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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #228637
Title: Enhanced solid-liquid separation of dairy manure with natural flocculants

Author
item GARCIA, MARIA - AG TECH INST., SPAIN
item Szogi, Ariel
item Vanotti, Matias
item CHASTAIN, JOHN - CLEMSON UNIV, CLEMSON SC
item Millner, Patricia

Submitted to: Bioresource Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/11/2008
Publication Date: 1/1/2009
Citation: Garcia, M.C., Szogi, A.A., Vanotti, M.B., Chastain, J.P., Millner, P.D. 2009. Enhanced solid-liquid separation of dairy manure with natural flocculants. Bioresource Technology 100:5417-5423.

Interpretive Summary: Natural flocculants have potential to replace the use of synthetic flocculants used for enhanced solid-liquid separation of livestock effluents, especially with increased cost of energy and renewed interest on organic farming systems. We conducted a study to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy wastewater using solid-liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy manure of varied solids content (0.4 to 3.2% total solids). Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective. However, mixing manure with chitosan before screening substantially increased separation. At optimum rate (0.5 g/L of chitosan for the highest manure solids content), separation efficiencies were higher than 95% for total suspended solids, 73% for total Kjeldhal nitrogen, and 54% for total phosphorus. The results of this study indicate that natural flocculants such as chitosan are useful for the solid-liquid separation treatment of livestock wastewater.

Technical Abstract: Natural flocculants have potential to replace the use of synthetic flocculants used for enhanced solid-liquid separation of livestock effluents, especially with increased cost of energy and renewed interest on organic farming systems. We conducted a study to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy wastewater using solid-liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy manure of varied strengths - 0.4, 0.8, 1.6 and 3.2% total solids (TS) content. Treatments consisted of nine rates of chitosan. The flocculated manure was dewatered using 1-mm and 0.25-mm screens. Separation by screening alone was not effective; average efficiencies were about 60% for total suspended solids (TSS), 22% for total Kjeldahl N (TKN), and 26% for total P (TP). Mixing manure with chitosan before screening substantially increased separation. At optimum rate (0.5 g/L for the highest strength effluent), separation efficiencies were higher than 95% for TSS, 73% for TKN, and 54% for TP. The results of this study indicate that natural flocculants such as chitosan are useful for the solid-liquid separation treatment of livestock wastewater.