Boson Whitewater — a water utility enterprise that converts handled water from sewage remedy crops (STPs) into high-quality potable water — has partnered with the non-profit Biome Environmental Belief to launch India’s first oblique potable water reuse undertaking. This revolutionary initiative, situated in Devanahalli, 40 kilometres northeast of Bengaluru, makes use of managed aquifer recharge to attain sustainable water reuse.
In response to the individuals [of this project], the undertaking produces 6.4 lakh litres of potable ingesting water per day, adhering to BIS (Bureau of Indian Requirements)-10500 requirements. The clear water instantly advantages 1000’s of residents within the Devanahalli municipality.
How does this work?
Merely put, handled wastewater from a sewage remedy plant is first pumped into Bagalur Lake, the place it’s diluted with rainwater. This water is then directed to Devanahalli’s Sihineeru Kere Lake by way of a pipeline, additional diluted with rainwater, and subsequently filtered by way of the earth to recharge the aquifer. The water is then picked up from the aquifer by way of a dug nicely and shallow filter borewells, handled, after which provided to the city residents.
Why is that this an oblique potable water reuse undertaking?
This undertaking makes use of an environmental buffer like a lake for dilution with rainwater and/or a groundwater aquifer for earth filtration. This water ultimately goes by way of a closing remedy stage earlier than it’s provided to residents.
What’s extra, the undertaking is an element of a bigger effort to rejuvenate 65 lakes in Bengaluru using handled wastewater and rainwater.
In response to the undertaking, “It includes reviving an outdated nicely and digging borewells to entry the aquifer, together with the set up of water remedy crops in two phases. Now, the system gives 6.4 lakh litres of water every day, serving to complement the home water requirement of 45,000 residents in Devanahalli. This was made potential by way of the collaboration of many organisations — together with Carl Zeiss, Rotary South Parade Bangalore, and Wipro Basis.”
Going additional, it claims that the undertaking is energy-efficient, utilizing simply 0.25 items of electrical energy per 1,000 litres, and follows the Union Authorities’s AMRUT 2.0 tips, thus serving as a mannequin for future city water administration. In 2021, the Union Authorities launched the AMRUT 2.0 scheme to “increase infrastructure for water provide, sewerage and septage administration and rejuvenate the water our bodies aiming to enhance the standard of life”.
Talking to The Higher India, Vikas Brahmavar, co-founder of Boson Whitewater, says, “For AMRUT 2.0, there are particular tips on making the undertaking commercially viable and guaranteeing water high quality, which suggests we’ve taken cautious steps to take care of excessive water requirements and an applicable design. By way of energy utilization, we can’t have a posh, elaborate remedy system that consumes a variety of energy for water remedy.”
“We solely use a number of pumps to maneuver water by way of the system, preserving energy consumption low. Now, think about if we had to make use of RO (reverse osmosis) and UF (ultrafiltration); it might turn out to be too complicated by way of energy necessities. For the reason that water from the nicely and the shallow aquifer meets IS 10500 requirements, we’re in a position to deal with it with a easy four-stage remedy course of to make sure security, making it appropriate for home provide,” he provides.
Vishwanath S, a civil engineer, water administration professional and advisor at Biome Environmental Belief, notes, “Devanahalli city depends closely on deep borewells for its water provide. By way of this undertaking, we goal to revive the native lake, recharge groundwater, and discover how a city can turn out to be self-sufficient by utilizing each native water sources and handled wastewater. The undertaking has the capability to satisfy Devanahalli’s 5.4 MLD (million litres per day) water demand.”
[1 MLD (million litres per day) is equal to 1,000 KLD (thousand litres per day)]
“In Section 1, a water remedy plant was put in to supply 240 kilo litres (2.4 lakh litres) of water every day. In Section 2, the undertaking expanded with the addition of 4 extra filter borewells, a reconstructed 60 kilolitres (KL) sump, and a brand new 400 KLD water remedy plant. The system now delivers 640 KL (6.4 lakh) of water every day, benefiting the Devanahalli residents,” he provides.
Vikas notes, “Our imaginative and prescient is to create a sustainable third supply of water by utilising each drop of wastewater generated in our cities.”
Now, let’s break down the undertaking into its finer particulars.
How did we get right here?
What Biome has been doing is that this:
There was an outdated nicely close to the Sihineeru Kere lake, estimated to be over 100 years outdated. As a result of lake’s dryness and lack of water seepage into the nicely, folks began utilizing it to eliminate particles. Biome, in collaboration with the native panchayat, cleaned out this nicely in 2020-21.
“As soon as the nicely was cleaned and handled wastewater was directed to the lake, the nicely, located about 25 to 30 toes from the lake, started to fill as water seeped by way of the earth from the lake. This pure earth filtration helped fill the nicely. Biome then examined this nicely water, which met the IS 10500 requirements. Over time, the Indian Institute of Science (IISc) received concerned, recognising the water high quality and exploring how one can make it usable for the general public. For the reason that nicely water filtered by way of the earth, it was deemed secure,” explains Vikas.
