Boson Whitewater — a water utility enterprise that converts handled water from sewage therapy vegetation (STPs) into high-quality potable water — has partnered with the non-profit Biome Environmental Belief to launch India’s first oblique potable water reuse venture. This revolutionary initiative, positioned in Devanahalli, 40 kilometres northeast of Bengaluru, makes use of managed aquifer recharge to realize sustainable water reuse.
In accordance with the contributors [of this project], the venture produces 6.4 lakh litres of potable consuming water per day, adhering to BIS (Bureau of Indian Requirements)-10500 requirements. The clear water instantly advantages hundreds of residents within the Devanahalli municipality.
How does this work?
Merely put, handled wastewater from a sewage therapy 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 a pipeline, additional diluted with rainwater, and subsequently filtered by the earth to recharge the aquifer. The water is then picked up from the aquifer by a dug effectively and shallow filter borewells, handled, after which equipped to the city residents.
Why is that this an oblique potable water reuse venture?
This venture makes use of an environmental buffer like a lake for dilution with rainwater and/or a groundwater aquifer for earth filtration. This water finally goes by a ultimate therapy stage earlier than it’s equipped to residents.
What’s extra, the venture is a component of a bigger effort to rejuvenate 65 lakes in Bengaluru using handled wastewater and rainwater.
In accordance with the venture, “It includes reviving an outdated effectively and digging borewells to entry the aquifer, together with the set up of water therapy vegetation in two phases. Now, the system gives 6.4 lakh litres of water each day, serving to complement the home water requirement of 45,000 residents in Devanahalli. This was made attainable by the collaboration of many organisations — together with Carl Zeiss, Rotary South Parade Bangalore, and Wipro Basis.”
Going additional, it claims that the venture 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”.
Chatting with The Higher India, Vikas Brahmavar, co-founder of Boson Whitewater, says, “For AMRUT 2.0, there are particular tips on making the venture commercially viable and making certain water high quality, which suggests we’ve taken cautious steps to keep up excessive water requirements and an acceptable design. By way of energy utilization, we can’t have a posh, elaborate therapy system that consumes numerous energy for water therapy.”
“We solely use a number of pumps to maneuver water by the system, retaining energy consumption low. Now, think about if we had to make use of RO (reverse osmosis) and UF (ultrafiltration); it might develop into too complicated by way of energy necessities. Because the water from the effectively and the shallow aquifer meets IS 10500 requirements, we’re capable of deal with it with a easy four-stage therapy course of to make sure security, making it appropriate for home provide,” he provides.
Vishwanath S, a civil engineer, water administration skilled and advisor at Biome Environmental Belief, notes, “Devanahalli city depends closely on deep borewells for its water provide. By way of this venture, we purpose to revive the native lake, recharge groundwater, and discover how a city can develop into self-sufficient through the use of each native water sources and handled wastewater. The venture 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 Part 1, a water therapy plant was put in to offer 240 kilo litres (2.4 lakh litres) of water each day. In Part 2, the venture expanded with the addition of 4 extra filter borewells, a reconstructed 60 kilolitres (KL) sump, and a brand new 400 KLD water therapy plant. The system now delivers 640 KL (6.4 lakh) of water each 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 venture into its finer particulars.
How did we get right here?
What Biome has been doing is that this:
There was an outdated effectively close to the Sihineeru Kere lake, estimated to be over 100 years outdated. Because of the lake’s dryness and lack of water seepage into the effectively, individuals began utilizing it to get rid of particles. Biome, in collaboration with the native panchayat, cleaned out this effectively in 2020-21.
“As soon as the effectively was cleaned and handled wastewater was directed to the lake, the effectively, located about 25 to 30 ft from the lake, started to fill as water seeped by the earth from the lake. This pure earth filtration helped fill the effectively. Biome then examined this effectively water, which met the IS 10500 requirements. Over time, the Indian Institute of Science (IISc) received concerned, recognising the water high quality and exploring tips on how to make it usable for the general public. Because the effectively water filtered by the earth, it was deemed protected,” explains Vikas.
Thus, a two-phase venture was initiated. The primary section, accomplished a yr and a half in the past, was designed to get better 200 KL (2 lakh litres) of water each day. Water from the effectively was processed by disk filtration, activated carbon filtration (with excessive iodine worth), UV (ultraviolet mild disinfection) therapy, and primary chlorine disinfection earlier than being despatched to a sump.
This sump additionally acquired deep borewell water. In that space, deep borewells, which attain depths of round 1,000 to 1,100 ft, usually include fluoride and different contaminants, making the water usable just for bathing and related functions. Water from the sump was pumped to the whole Devanahalli city, which requires about 5.4 to six MLD of water each day.
“Biome envisioned that by assembly simply 10% of the city’s water wants, they may display a viable mannequin for small cities throughout India. On this means, the place lakes and wastewater can be found, communities might successfully use such assets,” notes Vikas.
Part 1 was put in in July-August 2023, adopted by a yr of testing. As soon as it proved efficient, Part 2 was launched in August 2024. Now, each phases are operational, supplying 600 KL or 6 lakh litres of water per day.
“As the subsequent section, we’re planning to copy this course of at Doddakere Lake, a big lake with a number of unused wells at present stuffed with particles,” he provides.
Understanding the stream of water from lake to lake
Water is handled on the government-operated STP known as Hebbal Nagawara Remedy Plant (HN Valley Remedy Plant). From this plant, it’s pumped to Bagalur Lake by a pipeline after which from that lake it involves Sihi Neerukere Lake. There’s a particular purpose they do that.
“The lakes usually dry up, and the one method 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 might 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?
“Each time the handled water goes to the lake, throughout the wet season there may be all the time dilution from the rain, and Bengaluru most likely will get 47 or 60 days of rain throughout numerous months. So, based mostly on this rain, there may be all the time 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 the earth to recharge the aquifer.
“The Sihi Neerukere Lake will dry up if no water flows into it. Devanahalli all the time 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 function,” he says.
After this handled wastewater is as soon as once more additional diluted with rainwater, it’s subsequently filtered by the earth to recharge the aquifer.
For Part 2, they used one thing known as a shallow aquifer.
“So, as a substitute of digging a borewell at 1,000 ft, you dig a filter borewell (shallow aquifer) at a most depth of fifty to 90 ft. Right here, effectively water seeps once more by 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 therapy plant, the place the disc filtration is now absolutely automated. This technique features a higher-grade activated carbon filter, a number of UV techniques in parallel, and chlorine disinfection, after which the water is shipped to the sump,” he explains.
“Beforehand, the sump acquired 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 protected to provide to the whole village,” he provides.
The water is then picked up from the aquifer by a dug effectively and shallow filter borewells, handled, after which equipped to the city.
“The water high quality meets IS 10500 requirements. The TDS (whole dissolved solids) averages under 500 ppm, in comparison with 1800 ppm in deep borewells, and accommodates no fluoride, not like deep borewell water. Making issues higher, Devanahalli residents don’t pay for the water for the reason that native authorities physique provides it at no cost,” he says.
If the same mannequin is efficiently replicated throughout town, then Bengaluru might higher navigate its perennial water scarcity difficulty. In addition to providing the chance to forestall flooding, these lakes provide buffer areas for town to make use of its wastewater effectively.
(Edited by Pranita Bhat; Photographs courtesy Boson Whitewater)
