CORROSION WITHIN SEWER SYSTEMS AND DRAMATIC LIFT STATION REHAB IN LOUISIANA

摘要

Municipalities in the United States are annually spending hundreds of millions of dollars to replace and to repair corroded concrete infrastructures in their wastewater collection systems. In addition, billions more dollars will be needed in the coming years to restore, replace, and upgrade existing facilities all across the United States. Structures such as wet wells, grit chambers, sewer lines, and aeration basins all experience severe corrosion. These problems are aggravated by the fact that corrosion protection was typically not incorporated into the initial structure installation. Replacement of these structures can cost three or more times as much as an in-situ rehabilitation. Beyond the initial capital cost, replacement of these structures may involve traffic interruption and construction problems with buildings, highways, and other facilities. The money saved by rehabilitating structures, rather than replacing them, can further be used to fund more extensive rehabilitation projects or other programs such as Inflow/Infiltration (l&l) projects. Corrosion problems in municipal wastewater treatment systems are caused by quite different mechanisms than those corrosion problems typically found in industrial treatment systems. In industrial systems, corrosion attack is generally due to the direct aggression by chemicals and their reaction products, which are present in the various discharge streams being serviced by the system. In municipal wastewater systems, however, corrosion is caused by microbiological induced corrosion (MIC), not by discharged chemicals.