Industries are major consumers of water. With the pace of industrial development increasing, water demand too has been rising. A large quantity of the water consumed reappears as effluents, which are discharged into waterbodies without treatment, leading to their pollution. Approximately 13,500 mld of industrial wastewater is generated by manufacturing clusters, 60 per cent of which is treated at the country’s 194 common effluent treatment plants (CETPs). Currently, around 6.2 billion litres of untreated industrial wastewater is generated every day across India.
A snapshot of the effluent treatment scenario in the country, as well as the key trends and developments in this space, and the way forward…
As per India Infrastructure Research analysis, around 30 treatment plants have been developed by various industries. The plants have a total capacity of around 317 mld. Sector-wise, around 73 per cent of these plants have been set up in the oil and gas/petrochemical industries and at thermal power plants. In terms of capacity, these plants account for 79 per cent share in the total capacity analysed.
Small and medium industries generally find it difficult to establish and operate individual effluent treatment plants (ETPs) due to the limited size and scale of their operations. Most of these industries are located in industrial areas/estates, and CETPs are developed to achieve satisfactory treatment through collective efforts. There are around 194 CETPs in India with a total capacity of around 1,481 mld. In terms of number of CETPs, Tamil Nadu accounts for the maximum number (49), followed by Gujarat and Maharashtra with 30 and 27 CETPs respectively.
These 194 plants serve around 212 industrial clusters in the country, catering to various industries such as textiles, tanneries, chemicals and pharmaceuticals, and auto components.
Recycle and reuse initiatives
In light of the depleting water resources, the concept of recycle and reuse has gained importance. Many industries have started investing significantly in technologies that enable the utilisation of wastewater, and promote the reuse and recycling of water.
The Steel Authority of India has adopted a two-stage process at its Rourkela steel plant to treat wastewater before discharging in the Brahmani river. Meanwhile, Hindustan Petroleum Corporation Limited’s key water management initiatives include rainwater harvesting; installation of COD, BOD, TSS and pH analysers; commissioning of online steam and water analysis systems; and recycling of water through ETPs and sewage treatment plants (STPs). The Welspun Group has set up a 30 mld STP plant at its Anjar factory, which recycles sewage wastewater from neighbouring areas. This has led to zero intake of fresh water for manufacturing processes.
Initiatives have also been launched by urban local bodies (ULBs) across the country to ensure long-term availability of water. The Surat Municipal Corporation (SMC) has set a target of treating and supplying 550 mld of treated water to industrial units in Pandesara, Sachin, Palsana, Hazira and nearby areas. This will not only help the corporation save potable water but also earn revenue of Rs 5 billion each year. Currently, SMC is supplying 40 mld of water to industrial units in Pandesara from the Bamroli STP.
The Karnataka government approved a policy for wastewater reuse in urban centres in December 2017. The policy aims to achieve a target of 25 per cent of wastewater reuse by 2025 and 50 per cent by 2030. Accordingly, the recycled water will be used for agricultural, industrial and urban non-potable purposes. The policy includes a special focus on industrial reuse of treated urban wastewater, with the intention of supporting financial sustainability of ULBs and mitigating water supply risks for industry. Along the same lines, the Gujarat government released a policy for reusing treated wastewater in May 2018. It aims to reuse 75 per cent of treated wastewater by 2025 and scale it up to 100 per cent by 2030. The policy has also made it mandatory for all thermal power plants within a distance of 50 km from the STP or city limits to use treated water.
Increased focus on ZLD
As a growing number of industrial users are facing increasing water crises, a number of businesses are moving towards recycling and reuse of wastewater produced during their manufacturing process through the installation of captive zero liquid discharge (ZLD) plants. The utilisation of the ZLD technique has gained importance in a number of industries, most notably textiles. States such as Rajasthan, Tamil Nadu and Gujarat are seeing significant development in this regard. NTPC stations have installed ash water recirculation systems and toe drain recirculation systems for achieving ZLD from the ash ponds. Around 70 per cent of ash handling water is recirculated to the plants from the ash ponds. Further, the treated effluent is reused for suitable applications.
Arvind Limited has the single largest textile effluent ZLD plant in Asia with a capacity of 17,000 cubic metres per day. It deploys an advanced water treatment process that purifies and recycles wastewater at the end of the industrial process with zero liquid waste discharged. Deepak Fertilisers and Petrochemicals Corporation Limited’s manufacturing facilities in Taloja, Srikakulam, Panipat and Dahej have their own ETPs for recycling industrial effluents. In addition to ZLD and MEE, the company has deployed other technologies for wastewater treatment. Indian Oil Corporation Limited is undertaking a project to make its Mathura refinery the first to use 100 per cent effluent discharge and sewage water for industrial use.
Increased reliance on technology
Construction companies have started undertaking extensive surveys to avoid interruptions during the execution phase. The pace of technology adoption in the management of wastewater services has improved. ULBs are providing online civic services and deploying advanced treatment technologies for water and waste treatment as well as automation and control tools for operating and monitoring facilities. The government is also taking various steps to ensure that land acquisition and clearances are available to contractors without difficulty. Further, large budget allocations and project execution at the ground level are certainly encouraging for the construction sector.
Of late, decentralised wastewater treatment systems have gained prominence due to their lower energy requirements, enabling off-grid operations on alternative sources of energy. In addition, these plants can be customised to meet specific requirements. Another technology that has seen increasing acceptance is membrane bioreactor (MBR). MBR effluent is suitable for treated wastewater reuse, and can be applied to uses such as urban landscaping and toilet flushing without any additional treatment.
With regard to ultrafiltration, the treated water can be used for low-end industrial uses such as cooling. On the other hand, nanofiltration is mainly applied in drinking water purification process steps, such as water softening, decolouring and micro pollutant removal.
The wastewater treatment market in India has begun to unlock its potential. Many factors are lending momentum to this growth. According to India Infrastructure Research analysis, there are 97 upcoming CETP projects in the industrial segment, which offer major opportunities to various stakeholders.
With regard to technology uptake, in light of the Covid-19 pandemic, investment in the sector will be directed towards better treatment of wastewater and its recycling and reuse over the next couple of years. The next big challenge for utilities will be to deploy more advanced technologies and systems to fast-track project implementation while ensuring adherence to social distancing norms. They must communicate proactively with customers to serve them better, by developing multiple communication channels. This will lay the foundation for future growth and improvement in service provisioning.