Growing urbanisation and rapid resource depletion have prompted governments to switch from the conventional linear take-make-use-dispose system to a circular system of resource conservation. The circular economy is a long-term development strategy, based on the waste management principles of “reduce, reuse, recycle and recover”. Approximately 80 per cent of the water supply to municipalities flows back into the ecosystem as untreated wastewater, which is a critical environmental and health hazard. India has the capacity to treat approximately 36,668 million litres per day (mld), against a daily sewage generation of approximately 72,368 mld. Most wastewater treatment plants do not function at their maximum capacity. They do not follow the standards prescribed under the environmental protection rules for discharge into streams. There are social, political, technical and financial challenges, that impact the efficiency of wastewater management plants and the sector as a whole. Instead of treating it as a waste to be disposed of, wastewater should be considered as a resource for recycling and reusing. A paradigm shift from a “use and throw” to “use, treat and reuse” approach is required.
Water scarcity stands out as the major driver for initiating wastewater management. For industries located in a water-scarce area, treated wastewater reuse could be a viable option as it could become a source of continual water supply. Wastewater can be a ready source of phosphorus as fertiliser. The targeted areas (for wastewater management system) should be places where water is scarce, water tariffs are high, groundwater is depleting or salinised, and where high-priced desalinated water is being used. In India, untreated sewage flows amount to 35,700 mld. The freshwater abstraction by industries will be 10.1 per cent by 2050. All these factors make a strong case for a circular economy pathway in the wastewater sector.
Water and wastewater management should be integrated at strategic, planning and execution levels by utilities and government authorities. It is significant to build awareness around wastewater management. The government can assist in the development of acceptable solutions, certifications and approvals. Financial institutions can also assist by providing long-term patient capital. To strengthen public-private partnerships, create a blended finance model or viability gap funding, wherein the private sector could work in a build-own-operate-transfer mode, sharing equal risks. The government should allocate financial and land resources to wastewater management strategies, as well as establish an enabling environment.
Circular wastewater management reduces water consumption, which saves energy, as well as lowers effluent discharge fees. It also reduces operational costs and the risk of water scarcity for industrial users, as well as increases sustainability and promotes more sustainable use of the existing water resources. It improves climate change adaptation, pollution management and effluent reduction requirements by minimising freshwater withdrawal from natural waterbodies/ resources.
Challenges in circular water management
Water reuse can be hampered by regulations. To permit a circular approach to water management, rules would have to be changed. The direct use of wastewater in the production of consumer goods, for example, is currently prohibited in most cases. Similarly, lowering water consumption may result in violations of laws governing maximum quantities of certain substances in effluents. Obtaining a positive return on investment can be difficult. Low water prices and high infrastructure costs, or a combination of these variables, make achieving a return on investment in circular water management schemes difficult. Lack of awareness can sometimes be a barrier, resulting in opportunities being overlooked. It is critical to raise awareness of the benefits of reusing water on-site, especially in water-scarce areas. Proposals to minimise, reuse and recycle water are frequently met with conflicting priorities and opposition from key personnel, stakeholders and decision-makers. There is a lack of business infrastructure for water reuse, followed by a lack of operational measures in place to maximise water saving. Inadequate maintenance or a change in operations make it difficult to sustain water reductions. Currently, implementation and follow-up are also lacking in the system.
The implementation of wastewater reuse programmes is fraught with difficulties. Insufficient access to capital, high operation and maintenance costs, and limited market viability studies are among other financial hurdles. Institutional obstacles such as a lack of cooperation among authorities, lack of a robust legal framework and restricted data availability hinder these initiatives. In addition, the rise of wastewater reclamation and reuse in the country is hampered by insufficient treatment and distribution infrastructure, treatment technology constraints and a lack of water quality monitoring.
The state governments have either adopted or are considering policies to recycle and reuse treated wastewater in order to minimise their reliance on freshwater resources. By 2025, the government aims to reuse 70 per cent of the treated wastewater and by 2030, the government intends to reuse 100 per cent of it. Furthermore, the policy aims to promote the widespread and safe reuse of treated wastewater in India, reducing the strain on limited freshwater resources, reducing pollution, reducing public health concerns and achieving economic benefits through adoption of a sustainable circular economy model.
The National Urban Sanitation Policy of 2008 encourages the use of recycled water, recommending that a minimum of 20 per cent of the wastewater produced in each city should be reused. The National Water Policy (2012) also emphasises the significance of wastewater reuse in achieving the national environmental targets and suggests that a preferred tariff could be used to encourage the use of reclaimed water over fresh water.
The Surat Municipal Corporation aims to make Surat a net zero discharge city, after becoming a model city in the country for its circular economy – generating revenue through wastewater reuse. The procurement of 115 mld water regenerated from wastewater is generating Rs 1.4 billion for the city. The corporation aims to earn Rs 5 billion by selling treated water for non-potable purposes.
The Chennai Metropolitan Water Supply and Sewerage Board (CMWSSB) has embarked on several projects and investments to diversify water supply in order to protect against natural disasters, improve resilience and increase water availability. Chennai was India’s first city to make rainwater harvesting mandatory, as well as the first to reach a 10 per cent wastewater reuse rate. In addition, it is India’s only utility with two large-scale desalination units. When compared to other cities in India and around the world, it already has a diverse water supply. CMWSSB is also attempting to sell most of the biosolids generated as manure for application to agricultural land in more than half of its wastewater treatment plants (WWTPs). CMWSSB plans to increase the percentage of wastewater reused, rehabilitate aquifers and lakes, improve rainwater drainage and flood management, and reduce non-revenue water to strengthen the city’s resilience and push Chennai towards circular economy principles. Chennai is the first Indian metropolis to achieve nearly complete wastewater collection. It collects, transports and treats between 520 and 660 million litres of wastewater produced daily by 4.8 million residents in the city core, owing to a 3,000 km sewage network and 12 WWTPs with a total capacity of 727 mld (95 per cent coverage). CMWSSB has also enacted a number of by-laws to encourage wastewater recycling and reuse. In November 2019, the Haryana government approved a policy to treat wastewater for non-potable purposes, aimed at alleviating the stress on ground and surface water resources.
In January 2020, the Telangana government announced the launch of a sanitation hub. It is an incubator to promote start-ups and innovations in water, sanitation, sewage water management and wastewater recycling. A seed fund of Rs 250 million was earmarked for the initiative. In this context, the Nagpur Municipal Corporation recycles more than 90 per cent of its generated sewage and is in the process of increasing the capacity of its treatment plants with the aim of recycling 480 mld of wastewater. Delhi is also aiming to achieve 80 per cent wastewater reuse by 2027. Sterlite Technologies Limited (STL) is investigating creative techniques that promote circular use of this precious natural resource by appropriately treating wastewater for groundwater recharge, saving water, enabling access to clean and safe drinking water, utilising treated water for afforestation and agriculture, and sensitising stakeholders in communities and within STL through engagement programmes aimed at promoting responsible use.
The way forward
India’s population is putting a pressure on the existing water supply system. The country’s already depleted water reserves are being put under unsustainable strain by the country’s rising population. Groundwater wells are drying up and 21 major cities, including Delhi, Bengaluru and Hyderabad, are expected to run out of water soon, affecting the water supply of over 100 million people. Building a solid regulatory framework that explicitly tackles the issue of future water reuse is crucial. To enable wastewater recycling and reuse, all stakeholders must cooperate with one another. Circular water management will prove to be beneficial for the country.