Raising a stink: India’s big-little STP problem

There is one reality we are confronted with in almost all major Indian cities—the unmistakable, unshakeable stench of rotting sewage.

Year after year, Bengaluru’s lakes continue to froth angrily because of the high level of waste in them. But these lakes aren’t outliers. Like clockwork, every torrential monsoon in Mumbai sees the city’s roads flooded with sewer water. And in Delhi, the arterial Yamuna has been a cesspool for decades.

The cause for all this untreated sewage floating around is as obvious as it is revolting—sewage management in India is either non-existent or woefully unsatisfactory.

According to the Central Pollution Control Board’s (CPCB) estimates, the overwhelming majority—some 78%—of domestic sewage is left untreated in the country. It is either dumped into rivers and lakes or let out into fields, where it leaches into the soil, contaminating our groundwater. 70% of groundwater, according to the Composite Water Management Index, is already contaminated. At this rate, 21 Indian cities are well on their way to having no access to groundwater by 2020. (Read our story on India’s water scarcity problem)

India’s major cities are starved for clean water. Paradoxically, where clean water is scarce, the volume of sewage generated is growing unabated. In 2017, India’s class I and class II cities generated enough sewage to fill up 11,600 Olympic-size swimming pools daily—an estimated 29,129 million litres a day (MLD). In sharp contrast, the cumulative treatment capacity is a meagre 6,190 MLD. Over four times less than is needed. Even with another 1,742 MLD of sewage treatment capacity additions planned, the gap reduces by a mere 6%. According to the CPCB, this lack of treatment capacity has led to domestic sewage being the biggest polluter of our urban water resources.

All of this underlines an inarguable fact. Water runs in an unforgiving ecological loop. What you give is what you ultimately get back.

The root cause of this predicament are India’s centralised sewage treatment plants (STPs), which service most urban centres and provide reusable wastewater. And as urban populations continue to grow, the cracks in the system, long visible, are growing into gaping chasms.

Even where piped sewage networks exist, their patchy coverage across the city means that even the available capacity remains underutilised. “States like Tamil Nadu have spent a lot of money investing in a piped sewage network, but the volume of sewage flowing through them is very low,” says S.R. Ramanujam, a Mumbai-based water expert. As a result, only 33 of Tamil Nadu’s 73 sewage treatment plants are actually operational.

In light of all this, there is growing consensus that decentralised STPs are the way forward. Born in the 90s, in response to local community efforts, these have become a key strategy in the government’s plan to implement a ‘polluters pay’ principle. New regulations—targeted at apartment complexes with twenty or more units in Karnataka or large housing colonies in Maharashtra—have even mandated a 100% ‘zero liquid discharge’ policy. This means 100% usage of the wastewater by residents living near the STP. Most recently, the state government in Delhi is also considering mandating STPs in all new buildings.

First Mover

One of the first decentralised systems was set up at Pondicherry’s Aravind Eye Hospital in 2003. Built at a capital cost of Rs 1.12 crore ($155,135), this plant has a treatment capacity of 300 KLD

A local water treatment plant. 100% reuse of wastewater. Seems like a silver bullet situation to the urban sewage problem. But the execution on ground, with regulations not backed up by adequate oversight and standards, has created its own set of problems. An unsupervised grey market to treat grey water has sprung up. Online. Offline. Branded. Unbranded. On websites like IndiaMart, these systems cost between Rs 5-35 lakh ($6,926-48,000) for residential systems capable of treating between 10-300 kilolitres per day.

“There are maybe 3 to 4 branded STP technologies in the market. The rest of the supply comes from small-time, unorganised operators looking to make a quick buck,”says Hitesh Bhatia, a Delhi-based dealer for ION Exchange, one of the few branded players in the space. With no standards to guide consumers’ choices across technologies, capacity, operational requirements or prices, confused residents desperate to comply with regulations are left in the lurch.

The Wild West of wastewater treatment

The tech behind cleaning wastewater has been around for a while. The interaction between four main components—water, waste, bacteria and air—is at its core. However, the growing number of decentralised STP manufacturers have added mechanisation and electrification to make these systems capable of catering to dense population clusters. The Activated Sludge Process, the most common tech till a few years ago, has been superseded by souped up versions like the Membrane Bioreactor (MBR), Moving Bed Biofilm Reactor (MBBR) and Sequencing Batch Reactor (SBR).

“The current favourite in the market is the MBBR,” says R.S. Tomar, proprietor of J.M. Enviro Tech, a Delhi-based water treatment firm. Tomar’s company has been empanelled by the Delhi government to install STPs in its housing colonies. “The MBBR is a cheaper option, is not a technically complex machine, and generates good quality wastewater, in line with CPCB norms,” Tomar explains. A slightly more expensive version of the MBBR is the MBR, where the presence of a membrane raises the cost of the machine. An MBR plant usually costs more than double what a similar capacity MBBR plant is available for.



