibres, plus other fine mineral particles in order to prevent the formation of deposits in channels and pipelines and to protect pumps and other appliances against abrasion, so as to attain the maximum possible efficiency of the plant and control any downstream damages. The grit removed from the wastewater shall be Page 66 of 135

  21. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements classified prior to discharge in to a reception container. The Contractor shall install grit / sand classifier on the side of the grit tanks serving grit removal chamber to separate water and grits. The grit solids shall be removed from the lower chamber by an electrical super vortex sand pump to be installed outside the grit grease removal system for further classification and dewatering. Flushing valve shall be connected to the sand extraction pipe in order to prevent sand clogging. The Contractor shall also provide enough standby capacity to enable continuous grit and grease removal to take place during maintenance and in the event of breakdown. The grease and all other lighter organic particles shall be lifted to the surface of tank to be scraped out. A skimmer shall be installed at the top of the grit removal chamber to separate, sweep and removes grease and oil floating on the sewage surface and pushes them to a concrete oil and grease collection chamber channel, and then it shall be drained from this chamber to a lower collection chamber at the bottom of the grit tanks then pumped by special pumps for disposal outside of the treatment plant. The DB contractor shall make complete the plant providing all ancillary equipment’s including but not limited to grease collecting box, mounting accessories, lifting anchors, guide rails, safety rails, valves, magnetic flow meter, and gate valves. FOG TRAP As the Kitchen in the university is the main contributor to fat, oil and grease (FOG) in the waste water system, the DB contractor shall remove the fat, oil & grease from Kitchen waste water supplying and installing a pre-fabricated ACO GRP grease trap before it enters waste water treatment plant, so as to reduce interference with biological treatment of waste and increase efficiency of the plant and also to reduce odour. All accessories and spares of the trap shall be provided for maintenance purpose. CONTAINERS FOR WASTE MATERIALS The containers to be used for the collection and transportation off site of the screenings, grit and grease waste materials shall be designed such that no discernible odor can be detected from it. The containers shall be capable of being completely sealed to ensure that no spills occur during transportation and shall be protected against corrosion. REMOVAL OF WASTE MATERIALS Page 67 of 135

  22. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements The Contractor shall ensure that screenings, grit and grease are removed from the WWTP regularly to avoid the production of odor and attraction of vermins. The reception container shall, therefore, be removed and emptied at least once a week. 4.2.4.LIFT PUMPING STATION The Contractor shall provide a lift pumping station upstream of the grit chambers to introduce additional head so that the pretreated wastewater shall flow to the subsequent unit operations and processes by gravity. A wet well type lift pumping station shall be used. A minimum of at least two sets of dry well installation pumps in each set duty and stand by , with VFD drive shall be installed at the lift pump station and every possible safety provision shall also be provided. Flow measurement control signals for the operation of the pumps shall be provided by digital flow meters installed on the discharge line of each pump set. The operation of the pumps shall be automated through a PLC module. A local control panel shall also be installed for local starting and stopping of each pump. A dry running protection float type level switch shall also be installed in the intake well. Also, the operation of the pumps shall be cycled so as to equalize the pump operation time. A manual hoist for each pump station shall be installed above the pit in order to lift the pumps for maintenance purposes. The Lifting station detail design including diameter, and total depth of lifting station shall be designed by the DB contractor and approved by the Engineer before the construction including all the necessary auxiliary equipment. 4.2.5.INLET CHAMBER The DB Contractor shall provide a concrete tank inlet chamber or equalizing tank that accepts flow from the lift station and the gravity sewer line. A magnetic flow meter upstream of the inlet chamber shall measure the flow entering the plant. A bypass concrete channel in the inlet chamber will overflow to distribution chamber after screening during extremely rare events when flows exceed the peak hour flow or blockages occur in headworks components. The equalized evenly raw wastewater will then flow through the automated mechanical coarse and fine screen installed at the outlet of the tank. The structural material of equalization basin shall be reinforced concrete and watertight. The structure shall be heavy enough for groundwater pressure not to float it and the top of the basin Page 68 of 135

