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Wastewater Treatment Plant

Introduction

Under the visionary leadership of Sheikh Mohamed Bin Rashid Al Maktoum vice president and prime minister of UAE and Ruler of Dubai, Palm Jumeirah township was inaugurated as an iconic project constructed off the coast of the emirate of Dubai. The project was built in the shape of a palm and has extended the stretch of Dubai coastline by more than 120 km. As Palm Jumeirah is the only modern structure seen from space, so is Metito’s on-site sewage treatment plant achieving many firsts.

Being host to some of the world’s renowned dignitaries and celebrities meant that all associated utilities demanded challenging innovations, adherence, and commitment to maintaining the highest standards of environmental protection and architectural aesthetics. The location of the plant on prime land left extremely limited space for plant buildings and respective facilities. Architecturally, the treatment plant is inside a circular building constructed below ground to keep it invisible. The given geometry, limited space and underground conditions presented a very difficult task of arranging the equipment, facilities, and utilities. Metito employed the MBR (membrane bio-reactor) process technology which is the latest technology in treating waste. This process requires a considerably reduced footprint than other conventional schemes and has the added advantage of producing high-quality treated water.

Special designs were adopted for an approach to allow operational access and equipment maintenance. Limited headroom dictated the use of a specially designed serpentine monorail that covers the whole workspace. The status of the location demanded zero tolerance for any unpleasant odor emissions.

The ventilation system, dehumidifier and odor control units in the workspace were carefully designed taking into consideration these stringent demands.

Scope of Work

This included the detailed engineering, manufacture, inspection, supply, storage, installation, testing and commissioning, start-up, performance test and training of personnel at site. It also included operation and maintenance of the plant for eight years.

Plant General Information

The sewage treatment facility mainly comprises the following units:

  • Inlet-works
  • Biological treatment
  • Sludge handling
  • Chemical cleaning
  • Electrical and control system

Plant Technical Characteristics

Raw sewage from the residential community is transferred to a main sewage lift station through two intermediate pumping stations.

The sewage treatment plant is designed to treat 18,000 m3/day of domestic sewage. The collected raw sewage is received through a 600 mm diameter underground main, and the incoming flow is metered before it enters the treatment units.

Plant Data Summary

Average daily flow 18.000 m3/day
Peak daily design flow 21.700 m3/day
Peak factor 2.5
Peak hourly flow 1875 m3/hr
Peak flow duration 2 hours

Influent Analysis

Temperature 22 -35 0C
BOD5 250 mg/l
COD 500 mg/l
TKN 55 mg/l
Assumed biodegradable TKN 50 mg/l
Suspended solids 250 mg/l
Phosphates 8 mg/l
Alkalinity Min. 210 mg/l
Oil & Grease < 40 mg/l
pH 6 – 9
Ammonia nitrogen 35 mg/l
Ambient Temperature 10 minimum

50 maximum

0C

0C

 Treated Water Quality

BOD < 10 mg/l
COD < 50 mg/l
TKN < 5 mg/l
Suspended Solids < 10 mg/l
Ammonia – Nitrogen NH3(N) < 3 mg/l
Total Nitroge (TN) < 30 mg/l
Fecal Coliform < 10 mg/l

Process Description

Inlet Works

Metered raw sewage from the mains is released into a concrete channel through two 3mm perforated plate fine screens operating on a duty/standby basis. While screenings are removed, the screen surface is cleaned by spray nozzles as the basket is rotates. For clean and easy handling, the collected waste from the screens is compacted and dewatered up to 40% w/w. A Vortex type grit removal system with grit classifier is installed after the screens to remove heavy grit particles.

Partially treated raw sewage enters two compartment equalization tanks The tank is constantly purged with enough air to maintain the sewage in agitation and prevent it turning septic.

Downstream membrane treatment is divided into six process trains to cater for plant turndown and to provide flexibility in operation. The common pump sump has six duty/ six standby feed pumps dedicated to transfer sewage to the Anoxic tanks.

The biological treatment of each process train comprises the following process units:

Anoxic Tank

The anoxic tank receives partially pretreated equalized sewage that has been intimately mixed with recycled flow from the anoxic recycle pumps. The returned flows contain nitrate due to the nitrification of ammonia in the membrane tank. Bacteria utilize the soluble and particulate COD in the incoming sewage to effect de-nitrification under anoxic conditions. Submerged mixers in each anoxic tank keep the bacteria in suspension and homogenously mixed with the soluble nitrate.

