TREATMENT OF POLLUTANTS (Cont)
Many communities, feedlot operators, and industries use lagoons to control wastes. A lagoon is simply one or a series of shallow holding pits into which wastes are pumped and treated. In a well-designed lagoon system, the material is aerated so bacteria can break down the organic matter.
STANDARD: In municipal lagoons, the water generally stays in the lagoon for at least 30 days for this process to be completed. Then the water is removed and treated with chlorine as needed to destroy remaining bacteria. The remaining solids must be disposed of by spreading on farm fields or burying.
CONCERN: Lagoons are inexpensive to construct and operate compared to other systems. However, poorly constructed lagoons and lagoons built where the water table is very high have been found to leak. The most often found contaminant tends to be nitrates.