  23. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements shall be covered to control odor. Basins and connecting channels shall resist any chemical attack. In case of side line equalization, pump should be installed to make the basin dry as remaining wastewater becomes corrosive. Mixing Mixer shall be installed in equalization basin to blend the contents of tanks and prevent deposition of solids in the basin. The necessity of aerators shall be checked to prevent wastewater from becoming septic. In case mixing is insufficient to prevent deposition of solids, mechanical collector shall be installed. 4.2.6.PRIMARY DISTRIBUTION CHAMBER The Contractor shall provide a distribution chamber downstream of the preliminary treatment unit and ahead of the primary treatment unit for purposes of splitting the flow uniformly to multiple units of the primary treatment unit and for unit by unit bypass. 4.2.PRIMARY TREATMENT 4.3.1.PRIMARY CLARIFIERS The DB contractor shall construct as a minimum two water tight concrete tank circular in geometry primary clarifiers for the primary treatment. Effluent from the grit removal tank will flow to the Primary Clarifier chamber through pipe. The screened influent wastewater shall be distributed calmly and evenly. Each clarifier tank shall be fitted with floor scrapers to direct settled sludge to a central collection hopper. Rotating bridge equipped with hinged bottom scraper and surface scraper shall be used for all Clarifiers to push the sludge to the centre of the tank and the scum to the dedicated scum collecting box. Floor scrapers shall be hinged from a fixed support frame. Trailing scrapers fixed directly to the bridge shall not be permitted. Each clarifier tank is to be fitted with a scum removal system. The system shall be designed to minimize the volume of liquid discharged with the scum whilst providing efficient removal of the scum. Automatic weir channel cleaning systems shall be provided to all Clarifier. The primary clarified water shall then flow to pre-anoxic zone for further process and the collected scum to pumping station then to scum collecting chamber. Page 69 of 135

  24. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements At the primary sludge extraction station, settled sludge collected from the bottom of the primary clarifiers shall flow from each clarifier to a sludge pumping station, then pumped with submersible pumps to the primary sludge thickener. The Contractor shall provide a distribution chamber downstream of the primary treatment and ahead of the secondary treatment for purposes of splitting the flow uniformly to multiple units of the secondary treatment and for unit by unit bypass. 4.3.2.SECONDARY DISTRIBUTION CHAMBER The Contractor shall provide a distribution chamber downstream of the primary treatment and ahead of the secondary treatment for purposes of splitting the flow uniformly to multiple units of the secondary treatment and for unit by unit bypass. 4.3. SECONDARY TREATMENT The secondary biological treatment system shall be designed for reduction of organic matter and suspended solids, and nutrient removal. The biological treatment system shall be designed to achieve a treated effluent standard in accordance with the requirements stated in this Employer’s requirement. The treatment process shall be capable of treating the range of flows and loads expected from the date of commissioning of the plant up to the design flow. The secondary treatment process must fit within the envelope of the area identified for this process. It shall be designed to maximize energy efficiency. Controls shall be put in place to operate the aeration system in a way which matches the air input to the process requirements. 4.4.1.CONVENTIONAL ACTIVATED SLUDGE SYSTEM The Conventional Activated Sludge System CAS-20 equipped with pre-anoxic tank is selected for process design, as this system is recognized to be efficient on maximizing settleability of mixed liquor and on nutrient removal. The process shall provide the appropriate process conditions and recycle-streams to allow the biological removal of organic matter, Nitrogen and Phosphorus. Page 70 of 135

