Water Works and Sewer Board of the City of Prichard
Prichard, Alabama
To comply with a State issued Consent Decree, the Water Works and Sewer Board of the City of Prichard, AL had to replace or repair 1,000 private sanitary sewer laterals to reduce inflow and infiltration that was leading to sanitary sewer overflows (SSOs). The anticipated cost of this effort was expected to be between $800,000 and $1 million, a significant amount for a community with a median household income of less than $20,000. Early struggles with excessive paperwork, inadequate equipment, and inexperienced personnel led to concerns by the State about the lack of progress. A revised strategy that simplified analysis and streamlined work was developed. The results were a 30 percent reduction in inflow and infiltration at a cost of $550,000. Overall SSO volumes were reduced by 95% and the number of recurring SSOs dropped from eight to one. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Sanitary Sewer, Water Treatment | Tags: Cost Savings, Reduced Inflow and Infiltration, Reduced Sanitary Sewer Overflows | No Comments »
Boston Water and Sewer Commission
Boston, Massachusetts
The Boston Water and Sewer Commission has been implementing various combined sewer separation projects throughout the City of Boston in order to significantly reduce combined sewer overflow frequency and volume to Boston Harbor. Two of these project areas include the completed South Dorchester Bay area and the Reserved Channel area which is currently under final design. Both of these project areas include ultra urban, primarily residential, watersheds within the city that are currently being served by combined sewers with installations that date back to the late 1800’s and early 1900’s. The Reserved Channel Project area, located in South Boston, and the Dorchester Bay Project Area are approximately 365 acres and 2,700 acres respectively. The sewer interceptor systems currently serving these areas surcharge during wet weather events and the combined sewer overflows then need to be rerouted to outfall pipes that discharge to Boston Harbor. It is evident that early identification and removal of as much stormwater inflow as possible is a key part of the success of both sewer separation projects. It is evident that the removal of as much storm water inflow as possible is a key part of the success of both sewer separation projects. For the ultra urban areas, simply installing storm drains and picking up existing catchbasins does not appear to be enough to significantly reduce the CSO frequency and volumes to meet the long term control plan goals. It makes good sense to investigate, identify, and remove as many impervious areas as possible to reduce storm water inflows to the sewers. This approach leads to the need for a comprehensive look at reducing stormwater from private property such as roof areas, parking lots, and other impervious areas that can be removed from the sewer system to reduce storm water inflow to the sewers. A cost/benefit analysis should be performed that evaluates this additional level of separation as well as alternatives such as increasing interceptor capacity, limiting upstream wastewater flows and providing in-line or off-line CSO storage. Source: WEFTEC 2009 Proceedings
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Posted: August 27th, 2010 | Filed under: Sanitary Sewer, Water Treatment | Tags: Cost Savings, Reduced Inflow and Infiltration, Reduced Sanitary Sewer Overflows | No Comments »