Part 1: Water Tankers and the Wastewater Opportunity
Is there an opportunity here to steer tanker companies away from overexploiting groundwater at a time of worsening scarcity?
Sahana Balasubramanian and Shreya Nath
Water tankers are common fixtures on Bengaluru’s roads as the city’s growth far outpaces the delivery of essential services like piped water supply. The demand for tankers skyrockets during the summer months when even the piped supply is erratic.
But there’s a problem. Tanker companies currently source freshwater from deep borewells that tap rapidly-declining groundwater aquifers.
CSEI’s Green Cities Initiative has been exploring ways to substitute fresh water with treated wastewater. This solution can help save valuable freshwater for drinking and other critical uses for a much larger number of city residents while using treated wastewater instead for landscaping, construction, and other non-potable uses. This transition would also stem the flow of wastewater to lakes and other water bodies.
Read | Why wastewater holds the key to building climate-resilient cities
Despite these obvious benefits, we found that there are big hurdles to mainstreaming the use of treated wastewater. We had previously written about the ‘yuck factor’, the negative perception among apartment residents to reuse treated wastewater.
This blog is focused on another big challenge — the hesitance among tanker networks to transport wastewater. In Part 1, we argue that wastewater actually presents an alternative business model for tanker companies that currently transport freshwater and face an uncertain future as groundwater dwindles. Part 2 details a successful case study that shows how excess wastewater from an apartment was transported and used for construction work.
Bengaluru’s dependence on groundwater
In Bengaluru, the Central Ground Water Board (CGWB) estimates that nearly 40% of the residents depend on groundwater for their water requirements. This is mainly because peri-urban areas do not have access to formal piped water supply connections provided by the Bangalore Water Supply and Sewerage Board (BWSSB).
Our interviews with 20 RWAs living in apartments located in urban areas of Bengaluru revealed that nine out of 20 apartments depend on tanker water for their freshwater requirements throughout the year. To be clear, a large percentage of these apartments, despite not being in peri-urban areas, lacked piped water supply and said they relied on tankers.
For detailed information on these interviews, refer to our research brief.
The quantity of freshwater transported by tankers in the city is significant. It is estimated that there are over 3,000 tankers owned by 100–120 existing tankers companies in Bengaluru. Collectively, they have the capacity to transport 180 MLD (million litres per day), which can cater to the domestic water needs of 1.33 million people (almost 15% of the total population of the city).
On average, these companies transport 6,000 litres of water (one tanker load) for which they charge Rs. 450–600, depending on the season and distance that the water needs to be transported. The higher demand during the summer season raises the price as high as Rs. 1,500 for one tanker load.
Read | Why wastewater holds the key to building climate-resilient cities
Currently, groundwater is the major source of fresh water for these tanker companies. However, groundwater levels are steadily decreasing due to continuous extraction by residents and tanker companies. The groundwater levels in four taluks in Bengaluru is over-exploited. To make matters worse, there is a lack of enforcement by the government to prevent the over-extraction of groundwater sources.
This steady decline in groundwater levels has made tanker companies worry about the sustainability of their business. On the flipside, Bengaluru accumulates 720 million litres of wastewater a day. This got us thinking: Is there an opportunity here to substitute fresh water with treated wastewater and ease the threatened tanker business while reducing the pressure on groundwater sources?
Treated wastewater from apartment STPs
Residents living in apartments with decentralised STPs are struggling to reuse 100% of their treated wastewater and follow government rules like the Zero Liquid Discharge policy (ZLD).
If this water was transported for other non-potable uses within the city, an estimated 440 MLD of freshwater could be saved and this could serve 3.2 million users.
With residents hesitant to use treated wastewater for purposes other than toilet flushing and landscaping, apartments with smaller landscape areas are often left with excess treated wastewater and they receive penalties for discharging this into stormwater drains. Therefore, transporting the excess treated wastewater from these apartments could be a potential opportunity for the tanker companies.
This option seems to strike two birds with one stone, i.e. it ensures 100% reuse of wastewater and saves fresh water; plus, it offers the tanker business a more sustainable route and incentivises them to steer away from extracting groundwater. However, there are roadblocks to this switch in their business model. We spoke to tanker operators within the city to get their perspective on why this is the case to find three key reasons:
- Fear of losing the business on transporting freshwater
Tanker companies are hesitant to transport treated wastewater fearing that they would lose their business plying freshwater. This is because the end-users perceive that the same tankers are used for transporting treated water and freshwater.
- Lack of demand for treated wastewater
Instead of being discharged into lakes and stormwater drains, the treated wastewater could be substituted for activities that require water of non-potable quality. But there is a lack of awareness on the successful application of treated wastewater for use in construction, industries etc. among residents and the end-users of treated wastewater.
- Presence of tanker mafia
Tanker companies are not willing to come forward due to the tanker mafia. There is a lot of money at stake; residents who agree to pay higher for a tanker load receive the water sooner and the tanker companies gain a huge profit by doing so. Moreover, tanker drivers’ perception of the treated wastewater will also be a hindrance in this forward.
Watch | Green Lantern Engineering’s wastewater solutions at the Bangalore Club
These challenges cast doubt on the viability of the wastewater transport option. But we looked into a unique case study in another big metropolitan city that proves that this switch can be done successfully. It illustrates the potential for using treated wastewater outside the apartment fence for construction activities and how it can be an alternative business opportunity for the tanker company.
Read more in Part 2 of this blog series on tankers and wastewater. We also outline possible solutions to the above challenges in this second part.
Under CSEI‘s Green Cities Initiative, we are studying the potential of using the excess treated wastewater outside the apartment fence. To enable this, CSEI is collaborating with Karnataka Pollution Control Board (KSPCB) to pilot the use of excess treated wastewater from apartments for the greening of the public parks and gardens in the Yelahanka zone.
Edited by Kaavya Kumar
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