Thus, a two-phase undertaking was initiated. The primary section, accomplished a yr and a half in the past, was designed to get well 200 KL (2 lakh litres) of water every day. Water from the nicely was processed by way of disk filtration, activated carbon filtration (with excessive iodine worth), UV (ultraviolet gentle disinfection) remedy, and primary chlorine disinfection earlier than being despatched to a sump.
This sump additionally obtained deep borewell water. In that space, deep borewells, which attain depths of round 1,000 to 1,100 toes, usually comprise fluoride and different contaminants, making the water usable just for bathing and comparable functions. Water from the sump was pumped to your complete Devanahalli city, which requires about 5.4 to six MLD of water every day.
“Biome envisioned that by assembly simply 10% of the city’s water wants, they may exhibit a viable mannequin for small cities throughout India. On this method, the place lakes and wastewater can be found, communities might successfully use such sources,” notes Vikas.
Section 1 was put in in July-August 2023, adopted by a yr of testing. As soon as it proved efficient, Section 2 was launched in August 2024. Now, each phases are operational, supplying 600 KL or 6 lakh litres of water per day.
“As the following section, we’re planning to duplicate this course of at Doddakere Lake, a big lake with a number of unused wells at the moment stuffed with particles,” he provides.
Understanding the stream of water from lake to lake
Water is handled on the government-operated STP referred to as Hebbal Nagawara Therapy Plant (HN Valley Therapy Plant). From this plant, it’s pumped to Bagalur Lake by way of a pipeline after which from that lake it involves Sihi Neerukere Lake. There’s a particular motive they do that.
“The lakes usually dry up, and the one approach to refill them is by pumping handled wastewater. Authorities-run STPs are required to satisfy sure qualities in order that the wastewater they deal with may be pumped into the lakes. Provided that that high quality is met, the handled wastewater is shipped to the lake,” says Vikas.
However why does handled wastewater require additional dilution by rainwater in each Bagalur Lake and Sihi Neerukere Lake?
“At any time when the handled water goes to the lake, throughout the wet season there may be at all times dilution from the rain, and Bengaluru in all probability will get 47 or 60 days of rain throughout numerous months. So, based mostly on this rain, there may be at all times dilution within the lake. So, we don’t purposefully do it, however the concept of giving it to the lake is to dilute it with pure water,” he provides.
As defined earlier, handled wastewater that’s additional diluted with rainwater is diverted to Devanahalli’s Sihi Neerukere Lake. Right here, it’s additional diluted with rainwater, and subsequently filtered by way of the earth to recharge the aquifer.
“The Sihi Neerukere Lake will dry up if no water flows into it. Devanahalli at all times had issues with drought. Again in 2015-16, this lake nearly went dry. The native governing physique requested the Authorities to ship the handled wastewater to the lake as a result of it might go defunct. That was the preliminary goal,” he says.
After this handled wastewater is as soon as once more additional diluted with rainwater, it’s subsequently filtered by way of the earth to recharge the aquifer.
For Section 2, they used one thing referred to as a shallow aquifer.
“So, as an alternative of digging a borewell at 1,000 toes, you dig a filter borewell (shallow aquifer) at a most depth of fifty to 90 toes. Right here, nicely water seeps once more by way of pure filtration and enters the filter borewell. Filter borewells are primarily shallow borewells with pores within the pipe for filtering, and the plan was for about six or seven filter borewells, I imagine,” explains Vikas.
“Water then undergoes one other degree of earth filtration earlier than reaching one other sump,” he provides.
So, for the second section, they use shallow aquifer water from the filter borewells, directing it to the sump. “We added a extra superior remedy plant, the place the disc filtration is now absolutely automated. This method features a higher-grade activated carbon filter, a number of UV programs in parallel, and chlorine disinfection, after which the water is shipped to the sump,” he explains.
“Beforehand, the sump obtained deep borewell water excessive in fluoride, contaminants, and dissolved salts. Now, these points have decreased as a result of shallow aquifer water, and the psychological barrier can be gone since a number of ranges of earth filtration are used, making the water secure to produce to your complete village,” he provides.
The water is then picked up from the aquifer by way of a dug nicely and shallow filter borewells, handled, after which provided to the city.
“The water high quality meets IS 10500 requirements. The TDS (complete dissolved solids) averages under 500 ppm, in comparison with 1800 ppm in deep borewells, and accommodates no fluoride, in contrast to deep borewell water. Making issues higher, Devanahalli residents don’t pay for the water for the reason that native authorities physique provides it without cost,” he says.
If an analogous mannequin is efficiently replicated throughout the town, then Bengaluru might higher navigate its perennial water scarcity situation. Moreover providing the chance to stop flooding, these lakes supply buffer areas for the town to make use of its wastewater effectively.
(Edited by Pranita Bhat; Pictures courtesy Boson Whitewater)