Polyacrylamide for coliform bacteria removal from agricultural wastewater

ABSTRACT:

Pollution of surface flow and groundwater from animal waste application to soils has been well documented, Polyacrylamide (PAM) has reduced total coliform (TC) and fecal coliform (FC) bacteria in animal waste water flowing in irrigation furrows. We measured efficacy of PAM dissolved in water and as a “patch” application to soil to remove total and fecal coliforms from: 1) water flowing over dairy waste in furrow-irrigated, ungrazed forage production systems; 2) soil water after it flowed through 1 m of soil; and 3) influence of PAM on survival of total and fecal coliforms in surface flow, soil, and soil water. Total coliforms in surface flow did not differ when waste was applied to soil, regardless of PAM treatment or days since waste was applied. Total coliforms in surface flow decreased by tenfold over the 7 days after waste regardless of PAM treatment. Fecal coliforms in surface flow decreased by tenfold over the 7 days after waste application and one hundredfold over the 28 days after waste application regardless of PAM treatment. Total coliforms in soil decreased by tenfold over the 7 days after waste was applied, one hundredfold over the 28 days after waste was applied and one thousandfold over the 63 days after waste was applied, regardless of PAM treatment or soil depth. Total coliforms did not differ in control soils and soils receiving waste, regardless of soil depth or PAM treatment over the 28 and 63 days after dairy waste was applied. Fecal coliforms in soil were greater in the 0 to 5 and 5 to 15 cm soil depths when waste was applied to soil, regardless of soil PAM treatment. Fecal coliforms in all three soil depths decreased as much as one thousandfold over the 28 and 63 days after waste and PAM treatments were applied. In all treatments, except the waste application x PAM patch treatment, total coliforms in soil water showed a tenfold decrease over the 23 and 63 days after waste was applied. PAM may not provide additional protection to surface water from waste applied to ungrazed forage production systems, but the compound does not enhance survival of total or fecal coliforms in soils or water.