The Slidell Wastewater Treatment Plant is a 6 million gallon per day (mgd) facility located at 2800 Terrace Avenue in Slidell (St. Tammany Parish). The plant is a high- rate activated sludge facility. It discharges to the W14 Canal, which feeds the Salt Bayou and ultimately Lake Pontchatrain.
The following information was obtained by interviewing Chief Operator:
According to a rain gauge at the plant, the facility received 15 inches of rain from Katrina, resulting in 4 feet of water on-site and 30 inches of water inside the buildings. Plant staff waded into the plant the day after Katrina struck. A generator had tripped off early in the morning of the Katrina strike. This likely protected the generator. The plant used the generator for a week until power was restored. Several motors and other pieces of small equipment were destroyed.
Wastewater began entering the facility five days after the storm, at which time the plant was restarted. Flow to the plant was delayed because power was not available to the 90 (ninety) lift stations in the collection system.
The staff believes that the biomass was killed off by insufficient oxygen. After restart, water quality (BOD and TSS) have been good. Compounding the challenges, the plant has had to treat high strength wastewater from portable toilets and trailers. In addition, low rainfall (approximately ¾ inch since the storms) has affected settleability.
Other information from the Chief Operator:
He confirmed that St. Tammany Parish relies entirely on groundwater. The municipal supply comprises deep wells (about 2,000 ft deep) and chlorination. (Note: The municipal wellfield supplies water for 38,612 people. Its boil water order was lifted 10/7/05.)
Wastewater Treatment in New Orleans
He confirmed that wastewater service to New Orleans may not be established for nine months.
Submitted by James Jensen and
October 19, 2005