Water reuse - Sustainable solution for water security
India is one of the fastest growing economies in the world at the moment and there is no doubt that uninterrupted power and water supply will be the cornerstones to ensuring there are no hurdles in India's endeavour to emerge as a global economy.
Keeping this growth and the burgeoning population across the country in mind, it is only obvious that the demand for water is set to grow manifold. However, the reality presents a gloomy picture in terms of the fact that India is stressed in terms of its water resources. This presents an alarming picture considering the augmented challenges this scenario presents for the growth of this country.
Taking a serious note of the cascading effect a water stressed scenario can have, it is imperative to realise the true potential of the limited water resources available, in other words, water must be reclaimed. Water is too precious to be used just once and it is in this perspective that Water reclamation and reuse constitute one of the major trends in water management.
Among the list of prominent case studies in promoting municipal industrial partnerships, for over a decade now, secondary treated sewage from the 110 MLD Kodungaiyur STP in Chennai is further treated and served as intake water for the tertiary treatment plant in CPCL refinery, thus reducing the industry's dependence on freshwater sources and ensuring water security.
Leading by example with a model to ensure water security for the power sector, a state-of-the-art reclamation plant at NTPC, Badarpur. The plant, with a capacity of 2,500 cubic metres per day, was set up in 2014 to treat contaminated surface water and provide it as process water for the power plant. The technology put in place involved the processes of membrane bioreactor and reverse osmosis.
On a global scale, along the lines of Singapore's NEWater, the world's first municipal water reclamation plant for direct potable consumption with a capacity of 21,000 cubic metres at Windhoek Goreangab, Namibia is noteworthy. The project started way back in 2002 and it has been successfully operated for the last 15 years. The concept of water recycle has immense potential not only in the municipal sector but also in the industrial sector given the massive water requirement and the harmful contaminants present in the discharged effluent. Adding further credibility to the concept of reuse even in cases where a cocktail of effluents is to be treated, the Ujams Wastewater treatment and Water Reuse project stands tall which received the Distinction Award for the "Industrial Water Project of the Year" at the Global Water Summit held at Athens, Greece, 2015. The Award was given on account of numerous unique features. First, the project comprised the first industrial water reclamation plant and the first wastewater MBR plant in Namibia.
Second, the complex range of contaminants in the feed water-a blend of wastewater streams from a brewery, an abattoir, a tannery, a beverage company and a chocolate producer-presented a serious challenge. With a successful seven-month onsite trial,..WABAG proved the mettle of an innovative treatment train using its in-house developed fine sieving pre-treatment process, MICROPUR. Combining this with MBR, UV disinfection, sludge treatment and exhaust air treatment, the joint venture leveraged the best expertise the private sector had to offer to make its partnership work. Third, this project will see effluent treated to standards suitable not only for industrial process water and irrigation, but also for blending in with the city's drinking water system.
In India, the water reclamation plants at IOCL, Panipat are stand out references for treatment of effluent and recycle within the industrial facilities. The Indian Oil Corporation, Panipat had to build two water reclamation plants in response to the demands of the environmental authorities. Subsequently, WABAG was awarded the contract for construction, operation and surveillance of the plants.
The Panipat Refinery Expansion Water Reclamation Plant, which treats both secondary refinery effluents and various refinery/petrochemical process effluents, was commissioned at the end of 2006. The naphtha cracker and its downstream polymer units (Naphtha Cracker Complex) were commissioned in 2010. The Panipat Naphtha Cracker Water Reclamation Plant reclaims process water from naphtha cracker secondary effluent, cooling tower blow-downs and demineralisation regenerates.
In both cases, advanced multi-barrier systems have been utilised in order to meet the strict quality requirements for recycling as boiler make-up water. The processes employed at each of these plants comprise a wide range of technologies from clarification, ultrafiltration and reverse osmosis to demineralisation, using mixed bed ion exchange filters.
The benefits of adopting water reuse mechanisms to ensure water security and realise the true potential of water as a finite resource are immense. First, the revenue loss for industries due to water shortage can be averted. Second, by supplying treated water to industries, cash strapped municipalities earn revenue. Third, increase in demand for treated sewage as feed water for industries would mean that more sewage would need to be treated. This would in turn increase the percentage of wastewater treated in the country, which currently stands at a miserable 37 per cent.
Thus, water reclamation is beneficial not only from a business perspective but also in terms of ensuring both water and environment security by alleviating pollution. Fourth, the surfeit of freshwater used in industries could instead be used to supplement irrigation and in areas where the application of freshwater is essential.
Fifth, the concept of ZLD (zero liquid discharge) is consolidated. As stated in the beginning paragraph, uninterrupted water supply are not only critical for industrial development but also for progress in human development indices. WABAG has substantiated this point in terms of its value proposition that is reflected in the brand tagline 'Sustainable solutions for a better life'.
About the author Rajneesh Chopra, Global Head - Business Development, VA Tech WABAG Limited.