ARS | Publication request: Solid-liquid separation of dairy manure with PAM and chitosan polymers

Submitted to: Air and Waste Management Annual Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2007
Publication Date: September 16, 2007
Citation: Garcia, M.C., Szogi, A.A., Vanotti, M.B., Chastain, J.P. 2007. Solid-liquid separation of dairy manure with PAM and chitosan polymers. In: International Symposium on Air Quality and Waste Management for Agriculture, 16-19 September, Broomfield, Colorado. 8 p. 2007 CDROM.

Technical Abstract: Organic polymers are useful to increase separation of suspended solids and carbon compounds from liquid swine manure, but experiences with dairy manure are limited. In this experiment, two polymers, a synthetic polyacrylamide (PAM) and a natural chitosan were used to increase separation of suspended solids from dairy manure. Experiments were carried out using four different concentrations of dairy manure total solids: 0.4, 0.8, 1.6 and 3.2%. In this study, we evaluated whether the use of PAM and chitosan flocculants could improve the filtering characteristics of various size screens. Separation by screening alone was not effective, efficiencies were <42% for total suspended solids (TSS), <14% for total Kjeldhal nitrogen (TKN), <17% for total phosphorus (TP). With flocculation, the effective particle size was increased by agglomeration of small particles into a larger particle or floc that separated from liquid and dewatered more readily. This larger size significantly enhanced manure solids retention by screens. Removal efficiencies obtained after PAM addition and 0.25 mm screening were 95% for TSS, 73% for TKN and 65% for TP. Corresponding efficiencies obtained with chitosan were 99% for TSS, 73% for TKN, and 54% for TP. These results indicate that natural and synthetic polymers are both effective for liquid-solid separation of flushed dairy manure.