title: Nutrient release, recovery and removal from waste sludge of a biological nutrient removal system.
abstract: The uncontrolled release of nutrients from waste sludge results in nitrogen and phosphorus overloading in wastewater treatment plants when supernatant is returned to the inlet. A controlled release, recovery and removal of nutrient from the waste sludge of a Biological Nutrient Removal system (BNR) are investigated. Results showed that the supernatant was of high mineral salt, high electrical conductivity and poor biodegradability, in addition to high nitrogen and phosphorus concentrations after the waste sludge was hydrolysed through sodium dodecyl sulphate addition. Subsequently, over 91.8% of phosphorus and 10.5% of nitrogen in the supernatants were extracted by the crystallization method under the conditions of 9.5 pH and 400 rpm. The precipitate was mainly struvite according to X-ray diffraction and morphological examination. A multistage anoxic-oxic Moving Bed Biofilm Reactor (MBBR) was then adopted to remove the residual carbon, nitrogen and phosphorus in the supernatant. The MBBR exhibited good performance in simultaneously removing carbon, nitrogen and phosphorus under a short aeration time, which accounted for 31.25% of a cycle. Fluorescence in situ hybridization analysis demonstrated that nitrifiers presented mainly in floc, although higher extracellular polymeric substance content, especially DNA, appeared in the biofilm. Thus, a combination of hydrolysis and precipitation, followed by the MBBR, can complete the nutrient release from the waste sludge of a BNR system, recovers nutrients from the hydrolysed liquor and removes nutrients from leftovers effectively.
authors.affiliation: a School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology , Xi'an 710055 , People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Shu-Jian
authors.initials: SJ
authors.lastname: Zheng
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Pei
authors.forename: Li
authors.initials: L
authors.lastname: Ke
authors.forename: Dang-Cong
authors.initials: DC
authors.lastname: Peng
authors.forename: Si-Qing
authors.initials: SQ
authors.lastname: Xia
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D001704:Biopolymers / Q000032:analysis / Q000378:metabolism; D019149:Bioreactors; D002244:Carbon / Q000032:analysis / Q000378:metabolism; D011232:Chemical Precipitation; D003460:Crystallization; D004269:DNA, Bacterial / Q000032:analysis; D006868:Hydrolysis; D017404:In Situ Hybridization, Fluorescence; D017616:Magnesium Compounds / Q000737:chemistry; D009584:Nitrogen / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D012722:Sewage; D000069877:Struvite; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism
chemical_list: D001704:Biopolymers; D004269:DNA, Bacterial; D017616:Magnesium Compounds; D010710:Phosphates; D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D002244:Carbon; D000069877:Struvite; D009584:Nitrogen
keywords: nutrient; recovery; release; removal; waste sludge