Officials consider disinfection of effluent to contol E. coli
With the Mississippi River becoming more popular for recreational use, the city of Memphis, Tenn. is investigating disinfection of the effluent from the Stiles Wastewater Treatment Facility to control E. coli bacteria, according to a report by the Commercial Appeal.
The city, in response to a request by the Tennessee Department of Environment and Conservation (TDEC), recently conducted tests showing that using only minimal amounts of chlorine bleach could eliminate 99% of the E. coli, the newspaper reported.
If TDEC and the U.S. Environmental Protection Agency agree, the disinfection process could be required when a final permit is issued in the coming months, according to the newspaper.
In the past, the city has not been required to disinfect its effluent because of the vast dilution capacity of the Mississippi River and the fact that the river has not traditionally been a major recreational site.
Although there are health-related reasons to avoid disinfection, such as the possible formation of potential cancer-causing compounds known as trihalomethanes, officials cite the growing use of the river for recreation--including the canoeing and kayaking activities popular along Mud Island and in the downtown area--as a sign that E. coli should be removed from the Stiles plant effluent, the newspaper reported.
"We want to do the right thing. We don't want to be a problem there," said Paul Patterson, administrator for environmental engineering for the city.
The disinfection will add to operational costs at the plant, Patterson said, although no figures are available. The city will minimize the threat from trihalomethanes by using only small amounts of bleach, according to the newspaper.