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ARS Home » Southeast Area » Florence, South Carolina » Coastal Plain Soil, Water and Plant Conservation Research » Research » Publications at this Location » Publication #322396
Title: Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology

Author
item Dube, Patrick
item Vanotti, Matias
item Szogi, Ariel
item GARCIA-GONZALEZ, M. - Instituto Tecnológico Agrario De Castilla Y León (ITACYL)

Submitted to: Waste Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2015
Publication Date: 12/28/2015
Citation: Dube, P.J., Vanotti, M.B., Szogi, A.A., Garcia-Gonzalez, M.C. 2015. Enhancing recovery of ammonia from swine manure anaerobic digester effluent using gas-permeable membrane technology. Waste Management. 49:372-377.

Interpretive Summary: Environmental concerns over ammonia emissions from animal husbandry are important. In this study, ammonia recovery of anaerobically digested swine wastewater using gas permeable membranes was enhanced using low-rate aeration. Gas-permeable membranes allow for gaseous ammonia to pass through a microporous, hydrophobic membrane where it reacts with an acidic solution to form an ammonium salt, which can then be recovered in a concentration tank. The low-rate aeration reacted with the natural carbonates in wastewater and increased pH, which accelerated ammonia uptake in the gas-permeable membrane system without the use of alkali chemicals. Utilizing aeration, more than 96% of ammonia was able to be recovered in about 4 days’ time which significantly improves on the 25 days required to remove ammonia without aeration. Completing removal more than 5 times faster represented a 70% reduction in costs.

Technical Abstract: Gas-permeable membrane technology is useful to recover ammonia from manure. In this study, the technology was enhanced using aeration instead of alkali chemicals to increase pH and the ammonia recovery rate. Digested effluents from covered anaerobic swine lagoons containing 1375 to 2089 milligram ammonia-nitrogen per liter were treated using submerged membranes (0.13 square centimeter area per cubic centimeter liquid volume), low-rate aeration (120 milliliter air per liter manure per minute) and nitrification inhibitor (22 milligram per liter) to prevent nitrification. The experiment included a control without aeration. The pH of the liquid manure with aeration rose from 8.6 to 9.2 while the manure without aeration decreased from 8.6 to 8.1. With aeration, 97-99 percent (%) of the ammonia was removed in about 5 days of operation with 96-98% recovery efficiency. In contrast, without aeration it took 25 days to treat the ammonia. Therefore, the recovery of ammonia was five times faster with the low-rate aeration treatment. This enhancement reduced cost by 70%.