  25. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements The system shall be designed to maximize the settleability of the mixed liquor and nutrient removal in the final clarifiers. Complete mix systems is the preferred option and selector tanks shall be provided. The sizes of the pre-anoxic, anaerobic, anoxic and aerobic tankers shall be designed and constructed with a water tight high grade reinforced concrete structures complete with all the facilities requiered to make the work complete including pumps, aerators, mixers, agitators as requiered based on the system requirement. In general the system shall incorporate the following features: •Pre-Anoxic Tank: The effluent from the primary clarifier and return activated sludge (RAS) shall be introduced into the pre-anoxic compartment. The pre- anoxic compartment shall be operated without aeration, but with gentle mixing using agitators. The residual nitrate contained in the RAS is removed by de- nitrification using the primary effluent to accelerate the process. •Anaerobic Tank: The overflow from the pre-anoxic tank shall be introduced in to an anaerobic process compartment. This process compartment shall be operated under anaerobic conditions, since there are no free and little bound oxygen compounds available. Anaerobic conditions and the availability of readily biodegradable soluble COD compounds stimulate growth of a phosphate releasing/ accumulating bacterial population. Complete facilities to dose Ferric chloride (FeCl3) chemical for removal of phosphorus shall also be provided to the anaerobic chamber to aid with denitrification. A special place for the storage of this product shall be provided for safety reason, fitted with all the safety equipment associated with the use of this type of product and two pumps whose flow rate can be adjustable depending on the results of treatment process and control by the inlet flow of the station shall also be installed for dosing of the chemical. •Anoxic Tank (Denitrification Tank): The overflow from the anaerobic compartment shall be introduced in to an anoxic tank. The anoxic compartment shall receive a recycle of nitrate rich mixed liquor from the downstream aerobic process compartments. Process conditions are conducive to the removal of nitrate via a process of converting the nitrate to nitrogen gas in the presence of biodegradable COD compounds. Page 71 of 135

  26. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements •Aeration Tank (Nitrification Tank): The anoxic compartment overflow shall enter the aerobic compartment, where the process involves air or oxygen being introduced into a mixture of screened, and primary treated effluent combined with organisms to develop a biological floc which reduces the organic content of the effluent. Aerated conditions with a target dissolved oxygen concentration of 2 mg/L shall be maintained. The aeration tank shall be supplied with process air using surface aerators, and the level of noise of surface aerators shall be seriously considered and permanent concrete structure integrated with the structural design of the tankers shall be provided to cover the surface aerators. Designed size of de aeration tank or gas removal tank shall also be constructed to achieve removal of gases contained in the activated sludge exiting from aeration tank and before entering the clarifier and it shall also be equipped with scum removal, scum collection hopper, pipe with valve connected on the by-pass of the station to isolate the clarifier. Redox measurement device, dissolved Oxygen Measuring Device and Nitrate Measuring Devices shall also be supplied and installed. Dead spots shall be eliminated by providing baffle walls and fillets to corners of tanks where necessary. A minimum freeboard of 0.75 m shall be provided in all aeration tanks, and suitable arrangements shall be provided for draining aeration tanks. The inlet and outlet channels and or pipework shall be designed to permit any of the individual tanks to be taken out of service. 4.4.2.BIOLOGICAL TANKS MIXING The aeration, anoxic and pre-anoxic tanks shall be provided with mixing equipment’s to ensure that sludge remains in suspension in the mixed liquors at all times. The mixers shall be mounted in a way that allows them to be lifted easily from the tank for inspection and maintenance. A permanent suitable lifting mechanisms shall be installed on the treatment plant site for this purpose. The design shall include a system for the removal of foam. 4.4.3.AERATION SYSTEM Aeration systems shall be designed to maximize oxygen transfer and to react to the changing oxygen demands in biological treatment systems using surface aerators. Consideration should Page 72 of 135