Ultimately, consumers’ choices are dependent on a wide range of factors. These factors range from available surface area, how much electricity is required and the desired quality of wastewater, says Akshay Syal, an entrepreneur from the wastewater treatment space. Syal co-founded a water treatment company called WaterNeer in 2010, and has been promoting a highly-automated approach to treatment and reuse of waste water.

The elaborate catalogue of STP types indicates a burgeoning, yet fractured market for wastewater treatment. This makes it hard to pin down the exact economic potential of this market. Syal believes that—given the number of households, schools, universities and offices that now demand decentralised systems—the headroom for growth is exponential. According to a report published by research organisation Global Water Intelligence, the total compounded annual growth rate for wastewater management in India is projected to be 8-10% between 2015-2020.

Despite the opportunity that lies ahead, Syal cuts a frustrated figure. He worries that the technological standards of the current STP market are far from sufficient. They present more of a band-aid solution than a permanent fix. His grouse, especially, is with the mushrooming of retail plug-and-play systems found online on e-commerce sites such as IndiaMart.

Bhatia, from ION Exchange, echoes Syal’s concern about the unorganised market. “There is no great differentiation between the offerings of branded versus unbranded players. Branded players end up charging more for the same tech, pushing buyers into the hands of smaller, unbranded vendors, who can offer the same tech at a lower cost,” says Bhatia. For instance, they can use cheaper materials to assemble the plant, which could cause defects and breakdowns in the long run.

Cost over quality

With no mandated standards, builders—who are tasked with installing STPs at the time of construction—opt for cheaper systems. This has the potential to backfire as more residents occupy the property. “Vendors will sell plants to builders when the residential buildings are at their least capacity. As the flats begin to fill up, and sewage load increases, these decentralised STPs malfunction,” says Bhatia. The fault lies with the state, but citizens have to bear the repercussions. “In its rush to mandate decentralisation, the utilities have paid little attention to laying out any detailed standards for the treatment quality of the plant,” adds Syal.

Without an understanding of the tech involved in treating wastewater, comparing specs on STPs is a nigh on impossible. “The market is full of small operators who’ve broken away from bigger firms and have basic knowledge on how to assemble these domestic STPs,” says Syal. Bhatia explains the problem with this. “A branded vendor would correctly assess the size of the tank required, the potential load on the system, and be able to customise the STP. A local vendor, with little knowledge would muddle through it, and hand over a substandard product,” he says. In the rush to comply with state regulations, however, these differences often go unheeded.

The unchecked spread of unbranded decentralised STPs finally pushed the Bangalore Water Supply and Sewerage Board’s (BWSSB) to publish guidelines for residents in 2016. However, it was long, dense and jargon-filled, making it virtually impossible to follow for anyone without a technical background.

And even as over-regulation spawned a dodgy marketplace, under-enforcement has helped it flourish. The Karnataka State Pollution Control Board (KSPCB) is supposed to do monthly checks of the machines installed in apartment complexes and housing colonies. But thanks to the regulation mandating STPs, the number of STPs has skyrocketed from 14 to 2,200 in the last decade. “It’s impossible for inspectors to be scurrying around the city, checking up on these STPs,” says Syal.

Little wonder then that choosing STPs has largely remained a patchy, word-of-mouth affair, based primarily on convenience and price.

A heavy price for low costs

In the long run, though, the desire for cheaper options may come at a heavy cost. Our urban water situation is a pendulum oscillating between an abundance of contaminated water flowing into our rivers and a depleting groundwater table. “The policy push towards decentralised STPs comes from the realisation that major cities in India are running out of fresh water. Especially in cities like Chennai and Bengaluru, where communities often have no access to fresh water or a sewage line. They have to think seriously about reusing wastewater for non-drinking purposes,” says Ramanujam. Without this, precious freshwater is wasted on washing, gardening, and even flushing.

The BWSSB was one of the first bodies to mandate a shift in this direction. In 2004, BWSSB ordered that all new housing units with more than 50 flats must set up and run decentralised STPs on-site. Builders were tasked with installing the STP during construction, with Resident Welfare Associations taking responsibility after. BWSSB then went a step further—all these buildings needed to reuse 100% of the treated wastewater they generated. Finally, in 2016, the BWSSB issued a missive directing all apartment complexes with over 20 flats to establish on-site STPs. Regardless of whether they were connected to municipal sewer lines.

But while regulators may have hoped the ecological costs alone would drive compliance, the economic costs have ensured that citizens have remained indifferent. The cost-benefit of paying for an STP simply doesn’t add up for users. This was borne out by a study conducted by ATREE, a non-profit research group, on the efficacy of Bengaluru’s STPs. The study indicated that residents who had access to sources of fresh water—through borewell or municipality connections—were less interested in reusing wastewater. Adding to their complacency is the fact that freshwater sources are heavily subsidised.