Aeration Tank

Sewage from the anoxic tanks passes to the aeration tanks by gravity. The aeration tanks provide an aerobic environment to ensure nitrification of ammonia and oxidation of BOD achieved by the provision of high efficiency fine bubble diffused aeration. The air supply to the diffuser system is monitored and controlled automatically to maintain optimum residual dissolved oxygen (DO) concentration in the tanks.

Membrane Bioreactor Tanks

Six membrane bioreactor tanks serve the function secondary aeration tank, whilst also assisting in the provision of air for the biological degradation processes. Each membrane tank contains 12 membrane units arranged in a double-deck configuration. To prevent surface, fouling, and membranes are continuously scoured by air supplied through diffused air pipe distributors below the membrane block.

Provision was made to chemically clean the membranes, if and when required. A diffuser flushing system is used to periodically flux the coarse bubble diffusers. Flux rate control is a critical operational feature hence flow through the membranes is controlled by modulating the permeate control valve to required flowrate through the flow meter on the permeate line.

Recycle Pump Control

The recycle pumps are subjected to intermittent operation to ensure a maximum recycle rate it low flow conditions. Intermittent operation is set according to the pre- determined schedule by a PLC.

Disinfection

The membrane process removes a large portion of bacteria from the sewage. Chlorination using sodium hypochlorite is imparted into treated streams to remove or inactivate any pathogenic bacteria that may grow in the tanks.

Sludge Digestion and Handling

Biological sludge is pumped to sludge digesters where it is digested and stabilized under aerobic conditions. Digested sludge is pumped to a dewatering centrifuge to produce sludge of 20 – 25% dryness. Concentrate from the centrifuge is returned to the plant inlet for recovery.

Electrical and Control Equipment

This includes state of an art SCADA system, PLC control panels, and MCCs. SCADA is implemented with a graphical depiction of the process as well as the graphical representation of process parameters and plant data that is also archived and retrievable. Power to the STP plant is fed from the facility substation which is equipped with dual incomers mains supply from DEWA as well as emergency supply from a generator. The design of the control equipment has taken into consideration the necessity for separate and independent operation of the MBR streams. so that failures in the control equipment associated with one stream will result in the shutdown of the affected stream only.

Project execution involved complying with the international standards and specifications drawn by the consultants. Important factors such as availability of plant, efficient use of manpower, high reliability and simplicity of maintenance have been considered in the design. The plant utilized minimum space whilst maintaining the overall architectural requirements. Technically, it provided a modern up to date process that ensures consistent water treatment quality. Metito completed this most challenging task to the entire satisfaction of the owner, and the successful operation of this entire complex was subsequently managed by Metito’s workforce.

Treated Sewage Effluent Polishing Plan, Mixed Bed Bio-Reactor (MBBR/Ultra-Filtration/ Reverse Osmosis)

Introduction

Dubai Parks and Resorts is an iconic project and the Middle East’s largest multi-themed leisure, entertainment, and theme park destination. The establishment is located on Sheikh Zayed road in Dubai, UAE, strategically located midway between Dubai and Abu Dhabi International Airports. Dubai Parks and Resorts is spread over 25 million square feet and features more than 73 attractions and rides spread across three theme parks: Motiongate Dubai, Bollywood Parks Dubai and Legoland Dubai. The park also includes: Lapita, a global Marriott operated family resort hotel (known as Hotel Lapita’’); River park; and a complementary and centrally located retail, dining and entertainment district connecting the three theme parks and the hotel.

An integral part of the infrastructure development for Dubai Parks and Resorts is the Lagoon which is strategically constructed across the establishment to enhance the overall landscaping and beautification of the resort. Considering the year round hot climate in the UAE, it is expected that the lagoon water may experience considerable evaporation. To address this challenge the Treated Sewage Effluent Polishing Plant, Mixed Bed Bio-Reactor (MBBR/Ultra-Filtration/Reverse Osmosis) project was developed as a sustainable solution.

Scope of Work

The scope of works awarded to Metito included the complete design engineering (process, mechanical, electrical, automation & control), equipment supply, and the installation and commissioning of the treatment process system and plant.