  27. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements be given to the separation of aeration and mixing mechanisms in aeration tanks where appropriate to maximize energy efficiency. The aeration system shall be capable of delivering maximum air requirements with the largest single unit out of service, capable of delivering at least 150 per cent of the air requirements based on the maximum design loading. The aerators shall be supplied and installed as a duty and standby to give non-stop full time service during operation and maintenance, and the quantities of aerators shall be as per the final approved design. The Contractor’s design shall be such that it is feasible to carry out performance testing of the aeration system on a full-scale section of the plant. The DB contractor shall also supply and handover to the Employer one surface aerator and agitator to the Employer, which can be installed at later stage incase one of the equipment failed to operate. 4.4.4.INTERNAL RECIRCULATION SYSTEM The contractor shall ensure the necessary quantities of the mixed liqiuor are re- circulated from the aeration tanks to the anoxic tanks to meet the effluent limits set for nitrogen in Technical Requirements. The mixed liquor that shall be re-circulated shall be 200% to 500% of the design flow. 4.4.5.RETURN ACTIVATED SLUDGE SYSTEM The Contractor shall ensure the necessary quantities of sludge are returned to the activated sludge system to maintain the required mixed liquor suspended solids concentration of 3000 mg/l in the tanks. The system shall be such that the sludge from the final clarifiers shall be conveyed to a common collection pit / pumping station by gravity from where a part of the sludge is returned back to the pre-anoxic tank whereas the remaining (waste activated sludge) is pumped to the sludge treatment system. The returned activate sludge shall be 50% to 150% of the design flow. The DB Contractor shall provide adequate standby pumping capacity for both the return activated sludge and waste activated sludge. 4.4.6.SECONDARY CLARIFIER Page 73 of 135

  28. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements The mixed liquor produced from the bioreactors / aeration shall enter secondary / final clarifiers for the purpose of settling sludge, to give a final effluent quality to the standards set in the Employer’s Requirement. A minimum of two equal size circular concrete tanks shall be provided. The design of the tanks shall be based on either of the solid flux or surface overflow rate methods and each clarifier shall include a Clifford (calming cylinder), scraper arm, scum trough, scraper mechanism and an access bridge. The clarifiers shall be designed to stay below maximum solids loading rates (SLR) and surface overflow rates (SOR). The design of the clarifiers for surface overflow rate at average flow with all tanks in operation and with one tank out of service for maintenance, the minimum hydraulic retention time and the maximum solids loading rate shall consider the full operation of the system subject to the approval of the Engineer based on the final design output of the system. Settled sludge collected from the bottom of the secondary clarifiers shall flow from each clarifier to a sludge pumping station wet well via pipes underneath of the clarifiers. Some of the sludge shall be pumped to the upstream end of the bioreactors as return activated sludge (RAS) to be integrated back into the process to maintain biological activity. The remaining sludge shall be pumped to biological thickener then to aerobic digesters for stabilization prior to dewatering and disposal as waste activated sludge (WAS). Approved types of pumps shall be provided for RAS & WAS. As a minimum there shall be three RAS pumps (two duty, one standby) and two WAS pumps (one duty, one standby). Scum from the secondary clarifiers shall be pumped by one of the two scum pumps (1 duty, 1 standby) to the aerobic digester for stabilization. In all cases the following shall apply: •The tanks shall incorporate rotating bridge scrapers and scum removal systems; •Scum removed from the surface of the tanks shall not be returned with the return sludge; •The inlet pipe shall discharge within a feed well box or diffusion mechanism located at the centre of the tank. The Contractor’s design shall include for a means of removing scum from the feed well; •Sludge return pumps shall be capable of returning flows in the range not narrower than 0.5 to 1.5 times the average inlet flow. 4.4.TERTIARY TREATMENT Page 74 of 135

