title: Treatment of farm dairy effluent with hybrid upflow multilayer bioreactor and activated sludge module.
abstract: Biological removal of nitrogen and carbon from farm dairy effluent (FDE) was studied with two laboratory-scale systems following nitrification and denitrification processes. Each system consisted of an upflow multilayer bioreactor (UMBR) as a pre-denitrification unit, an aeration tank (AT) as nitrification unit and a secondary clarifier. The optimization of two operational variables, total hydraulic retention time (HRT) and internal recycle (IR) rate with both real-FDE and a synthetic-wastewater were investigated. First, HRTs of 2, 3, 4 and 5 days were tested with synthetic-wastewater at uniform IR rate. The HRT of 4 days proved optimum with high efficiencies for nitrification (>90%), denitrification (>90%) and total chemical oxygen demand (COD) removal ( approximately 90%). The lowest efficiency was recorded at 2 days HRT with 7% nitrification efficiency. This was followed by experimentation with IR rates of 200%, 300% and 400% on both real-FDE and synthetic-wastewater at optimized HRT. The increase in IR to 300% improved the denitrification potential and overall performance with continuous high nitrification efficiency and COD removal whereas IR of 400% retarded the process. The application of combined UMBR and activated sludge system showed good potential for biological removal of nitrogen from FDE.
authors.affiliation: Department of Civil and Environmental Engineering, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. dsha097@aucklanduni.ac.nz
authors.forename: D F
authors.initials: DF
authors.lastname: Shams
authors.forename: N
authors.initials: N
authors.lastname: Singhal
authors.forename: P
authors.initials: P
authors.lastname: Elefsiniotis
authors.forename: A
authors.initials: A
authors.lastname: Johnson
mesh_terms: D000818:Animals; D019149:Bioreactors; D001785:Blood Gas Monitoring, Transcutaneous; D002417:Cattle; D003612:Dairying; D005260:Female; D009584:Nitrogen / Q000737:chemistry; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014877:Water Pollution, Chemical / Q000517:prevention & control
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D009584:Nitrogen