Sewage spilled in Delaware River
May incident just recently disclosed
12:41 AM, Aug. 8, 2011
An electrical fault in a key pumping system sent 13.5 million gallons of partially treated sewage into the Delaware River at Wilmington on May 20, but details of the mishap came to light only recently in a state notice of environmental law violations.
Department of Natural Resources and Environmental Control officials said the power loss and spill occurred on a stormy day when backup systems failed to activate, shutting down transfers of partially treated water to a lagoon near Wilmington’s regional wastewater plant. Emergency bypass systems diverted the water directly to a river discharge, where it was combined with fully treated wastes.
“The only thing it didn’t have was disinfection,” said Glenn Davis, a DNREC water division engineer, who said the wastewater missed a treatment with bleach solution. “It already had gone through preliminary, primary and secondary treatment.”
Officials had no explanation for why the incident was not immediately disclosed on DNREC’s public environmental release notification system, under a program started after a series of pollution releases in the early part of the last decade.
State lawmakers voted after those incidents to require notifications by Internet and in some cases by telephone and facsimile.
Sen. David B. McBride, D-Hawks Nest, who sponsored a series of notification and chronic violator reform bills, said he did not recall the Wilmington spill, but said he would have expected a notification for one of that size.
Davis said contractors are still seeking the cause of the pump shutdown and a reason for the failure of backup systems.
DNREC has fined the city in the past and ordered systems improvements after large releases caused by maintenance problems at the plant, operated under contract by Veolia Water.
“There was another incident like this in 2008 and the city spent a lot of time and money trying to find the cause and spent a lot of time and money on breakers and timers,” Davis said.
The amount spilled over three hours totaled nearly 10 percent of the city’s regular 135 million-gallon daily discharge limit. Releases can run higher, during rainfalls as stormwater from Wilmington’s combined storm and sewer system surges into the plant.