  29. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 4.5.1. DISINFECTION Secondary effluent that overflows from the secondary clarifiers merge into a downstream pit shall be disinfected before it is discharged in to the receiving water or put to reuse. A magnetic flow meter to measure the flow of secondary effluent upstream of the Chlorine disinfection units shall be installed. The disinfection facility shall have a minimum of two units and shall be designed to meet the bacteriological quality requirement stated in the Employer’s Requirement (ER). Chlorine / de- chlorination design shall be done and the de-chlorination facility shall be provided by the DB contractor if chlorination with sodium hypochlorite is preferred for the plant. Final disinfected effluent water drain through the concrete channel to a final 500 m3 effluent water holding tank to be constructed by the DB contractor. Two pumps (one duty, one standby) in the final effluent water holding tank shall provide plant service water to the Belt Filter Press, aeration tanks, RAS / WAS pumping station, Ferric Chloride room, grit vortex. The DB contractor shall also provide two pumps (one duty and one standby) to transfer the water to another water holding tanker at the elevated area in the compound for gravity draining to the landscape compound beautification of the university. The remaining final effluent water shall drain by gravity to the catchment or nearby lowest area water body or lake. All the pumps shall be installed and fixed in another concrete chamber with removable cover from top for safety and maintenance. The supernatant or residual water from all the plant services (screening, grit and grease removal, clarifiers, sludge treatment building, car washing, landscaping, irrigation, etc….) including operators’ toilets and showers shall be drained to all water station / return to the beginning of the plant for getting treated with new wastewater treatment flow. There shall be two pumps (1 duty and 1 standby) to operate automatically with level switches for this purpose. 4.5. SLUDGE HANDLING & TREATMENT OF PRIMARY SLUDGE Waste activated sludge (WAS) requires stabilization and dewatering prior to disposal. Stabilization shall be achieved by aerobic digestion, and the stabilized sludge shall be dewatered in a mechanical Belt Filter Press. Stabilized, thickened and dewatered material will be trucked to the landfill and used as cover material (in the case of employer’s readiness to acquire composting Page 75 of 135

  30. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements facility, the dewatered solids can be used for fertilizer). During periods when spreading does not occur, the material can be stockpiled 'at the landfill or drying bed or other Town property. 4.6.PRIMARY THICKENING SYSTEM There shall be primary thickening system of the primary sludge from the primary clarifiers prior to digestion. The gravity thickener shall be equipped with rotating primary thickening system mounted on a concrete bridge with gearbox and base plate. The rotating mechanism is made in stainless steel arranged in a herringbone manner with fasteners and central access. V-notches will allow the supernatant to return to start of the plant. The sludge will be extracted to aerobic digester. There will be one static thickener for the primary sludge. The Contractor’s design for primary sludge thickening shall consider the possibilities for flotation occurring in the thickening tanks due to the nature and composition of the wastewater. The Contractor shall provide full details of his proposed systems for approval by the Engineer for thickening primary sludge including details of energy requirements, and service life of major components. 4.7. PRIMARY SLUDGE STABILIZATION The thickened primary sludge from the gravity thickener shall be stabilized in a stabilization tank. The stabilization becomes through aeration of the sludge. The stabilization tank shall be designed for a minimum sludge retention time of 15 days. The aeration system shall be based on bottom aeration, with compressed air introduced into the tank by stainless steel tubular diffusers placed at the bottom of the tanks. The design of the system shall allow trouble free dismounting of each of the diffuser unit. 4.8. BIOLOGICAL SLUDGE THICKENING SYSTEM Sludge produced in secondary biological treatment processes shall be thickened to a minimum dry solids content of 4% by gravity thickeners. CO-thickening with primary sludge is not allowed. The gravity thickener shall be equipped with bottom suction scrapers. The scrapers are to operate automatically. The design of the scrapers shall be adequate compared to the specific layout of the tanks. Page 76 of 135

  31. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements The supernatant shall overflow through double V-notched overflow weirs that will be mounted in each sludge thickener tank to create tranquilly hydraulic conditions, for the sludge to settle unhindered. The Thickener shall be fitted with sludge blanket detection system. Tanks shall be designed to provide a minimum hydraulic retention time of 15 hrs at maximum daily sludge flow rates, with bottom slope of about 7%. The Contractor shall provide full details of his proposed systems for thickening biological sludge including details of energy requirements, and service life of major components. 4.9. AERATED SLUDGE MIXING TANK The thickened and digested primary sludge shall be mixed with the thickened biological sludge in a mixing tank prior to dewatering. The mixing tank shall be designed for a minimum detention period of 2 days. The dewatering facility shall be operated for 7 days per week and 10 hrs per days. Consequently, the mixing tank shall also be used as a balancing tank. Aeration shall be used not for the stabilization of the sludge but for mixing. The aeration system shall be based on a concrete tank in which there will include 4 surface aeration system which will assure mixing within addition to submersible mixer. 4.10. STABILIZED SLUDGE HOLDING AND DEWATERING Stabilized sludge from the aerobic digester shall be mixed in the solid holding tank by a mixer located in the aerobic digester. The digested sludge from the holding tank shall be fed by two pumps (one duty, one standby) to the Belt Filter Press in the Solids dewatering building, adding polymer to the feed pipe to enhance dewatering. The thickened and digested sludge from the mixing tank shall be dewatered to a minimum dry solid concentration of 20%. The quality of filtrate produced during dewatering shall be to the highest possible quality. The dewatering unit provided shall be capable of handling the sludge quantity produced at the treatment plant at all times. The Belt Filter Press plant shall be designed for the continuous dewatering of all types of sludge with very effective ratio of performances versus running costs, comprising of a stainless steel structural frame, highest quality filter belts, sludge distribution system, gravity filtration section, pre-pressing stage, pressing section, belt tensioning system, Page 77 of 135