According to the study, localities, depending on their size, pay an average of Rs 87,000 ($1,204) per month to meet the manpower costs of operations and maintenance. Naturally, the more sophisticated the technology, the greater the likelihood of a higher maintenance bill. The economies of scale only kick in, say the authors, when the dwelling size is over 150 apartments. Under that threshold, it makes little sense for consumers to willingly switch to a treat and reuse strategy. “Decentralised wastewater treatment is an industry in flux. In the long run, as the tech gets more efficient, the cost of reuse will become comparable with using freshwater,” says Ganapathy.

Is automation the solution?

Syal believes the solution to all of this is automated, high-quality tech. And by automated, he means machines that are remotely monitored, controlled and reset. “Unless a system is automated and runs without human intervention, it’s difficult to make the case for decentralised STPs to work at scale,” he says. Syal believes there is no other way out. “There is no succour in the current system. In decentralised systems, we need to focus on how quickly we can get to automation and quality,” he says.

However, the cost to automate MBR and MBBR systems is very high. For instance, says Bhatia, automating a MBR machine might cost an extra Rs 5-10 lakh ($6,926-13850) over the initial Rs 45 lakh ($62,322). “Consumers tend to choose cheaper models without really worrying about its efficacy. When there’s always a vendor around to slash costs, why wouldn’t they?” says Bhatia. Syal, though, believes that these mindsets are changing. The clients he caters to, he says, want their water back because they also realise that the cost of freshwater in the future will far outstrip what they’re investing in treatment now.

The other benefit, as per Syal, is the reduced need for human intervention in the system. This human element, according to him, is a critical point where the system can break down. “There could be an electrical failure, or the machine could stop working for other reasons. Or the person supposed to be manning it could be absent,” he says. Sometimes, operators simply switch the machines off when there is a power shortage.

Not everyone concurs with this claim though. While Tomar talks about how many new STPs are highly automated, he is careful to add a caveat. Going automatic, he says, doesn’t necessarily mean no manpower is required to run the system. For instance, the removal of sludge can’t be an automatic process. Bhatia and the other experts concur with Tomar, saying that several parameters involved in running an STP—flow of sewage, quality checks on effluents, and chemical clean-up of the water—still needs constant supervision.

“As I see it, the market is still 5-7 years away from complete automation. For one, every time the colony loses power, the system will have to reboot itself. Automation is a specialised fields, and these automatic plants would require skilled manpower to operate,” says Sachin Angirish, founder of an ecological group-cum-STP manufacturer Water2People.

But even as experts go back and forth on what the future holds, there needs to be a change of approach in the here and now to bring decentralised STPs into the mainstream.

Coercing compliance

At present, explains, S. Vishwanath, an urban water specialist from Bengaluru, compliance is still mostly driven by regulation. RWAs are held directly responsible by State Pollution Control Boards if STPs fail to function at full capacity. In Bengaluru, at least, RWAs’ fears of falling foul of the regulation are evident. With 300 notices already issued by KSPCB to RWAs for non-compliance, some RWAs in areas like Bellandur have banded together to protest this regulation. Retroactively, they claim, installing STPs in their old apartment complexes is almost impossible due to a lack of space and weak foundational structures.

Singapore’s NEWater

Singapore depends on neighbouring Malaysia for half of its water needs. But this arrangement will expire by 2061. In preparation, Singapore’s public utility generates NEWater—treated sewage fit for potable use. It’s already meeting 30% of Singapore’s water needs

However, the reluctance goes beyond just the functional. Consumers have a trifecta of reasons dissuading them from buying into decentralised STPs. A lack of information about the need for quality STPs, access to cheap sources of freshwater, and a long-held bias against wastewater. This last reason is a significant one, according to Vishwanath. “If given a choice, consumers would still prefer to see their sewage go into the municipality pipeline. The idea is that no one wants sewage in their backyard,” he says. These can only change with a sea-change in mindsets.

Instead of a penalising approach, the way utilities like BWSSB are doing, Vishwanath suggests the establishment of a ‘decentralised STP’ knowledge platform, spurred by the utility itself. A platform that will “empanel a list of vetted providers so that consumers can make an informed choice about what they’re buying.”

Vendors like Bhatia, however, believe that awareness alone won’t do the trick. “The enforcing authority should do regular checks on the quality of wastewater being generated. They must also monitor the usage of this water by the consumers. Are they consuming this water in their gardens? Have they installed a dual piping system for their flushes?” he explains. Ultimately, Bhatia says, the idea is to cut down the intake of freshwater in these water-starved areas. The way forward, though, is likely somewhere in the middle. Without the convergence of the right tech, enlightened regulation, and the political will to make decentralised water treatment work, Indians are looking down a long, dry, bottomless well.

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