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ENVIRONMENTAL TECHNOLOGY VERIFICATION: Separation of Manure Solids from Flushed Swine Waste. Hoffland Environmental Inc. Drag Screen and Clarifier
Citation:
NSF International, AND North Carolina State University. ENVIRONMENTAL TECHNOLOGY VERIFICATION: Separation of Manure Solids from Flushed Swine Waste. Hoffland Environmental Inc. Drag Screen and Clarifier. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-08/024, 2004.
Impact/Purpose:
to inform the public
Description:
Verification testing of the Hoffland Drag Screen and Clarifier was conducted at the North Carolina State University's Lake Wheeler Road Field Laboratory, in Raleigh, North Carolina. The farm is designed to operate as a research and teaching facility with the capacity for 250 sows. Under normal operating conditions, waste at the site is removed by flushing under-slat pits with treated wastewater from the on-site anaerobic lagoon. Flushed waste then flows back to the lagoon for treatment. During testing, the flushed waste was diverted to a mixing tank designed to keep the solids in suspension with minimal aeration. Flow was then pumped from the mixing tank to the treatment system. Liquid discharged from the treatment system was collected an effluent tank, and the separated solids were collected in a 300-gallon poly tank. Over the entire four-week test period, the effluent stream from the Hoffland Separator had an average solids concentration of 2,650 mg/L, which when converted to mass based on the volume of the effluent, represents 29% of the of the mass of the suspended solids in the influent. Solids recovered by the Hoffland Separator contained 13.4% dry matter (86.6% moisture). The Hoffland Separator recovered 273 lb of the dry solids, representing 12% of the 2310 lb of suspended solids in the influent. Suspended solids remaining in the clarifier at the end of the test accounted for 26% of the influent suspended solids. Overall separation efficiency for total solids was 51%