Anoxic-aerobic treatment of the liquid fraction of cattle manure.
Cattle manure from a dairy farm was treated in order to reduce its pollution potential. The manure came from a farm with 120 cows kept in stables in a free stall barn. As pretreatment, the manure is usually filtered on the farm using a screw press separator with a 0.5 mm mesh. Approximately 70% of the total filtered volume passes through the screen, thus constituting the liquid fraction. This fraction, with a composition of around 64,500 mg COD/l, 5770 mg total-N/l and 800 mg total-P/l, was subjected to centrifugation followed by a two-step biological treatment (anoxic-aerobic) to reduce organic matter (COD), nitrogen and phosphorus compounds. Centrifugation led to the following removal efficiencies: 35% total solids, 60% COD, 75% total phosphorus and 20% total nitrogen (mainly organic nitrogen). With the subsequent anoxic-aerobic treatment, average removal efficiencies of 85% for COD, 90% for total phosphorus and 75% for total nitrogen were achieved.
Castrillón
L
L
Department of Chemical Engineering and Environmental Technology, Asturias Institute of Industrial Technology, University of Oviedo, 33203 Gijón, Asturias, Spain.
Fernández-Nava
Y
Y
Marañón
E
E
García
L
L
Berrueta
J
J
D000332:Aerobiosis; D000818:Animals; D002417:Cattle; D003612:Dairying; D005243:Feces; D010100:Oxygen / Q000737:chemistry*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
D010100:Oxygen