11-25-1991 Council Packet - Laserfiche WebLink

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Also located on this plat is an abandoned waste water treatment lagoon (sometimes lagoons are also referred to as stabilization ponds). The lagoon has not received wastewater since the Long Lake interceptor came on-line in the early 1980's. Two soil borings were completed in the lagoon in February, 1905 to depths of 12 and 17 feet and two sediment samples from the lagoon were analyzed for organic and inorganic constituents in July. 1989. The soil boring results show black peat was the original bottc- material in the lagoon, indicating the lagoon probably was constructed without a clay liner. Cray sandy silt lies underneath the peat. The peat permability is slow enough that the lagoon will be wet in years with average rainfall. The water elevation in the lagoon was 941.99 on September 9, 1991, which is above the elevation of the adjacent Long Lake Stream. On our visit of September 13. 1991, water level in the lagoon was below the surface outlet structure for the lagoon. If water in the lagoon ever rises above the invert of the outlet structure, water will discharge to the Long Lake Stream. The result of the chemical analysis for the two sediment samples from the lagoon do not Indicate any problems with sediment contamination. Results are comparable if not better than what is found in some storm water detention basins. Results of testing for priority pollutant organic volatile, semivclatives, pesticides and PCBs showed aix determinations were below detection levels. Inorganic analysis (which includes heavy metals) indicated sediment concentration typical for lake and pond sediments in urban areas. I made several contacts at the MPCA to ask about potential problems with property transfer involving wastewater treatment lagoons. The contacts were* Mike Conley (297-1459), Property Transfer Group; John McQuire (296-8723), Municipal Permits Section; Doug Hall (297-1932), Industrial Permits Sections; and Dave Nelson (296-9274), Water Quality Group. This type of water body (a non~hazardous waste site, with no municipal, or industrial, or stormwater runoff entering, and a wastewater discharge permit that has been closed out) does not fit neatly into any single MPCA group. Basically, the MPCA does not require any further testing. It's my opinion, based on the non-industrial setting of the lagoon, and the fact that two soil samples do not show any unusual characteristics, (aluminum was elevated, but probably due to alum treatment) for typical stormwater detention ponds or wastewater lagoons that the likelihood of serious sediment contamination is small and no additional sampling is needed at this time. Jeanne, if there are any questions or a need for additional information please contact me. Sincerely, BCINESTROO. ROSENE, ANDERLIK & ASSOCIATES. INC.ICUIESTROO. Steven R. McComas SRM:lk cc: Glenn Co<v BRA David Sqi MFRA 210