Operators asked to use alternative methods to bring down coliform content
The Kerala State Pollution Control Board (PCB) has found the functioning of the sewage treatment plant (STP) at Sabarimala Sannidhanam faulty.
A detailed inspection of the STP by an expert team led by District Environmental Engineer of the PCB Alexander George has revealed that the ozonisation system is not working.
The ozonisation system, which forms a key component of the fully biological sewage treatment plant, is used for disinfecting treated sewage. In the ozonisation process, atmospheric oxygen is converted into ozone by passing it through high- voltage electricity. This ozone is injected into water and the ozonised water is used to disinfect treated sewage, he says.
The PCB found from the regular monitoring of the STP that the existing system is inefficient in controlling the coliform count, leaving the total coliform count in the treated effluent at 40,000 to 50,000 every 100 ml. To address the issue during the ongoing pilgrim season, the PCB has directed the operators to use hypochlorite solution for disinfection, which has led to a drastic drop in the coliform count from November 29, he said.
High oil, grease content
Mr. George says the oil and grease content in the treated sewage was observed to be very high, up to 200 mg per litre against the permissible limit of 10 mg. The oil and grease are generated from the Appam-Aravana plant. But, there is no separate treatment system for the effluent generated at the Appam-Aravana plant.
The PCB engineer is of the view that the capacity of the 5 mld STP should be augmented to 10 mld in view of the huge quantity of sewage generated at Sabarimala during the annual pilgrim season. The Travancore Devaswom Board’s failure to connect all the sewer lines to the STP was another issue posing pollution threat at Sabarimala, he said. The PCB has submitted its inspection report to the High Court.
Meanwhile, the contractor, Viswanathan Arangath, said the TDB was yet to clear his final bill of Rs.1.23 crore even after the commissioning of the plant a year ago.