A report released in 2020 by the technical group on population projections constituted by the Ministry of Health and Family Welfare indicates that India’s population is expected to touch 1.52 billion by 2036.

The distribution of water in India’s cities is based on rainfall. We monitor the level of water in our reservoirs/dams and adjust our distribution accordingly. As rainfall patterns change, it is becoming more challenging to rely solely on rainwater for our water demands. One of the ways to manage this is by tapping into unused wastewater.

A report by NITI Aayog indicates that nearly 600 million people in India are facing high to extreme water stress. The same report states that India ranks 120th out of 122 countries in terms of water quality, with roughly 70 per cent of the water being contaminated. As cities grow, we should depend less on fresh water and rely more on treated high quality wastewater.

How waste water can help in the shortage and water crisis

• Residential apartment complexes generate anywhere between 30,000 litres and 3 lakh litres of wastewater everyday. Currently, only a small percentage of this wastewater is getting used and the rest goes into our lakes and rivers.

Wastewater can be divided three major categories:

• Untreated sewage wastewater predominantly from independent buildings and apartments less than 100 people.
• Treated sewage which is usable for garden and flushing. Currently, only 20 per cent is actually reused inside the apartment premises and the remaining STP (sewage treatment plant) water is drained into our lakes.
• Industrial effluents which are currently not fully discharged into our lakes due to the zero liquid discharge

• Eighty per cent of treated STP (sewage treatment plant) water from apartments is wasted: Currently, both untreated and treated STP water mix together in common government drains and enter our lakes. As per government norms, apartments are mandated to reuse only 20 per cent of their treated wastewater for secondary application. The majority of treated wastewater is still drained, and this water becomes polluted again when it combines with untreated sewage from standalone residential buildings. All this wastewater enters into our lakes and rivers thereby polluting our water bodies.
• Centralised government STPs are non-viable and non-operational: The majority of centralised government STPs are under design, and by the time a new STP is completed, the sewage or wastewater load has increased to a level that exceeds the STP’s designed capacity, making it extremely difficult to maintain it for many years. The centralised wastewater treatment plant becomes commercially unviable and consumes a significant portion of the government’s water budget.
• Subsidised fresh water cost: Every city in India gets subsidised freshwater supply. For example, the Bangalore Water Supply and Sewerage Board spends about ₹85-90 per kilo litres. However, the water that is supplied to the residents is at an average of ₹7/8 per kilo litres, which is a drastically subsidised cost for freshwater. This makes wastewater recovery and reuse commercially non-justifiable as a replacement for municipal supplied water.

Way forward

• Indirect Potable Reuse (IPR) and Direct Potable Reuse (DPR) is an approach where treated high quality wastewater is released into groundwater/reservoirs or introduced into the municipal water system. In IPR, treated wastewater is released into the groundwater basin or a reservoir, whereas in DPR, treated high quality wastewater is introduced directly into the municipal supply system.
• Instead of planning for a new massive sewage treatment plant, if the government plans for stages of IPR implementation at their existing working STPs, cities would greatly benefit.
• Just like how areas have air quality monitoring, there can be water quality dashboards displayed in public places.
• A market can be created for highest quality recycled water or ‘whitewater’. This will enable citizens to choose the kind of water they want to buy — ‘treated highest quality water’ or ‘untreated borewell water’.

https://www.thehindubusinessline.com/opinion/dont-waste-wastewater/article65408424.ece

How to structure

1. Give a brief intro about India’s water shortage
2. Discuss how waste water can help in the shortage and water crisis
3. Mention challenges
4. Suggest solutions and link it to schemes
5. Conclude