The Efficacy of Polyacrylamide and Related Compounds to Remove Microorganisms and Nutrients from Animal Wastewater

Abstract

AbstractPolyacrylamide (PAM) is an effective flocculent and we hypothesized that it would reduce transport of microorganisms and nutrients in water flowing over and through soil. We measured nutrients, total coliform bacteria, fecal coliform bacteria, fecal streptococci, active and total fungi, and active and total bacteria in water leached through cattle, fish, and swine manure, PAM, PAM + Al(SO4)3, or PAM + CaO mixtures, and 25‐cm sand columns. In the laboratory study, PAM, PAM + Al(SO4)3, and PAM + CaO treatments reduced total coliform bacteria, fecal coliform bacteria, and fecal streptococci by 10‐ to 1000‐fold in water leached through sand columns. Polyacrylamide + Al(SO4)3 and PAM + CaO treatments reduced the concentration of NH4, total P, and PO4 by 20 to 60% in leachate when cattle and swine manure were applied. In a field study, after water flowed over all three manure sources and then PAM, PAM + Al(SO4)3, or PAM + CaO in furrows, total coliform bacteria, fecal coliform bacteria, and fecal streptococci were reduced by 10‐ to 1000‐fold in water flowing 1 and 27 m downstream of the treatments compared with the control treatment. When water flowed over cattle manure and then PAM + Al(SO4)3 or PAM + CaO, PO4 concentration was reduced by 50 to 70% and total P concentration was reduced by 0 to 75% in water 27 m downstream of the treatments compared with the PAM alone treatment. Polyacrylamide + Al(SO4)3 and PAM + CaO should be able to reduce the numbers of enteric microorganisms and nutrient concentration in animal wastewater running off animal confinement areas, reducing the amount of these pollutants entering surface and ground waters.