The One City One Operator model marks a paradigm shift in India’s sewage management as a one stop solution for sewage management of an entire city.

Project Highlights

• Operation, Maintenance and Management of the sewage treatment and network infrastructure in the cities of Agra and Ghaziabad
• O&M of 22 STPs (670 MLD), 22 PS and underground network of > 3,000 km
• O&M period: 10 years (2019-2029)

The Koyambedu Tertiary Treatment Reverse Osmosis (TTRO) Plant, designed and built by WABAG in consortium with IDE is one of the largest and technologically most advanced water reuse plants in India. The project marks a decisive step in the direction of municipal water recycling, thereby promoting an alternative and viable model for urban water governance.

Project Highlights

• Pre-disinfection and Pre-oxidation using Chlorine dioxide dosing
• Advanced pre-treatment with dual media rapid gravity filter
• Waste water polishing using state-of-the-art Ultrafiltration(UF) system
• 3 stage Reverse Osmosis(RO) system to achieve an excellent overall recovery of 80%
• First reuse plant in the country to integrate Ozonation technology for disinfection
• Technological excellence saves over 1600 crore litres of fresh water every year
• DBO contract with 15 years O&M

Wastewater Infrastructure – A necessity to bolster sustainable growth in GCC

In recent years, Bahrain has proved itself to be a front runner in the quest for development not only in the Middle East but the entire globe. Considered one of the best places to reside in the world, it is home to a plethora of developmental projects. The spectacular water front of Bay of Bahrain , the modern city of Diyar-Al-Muharraq or the Bahrain monorail are only some of the manifestations of a nation growing rapidly. With the major chunk of its GDP arising from the services sector, Bahrain is an important economic hub in the GCC which characterises itself with high ease of doing business and a welcoming immigration policy.

This favorable business and social environment attracts people from all across the globe. In addition to the immigrants, Bahrain’s own population is close to 1.3 million housed in an area of 710 sq. kms. This denotes one of the highest population density rates in the world, projected to grow at a rate of 4.6% annually.

Effectively sustaining this population while maintaining their quality of life makes efficient water management the need of the hour. Water management includes not only water treatment for one time consumption but a holistic approach including provision of necessary treatment of the resulting wastewater. This approach should also be augmented with a provision of water recycling to round off the water cycle.

This utopian idea of holistic wastewater management is being put to implementation at Bahrain in the form of the 40,000 m3 per day WWTP of Madinat Salman.

The Madinat Salman Plant: A Technological Marvel

The Engineering, Procurement & Construction of the plant was awarded to VA Tech Wabag in collaboration with Belhasa projects. The scope of the order award also includes 5 years of O&M.

The site is built on 13 islands of reclaimed land which accounts to 750 hectares of total plant area.

21 m deep terminal lift pumping station:

The process scheme begins with the inlet chamber and an 85,000 m3 per day terminal lift pumping station which sits at a depth of 21 metres. The water from the deep sewage gravity network is pumped through this depth with the help of a dry well pump.

Efficient Reuse & Resource Recovery

The heart of the plant is the tertiary treatment which renders it further purity through disc filters and disinfection using chlorination. The plant runs on the philosophy of resource recovery for the environment to the maximum extent. The collected sewage is digested, thermally dried and bagged through an automatic bagging plant for sale to farmers as manure.

WABAG- Setting new standards in execution

Executing this project was a huge challenge as it was situated on reclaimed land surrounded by sea from 3 sides and a hill in the middle which proved to be a bottle neck for construction.

The project stands out as a structural marvel with 25,000 cubic meters of concreting and reinforcement of over 7,000 MT of steel. The 85,000 m3 per day deep terminal lift pumping station sits over 160 piles carefully inserted over an unstable surface which housed an aquifer below it.

The 4.5 km long outfall pipeline which rounds off the plant process involved both onshore and offshore HDPE piping of 1200 mm diameter. The offshore piping involved plastic welding of numerous sections of length 1.5 resulting in two huge portions of 750 meters each. Both these portions were tugged to the ocean and systematically sunk into trenches made using specialized sea water dredging machines.

Despite all these challenges, no compromise was made on safety and quality. With an eye for customer satisfaction, Wabag overcame these challenges and completed the project on time, clocking a total of 3.5 million safe man hours. Wabag was also commended for the hydro-testing and commissioning which was successfully completed in the first go itself.

