METHODS AND APPARATUS FOR TREATING ANIMAL MANURE

摘要

A method of treating animal manure yielding a final liquid fraction and soli d fractions whereby the final liquid fraction has a suspended solids (SS) content of about 3g/L or lower comprising subjecting at least a part of said manure to a first biological passive flotation step in a flotation unit (6) having a hydraulic residency time (HRT) of about 4 to about 24 hours with a polymer to yield a first flotation solid fraction and a first flotation liqu id fraction, said method comprising a further treatment. An apparatus for treating animal manure comprising a main flotation unit (6) having a HRT of about 4 to about 24 hours, said main flotation units (6) including skimming means (7) for removing floating solids (8) from at least a portion of the surface of the manure and dredging means (12) for removing settled contaminants from at least a portion of the bottom of the tank, whereby at least a part of said manure is directed to the main flotation unit (6) where in it is separated in a first floating solids fraction, a second liquid fractio n and a first settled solids fraction and wherein the second liquid fraction h as a SS content of about 3g/L or lower.