  • TSE Polishing: In this package, water from five streams: TSE water from Dubai Municipality and Dubai Parks STP: cooling tower blowdown and spent backwash water from carbon filters, UF systems and high-rate sand filters of the side stream filtration, are all treated by the UF-RO system to produce makeup water for the lagoon.
  • Side Stream Filtration: Overflow water and water drawn off by skimmer pumps from the lagoon is treated in high-rate sand filters and UV units to remove suspended impurities and disinfect the water. The disinfected water is then aerated and discharged back into the lagoon.
  • Pool Water Filtration & Chlorination: Overflow water and water is drawn by skimmer pumps from the Water Wheel Pool, another attraction in Dubai Parks, is passed through Dual Media Filters. Filtered water is then chlorinated to disinfect the water and discharge back into the pool.
  • Pumping Stations: The scope of work in this package is limited to providing the pumps and associated valves and piping for subsequent uses.

Key Benefits 

Dubai Parks and Resorts is a destination designed to be one of the most environment-friendly developments of its kind. Extensive landscaping and eco-friendly policies underline its focus on a green, clean environment. With the lagoon being an integral part of the destination landscaping, developing the TSE Polishing Plant as a solution to treat, recycle and reuse water as makeup water for the lagoon has many benefits:

  • The solution offers a more economically viable alternative for water provision compared to using other water resources for makeup water
  • The utilization of environmentally friendly and energy saving technology lowers the environmental footprint to a minimum, in line with the policies implemented across the establishment

Water Treatment for South Bangkok Combined Cycle Power Plant Stage II

Introduction

To cater for the increasing demand for power and for the surge in industrial needs, the Electricity Generating Authority of Thailand (EGAT) decided to build stage II of the South Bangkok Combined Cycle Power Plant to produce an additional 744 MW of power. The multi-million dollar contract was directly awarded by EGAT to Metito against international competition. The project demanded execution to the most stringent requirements laid down by EGAT and their consultants Black and Veatch International, Kansas City and Sindhu Pulsirivong Consultants, Bangkok. The complete works including the performance guarantee tests had to be executed within the jurisdiction of ASME codes, and the project had to be completed within a critical time frame. Metito took on the challenge, and fully performed to the satisfaction of the respective authorities.

Scope of Work

The scope included the complete design, engineering, manufacture, supply, inspection and testing, fabrication, installation, commissioning and performance test of the water and wastewater treatment packages which comprise the following:

  • Circulating water make-up treatment system utilising four automatic cyclone separators to treat a flow of 3780 m3/h. The system clarifies water from the Chao Phraya river, where suspended solids level varies widely due to strong tidal influences
  • Ion exchange demineralization plant for cycle make-up system with a capacity of 147.6m3/h, including activated carbon filters, primary cation exchangers, forced draft degasser, primary anion exchangers and a mixed bed polisher, all in two 50% streams
  • Chemical waste collection and treatment system operating on a 600 m3 batch treatment principle
  • 90 m3/day extended aeration sanitary drainage & treatment system
  • Auxiliary water supply units – 150 m3/h each
  • Miscellaneous mechanical and architectural services along with HVAC, lighting, fire protection and communication systems
  • DCIS based complete control systems for overall plant operation

Key Benefits

  • A total solution for the power plant water and wastewater treatment needs
  • An efficient design that takes into consideration the stringent requirements laid down by the owner and the project manager
  • Client ease of mind since all packages are handled by one contractor, Metito
  • A reliable plant that takes into consideration the varying quality of the feedwater
  • A safe proof design that meant trouble free operation and minimum downtime
  • Timely execution which was imperative for startup of the power plant
  • Full local support from a well established company with ‘’Local Presence and Global Knowhow’’

Storm Water Pumping Station

Introduction    

Aligning to its mission of achieving sustainable development in planning, establishing and maintaining infrastructure projects and optimising the national-housing the national-housing sector through outstanding performance, The Ministry of Infrastructure Development awarded Metito the project to construct PS1OB Storm Water Pumping Station and Rising Main from Sheikh Mohammed Bin Zayed Road to the Golf near Al Khan area.

This fourth phase of upgrading the Fifth Industrial Square in Sharjah is aimed at providing the city with a new Pumping Station and Rising Main for efficiently handling potential Storm Water in Industrial Area 5. The station has a total capacity of 345,600m3/day making it the biggest of its kind in the GCC.

Furthermore, the project features 1800mm diameter Rising Main to discharge storm water from a new drainage system at the E311 highway of the Fifth Industrial Square in Sharjah to the sea in Al Khan area.

Scope of Work 

The pumping station consists of an inlet screen area and three sumps: A, B and C.

These sumps are provided to host three different sets of pumps which discharge the collected storm water to the sea. Sump A houses Storm Water Pumps (SWP01/02/03), Sump B houses the Dry Weather Flow Pumps (DWFP01/02/03), and Sump C houses the future Storm Water Pumps (SWP04/05/06).