Effect on people’s lives and the future of Reuse

The project touches the lives of almost 100,000 civilians as it promotes water sustainability with a potential to reclaim water from sewage at the city of Madinat Salman in the rapidly growing kingdom of Bahrain. The plant is a showcase model and proposes a fitting solution to the wastewater treatment needs of not only Bahrain but the entire GCC region as such.

Initial state

The port town of Paradip in Jagatsinghpur district, Odisha was facing acute drinking water shortage due to over exploitation of groundwater resources by industries surrounding the town. The port town is home to about two lakh people.

IOCL’s refinery at Paradip is also one among the industries relying on the water sources available around Paradip. A refinery requires huge amount of water for its daily operations. The water crisis became more severe during the summer. Realizing the fact that “Drinking water is the fundamental right of living beings”, IOCL decided to set-up an effluent treatment and water reclamation plant inside its premises to reduce the dependency on external water sources and to prioritize freshwater for the residents of Paradip.

Challenges

Efficient treatment and recycle of the complex effluent generated by the refinery. Need for a proven and innovative blend of processes based on the variation and contamination in the effluent. To attain more efficiency in the process for obtaining greater volume of water that can be reused as a significant contribution towards conservation of fresh water.

The solution

WABAG was entrusted with the design, engineering, procurement, construction, installation, and start-up and test operation of an environmental friendly and cost efficient water management system for IOCL Paradip.

The effluent treatment and recycling plant, which is the largest industrial recycling plant in India, ensures this by recycling around 54,000 m3 of treated water every day for the refinery. Enabling water reuse of such a huge quantum by WABAG’s processes is outstanding in nature and sets a precedent for similar sustainable water management infrastructure in upcoming refineries. By ensuring maximum reuse of the generated effluent for application as process water in the refinery, dependence on freshwater is reduced by over 17,000 ML every year, helping prioritize fresh water for irrigation & domestic purposes, the priority sectors in India.

Technologies

The effluent is a cocktail of Oily water, stripped sour water, spent caustic, cooling tower blow down, sanitary wastewater & DM Plant regeneration waste which could severely impact the environment if discharged untreated.

This complex effluent is treated in a number of stages comprising free oil removal through API and TPI separator, emulsified oil removal through DAF (Dissolved Air Flotation), biological treatment using bio-tower and activated sludge process, treatment for spent caustic and treatment for landfill leachate. Subsequently, the treated effluent is subjected to further treatment (Ultra Filtration & High Efficiency Reverse Osmosis achieving a consistent recovery rate of around 85%) to enable reuse in the refinery. The concept is rounded off by final sludge treatment with thickening and dewatering in centrifuges.

The project highlights a comprehensive treatment model for a complex effluent where WABAG’s vision for eco-friendly solutions is reflected in the treatment of VOC (Volatile Organic Compounds) and passing of RO reject water through a hard COD management unit before discharge into the sea. This ensures the environment around the refinery is not polluted with harmful contaminants.

Global Recognition

ASSOCHAM honoured WABAG with Water Management Excellence Awards 2018 for “Outstanding Contribution in Water Efficiency & Conservation” for its comprehensive water management system for IOCL, Paradip at the National Conference-cum-Expo & Awards in Water Management, New Delhi.

Conclusion

Oil & Gas is the one of the major growth drivers of India’s economy. With a no. of mega refineries and petrochemical complexes planned in the next 3 years, the demand for water for process applications in such complexes is expected to grow manifold. In view of India’s water scenario, where the per capita availability is reducing, there is a need to provide feasible and sustainable water solutions. This will benefit in three ways. First, ensuring water security for industries, thus averting shutdowns, enhancing productivity. Second, water reduction in burden on limited freshwater sources available. The limited freshwater can be prioritized for domestic and agricultural consumption. Third, eco-friendly discharge of harmful and complex effluents is ensured in line with global environmental norms.

Initial Situation – every drop counts

Windhoek lies in the middle of Namibia, the driest nation south of the Sahara. The city has always struggled with water shortages and – as an answer – since the 1960s, has been employing Water Reclamation facilities to enhance water security.

The Ujams Industrial Water Reclamation Plant is located in the city’s northern industrial area and treats around 1.5 million m3 industrial effluents per year. The existing WWTP had to be replaced with a new treatment plant to meet the new discharge regulations into sensitive freshwater sources.