  32. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements belt alignment system, cake discharge, belt drive system, belt washing system, drainage system, stainless steel fasteners, rollers, bearings and bearing housings, safety devices, electrical connection, compressed air system, odor extraction cover, wash water pump, and sludge discharge Conveyor. The plant has to be operated 5 days per week, 6-8 hrs per day and the dewatering systems shall be fully enclosed within a building. The whole plant shall be capable of automatic operation without plant operators permanent presence and it shall be a complete high-performance dewatering system. In order to provide for maintenance, the contractor shall supply and install a suitable lifting device, located directly over such unit, of capacity 50% in excess of the total unit dead weight. The Contractor shall provide and handover to the Employer sufficient quantities of complete set of additional spares including tools and accessories for easiness of any future maintenance which can serve for at least for five years of operation, and shall also be provided with an easy regular cleaning mechanisms of the system. For all the plant system on test report, product quality certificate and all other certifications shall be provided for approval by the Engineer. 4.11. CHEMICAL DOSING SYSTEM Chemicals shall be added throughout the process to enhance removal of contaminants and control conditions, dosed from tanks in the Solids dewatering and disinfection building. Polymer shall be added to the digested sludge prior to dewatering in the GBT and BFP to enhance dewatering. The sludge shall be conditioned with polymer prior to dewatering. The polymer make-up system shall be suitable for the sludge type, specified sludge through put and the type of the mechanical device. The systems shall comprise make-up units transfer pumps, mixer, polymer sludge mixing flocculator, polymer storage, electromagnetic flow metre, sludge feeding pumps, and dosing pumps operated on a duty and standby basis. Potable water shall be used for initial dilution of the polymer. Treated final effluent may be used to prepare the final dosing solution. The polymer make- up system shall be supplied complete with all necessary pipework, valves and instrumentation. The polymer preparation and dosing system shall be in the dewatering building. It shall be provided in a bunded area to control spillage which shall be drained without causing contamination or blockage to other areas of the WWTP. Adequate clean and dry space shall Page 78 of 135

  33. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements be provided for storage of liquid or powder polyelectrolyte. The minimum bund capacity shall be 110% of the tanks with in the bund. The bund design shall allow for access for routine visual inspection and maintenance. The Contractor shall ensure that the installation is designed so that the risk of spillage is minimized. In choosing the system, emphasis shall be placed on efficiency with respect to space required, labor input for operation and maintenance, chemical and energy usage. 4.12. RETURN LIQUOR Liquors generated during sludge treatment shall be returned for treatment in such a manner that any adverse effect of shock loads on treatment process is avoided. 4.13. AUTOMATION Key processes within the WWTP shall be controlled, regulated and monitored through a centralized telemetry system. The Contractor shall supply full details of his proposals for approval in this regard. The system shall have restricted web-based access to allow the Employer and Employer's Representative to remotely view data generated by the system. 4.14. TREATED EFFLUENT RE-USE Treated effluent may only be re-used as wash water where there is no requirement for manual handling or direct human contact. The plant design shall include 500 m3 concrete water tanker to reserve the finally treated water for irrigation and compound watering purposes. Water pumps shall also be provided for pumping of the treated water to the water tanker existing around the highest elevation level in the compound, for watering the compound landscaping and nearby irrigation areas. 4.15. WEATHER STATION The Contractor shall provide an automated weather station at the Wastewater Treatment Plant, which shall be designed to measure rainfall, temperature, atmospheric pressure and wind direction. The weather station shall be linked to the telemetry system at the Wastewater Treatment Plant to give continuous data. The Contractor shall consult with Ethiopian Meteorological Agency before deciding on the position of the weather station to Page 79 of 135

