title: Long-term operation of a novel pilot-scale six tanks alternately operating activated sludge process in treating domestic wastewater.
abstract: The performance of a new pilot-scale six tanks activated sludge process has been evaluated for 303 d, receiving real domestic wastewater with a flow rate of 15-24.4 L/h. Partial nitrification via nitrite and microbial community structure were investigated in this system. The result shows that the nitrite accumulation rate was achieved successfully over 94% in the last aerobic compartment through a combination of short hydraulic retention time and low dissolved oxygen (DO) level. Fluorescence in situ hybridization analysis was used to correlate ammonia-oxidizing bacteria (AOB) numbers with nutrient removal via nitrite. It was shown that in response to complete and partial nitrification modes, the numbers of AOB population were 7.7 x 10(7) cells/g mixed liquor suspended solids (MLSS) and 5.31 x 10(8) cells/g MLSS, respectively. The morphology of the sludge indicated that there is a small rod-shaped and spherical cluster which was mainly dominantly bacterial according to scanning electron microscope. Higher pollutant removal efficiencies of 86.2%, 98%, and 96.1%, for total nitrogen, NH4+ - N, and total phosphorus, respectively, were achieved by a long-term operation of the six tanks activated sludge process at a low DO concentration and low chemical oxygen demand to nitrogen ratio which were approximately equal to the complete nitrification-ldenitrification with the addition of an external carbon source at a concentration of 1.5-2.5 mg/L.
authors: R N
authors: RN
authors: Mohammed
authors: S
authors: S
authors: Abu-Alhail
authors: L
authors: L
authors: Xi-Wu
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D005427:Flocculation; D017404:In Situ Hybridization, Fluorescence; D059013:Microbial Consortia; D008855:Microscopy, Electron, Scanning; D058465:Nitrification; D009573:Nitrites / Q000032:analysis; D009584:Nitrogen / Q000302:isolation & purification; D010100:Oxygen; D010758:Phosphorus / Q000302:isolation & purification; D010865:Pilot Projects; D062065:Wastewater / Q000032:analysis / Q000382:microbiology*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D009573:Nitrites; D009584:Nitrogen; D010100:Oxygen; D010758:Phosphorus; D062065:Wastewater