“Wouldn’t you like a nice anaerobic sludge blanket?” by Clean Ganga Campaign, Suparna Sharma, Swatcha Ganga Campaign
Sharma, S. “Wouldn’t you like a nice anaerobic sludge blanket?” Clean Ganga Campaign, 2002
By Suparna Sharma
Kanpur is a North Indian city along the Ganga that got hooked on a strange technology for cleaning the holy river.
Well into the 1980s some 300 leather tanneries in Kanpur spewed hazardous wastes into the river; raw sewage continued to meet the river every few yards; human corpses were slid into the murky waters, where thousands more urinated and defecated every day.
Then along came the Government’s ambitious Ganga Action Plan, and with it a newly imported technology to keep the river clean in Kanpur.
Bearing the unwieldy name Upflow Anaerobic Sludge Blanket (UASB), it seemed to answer many prayers. And since the Dutch were willing to fund it as well, the technology was welcomed with open arms.
Proponents said that UASB would not only keep the Kanpur stretch of Ganga clean, but would also be profitable – treated wastewater would be used for irrigation, and UASB plants, while cleaning the wastewater, would also generate electricity. Also, the sludge would be sold as manure.
It sounded ideal.
With UASB, drains would not be allowed to flow into Ganga. They would be intercepted, diverted and treated.
Since Kanpur produces about 350 MLD (million liters per day) of domestic sewage, plus 9 MLD tannery wastewater, three UASB plants were commissioned under GAP’s first phase – 5 MLD, 36 MLD and 130 MLD (the 36 MLD plant would treat only tannery wastewater).
These plants would have to deal with three main pollutant indicators: BOD (or Biochemical Oxygen Demand); TSS or Total Suspended Solids, and Coliform (total and fecal – as an indicator of disease-causing organisms).
If water contains large numbers of fecal coliform bacteria, it is possible that pathogenic (disease-causing) organisms are also present. Tannery wastewater also has chromium content, making it 15 times more hazardous than domestic sewage.
OK. But after the plants went onstream, the problems became evident. UASB is a biological process where water is retained in a pond and treated with bacteria that doesn’t require oxygen – and thus only tackles only the BOD problem. Reduction of TSS, coliform and chromium is incidental and minimal.
So what are the results of UASB’s core concern – BOD?
The 36 MLD plant – according to tests done by UP state government’s Ganga Pollution Control Unit in November last year – is able to reduce BOD from 419 mg per liter to 180 mg/l. The 130 MLD plant boasts better results: It brings down BOD to 58 mg/l from 259 mg/l.
Officials say treated wastewater can be discharged into a water body only if its BOD is 30 mg/l. And if the BOD is 100 mg/l, water can be used for irrigation. But treated wastewater from both these plants is being used for irrigation. And, treated water from the 5 MLD plant, which brings down BOD to 52 mg/l from 255 mg/l, is being diverted into the Ganga.
Sir, there’s a fly in your ointment
Officials in Kanpur directly responsible for UASB and its fallout dismiss concerns regarding pollutants in the treated wastewater.
But anyone who claims to make wastewater fit for irrigation has to be answerable. Especially since the claim accompanies an assertion that UASB is the best way to treat wastewater and keep Ganga clean. Now consider these:
Tests reveal that Ganga’s fecal count exceeds 7,000 MPN/100 ml. But the fecal count “must be nil if wastewater is to be used for irrigation or is being diverted to a river,” an official told me. Fecal coliform count of treated wastewater from the 5 and 36 MLD plants is 10,000 MPN/100 ml.
Though the 36 MLD plant treats tannery wastewater, it is not designed to. Though officials refuse to give figures, they say chromium content in the treated wastewater is “alarming… almost four times more than what it should be. Water that is used for irrigation, or is diverted to the river, should not have chromium.”
The issue of residual sludge is equally worrisome. Neither the Kanpur administration nor the Dutch made any provision for a safe dumping site. All solid waste – including chromium-laced sludge from the 36 MLD plant that amounts to 22 tons per day – is dumped in the open.