  34. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements ensure that the optimum location is found. The Contractor shall also provide a windsock in a position to be agreed with the Employer's Representative. 5.MONITORING, SAMPLING AND TESTING EQUIPMENT 5.1.FLOW PARAMETERS Flow measurement devices shall be installed to measure the following: •Volume and flow rate of wastewater influent •Volume and flow rate of treated wastewater discharged from the Works •Volume and flow rate of wastewater by passed •Volume and flow rate of internal recirculated mixed liquor •Volume and flow rate of return activated sludge •Volume and flow rate of waste activated sludge •Volume and flow rate of primary sludge •Volume and flow rate of thickened primary sludge •Volume and flow rate of thickened biological sludge All meters and other flow measurement devices shall be sited to avoid interference from flow turbulence and shall be accurate to within the following tolerances: Sewage: ± 1% Sludge, RAS, WAS: ± 3% Open channel (Parshall Flume): ± 3% The Contractor may include any additional flow monitoring; where it is considered necessary, at locations to be determined by the Contractor in the design. The flows shall be measured on a continuous basis by means of flow meters that are based upon ultrasonic (open channel) or electro-magnetic measuring principles. In addition, measurement at the inlet prior to preliminary treatment and at outlet of the Wastewater Treatment Plant shall be measured with open channel fitted with an ultrasonic level device. Flow measurement with an open channel flume shall be calibrated in accordance with the manufacturer’s instruction. Safe access shall be provided at open channel flumes to allow visual inspection and the taking of samples. A remote monitoring interface which shall allows an automatic communication with duty operators in case of problems on any installation, plus to collect and manage all of the operating data shall be installed in the operator building equipped with a laboratory and a workshop, which must be built by the DB Contractor to facilitate the work of the operators and the maintenance. Page 80 of 135

  35. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 5.2.SAMPLING AND TESTING EQUIPMENT Sampling equipment shall be provided at every places where samples are required to be taken including but not limited to the Inlet, after Preliminary Treatment, Primary Effluent, Pre- anoxic Tank, Anaerobic Tank, Anoxic Tank, Aeration tank, Treated Effluent, Primary Sludge, Return Activated Sludge, Biological Excess Sludge, Primary Thickened Primary Sludge, Stabilization Tank, Thickened Biological Sludge, Sludge Cake, Return Liquor from Primary Thickener, Return Liquor from Biological Thickener, and Return Liquor from Dewatering unit. The Contractor may include any additional sampling equipment, where it is considered necessary, at locations to be determined by the Contractor in the design. Sampling of the wastewater at the various locations shall be carried out using automatic flow proportional sampling units. The Contractor shall ensure that the sampling point at the outlet of the Wastewater Treatment Plant has suitable safe access to allow for the taking of grab samples of the treated wastewater before discharge to the outfall. The Contractor shall also provide on line process measurement devices to measure Flow, pH, Temperature, Pressure, Liquid level, Sludge level, Suspended solids, Dissolved Oxygen, Redox potential, Chlorine residual, Nitrate / nitrite, Phosphate, etc. 5.3.SITE LABORATORY AND EQUIPMENT The Contractor shall provide an onsite laboratory and supply all the necessary testing equipment that are required for proper plant operation and monitoring. The laboratory shall be of sufficient size and fitted out to enable the Contractor to complete t he duties specified in the Employer's Requirements for the Operation and Maintenance of the Treatment Plant. The testing equipment shall include but not limited to: • • • • • • • • • • Furnace Homogenizer Spectrophotometer, Drying Oven Vacuum pump Analytical balance Imhof cone Magnetic stirrer Water bath Centrifuge Page 81 of 135

