The dirty business of sewage disposal in Chennai

Despite the Corporation’s claim of installing Underground Drainage (UGD) systems  across the city, a bulk of the city’s sewage ends up untreated in the canals, lakes and other water bodies in the suburbs. 

According to the record books maintained by the Chennai Metro Water Supply and Sewerage Board (CMWSSB), sewage generated from houses and other buildings is collected through the UDS system that stretches across a length of 3,994 km in the city. This sewage is taken to 228 sewage pumping stations, which collect sewage from designated areas. The sludge is then taken  to various Sewage Treatment Plants (STPs) located in the city.  

The sewage system of the city is divided into five zones with independent zonal collection, conveyance, treatment and disposal facilities. The collected sewage from pumping stations is conveyed to six STPs. However, suburban areas like Maduravoyal, Ullagaram, Puzhuthivakkam and several other areas have no proper UGD systems. 

CMWSSB officials point fingers at the thousands of private tanker lorries that collect sewage from suburban homes and other buildings and dump them in open drains across the city as it is cheaper for them. This is the root cause of all the trouble, they say. 

The CMWSSB operates 32 lorries to collect sewage mainly when the sewage line is blocked in some points and bring it to pumping stations. 

Private lorry owners engaged in the business claim that they  sometimes have to wait for several hours to dump the septic tank waste. “Besides, we have to pay Rs. 100 to the pumping station before discharging the sewage. This business is so competitive that if we charge Rs.100 more besides transportation charges, we will lose out to others who charge less and dump it in open fields and canals,” said a private tanker lorry owner in Maduravoyal. B Varadharajan, president, Maduravoyal Residents Association Committee, says, “Due to lack of UGD systems in our area, sewage from households is being let into open places, which poses a health hazard. The officials should inspect the areas where there is a lack of such system and create proper UGD systems”. 

Arun Krishnamurthy, founder of Environmentalist Foundation of India (EFI), told DTNext that many sewer private lorries from the city dump sewage in the suburbs. 

“There should be a centralised STP and proper sewerage regulation is the need the hour.” Since most suburbs lack such a system, some residents living along the water bodies let sewage out openly, he said. A Veerappan, former special chief engineer, PWD, Chennai region,  felt  there should be  proper coordination between Chennai Corporation and CMWSSB so that dumping sewage in unauthorised places can be controlled. He added that the officials could rope in a few environmentally committed Non Governmental Organisations (NGOs) to help design proper disposal systems to bridge the gap.

Plenty of awareness: One of the Superintending Engineers, of CMWSSB told this newspaper that unlike in the past, there has been a growing awareness among the public on issues related to illegal dumping. “People immediately alert the police, if they see any lorry dumping untreated sewage in open places. Further, many private lorries which collect sewage approach us and pump  out the sludge by paying Rs. 100. We receive around 350 lorries on a given day,” he said. According to him, the treated water was being utilised to water plants in the medians and plants and trees belonging to the Corporation. 

However, he conceded that some private lorries continue to dump untreated sewage in  open places. Officials say  they have informed the Regional Transport Office to monitor such lorries. 

( Chennai Metro Water Supply and Sewerage Board office in Koymabedu)

In March, 2016, The Southern bench of National Green Tribunal directed concerned officials to monitor lorries dumping untreated sewage into canals and other  water bodies.

The Chennai Metro Water Supply and Sewerage Board (CMWSSB) claims that the board has capacity to treat 769 MLD in Chennai. 

545.97 MLD  is amount of sewage  generated in the city. 

Lorries illegally dump sewage in prime waterbody areas such as Buckingham Canal, Cooum, some stretches on OMR, Maduravoyal bypass road, Pallikkaranai, Virugambakkam and Arumbakkam drains.

In the past, surplus of sewage, beyond pumping stations’ capacity, drained into the water bodies- Cooum and Adyar rivers, Buckingham Canal and Otteri Nullah.

183  new sewage outlets are in the process of being laid by  CMWSSB officials.

7,78,488  consumers have underground drainage (UGD) in the city.

(Fact File)