As one of the most harmful pollutants in tannery waste, chromium affects air and soil quality and can be transmitted to at significant distances from its emission point. This gives rise to human health concerns.
Sunlight and ponds, a sensible option
Given the hard evidence of its ineffectiveness, it’s a mystery why the central government is devoted to UASB technology.
Most officials in Kanpur openly discredit the UASB plants. And in the same breath add that oxidization ponds are the best option, because they reduce BOD as well as TSS, fecal coliform and chromium.
The only problem with the pond technology, they say, is land. Oxidization pond technology relies on sunlight for treating wastewater. And since the ponds can’t be deeper than a meter, one hectare land is required (a hectare equals 2.47 acres) to treat one MLD wastewater.
Kanpur is spread over 79,876 hectares. For treating its entire wastewater – 359 MLD – about .45 per cent of its total land would be required.
Officials such as BP Shukla, senior environment engineer in-charge of Central Pollution Control Board’s Kanpur unit, pull no punches when openly criticizing UASB technology. “All the three UASB plants are operating at just 50 per cent efficiency level,” he says.
Last year, about six years after it started treating tannery wastewater, the 36 MLD plant got a generator. “Three-four hour long power cuts are normal in Kanpur. And since these plants have no holding capacity, raw sewage was either going into Ganga or into the farms.”
Shukla’s biggest grouse is that since the UASB process is not able to reduce chromium content, the “hazardous substance” is getting into “Kanpur’s food chain and contaminating groundwater”.
When I visited villages around Jajmau, which receive treated wastewater, farmers complained that their crop dies soon after they pump water into the fields. “Saab jal jata hai. Khari fasal mar jati hai (all standing crop gets destroyed).”
But FU Rahman, team leader of the Dutch funded Project Planning and Coordination Unit under the GAP Support Project, sits firmly on his side of the bank. He asserts that tapping tannery wastewater and stopping it from going into Ganga has been UASB’s biggest achievement.
But he, too, relents when challenged with statistics. “Though treated water from the 36 MLD plant is being used for irrigation, it should not be. It is dangerous because of the chromium,” Rahman said.
“Sometimes we get misled”
Dr Vinod Tare, of the Indian Institute of Technology, Kanpur – who regularly monitors the impact of GAP I by testing the Ganga and treated wastewater for the National River and Conservation Board, says the UASB plants “never, ever operated properly.
“The 130 MLD plant treats just 70-80 MLD wastewater. And despite contrary claims, there is chromium in all the treated water. And the fringe benefits – generation of electricity, revenue from manure – are nil. We should have never expected UASB to get us results.”
Then why did we opt for UASB? “Well, sometimes we get misled,” Dr Tare said.
But isn’t Kanpur’s Ganga cleaner after the completion of GAP’s phase one? “There has been no improvement. But one can say that there hasn’t been much deterioration either,” he said.
The bigger picture is dreary, with the sewage problem acquiring other dimensions: Solid waste, ground water and food chain contamination. But perhaps, most unfortunately, is the resigned attitude regarding UASB. Most officials in Kanpur assume that since UASB is the official technology there isn’t much point in even pressing for an alternative.
Environmental crusader Rakesh Jaiswal, of EcoFriends in Kanpur sums it up: “When GAP began, the leadership had a vision. An image of what Ganga should be like. Over the years that dream has got diluted and now it’s down to ‘well done! This month the BOD level was within limits.'”
Unfortunately, GAP’s success is measured more in terms of installation and commissioning of treatment plants rather than what’s happening to the Ganga. As Dr Tare says, “The first and only criterion of measuring success should be that the water must look clean. I shouldn’t be repulsed by it… Kanpur’s Ganga is black and thick with sewage.”
No one expected miracles when GAP commenced. Just that sewage water would be treated and accommodated safely, somewhere. But then, few took into account the effluence of UASB.
Suparna Sharma is a Delhi-based freelance journalist. All opinions expressed in this article are the author’s.