The inlet screen area consists of the following units:

  • Bar Screen installed at the inlet of this pumping station to avoid rubbish delivered to the pumping station. This screen must continuously be removed and cleaned to protect the pumps chambers.
  • Mechanical bar screens (SC01/02/03)
  • Screen screw conveyor(C01)
  • Screening compactor (CM01)
  • Washing water system which serves the Washing Pumps (WP01/02) and the Washing Water Storage tank (TK01)

Key Benefits

In case of floods, due to heavy rain during the winter season, the storm water drainage system will divert the storm water and rainfall to the PS10B Storm Water Pumping Station will then discharge it to the sea through the pipeline and outfall system. This will help ensure that no environmental, physical or other damages occur in the area’s infrastructure and surroundings which makes it a progressive and sustainable solution that is both cost saving and preventative.

Seawater Reverse Osmosis Plant

Introduction

Due to Egypt’s scarce water resources, and the rising demand between the supply and demand of water, the country is embarking into a strategic direction to capitalize and further focus on seawater desalination as a key source for municipal water supply, particularly for coastal areas.

Accordingly, the Egyptian Government has launched the Al-Yosr project in the city of Hurghada, Red Sea Governorate, to construct a Seawater Reverse Osmosis Desalination Plant with a capacity of 80,000m³/day to produce water with potable standards for drinking purposes to serve the city and a population of more than 500,000 residents.

Metito was awarded the project based on its extensive engineering experience and history with developing desalination projects and its world class quality process design, construction, operation and maintenance of plants utilising the Reverse Osmosis technology.

As part of the mandate set by the Egyptian Government, Al-Yosr SWRO plant was realised as the first large SWRO in Egypt.

Scope of Work

The scope of work included:

  • Detailed engineering for the full plant which included: intake works, civil works, process and electrical works and delivery of all equipment, material, and spare parts
  • Installation, commissioning and startup
  • Onshore & offshore Training
  • Full operations and maintenance

The plant consists of:

  • Raw water intake system
  • Chemical pre-treatment
  • Multi-Media Filtration
  • Micron Filtration
  • Desalination with Double Pass Reverse Osmosis System
  • Energy Recovery System (by Isobaric Pressure Exchangers)
  • Post Treatment – Langelier Saturation Index adjustment by:
    • Lime stone Contactors
    • CO2 Injection System
    • Degasser with Blending Tank and Pump station
  • Water treatment laboratory
  • Stand-by generators covering 50% of plant capacity
  • Step-down transformers and substation
  • Medium and low voltage distribution system
  • Instrumentation, controls, and SCADA system

Key Benefits

  • A comprehensive solution: Al-Yosr SWRO is a total solution for the potable water shortage crisis in the city of Hurghada and a progressive approach aimed at coping with the expected
    future growth in population and demand.
  •  Economic viability: Al-Yosr is a large reverse osmosis plant that is in-line with Egypt’s strategy to utilize seawater desalination for the supply of municipal water in remote coastal areas. This solution offers a more economically viable alternative for water provision compared to using transfer pipelines extended for over 200km from the Nile River.
  • Trouble free operation: Utilizing novel and reliable technology and integrating it across the design of the plant lead to minimum downtime and more sustainable operations.
  • Energy Savings: Utilising state of the art technology in energy recovery lowers the plant energy consumption and carbon footprint to a minimum.
  • Safe and clean water supply: Product water remineralization systems ensure the supply of high quality water to consumers as well as protect the city water distribution pipe grid. The treated water quality meets international standards and the most stringent requirements for potable water achieving permeate water with Boron levels less than 0.5 mg/l.

Treated Sewage Effluent Polishing Plan, Mixed Bed Bio-Reactor (MBBR/Ultra-Filtration/ Reverse Osmosis)

Introduction

Dubai Parks and Resorts is an iconic project and the Middle East’s largest multi-themed leisure, entertainment, and theme park destination. The establishment is located on Sheikh Zayed road in Dubai, UAE, strategically located midway between Dubai and Abu Dhabi International Airports. Dubai Parks and Resorts is spread over 25 million square feet and features more than 73 attractions and rides spread across three theme parks: Motiongate Dubai, Bollywood Parks Dubai and Legoland Dubai. The park also includes: Lapita, a global Marriott operated family resort hotel (known as Hotel Lapita’’); River park; and a complementary and centrally located retail, dining and entertainment district connecting the three theme parks and the hotel.

