title: Treatment of anaerobically digested dairy manure in a two-stage biofiltration system.
abstract: High concentrations of ammonium and phosphate present a challenge to cost-effective treatment of anaerobically digested dairy manure. This study investigated the efficacy of a two-stage biofiltration system for passive treatment of digested dairy manure. The first stage pebble filters were batch loaded. When the slurry-like digested dairy manure was retained on pebble beds, soluble contaminants were removed before liquid infiltrated over 8-17 days. The pebble filters removed 70% of soluble chemical oxygen demand, 71% of soluble biochemical oxygen demand, 75% of ammonium, and 68% of orthophosphate. Nitrogen removal was attributed to the conventional nitrification - denitrification process and novel nitritation - anammox process. Aerobic ammonium oxidizing and anammox bacteria accounted for 25 and 23% of all bacteria, respectively, in the filtrate of the pebble filters. The longer it took for filtration, the greater the removal efficiency of soluble contaminants. The second stage sand filters had removal efficiencies of 17% for soluble chemical oxygen demand, 45% for soluble biochemical oxygen demand, 43% for ammonium, and 16% for orthophosphate during batch operations at a hydraulic retention time of 7 days. Aerobic ammonium oxidation and anammox were primarily responsible for nitrogen removal in the sand filters. Vegetation made an insignificant difference in treatment performance of the sand filters.
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijing, China.
authors.forename: Mengjing
authors.initials: M
authors.lastname: Xia
authors.forename: Wendong
authors.initials: W
authors.lastname: Tao
authors.forename: Ziyuan
authors.initials: Z
authors.lastname: Wang
authors.forename: Yuansheng
authors.initials: Y
authors.lastname: Pei
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D019149:Bioreactors; D002417:Cattle; D003612:Dairying; D005160:Facility Design and Construction; D005260:Female; D005374:Filtration / Q000295:instrumentation* / Q000379:methods*; D008372:Manure; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D008372:Manure