  36. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements • • • • • • • • • Incubator chamber Thermo reactor, BOD manometric measurement kit pH and conductivity meter. Sterilizing oven Amperometric titrator Desicator Vibrating shaker Turbidity meter. Page 82 of 135

  37. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT Employer’s Requirements 6.SPECIFIC PROCESS REQUIREMENTS The Contractor shall follow the process design requirements set out below. 6.1.PROVEN TECHNOLOGY The Contractor shall use only treatment process, plant and equipment under the selected technology that: •have been shown to operate satisfactorily and consistently on at least three municipal wastewater treatment plants of similar or greater sizes and in similar climatic conditions that are prevailing at the site; •shall be the most modern and up to date without entailing excessive cost. Full details of the processes, plant and equipment being offered shall be submitted with the tender. 6.2.OPERATIONAL FLEXIBILITY The Contractor shall ensure that operational flexibility is given through the wastewater treatment plant design by adoption of the following principles •The provision of standby facilities, •The provisions of unit by unit and total plant bypasses, to maintain plant operability during emergency, maintenance and / or breakdown, •The standardization of plant components, where practicable, to permit interchangeability and reduction of spare parts holdings, •The contractor shall adopt a modular approach noting that the full design flow may not be available at the beginning and early years of the operation of the plant. In selecting the appropriate modular system, the contractor shall also give due consideration to testing and commissioning of the whole plant when only a partial of the design flow is available during this period. 6.3.STANDBY CAPACITY The Contractor shall ensure that sufficient standby capacity is provided to maintain the operation of the wastewater treatment plant on a continuous basis in the event of breakdown or planned maintenance. 6.4. SPACE FOR MAINTENANCE An adequate amount of space shall be provided around plant and equipment to ensure that operational tasks and maintenance can be carried out safely and efficiently. Page 83 of 135

  38. JINKA UNIVERSITY DESIGN, BUILD AND OPERATE WASTEWATER TREATMENT PLANT PROJECT 6.5. Employer’s Requirements FLOW MEASUREMENT The flow through the wastewater treatment plant shall be measured at the following locations •At the inlet to the wastewater treatment plant prior to preliminary treatment •Before secondary treatment on every stream, •At the outlet of the wastewater treatment plant •At the outlet of the disinfection unit •On Internal Recirculation lines, On RAS and WAS lines •On all bypass flows •On potable water lines • A weighing system for dewater sludge shall furthermore be established. The Contractor may include any additional flow monitoring; where it is considered necessary, at locations to be determined by the Contractor in the design. The flows shall be measured on a continuous basis by means of flow meters that are based upon ultrasonic (open channel) or electromagnetic measuring principles. Flow measurement with an open channel shall be calibrated in accordance with the manufacturer’s instructions. Safe access shall be provided at open channel flumes to allow visual inspection and the taking of samples. 6.6. SAMPLING LOCATIONS Sampling equipment shall be provided at every places where samples are required to be taken including but not limited to the Inlet, after Preliminary Treatment, Primary Effluent, Pre-anoxic Tank, Anaerobic Tank, Anoxic Tank, Aeration tank, Treated Effluent, Primary Sludge, Return Activated Sludge, Biological Excess Sludge, Primary Thickened Primary Sludge, Stabilization Tank, Thickened Biological Sludge, Sludge Cake, Return Liquor from Primary Thickener, Return Liquor from Biological Thickener, and Return Liquor from Dewatering unit. The contractor may include any additional sampling equipment, where it is considered necessary, at locations to be determined by the Contractor in the design. Sampling of the wastewater at the various locations shall be carried out using automatic flow proportional sampling units. The Contractor shall ensure that the sampling point at the outlet of the WWTP has an open section suitable safe access to allow for the taking of grab samples of the treated wastewater before discharge. Page 84 of 135

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