CCP 03-28-1994 - Laserfiche WebLink

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. , . TCAAPINTERCEPTOREVALUATION RACK~ROTTND TNFO~l\JA TTON The Twin Cities Army Ammunition Plant (fCAAP) was originally constructed for the World War n war effort. Since 1941, .the facility has manufactured small arms ammunition with production at the facility peaking during war times. TCAAP consists of a number of buildings served by an extensive on-site wastewater collection system. For the most part, the on-site collection system is a gravity system. The on-site collection system conveys sanitary and process wastewaters to the on-site pumping system which consists of a comminutor, detention tank, and main lift station. The off-site system consists of 61h miles of 18-inch forcemain and 7 miles of 24-inch forcemain which convey the pumped flow to the City of Minneapolis sanitary sewer system. When originally constructed in 1941, TCAAP wasphysically isolated in an undeveloped area. Collected wastewater was conveyed to the nearest municipal (Minneapolis) sanitary sewer system via an 18-inch diameter forcemain approximately 6l/z miles long. The system was upgraded in 1953 through construction of a supplemental 24-inch diameter forcemain approximately 7 miles long. Today, both forcemains still discharge to the City of Minneapolis sanitary sewer system. The City, in turn, discharges its wastewater to the Me~opolitan Waste Control Comm~~~ system for treatment. - ~-. ,,-'-'-" ,- - - . Because of their length and age, maintenance of the forcemains has become an ever-increasing - - problem. Leaks are becoming more frequent, resulting in higher annual repair costs. Pumping wastewater 7 miles is also resulting in the needless expenditure of electric energy. The comminutor, the detention tank, and main lift station were constructed with the 18-inch forcemain in 1941. Because of their age, the pumps, valves, piping, and other mechanical equipment in these structures are outdated. In the future, many of these components would have to be replaced if the existing system was to remain in operation. ~ Since 1941, the Twin Cities metropolitan area has grown dramatically. TCAAP, itself, is surrounded by residential and commercial/industrial development. The area along the alignments for the two forcemains is nearly 100% developed. The Metropolitan Waste Control Commission (MWCC) was formed in 1970 to convey and treat wastewater for the entire Twin Cities area. MWCC facilities capable of accepting TCAAP's wastewater flow now exist within a mile of TCAAP's main lift station. As part of the Department of Defense's efforts to reduce their operating budget, TCAAP has been downgraded from "standby" status to "modified caretaker" status. Simply stated, "modified caretaker" status means that the U.S. Army has no plans to ever put TCAAP back into production. Under "modified caretaker" status, the wastewater flow generated by TCAAP is estimated as . follows: II ) .\ V-;~l ( 049-2203.1 S20-049.70