Urban shit: Where does it all go?

Manoj Kumar should know the national capital’s dirty little secret. Where does the excreta of its residents not connected to the sewer system go? He has been working as a septic tank cleaner for 20 years. By now he owns three vacuum tankers that suck faecal sludge from septic tanks. Accompanied by his helper Rajbir Pal, he arrives at a house in Sangam Vihar locality in south Delhi. Rajbir Pal hops off the tanker and lays out a pipe to the septic tank in the house. He uses bare hands and laughs sarcastically at the idea of using a gas mask. “We have heard of instances where workers die when they have to go deep into the tank where toxic gases are emitted. We should, at least, be provided gloves,” he says.

It is a two-storey building that houses seven families. The septic tank should ideally have two chambers, with an outlet connected to a soak pit or some other treatment system for safe dispersal of effluent after the faecal sludge has settled at the bottom. Instead, it is a single-chambered tank without any outlet, so its entire content has to be emptied. Small wonder the owner, Birender Singh, complains, “We have to empty it every month.”

Amid the roar of the vacuum pump slurping the sludge from the tank, Singh seems contented, having managed to get rid of the excreta generated in his house. But does he know where the tanker is headed? “We don’t know, madam. And frankly, we don’t care,” he says. In seven minutes the tank is emptied. He pays Rajbir Pal Rs 1,000 and that for him is the end of his problem.

Back on the vacuum tanker, Kumar and Rajbir Pal head straight towards Batra Hospital, Tughlakabad. They empty the sludge into the drain outside the hospital which ends up in a bigger drain that opens into the Yamuna. When asked why they do not go to one of the 36 sewage treatment plants (STPs) spread across 21 locations in the city, Rajbir Pal minces no words. “If we go to a treatment plant, it will eat away into our earnings. We can cover three-four houses in that time.” But what if they are caught? “We pay Rs 100-200 and get away.”

Kumar is part of an informal union of cleaners operating from outside Batra Hospital. He makes 10-15 trips in a day; in monsoons, the number of trips shoots up. His tanker is just one of the 350 to 400 vacuum tankers run by individuals or unions in the National Capital Territory. So one can imagine the enormous amount of faecal sludge generated in the region—and India.

Only a third of urban houses in India are connected to the sewer system. The majority of the houses—38.2 percent, as per Census 2011—use toilets connected to septic tanks. The problem is that the construction quality of the tanks, buried underground in populated areas, is often poor. As a result, the treatment of sewage is partial. Then there is no system for the disposal of the faecal sludge, which is, in most cases, emptied out surreptitiously into water bodies and municipal sewers.

It is not even practical to connect every house to the sewer system. In India, over 1.2 billion people generate nearly 1.75 million tonnes of excreta daily. A large proportion of these then proceeds to release the lever on the flush attached to the toilet. Ironically, this only aggravates the problem. Now the volume of sewage has expanded several times and the municipalities will have to separate the excreta from water at a huge cost.

If the house is connected to sewerage this sewage will travel from the building’s internal wastewater collection system to the municipal sewer system. Propelled by pumping stations, the wastewater will finally reach an STP if there is one. Creating this infrastructure for all will be prohibitively costly. Nor is it suitable to all terrains. Management of excreta on the site by using septic tanks and pit latrines is, therefore, a necessity.

Census figures show that nearly 45.3 percent of urban houses depends on on-site systems. A large part of the wastewater from these systems seeps into the soil. This may penetrate deep enough to pollute groundwater. Emptied faecal sludge should ideally be sent to a treatment facility, where it should be treated to meet the standards set by the Central Pollution Control Board (CPCB). This, however, does not happen in most cases. Census data shows 65 percent of the cities in the country do not have a proper arrangement for safe collection of human excreta, forget about disposal. 

India does not even have specific legal provisions related to the management of faecal sludge, also called septage in the municipal parlance, although a number of laws cover sanitation services and environmental regulations. It was only in 2013 that the Ministry of Urban Development issued an advisory note on septage management in urban India. As per this note, city sanitation plans, recommended by the National Urban Sanitation Policy, should be supplemented with a septage management sub-plan.

The Bureau of Indian Standards (BIS) specifies the guidelines for construction of septic tanks in houses. The minimum liquid-holding capacity of a tank should be 1,000 litres. When the capacity of a septic tank is more than 2,000 litres, it must consist of two chambers separated by a partition. The first chamber should be twice the size of the second. BIS also mandates that the floor of the tank should be watertight. All in all, an ideal septic tank is a two-chambered lined containment either connected to a soak pit to drain out the effluent after primary treatment or connected to some other secondary treatment system.

But these guidelines are only suggestive, not binding. As a result, most septic tanks do not conform to the recommended design. A lot also depends on the skills and experience of the mason building a septic tank and the area available to him. Consider the septic tank at the Sangam Vihar house in Delhi. Given its volume of 6,000 litres, it should have two chambers. But space constraint in Singh’s house meant a two-chambered septic tank was out of the question. Sangam Vihar is a clustered colony where the surface area of a house is no more than 21 square metres.

In Delhi, the capacity of septic tanks varies from 3,000 litres to 8,000 litres in individual houses. “But most septic tanks in Delhi are single-chambered,” says P K Jha, chairperson of the Delhi-based NGO, Foundation for Environment and Sanitation.

In areas like Meethapur and Pratap Vihar in Delhi, the effluent from septic tanks is discharged directly to an open ground. The Centre for Science and Environment (CSE) also found that some tanks were designed with an outlet to an open drain, such as in Harsh Vihar. This is when the National Building Code, 2005, specifies that “under no circumstances shall effluent from a septic tank be allowed into an open channel drain or body of water without adequate treatment”. In parts of Maidangarhi and Meethapur, the CSE found cesspools, which are lined tanks with no outflow. “Poor houses have a storage tank in the name of a septic tank,” Jha says.

Some may think that a law to ensure compliance with BIS standards will serve the purpose. But the field study in Agra showed this is not necessarily the case. According to the Uttar Pradesh Water Supply and Sewerage Act of 1975, the Agra Nagar Nigam (municipal body) has the power to fine the owner of an improper septic tank. Despite this, septic tanks in Agra generally do not conform to the design specified by BIS and the effluent is allowed to flow into open drains. Unlined pit latrines are also a prominent feature in the city.

It is the same case in Tiruchirappalli. Tamil Nadu’s septage notification of 2014 states that the owners of septic tanks that do not meet the standards will be issued notices as per the Tamil Nadu Public Health Act, 1939. Yet septic tanks in Tiruchirappalli were not found to adhere to the standards.

Then there are cases where a mason’s knowledge of local conditions beats BIS’ scientific standards, such as in Bikaner. In this city of Rajasthan, septic tanks are mostly in the form of kuiis, lined pits with semi-permeable walls and an open bottom with no outlet or overflow. A slab is used to cover a kuii, which gets filled in 20-30 years. It is a common feature in peri-urban areas in Bikaner. 

Although kuiis are not a scientifically viable solution because they have an open bottom and may pollute groundwater, CSE believes that in an area like Bikaner, where the groundwater level is astonishingly low, leachate from a kuii cannot percolate to groundwater. It is better to have the faecal sludge contained in the soil where, microorganisms can digest it, instead of having a conventional septic tank and risking discharge of effluent into open drains or fields.

In coastal cities, Cuttack and Srikakulam, pits outnumber septic tanks. This is because in these cities pits are designed in the form of concrete rings placed one over another which makes them inexpensive and easy to close and replace.