India generates over 72 million litres per day (mld) of sewage, creating a huge health hazard due to its mixing with potable water. Reportedly, the treatment and reuse of wastewater can meet up to 65 per cent of urban water needs. However, the existing facilities at sewage treatment plants (STPs) and effluent treatment plants in India are in a dismal condition. As a result, the efficiency of wastewater treatment is low, leading to low quality water and water shortage in many areas. Technological innovations in the sector demand wider application to cope with the adverse consequences of the accumulating sewage.
Therefore, these challenges are being converted into opportunities with the implementation of improved technologies and the development of new technological solutions. City authorities, public institutions and private companies are creating possibilities to integrate these technologies with the treatment process. Intelligent self-administered self-monitored automatic chemical dosing (ISASMA-CD), digital detection sensors, integrated software platforms, and automated hardware tools are being promoted for better working of STPs. Many upcoming solutions such as EcoStruxure Automation Expert, The Energy and Resources Institute’s (TERI) Advanced Oxidation Technology (TADOX), and N-treat hold the potential to expand further through collaborations with live projects.
Implemented technologies
Public authorities have taken an active role in implementing new wastewater treatment technologies in many cities. For instance, the Delhi Jal Board, in August 2022, introduced ISASMA-CD technology at four STPs at Yamuna Vihar and Okhla to treat wastewater. Chemical dosing is a process that treats wastewater with chemicals such as iron, aluminium and some salts. With the help of this technology, the biochemical oxygen demand (BOD) and the total suspended solids (TSS) have been reduced to standard levels. This technology also enables the monitoring of real-time data and the condition of the plant with the support of artificial intelligence software. Both plants have improved significantly after the installation of this technology and have maintained the prescribed standards of pollutant levels in the wastewater, which is less than 10 parts per million (ppm). The Yamuna Vihar plant has recorded 8 ppm BOD and 7 ppm TSS levels, which were previously 25 ppm BOD and 90 ppm TSS respectively, whereas the Okhla plant recorded improved levels of 5 PPM BOD and 8 ppm TSS.
The private sector has also geared up to resolve the issues facing the sector and is contributing new solutions. An Indian water management solution start-up called Digital Paani has provided solutions for a dysfunctional STP located at a commercial complex in the Delhi-National Capital Region. The company used digital sensors to detect the problematic areas in the defective parts that were unaddressed for 14 years. It provided specialised solutions based on its software-based analysis along with real-time data of the plant’s processes by installing approximately 15 sensors in different parts of the plant. The company provides an integrated software platform and automated hardware tools for efficient working of STPs. It plans to work with 25 STPs across India. It is also exploring new ways to develop such advanced methods for the sector.
Technologies in the pipeline
New technologies are being developed rapidly in the wastewater treatment sector but are yet to be integrated into active projects. Schneider Electric is providing a hands-on experience with the internet of things-enabled software and technology called EcoStruxure Automation Expert. In line with the Jal Jeevan Mission, the technology is intended to bridge the gap between different digitalisation processes in wastewater treatment facilities. It is expected to help in integrating complete life cycle management, information technology and operational technology while improving automation system diagnostics in wastewater treatment plants. STP operators would also be able to optimise their costs with this upgraded system. It had also launched the Green Yodha Yatra in Bengaluru in November 2021.
In another development, TERI has developed TADOX, a technology that treats wastewater samples from municipal areas and effluents from polluting industries. The water streams around municipal and industrial areas are contaminated with high chemical oxygen demand, BOD, total organic carbon, dissolved organics, micropollutants, and non-biodegradable and persistent organic pollutants. As a patent technology, it involves ultraviolet-photocatalysis with advanced oxidation nanotechnology which leads to oxidative degradation and mineralisation of targeted pollutants. With the least use of chemicals in the overall treatment, it helps in reducing the amount of sludge in wastewater. The potential application of this technology is in micro-STPs, decentralised wastewater treatment systems and infrastructural projects, including townships, green buildings and commercial complexes, under the Atal Mission for Rejuvenation and Urban Transformation and smart city projects. At present, TADOX is at technology readiness level 7, which can be commercialised in collaboration with industry and the government.
Similarly, IIT Bombay has initiated a sustainable technology called N-treat for in-situ treatment of sewage in Mumbai through their Society for Innovation and Entrepreneurship. It involves a seven-stage process for water treatment with the application of screens, gates, silt traps, curtains of coconut fibres for filtration, and disinfection using sodium hypochlorite. It is installed in the nullah channels on the site itself without the requirement of additional space. The Brihanmumbai Municipal Corporation (BMC) plans to use this technology for a collective water flow of around 0.11 million kl per day. It has initiated efforts to prevent sludge and sewage from 25 storm water drains between Bandra and Dahisar from mixing into the seawater. This technology would be a cost-effective solution for BMC, eliminating the need for manual pumping, and saving electricity and maintenance requirements.
Future opportunities
Concerted efforts are being made in the sector for mitigating the challenges and achieving Sustainable Development Goal (SDG) 6, which is to ensure the availability and sustainable management of water and sanitation for all. Innovations along with research and development in the sector would form the backbone for exploring new opportunities. One such effort includes the high quality empirical and applied research by IIT Guwahati for the treatment of wastewater and its supply to rural areas. It is developing various prototypes to eliminate iron, arsenic, fluoride and other contaminants from drinking water with a patented water treatment technology.
Moreover, strong government actions will help in the all-round accomplishment of SDG 6. To this end, the Chennai
Metropolitan Water Supply and Sewerage Board has undertaken the upgradation of its STPs with the adoption of German technology. In September 2022, it signed an MoU with the German Water Partnership for the renovation of a 48-year-old STP at Nesapakkam in Chennai. Currently, it has the capacity to treat 23 mld of wastewater which is targeted to be increased to 50 mld while reusing reclaimed water. The project is planned to be executed with financial aid from the German government. Similarly, in November 2022, the central government signed an MoU with Denmark for cooperation in the field of water resources development and management. This is expected to increase digitalisation, enable integration and development of smart water resources, ease information access, etc. It would also allow innovations in water quality monitoring and management, sewage/wastewater treatment as well as improvement in the circular economy for the reused and recycled wastewater.