Requirements

The aim of the new advanced industrial wastewater treatment plant was to purify the effluent and reclaim the water for further reuse in augmentation of the Klein-Windhoek River and other applications such as dust control during road construction. The plant treats a cocktail of effluents: an abattoir, a brewery and a tannery are the main sources of the wastewater. The major challenge was to cope with extreme variations in terms of influent load and characteristics – high and fluctuating COD (peaks > 10,000 mg/L) and nitrogen (peaks > 300 mg/L) concentration.

The solution – showing an extremely compact and flexible process design.

Within the framework of an international tender the City of Windhoek chose WABAG as an innovative and reliable partner to realize the water reclamation plant on BOOT model.

WABAG designed a compact, highly-efficient and flexible process including its new fine sieving technology MICROPUR® as advanced pre-treatment. This innovative fine sieving system significantly improves removal efficiency for organic contaminants & fibres as well as oils and fats, resulting in enhanced operational safety and reducing the load on downstream treatment steps. This ensures optimization of the complete wastewater treatment plant in terms of efficiency as well as a reduction in operating costs.

MICROPUR-MBR® – WABAG employed a combination of advanced fine sieving technology MICROPUR® with the well-known membrane bioreactor technology MARAPUR® This complete low footprint technology is characterised by high biomass concentrations in the activated sludge tanks, enhanced phosphorus and nitrogen removal and reduced activated sludge tank volumes.

The entire process scheme comprises fine screen, grit separation, dry weather buffer tank including pH-correction, microsieving of raw wastewater, biological process of denitrification and nitrification, membrane filtration with hollow fiber membranes, UV-Disinfection, clear water tank incl. utilities and firefighting, sludge treatment and odour treatment.

Prior to full-scale installation, the proposed patented, low footprint process design was verified by setting up a pilot plant and diligently testing for 7 months.

Public-private partnership – BOOT project

WABAG not only financed the project through a long-term loan from the German DEG, but also provided innovative, in-house developed technologies for sustainable water recycling. Moreover, the WABAG JV is responsible for professional plant management for a period of 21 years.

Know-how transfer right from the start

WABAG has been committed to continuous development of local expertise for effective plant management through training modules of international standards, starting with the operation procedure of the pilot plant. The project presents an exemplary cooperation in Windhoek, Namibia. It is the first BOOT project in the water sector for the city of Windhoek, the capital of Namibia.

Initial state

North Chennai has historically been the hub for manufacturing activities and in the last decade, is considered an area of stagnant growth with a sizeable and burgeoning population.

However, due to inadequate wastewater management infrastructure, the exploding population which is labour oriented started facing a lot of health and environment issues. This was hampering the productivity of the population and the economic progress of the region.

Challenges

Development of a sustainable wastewater infrastructure for North Chennai which will ensure the safe discharge of treated sewage after removal of the contaminants for replenishing the nearby water bodies.

The solution

Chennai Metro Water Supply and Sewage Board decided to set up a first of its kind sewage treatment plant at Kodungaiyur and VA Tech WABAG was entrusted with the turnkey realization of a new biological sewage treatment plant being the reliable and trusted partner of CMWSSB for developing sustainable water infrastructure.

The contract assigned to VA TECH WABAG was on Design-Build-Operate mode in the year 2003 and was successfully commissioned in the year 2006 with a capacity of treating 110 million liters of sewage per day.

Technologies

The entire plant operates in two different stages. The first stage ensures safe discharge of treated sewage through an aerobic process. Whereas in the stage phase the sludge is treated through an advanced anaerobic process to generate green power from bio-gas and thus makes the plant power neutral, i.e. on self-sustaining basis without depending on grid power.

The plant handles 110 MLD (million liters per day) of sewage and the treatment process is based on activated sludge process with anaerobic sludge digestion and biogas utilisation by means of a power plant based on gas engine (capacity 1,317 KVA). After commissioning in 2006, WABAG also assumed responsibility for operations & maintenance of the plant for over a period of 12 years. It is the largest plant of its kind in India and the most energy efficient one among the 9 STPs in Chennai – achieving 98% self-sufficiency in terms of power consumption.

Comprehensive technical and economic know-how of WABAG has guaranteed efficient project realization and a highly commendable operations phase of the plant for over a decade. The Kodungaiyur STP has the distinction of completing maximum hours of run time with a single gas engine, which has run successfully for over 90,000 operating hours with producing over 50,000 MWh over the last 12 years.

