The country’s increasing population along with rapid urbanisation and industrial growth have led to tremendous stress on its finite water resources. Per capita water availability has declined at an alarming rate from 1,816 cubic metres in 2001 to 1,545 cubic metres in 2011. The gap between demand and supply of water is increasing and it is expected to widen further in the coming years. In view of the limitations on the availability of water resources, sustainable water management has acquired critical importance.
There has been a rising focus on developing alternative sources of water supply through practices such as recycling and reuse of treated water and desalination. These processes have also been promoted under various government policies and programmes including the Swachh Bharat Mission, the Atal Mission for Rejuvenation and Urban Transformation, and the Namami Gange programme. In the past few years, the adoption of decentralised wastewater treatment systems has also gained significance due to the high costs associated with and inadequate coverage by centralised sewage treatment plants (STPs). The deployment of digital technologies such as smart meters and supervisory control and data acquisition systems has also progressively transformed the way water resources are managed in the country. These solutions and innovations will play a key role in strengthening the sector and meeting the fast growing water requirements.
Wastewater recycling and reuse
The use of recycled water for meeting the needs of the residential, municipal and industrial segments is slowly gaining ground in the country. As freshwater resources become scarce, treated wastewater can play an important role in mitigating water stress by providing an additional source of water. Further, it can also help in preventing pollution of waterbodies as minimal effluents and sewage are discharged into the ecosystem after proper treatment.
At present, only 30 per cent of the wastewater generated in the country is treated, offering tremendous potential for wastewater recycling and reuse. The treated water can be used for several non-potable purposes such as landscaping, cleaning vehicles, toilet flushing and construction activities. It can also be used in industries such as textiles, power plants, paper mills and oil refineries. Moreover, municipal bodies can also benefit by selling treated sewage to industries as it can help them recover their capital costs. For instance, the Nagpur Municipal Corporation (NMC) has entered into an agreement with Maharashtra State Power Generation Company Limited (Mahagenco) for procurement of 190 million litres of treated water for its Koradi and Khaparkheda thermal power stations. NMC is planning to the meet sewage treatment expenses through the money to be paid by Mahagenco.
While wastewater reuse is endorsed under several government policies and programmes including the Jal Shakti Abhiyan, the Swachh Bharat Mission and the Namami Gange programme, there is lack of a uniform policy and clear guidelines in the country, creating challenges in implementation of such projects. However, states such as Maharashtra, Gujarat and Karnataka have formulated their own policies for encouraging water reuse. Some other factors that limit the reuse of wastewater include negative perception about wastewater recycling, lack of technological awareness and fragmented nature of the market.
Desalination
Given India’s vast coastline, desalination is increasingly becoming an important option for meeting the burgeoning water demand in coastal areas. So far, the use of desalinated water has been explored for both municipal and industrial purposes. In the municipal space, desalination projects have been executed to meet drinking water requirements of the growing urban population. In the industrial segment, desalinated water has been used primarily for meeting the requirements of thermal power plants. Besides, it has also found application in oil refineries, and steel and cement industries.
Desalination plants for industrial and public distribution are currently operating in states such as Tamil Nadu, Maharashtra, Gujarat and Andhra Pradesh. However, it is only in Tamil Nadu that the technology is operational on a big scale for public water distribution. Currently, two desalination plants at Minjur and Nemelli with a capacity of 100 million litres per day (mld) each are operational in the state’s capital city. Chennai’s water authority is working to develop another two plants with a capacity of 150 mld and 400 mld, at a cost of Rs 12.6 billion and Rs 60 billion respectively. The Gujarat government is also working towards setting up of desalination plants for drinking water purposes. While a 100 mld plant will be set up at Jodiya in Jamnagar district, seven other desalination plants with a capacity of 270 mld each are being planned at Mundra, Mandvi, Dwarka, Porbandar, Sutrapada, Rajula and Ghogha in the Saurashtra-Kutch region.
Besides, the National Water Mission identifies desalination as a major means to make sea and brackish water accessible to people. Further, a national mission on desalination under which appropriate technologies will be identified, nurtured and promoted to provide drinking water to all water-scarce areas in coastal states is expected to be launched soon. NITI Aayog has also proposed the setting up of desalination plants to address the country’s water woes. The proposed plants will float on sea and leverage solar or ocean energy.
Although desalination has emerged as an innovative solution to combat the country’s water crisis, there are specific challenges including high economic costs and environmental concerns that have held back wider adoption. The setting up of desalination plants entails high initial capital costs. Further, the operation and maintenance costs are also significant owing to high power requirements. The technology though has an adverse impact on the marine environment due to brine (high-concentrated solution of salt in water) discharge. The use of renewable energy to run these plants can, however, help in reducing the carbon footprint and be a game changer for future desalination projects.
Decentralised wastewater treatment
Urban wastewater management in the country suffers from inadequate availability of centralised STPs as also dismal performance of most existing plants. Further, centralised systems are not only expensive but also have unequal coverage and services. In such a scenario, decentralised wastewater treatment systems that treat water at the source have emerged as a cost-effective option. They also enable maximum local reuse of the treated water, and this can help in reducing the freshwater needs.
These decentralised systems have not only proven to be beneficial for smaller towns and cities with limited finances but also for the big metro cities of Delhi, Bengaluru and Mumbai that have space constraints and competing land uses. Bengaluru city has emerged as a forerunner in the adoption of these systems. In 2004, to reduce pollution levels in the city’s lakes, the Karnataka State Pollution Board mandated that buildings with either more than 50 residential units or a built-up area of more than 5,000 square metres had to install on-site STPs and reuse all the water generated. This has resulted in the installation of over 2,000 decentralised systems in the city.
Going forward, India can benefit by adopting hybrid systems with both centralised and decentralised facilities. However, an integrated national-level policy is required to encourage setting up of decentralised treatment systems in the country.
Smart metering initiatives
Several water utilities in the country continue to deal with high non-revenue water, unchecked leakages and unauthorised and reckless water consumption leading to poor recovery of operation and maintenance costs. This has led to a growing demand for smart water meters that help utilities in gauging consumption and managing leaks and also improve their revenues. Smart metering solutions have also been promoted under government programmes such as the Smart Cities Mission.
Various utilities including those in Delhi, Hyderabad, Bengaluru and Pune have undertaken projects to replace conventional meters with smart metering solutions. Several private players have been engaged to provide end-to-end metering solutions. LoRaWAN-based smart metering solutions have also gained ground in cities such as Nashik and Chandigarh. Cities like New Delhi and Thane have also adopted advanced metering infrastructure, an integrated system of smart meters, communication networks and data management systems, that enables two-way communication between utilities and consumers.
Conclusion
India has 4 per cent of the world’s water resources and 18 per cent of the world’s population. Around 48 per cent of the country’s population is reeling under high to extreme water stress. Sustainable water management with a focus on identification of alternative water sources along with the adoption of advanced technologies will thus be critical for averting the looming water crisis.
Currently, water resource management in the country is impeded by conflicts between the authorities and various sectors. The government will have to play a key role in not only addressing the above issues but also laying down national-level guidelines and frameworks for successful implementation of wastewater reuse and desalination projects. Moreover, an environment for attracting private sector participation to improve service quality and efficiency of operations needs to be created.