Delhi's Old CETPs Struggle with Sewage Overload

Delhi's industrial sector faces a critical infrastructure challenge with 11 out of 13 Common Effluent Treatment Plants (CETPs) nearing their 20-year lifespan. These facilities, vital for treating wastewater from over 23,000 industries, suffer from aged civil infrastructure and deteriorating mechanical and electrical components. The influent characteristics have also changed significantly, with a greater proportion of domestic sewage now entering the systems, which were not designed for such a mix.

The Confederation of Delhi Industries and CETP Societies has highlighted that the existing CETPs, with a cumulative capacity of 212 MLD but currently receiving around 80 MLD, are underutilized. Stricter pollution control norms by the Delhi Pollution Control Committee (DPCC) are difficult to meet. Anil Gupta noted that illegal domestic sewage inflow and changes in land use have increased biochemical oxygen demand (BOD) loads beyond design parameters, creating operational difficulties. Desilting of the conveyance system is also urgently needed.

To address these issues, the National Environmental Engineering Research Institute (NEERI) is conducting a survey to identify upgradation requirements for the 11 CETPs. The survey, expected to yield reports from next month, will guide future actions. Experts emphasize the urgency of upgradation, especially to treat heavy metals from industries like illegal dyeing units. The policy of zero liquid discharge, introduced in 2019, also remains unimplemented.