In line with Govt. Policies

• MNRE (Ministry for New and Renewable Energy) programme offering subsidy to utilities and operators for setting up green power generation units inside WWTPs
• CPCB (Central Pollution Control Board) circular to all SPCBs (State Pollution Control Boards) mandating green power production from methane present in biogas produced through anaerobic digestion of sludge
• India’s ratification at COP 21 Paris Climate Convention to satisfy 40% of its energy requirements from non-fossil sources to reduce carbon emission

Key Highlights

• One of the largest Power Neutral Plant of India and achieves 98% self-sufficiency in terms of power consumption.
• Enables reuse of treated wastewater to reduce the burden on freshwater- relevant especially in a city like Chennai which depends on groundwater. Supplies 21 MLD of Treated Sewage to nearby Chennai Petro Chemicals Limited & 5 MLD of treated Sewage to Manali Petro Chemicals for industrial uses.
• 84 MLD treated wastewater routed to nearby Buckingham canal reducing environment pollution.
• Silt generated from Inlet chamber is being used to raise the entire low lying area of the plant.

Conclusion

There are many time tested and successful case studies in India which testify to the viability of power neutral STPs. Kodungaiyur set a precedent in this novel concept. The plant stands as a role model plant for “Comprehensive Sewage Treatment” which focuses on resource recovery with the conviction that “Sewage is a resource with economic value, not a liability.

Challenge – Sustaining a water starved city:

India is the second most populated country in the world. With one of the highest rates of urbanization, we are no stranger to the water crisis. It sustains 18 percent of the world’s population but on the contrary has access to only 4 percent of the total usable water sources of the Earth.

Due to the lack of alternatives the country is majorly dependent on the surface water sources. But these are unevenly distributed across its states. Such conditions give rise to certain geo-political water disputes which further aggravate the water crisis and threaten the per capita availability of water.

The city of Chennai in Southern India was also facing similar issues. It has been historically dependent on surface water sources to sustain its drinking water needs. Since the city receives irregular rainfall, the replenishment of such water bodies was highly uncertain. At times when these reservoirs were running at a fraction of their capacities the residents had to resort to the use of ground water which had a negative impact on the water table of the city, thus causing sea water ingression.

The situation put enormous pressure on the government think tank and advisory committees to come up with a solution that would not only curb the prevalent water crisis but ensure water sustainability for future generations as well.

The solution:

Chennai being a coastal city is blessed with an abundant coastline, hence the city sought an answer to the water crisis in the form of large scale sea water desalination. There were certain challenges in the form of high power requirement to run such desalination plants and to build a plant which can treat sea water with varying salinity.

The situation called for technology experts who were commercially competitive as well, thus entrusting VA Tech WABAG with the responsibility.

Embodiment of the solution – The 110 MLD Nemilli Desalination Plant

In order to tackle the growing water stress, a 100 MLD (Million Litres per day) desalination Plant was envisaged along the coast of the Chennai City at Nemmeli

VA Tech WABAG was given the responsibility to design, build and operate this mega project, first of its kind for India.

The plant is equipped with the most advanced technology in the field of desalination. The entire process starts with the inflow of sea water through gravity flow in a 1 Kilometre pipeline embedded at the sea floor at a depth of 10 metres. The inlet water from the sea is pre treated with a state of the art pre treatment technology – Lamella Clarifier. The Lamella Clarirfier not only efficiently removes high amount of suspended solids in the incoming water but its compact size also reduces the footprint of the entire facility. The process water then flows through the disc filters to the Ultra-Filtration units.

Post the Ultra-Filtration, the water is treated by a single pass SWRO system which enables the removal of dissolved solids. A significant reduction in the salinity from around 35000 ppm to less than 500 ppm is achieved in this stage, which is the process core of the project.

The plant ensures production of the highest quality of desalinated water coupled with a process that optimizes power consumption. This is enabled by the use of high end pressure exchanging mechanism which uses the residual pressure of the reject from the RO membranes, thus boosting the pressure of sea water feed to the RO system.

The plant ensures production of the highest quality of desalinated water coupled with a process that optimizes power consumption. This is enabled by the use of high end pressure exchanging mechanism which uses the residual pressure of the reject from the RO membranes, thus boosting the pressure of sea water feed to the RO system.

The treatment cycle is complete with the remineralization of the process water with Carbon Dioxide and Lime in order to make the desalinated water fit for human consumption.

This project is a testament to the feasibility of desalination as an alternative coupled with WABAG’s process know how to optimize the lifecycle cost at INR 35 for every thousand litres of desalinated water produced.

