title: Enhanced solid-liquid separation of dairy manure with natural flocculants.
abstract: The aim of this study was to determine the effectiveness of natural flocculants to reduce solids and nutrient loads in dairy cow wastewater using solid-liquid separation; chitosan was used as a model. Its use efficiency and optimum application rate were determined using flushed dairy cow 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 nitrogen (TKN), and 26% for total phosphorus (TP). Mixing with chitosan before screening substantially increased separation. At optimum chitosan rate (0.5g/L for the highest strength effluent), separation efficiencies were >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.
authors.affiliation: Agriculture Technological Institute of Castilla and Leon (ITACyL), Animal Waste Research Line, Valladolid, Spain. GarGonMi@itacyl.es
authors.forename: M C
authors.initials: MC
authors.lastname: Garcia
authors.forename: A A
authors.initials: AA
authors.lastname: Szogi
authors.forename: M B
authors.initials: MB
authors.lastname: Vanotti
authors.forename: J P
authors.initials: JP
authors.lastname: Chastain
authors.forename: P D
authors.initials: PD
authors.lastname: Millner
mesh_terms: D048271:Chitosan / Q000737:chemistry; D003612:Dairying; D005427:Flocculation; D008372:Manure / Q000032:analysis*; D009391:Nephelometry and Turbidimetry; D010100:Oxygen / Q000302:isolation & purification; D010758:Phosphorus / Q000032:analysis; D012037:Refuse Disposal / Q000379:methods*; D014835:Volatilization; D014865:Waste Disposal, Fluid
chemical_list: D008372:Manure; D010758:Phosphorus; D048271:Chitosan; D010100:Oxygen