The sanitary sewerage system in New Orleans is a gravity collection system, consisting of 1,600 miles of lateral and trunk sewers, ranging in size from eight inches to seven feet in diameter.
Lifting and conveying the sewage (also called wastewater or effluent) by trunk sewers and force mains requires 83 electrically operated pumping and lift stations. Seventy-nine of those stations are automatically operated.
Sewer stations "A" and "D" on the East Bank and station "C" on the West Bank are large, attended stations. These, along with all automatic stations, transfer the total collected sewage from the entire city to two treatment plants.
The S&WB system has two sewage treatment plants, one on the East Bank and one in Algiers. The combined treatment capacity of the two plants is 132 million gallons per day. The plants are currently operated by U.S. Filter. Both plants were built in the 1970s and have been upgraded, modernized and expanded to increase capacity and to keep up with the growth of the city. The plants discharge treated wastewater into the Mississippi River.
Sewer service rates in New Orleans are considered to be among the most reasonable in the nation. The Sewerage Department is funded only through the sewer fees charged on monthly bills for customers.
Like other S&WB services, sewerage operations run 24-hour a day, seven days a week. In addition to regular staff on duty for three eight-hour shifts, emergency crews are on stand-by to be called in if needed.
Design of the sewerage system was begun in 1898 and construction of the early phases was completed in the early 1900s. Through the years, the system has been expanded and modernized. As the city grew geographically and EPA requirements became more stringent, new construction added miles of underground mains, new lift and pumping stations and larger and more efficient treatment plants.
Continuous maintenance and repairs have been carried out by the Board over the years, but the age of the system, and the soil, weather and other conditions unique to this area resulted in the need for an evaluation of the entire collection system. The first several phases of the evaluation have led to massive improvements and it's expected that future phases will reveal the need for millions in repair work in each area of the City.
The Sewer System Evaluation and Rehabilitation Program (SSERP), underway since 1996, is part of the EPA Consent Decree the Board signed in 1998. It focuses on the sanitary sewer portion of the sewerage system which collects wastewater from homes and businesses and transports it to the wastewater treatment plants.
SSERP is a ten-year effort to study and repair the system throughout the city. The approximate cost estimate for the improvements is greater than $600 million.
To best carry out the plan to study and rehabilitate the sewerage collection system areawide, the S&WB divided the city into 10 basins.
The process in each basin is first testing. The results are analyzed and construction is carried out to repair damaged manholes, pipes, trunk lines and pumping stations. Testing in each district includes flow monitoring, videotaping of lines, smoke tests and dye tests to locate breaks, clogs and broken joints. Pumping stations are being tested for efficiency and output.
Modern techniques for repairs are being used wherever possible to reduce the need for digging trenches in streets or sidewalks.
The Board has already tested in Lakeview, the CBD/French Quarter/Warehouse District, Gentilly, Uptown, Mid-City and the Lower Ninth Ward. Repairs were completed in Lakeview last year and are underway in the CBD/French Quarter/Warehouse District and Gentilly. Repairs will begin in Uptown and Mid-City next year.
Work on the sewerage treatment plants includes major repairs to the headworks at the East Bank Treatment Plant, along with replacement of the inflow channel. In Algiers, a complete expansion of the plant is underway to greatly improve its efficiency, and work has already been completed to double its capacity.
The Board is proud of its record with the EPA Consent Decree, as it has met every construction and reporting deadline outlined in the decree and had no fines relative to construction or reporting schedules.
The S&WB is coordinating its efforts with the City's Department of Public Works streets repair and replacement program to minimize inconveniences and to save money. Where possible, the S&WB is employing state-of-the-art trenchless methods of sewer repair which allows repairs without the need to dig up streets and yards.
SSERP is managed for the S&WB by MWH Consulting Engineers.
One modernization project on line now for six years is SCADA (supervisory control and data acquisition), a sophisticated computer system which provides online monitoring of the 83 sewer lift stations and pumping stations located throughout the city. Each facility is monitored for pressure, electrical power, mechanical functions, flow and security.
Sewer Pumping Station A, located behind the Municipal Auditorium, houses the "heart and brain" of a state-of-the art $1.7 million monitoring system.
Personnel on duty 24 hours a day at Station A monitor the functions at all stations and crew can be quickly dispatched to a location at the first indication of a malfunction.
Depending on the eventual total costs, funding for all the projects of SSERP will come from three sources: Federal funds, via EPA Grants, S&WB matching funds, and other S&WB operations and maintenance funds. The S&WB has already received $38 million in Federal grants.
The Board will continue to work with the Mayor's Office, the City Council, the area's Congressional delegation and the White House to obtain additional funds for sewerage, but the Board must be able to provide local matching funds.