In 2016 the plant’s capacity was further enhanced by 10 MLD with an innovative process retrofit and optimization by VA Tech WABAG’s water professionals. This was a welcome step for a city which was experiencing a dry spell that year.

Awards and accolades:

The Nemmeli plant today supplies water to over a million south Chennaites, thus projecting an alternative, sustainable and viable technological solution for water security which has been a challenge for decades.

Being the largest desalination plant in India to be executed on Design Build Operate basis, recognitions for this project have been global in stature. Success of this project reinforced the recognition given by Global Water Intelligence ranking WABAG among the top 10 desalination companies globally.

The plant was awarded with the Dun and Bradstreet Infra Awards in 2016. Another feather in WABAG’s cap was the International Engineers Institution’s Industry Excellence Award in 2016 that complimented the technology employed to make the project feasible and sustainable.

Present Status and the future of Desalination:

The Nemmeli desalination plant has satisfactorily helped bridge the water demand- supply gap (desalination caters to 25% of daily water supply in Chennai).This proves that advanced technology can provide solutions to one of humanity’s most critical problems – the scarcity of drinkable water.

Seeing this the Government of India has also acknowledged the sustainability promised by desalination especially along the coastal cities of India.

The recent announcements of two new desalination plants – a 150 MLD Plant and 400 MLD plant at Chennai are a few welcome measures promoting desalination as a reliable source to safeguard our country’s water security.

Introduction

Water being scarce resource, its treatment, storage and distribution to public uninterruptedly is a challenge to most operators. Large WTP/WWTP use high capacity pumps for transfer of treated water. In most plants pumps are driven by electrical drive which draws huge current during start up. Reducing starting current and stress on conductor and drive poses challenge to most electrical engineers. Thanks to technology that helped to address this challenge and today most high capacity pumps are equipped with soft starters. Here is a simple case study on elimination of its failure.

Challenges

Soft starters minimize the starting current and ensure smooth ramp up by switching IGBT/ SCR thereby mechanical stress on motor and driven equipment is drastically reduced. 50MGD WTP in Dwaraka Delhi treats raw water and supplies potable water to nearby residents. Treated water pumps are driven by 110Kw,415V motors. Installed soft starters are Danfoss MCD500 internal bypass type(fig.1) thus motor starts with soft starter and once full speed is achieved load is seamlessly changed over to bypass contactor and motor runs on DOL (Direct on line) mode. Soft starters were frequently failing and warranting frequent repair and replacement of control and power cards. On an average INR 6lacs PA was spent to keep treated water pumps running on account of this alone. This has inflated OPEX and jolted complete economics.

Principle Cause

Detailed RCA (Root Cause Analysis) was done and concluded that soft starter internal components were failing due to temperature. While drive running surface Temp. of soft starter was measured with IR temp. gun and found high (Table 1). Therefore it is very evident that PCB and components would be certainly higher than OEM recommended temperature which is 50 deg.c. Temperature rise is due to heat dissipation from internal bypass contactor which is continuously ON while drive is running soon after soft starter goes to bypass mode. There was no quick means of removing this heat due to compact design. As a result, power card and control cards started heating and components started malfunctioning finally leading to soft starter failure.

Resolution

Now the challenge is to isolate heat sensitive components from heat dissipating components. Hence internal bypass soft starter has been retrofitted with external bypass soft starter which has its bypass contactor outside the soft starter (fig 1). Previous version was replaced with Schneider ATS48C25Q soft starter. Post modification significant reduction in temperature of about 16 deg C was evident (Table 1).

Figure 1. GA of soft starter with internal and external bypass

Conclusion

100% uptime of equipment in water treatment is critical for known reasons. This makes us constantly thrive for higher MTBF (Mean time between failure). Higher MTBF not only reduces OPEX but also improves brand in such sensitive public related business. Retrofitting of internal bypass soft starter with external bypass irrespective of rating at right time and consideration of this scheme initially in capital projects makes sense in such competitive industry. ROI is just less than a year!

MICROPUR® MBR based compact and highly-efficient water
reclamation plant at the Industrial Park UJAMS in Windhoek,
Namibia – designed, built and operated on BOOT basis.

Outstanding Contribution in Water Efficiency and Conservation:
COMPREHENSIVE WASTEWATER MANAGEMENT and RECYCLING SYSTEM FOR A COMPLEX EFFLUENT