The costs of fertilizers have rapidly increased in recent years, especially nitrogen fertilizer such as anhydrous ammonia which is made from natural gas. Thus, new treatment technologies for abatement of ammonia emissions in livestock operations are being focused on N recovery in addition to the N removal. Nitrogen recovery from swine manure was investigated using a new technology that uses gas-permeable membranes at low pressure. Membrane manifolds are submerged in the manure and the ammonia is removed from the liquid before it escapes into the air. Bench experiments were conducted using raw liquid swine manure collected from manure pits in nursery, finishing and sow barns. This provided manures of various strengths (low, medium and high) with ammonia concentrations ranging from 1065 to 2285 mg/L and total solids concentrations from 8.6 to 24.9 g/L. As ammonia content increased in manure, more N was captured by the process. The process was optimized by controlling the pH. It recovered, in a concentrated form, more than 80% of the ammonia contained in the raw manure. The volatile solids did not pass through the gas-permeable membrane. These results suggested that the new technology is useful for recovering and concentrating the ammonia contained in raw swine manure, reducing environmental pollution potential while converting ammonia into a valuable plant fertilizer.

Removal and recovery of ammonia from livestock wastewater using hydrophobic gas-permeable membranes

248th National Meeting (2014)

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