Amongst the many challenges posed by the increasing urbanisation in India, one of the biggest is the massive increase in wastewater generation. The Central Pollution Control Board estimates that about 80 per cent of the water supplied for domestic use is discharged as wastewater. This calls for a shift from the present water management approach to one that is sustainable and emphasises reuse and recycling of wastewater. Depending on the level of treatment, treated wastewater can be reused for agricultural, industrial and other non-potable purposes. Urban local bodies (ULBs) across the country have set up plants to treat wastewater and enhance its reuse. Additionally, key industrial players have undertaken initiatives such as recycling and reuse of treated wastewater, zero liquid discharge (ZLD) practices, desalination, and treatment of effluents to ensure opitimised usage of water.
A look at the key initiatives taken in the municipal and industrial sectors to treat wastewater…
Initiatives taken by the municipal sector
The per capita availability of water in India is steadily declining. While it stood at 2,209 cubic metres in 1991, it is estimated that it will plunge to 1,341 cubic metres by 2025. In a bid to ensure sustainable availability of water, ULBs across the country have undertaken various initiatives. The Delhi Jal Board has developed 36 wastewater treatment plants (WWTPs) to treat wastewater for non-potable purposes. At present, nearly 420 million gallons per day of treated water is being produced at these WWTPs. Delhi is also aiming to achieve 80 per cent wastewater reuse by 2027. Treading on the same lines, the Chennai Metropolitan Water Supply and Sewerage Board supplies 36 million litres per day (mld) of treated wastewater to industries; it has also developed two tertiary treatment plants with a combined capacity to treat 90 mld of wastewater.
Further, the Municipal Corporation of Greater Mumbai (MCGM) has planned to develop WWTPs in Colaba, Worli, Malad, Dharavi, Bandra, Versova, Ghatkopar and Bhandup in order to generate up to 1,800 litres of tertiary wastewater. In an attempt to ensure that housing societies use treated wastewater from WWTPs, the MCGM has decided to make the use of treated wastewater a factor in giving redevelopment permission. Meanwhile, the Nagpur Municipal Corporation (NMC) recycles more than 90 per cent of its generated sewage water, and is in the process of increasing the capacity of its WWTPs to recycle 480 mld of wastewater. In another major development, the NMC, Maharashtra State Power Generation Company and a private operator have signed a tripartite agreement for the construction of an STP for the supply of 150 mld of treated sewage for power generation.
In March 2020, the Noida Authority decided to supply treated wastewater for irrigation purposes at the new golf course in Sector 151A and the newly developed areas along the Noida-Greater Noida Expressway. The decision was taken after the National Green Tribunal mandated the conservation and use of groundwater for potable purposes only. The authority has also started supplying treated wastewater to the golf course in Sector 38A, terminating the use of groundwater in the area.
The Bruhat Bengaluru Mahanagara Palike (BBMP) has set up four tertiary treatment plants at the Cubbon Park, Lalbagh, Vrushabhavathi Valley and Yelahanka supplies. The treated water is supplied to various industries and neighbouring regions. the BBMP has also made it mandatory for treated wastewater to be used at construction sites in order to conserve groundwater. Further, the civic body has stated that it will not issue occupancy certificates to building owners who fail to use treated water from STPs. The Karnataka government also approved a policy of wastewater reuse for urban centres in December 2017. The policy aims to achieve a target of 25 per cent wastewater reuse by 2025 and 50 per cent by 2030.
Driven by a judiciary ruling, the Tamil Nadu Pollution Control Board has made the ZLD system mandatory for all high-polluting industries including textiles, and the dyeing and bleaching. Meanwhile, the Surat Municipal Corporation is supplying nearly 40 mld of tertiary treated wastewater to industrial units in Pandesara.
The use of technology in the management of wastewater services has also increased. ULBs are introducing online portals for civic services. They are also deploying advanced treatment technologies for wastewater treatment, as well as automation and instrumentation tools, and solutions for asset monitoring and maintenance. The upcoming STP at Okhla is expected to be fully automated and fitted with a supervisory control and data acquisition (SCADA) system. Meanwhile, the Bhandewadi STP will also deploy SCADA for carrying out operation and maintenance activities.
Initiatives undertaken by industries
Given the current pace of development, industries in India are bound to face an acute shortage of water for their operations. This has led the key players in the industrial sector to make efforts to ensure better and more efficient utilisation of water resources. Industries are now investing extensively in technologies that facilitate the reuse and recycling of wastewater.
Many companies have started moving towards recycling and reuse of wastewater through the installation of captive ZLD plants. ZLD is a water treatment process involving ultrafiltration, reverse osmosis, crystallisation and fractional electrode ionisation of wastewater. After the process, the entire volume of treated wastewater is fit for reuse. Arvind Limited, a major textile sector player, has installed India’s largest ZLD plant, which facilitates the recycling of 16 mld of wastewater. Tiruppur, a textile manufacturing hub in Tamil Nadu, was the first industrial cluster to implement ZLD in the country and the first textile cluster in the world to do so. Moreover, JSW Steel has taken initiatives to improve the utilisation of water through the installation of a 4 mld ZLD facility at Salem. It has also taken steps to ensure recovery of quality water through reverse osmosis technology.
Tata Steel’s Bara tertiary treatment plant in Jamshedpur has a treatment capacity of 30,000 cubic metres per day. The ultrafiltration treatment plant is part of the company’s plan to make Jamshedpur the first ZLD city in the country. It has resulted in a 16 per cent cut in the intake of fresh water from the Subarnarekha river.
The Power Grid Corporation of India has installed soak pits at its substations for the treatment of domestic sewage water. The treated water is used for operational activities within the campus. Meanwhile, the Steel Authority of India has adopted a two-stage method at its Rourkela steel plant to treat wastewater before discharging it into the Brahmani river. The Welspun Group has set up a 30 mld STP plant at its Anjar factory, which recycles sewage wastewater from the neighbouring areas. This has led to zero intake of fresh water for manufacturing processes. Understanding that water is a scarce natural resource, Grasim Industries has implemented the 3R principle (reduce, reuse and recycle) across all its units.
The water crisis in India is worsening with every passing day. By 2030, the country’s water demand is expected to be twice the available supply. Not only have groundwater levels depleted, surface waterbodies have also become highly polluted due to the discharge of untreated wastewater.
The Covid-19 outbreak has re-established the need for proper, universal access to safe water and sanitation. This is not achievable in India without the integration of proper wastewater management systems. Therefore, there is a need to develop a market for treated wastewater and promote the use of treated water in the agricultural, construction and industrial sectors. The adoption of a proper wastewater management approach can play a vital role in addressing the problem of water scarcity and pollution.
Going forward, the recycling and reuse of wastewater should be made mandatory to reduce the pressure generated by the demand for fresh water. To enable widespread adoption, the government should provide incentives such as tax reliefs and excise exemptions, both for the industrial and the municipal sector.
Garima Arora and Disha Khanna