An integral part of the infrastructure development for Dubai Parks and Resorts is the Lagoon which is strategically constructed across the establishment to enhance the overall landscaping and beautification of the resort. Considering the year round hot climate in the UAE, it is expected that the lagoon water may experience considerable evaporation. To address this challenge the Treated Sewage Effluent Polishing Plant, Mixed Bed Bio-Reactor (MBBR/Ultra-Filtration/Reverse Osmosis) project was developed as a sustainable solution.

Scope of Work

The scope of works awarded to Metito included the complete design engineering (process, mechanical, electrical, automation & control), equipment supply, and the installation and commissioning of the treatment process system and plant.

  • TSE Polishing:In this package, water from five streams: TSE water from Dubai Municipality and Dubai Parks STP: cooling tower blowdown and spent backwash water from carbon filters, UF systems and high-rate sand filters of the side stream filtration, are all treated by the UF-RO system to produce makeup water for the lagoon.
  • Side Stream Filtration:Overflow water and water drawn off by skimmer pumps from the lagoon is treated in high-rate sand filters and UV units to remove suspended impurities and disinfect the water. The disinfected water is then aerated and discharged back into the lagoon.
  • Pool Water Filtration & Chlorination:Overflow water and water is drawn by skimmer pumps from the Water Wheel Pool, another attraction in Dubai Parks, is passed through Dual Media Filters. Filtered water is then chlorinated to disinfect the water and discharge back into the pool.
  • Pumping Stations:The scope of work in this package is limited to providing the pumps and associated valves and piping for subsequent uses.

Key Benefits 

Dubai Parks and Resorts is a destination designed to be one of the most environment-friendly developments of its kind. Extensive landscaping and eco-friendly policies underline its focus on a green, clean environment. With the lagoon being an integral part of the destination landscaping, developing the TSE Polishing Plant as a solution to treat, recycle and reuse water as makeup water for the lagoon has many benefits:

  • The solution offers a more economically viable alternative for water provision compared to using other water resources for makeup water
  • The utilization of environmentally friendly and energy saving technology lowers the environmental footprint to a minimum, in line with the policies implemented across the establishment

Industrial Water Treatment Plant

Introduction

Maáden Waád Al Shamal Phosphate Company (MWSPC) planned the development of Waad Al Shamal area in the northern region in 2010 in line with the Kingdom of Saudi Arabia strategy to establish new industrial areas similar to that of Jubil.

Project development is set to be done in phases and the first phase comprises the development of a fertilizer factory at Waad Al Shamal that is expected to export 90% of its daily production.

The MWSPC awarded Metito the raw water treatment package under a utilities contract which covers the following scope of work: design, engineering, procurement, supply, installation and commissioning, all on a fast track basis to meet the deadline and start operations in 2016.

To MWSPC satisfaction, Metito secured all requirements within the committed budget and successfully delivered and commissioned the plant within the desired timeframe.

Umm Wu’al Phosphate Fertilizer Plant is located in Sirhan-Turaif region, approximately 40 kilometres from the city of Turaif and approximately 100 kilometres to the west of Maaden Phosphate Company complex at Haram Al-Jalamid.

Scope of Work

Metito developed the raw water treatment package for supplying the demineralised water required for the fertilizer factory, utilities and boiler. Under this scope Metito was responsible for:

  • Securing delivery of the equipment, tools and spare parts
  • Commissioning and startup of the complete scope
  • Onshore / offshore operation and maintenance training

Securing the following systems and processes:

  • Pre-Treatment Package (PTP)
    • Sand filtration system
    • Degasification system
    • Ultra filtration system
    • Micron filtration
  • Desalination with double pass reverse osmosis system
  • Second pass desalination plant
  • Co2 injection system
  • Demineralization package including anion / cation and mixed bed polishers complete with chemical injection package
  • Condensate polisher package including anion/cation and mixed bed polishers complete with chemical injection package
  • Potable water package complete with calcite filters and chemical treatment
  • Chiller water system
  • Complete chemical injection system for the entire plant

Key Benefits

  • A total solution for the industrial water treatment needs of this establishment
  • Efficient design that takes into consideration the stringent requirements laid down by the owner
  • Reliable and safe proof design that meant trouble free operation and minimum downtime
  • Timely execution which was imperative for the startup of the plant by the tight deadline
  • Full local support from Metito, a well established company with local presence and global knowhow, ensuring ongoing support