Phosphorus removal of dairy wastewater via lime precipitation

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Conference Proceeding

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Phosphorus (P) recovery from dairy manure has the potential to improve water quality and nutrient cycling, extend P reserves and generate additional revenue for livestock producers. The purpose of this study was to evaluate the efficacy of a lime precipitation system without biological pre-treatment to remove phosphorus from dairy wastewater. Three dairy manure and wastewater management systems were investigated in South-central Idaho and Southeastern Louisiana, namely: separated parlor wastewater, separated flushed manure, and an anaerobic lagoon system receiving raw parlor water. Lime precipitation was found to remove 83 % of total phosphorus (TP) and 99.7 % of the dissolved P, with the addition of 4.17 %, by volume, of a 1:9 hydrated lime (Ca(OH) 2)to water solution. Using the same lime solution, a 66 % reduction in dissolved and TP was observed with a 10 %, by volume, addition to separated flushed dairy manure with approximately 45 % total solids. Additions of 5 % of Ca(OH)2 solution, by volume, resulted in 63 % and 78 % reductions in dissolved and TP when tested on non-separated parlor wastewater. A 5 % lime slurry addition was found to have a 6-log reduction of fecal coliforms, from raw dairy parlor wastewater, and a 5.5-log reduction when added to the lagoon effluent. If the proposed lime precipitation system was implemented to treat lagoon effluent, it is anticipated that an 8-log reduction in fecal coliforms would be observed, greatly reducing the potential risk from pathogenic organisms during the application of treated manure.

Publication Source (Journal or Book title)

ASABE - International Symposium on Air Quality and Waste Management for Agriculture 2010

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