Raw sewage is often drained into various water bodies in the city (Representational Image)
CHENNAI: Only around half of the sewage generated in Chennai Metropolitan Area (CMA) is collected by the existing sewerage system, leaving the remaining uncollected, the CAG report tabled in Assembly on Thursday said.
As of March 2019, only 52% of the sewage in the CMA was being collected through the sewerage system. Of the collected sewage, only 88% was being treated before being let out, the report stated.
The audit stated that the Government of Tamil Nadu, in response to the audit, said that the claim that only 52% of sewage was collected was based on theoretical calculations. However, the CAG stated that the reply was ‘untenable’.
“.. the quantity of sewage is always worked out theoretically based on a scientific formula devised by the CPHEEO (Central Public Health and Environmental Engineering Organisation) and similar theoretical calculations are used by CMWSSB for calculation of sewage generated in different parts of the city,” the report stated. “The fact that 48% of the waste remained uncollected, was an indicator of the seriousness of the issue.”
Also, an estimated 242.73 MLD of raw sewage enters storm water drains and mixes with waterbodies including the Adyar river, Buckingham canal, Cooum etc. The plugging of polluted sewage outfalls into waterbodies, being executed under the aegis of the Chennai Rivers Restoration Trust (CRRT), remained ‘unachieved in full’ even four years after the scheduled date, the report by CAG stated.
The underground sewerage system, as on November 2019 was provided in only 11 of the 42 newly-added areas. The CAG recommended an institutional mechanism for ensuring coordination of all line departments in implementing underground drainage system (UGSS) and ensuring availability of work site and all mandatory clearances from line departments before awarding tenders for UGSS, among other recommendations.
Depts should join hands
The underground sewerage system, as on November 2019, was provided to only 11 of the 42 newly added areas. The CAG recommended an institutional mechanism for ensuring coordination of all line departments in implementing underground drainage system (UGSS) and ensuring availability of work site and all clearances from line departments before awarding tenders for UGSS
