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Don’t waste wastewater


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. To keep up with the growing population and its demands, the right kind of infrastructure has to be developed to ensure a good quality of life. Over the last decade, cities in India have grown vertically as well as horizontally. In spite of this enormous growth, our water infrastructure has remained more or less the same. Making any changes to the current infrastructure not only requires huge motivation but also an enormous budget. It wouldn’t be wrong to say that it’s impractical to make any drastic changes to the current water infrastructure.

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.

Everyday, a city like Bengaluru produces about 1,400 million litres of wastewater and a majority of it ends up in our drains and lakes. 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. Imagine the potential wastewater has in addressing water shortages in our cities and towns? Water is a finite resource, and the only way to prevent its depletion is to reduce, treat, and reuse what we already have.

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 discharg

In spite of having huge volumes of wastewater that gets generated, we are still unable to tap into its true potential. Here are the reasons

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.

When we use the term ‘recycled water’, most people never think of potability reuse. They always assume that recycled water is purely for secondary use. This perception needs to change. We need to find smart solutions to ensure that our wastewater is not wasted. Here are a few possible solutions

Creating a win-win

Currently, most industries buy water from water tankers for their water requirements and process their wastewater in-house. However, in spite of recycling it in-house, they are unable to obtain high quality water due to the operational efficiency of wastewater plants. On the other hand, we have apartments that are draining out at least 80 per cent of unused wastewater because they have no avenues to use them or discharge it for other purposes.

What if the excess STP treated water from apartment and commercial complexes is processed to a very high quality suited for industrial processing and mapped to industries within a 2-3 km radius? This would make the economics viable for both sides and this can be enabled by private players that supply processed water to the industry.

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. Over a period of time, government can plan DPR for industries for at least few months in a year and then move to IPR

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’. This should be enabled with a central dashboard with real-time water quality monitoring centres across the city’s working IPR implementations. Just like how areas have air quality monitoring, there can be water quality dashboards displayed in public places.

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.

If cities continue to use up fresh water from rivers, the entire agricultural belt that’s dependent on rivers will be left with no water. Wastewater has great potential to address water shortage and bring solutions to India’s water crisis.

The writer is CEO and Founder, Boson Whitewater

Published on May 12, 2022

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