Pune instals online system to check quality of treated sewage quality

12 Feb 2021 CW Staff

The Pune Municipal Corporation (PMC) will install an online system to check sewage water meter on sewage treatment plants (STPs) that checks the quality of treated water, which is released to Mula-Mutha rivers. It will also help to know how much water is treated and released in rivers.

The Mula-Mutha river is one of the 302 polluted river stretches of the country identified by the Central Pollution Control Board (CPCB).

A total of 744 MLD of sewage is generated in the PMC limit. Of the 744 MLD, the civic body treats around 460 MLD sewage through nine STPs and discharges into the Mula Mutha rivers. Pune City covered 92 % of the sewerage network of 2,200 km. Normally, sewage water calculates 80% of the daily supply of drinking water. At present, the corporation supplies around 1,100 million liter per day (MLD) in the city. So, the city generates 880 MLD sewage water.

According to corporation data, PMC does not have 100% collection efficiency of sewage networks and adequate sewage treatment capacity as per service benchmark. The PMC has mentioned 64% capacity in the Environment Status Report (ESR-2018-19). However, the PMC drainage department has claimed 100% quality of sewage treatment in the ESR-2018-19 report.

The new online system will help to prove the claim of PMC. As per the Central Pollution Control Board (CPCB) and Maharashtra state pollution control board directives, the PMC has decided to install an online system that will display inlet and outlet water samples of sewage.

Shriniwas Kandul, the additional city engineer of the electrical department, said, “It is an online testing system. We will place a meter inlet and outlet of sewage plant which will show characteristics of water such as the Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand level (COD) of sewage and treated water, pH (acidity or basicity of water).”

“The BOD and COD level is one of the major parameters to check the quality of sewage water. Both should be below 30 milligrams per liter of water. Normally, sewage water BOD and COD level is more than 150 milligrams per liter of water. After treatment, it comes down to 20 milligrams per liter of water. The system will also show people how much water PMC treats in each STP,” he added.

According to Kandul, the PMC is not treating 100% sewage. However, the corporation has planned to construct 11 new sewage treatment plants (STPs) in the future.

“It will result in a creation of an additional treatment capacity of 396 million liters per day (MLD) over the existing treatment capacity of 477 MLD, laying of 113.6 km of sewer lines and renovation/rehabilitation of four existing intermediate pumping stations,” Kandul said.

How does the sewerage system work?
The sewage system consists of a collection network, conveyance lines, pumping stations, and sewage treatment plants. The collection network collects sewage from houses, apartments, commercial complexes, or from other sources.

This collected sewage is further carried to pumping stations or Sewage Treatment Plants (STP) via conveyance lines. Pumping stations pump the sewage to STPs where primary and biological secondary treatment is given to sewage water before discharging into any natural watercourse.