title: Selective release of phosphorus and nitrogen from waste activated sludge with combined thermal and alkali treatment.
abstract: Selective release characteristics of phosphorus and nitrogen from waste activated sludge (WAS) were investigated during combined thermal and alkali treatment. Alkali (0.001-1.0N NaOH) treatment and combined thermal-alkali treatment were applied to WAS for releasing total P(T-P) and total nitrogen(T-N). Combined thermal-alkali treatment released 94%, 76%, and 49% of T-P, T-N, and COD, respectively. Release rate was positively associated with NaOH concentration, while temperature gave insignificant effect. The ratio of T-N and COD to T-P that released with alkali treatment ranged 0.74-0.80 and 0.39-0.50, respectively, while combined thermal-alkali treatment gave 0.60-0.90 and 0.20-0.60, respectively. Selective release of T-P and T-N was negatively associated with NaOH. High NaOH concentration created cavities on the surface of WAS, and these cavities accelerated the release rate, but reduced selectivity. Selective release of P and N from sludge has a beneficial effect on nutrient recovery with crystallization processes and it can also enhance methane production.
authors.affiliation: Department of Environmental Sciences and Biotechnology, Institute of Energy & Environment, Hallym University, Chuncheon, Gangwon 200-702, Republic of Korea.
authors.forename: Minwook
authors.initials: M
authors.lastname: Kim
authors.affiliation: Entecs Ltd., Gwangsan-gu, Gwangju 506-500, Republic of Korea.
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Han
authors.affiliation: Department of Environmental Sciences and Biotechnology, Institute of Energy & Environment, Hallym University, Chuncheon, Gangwon 200-702, Republic of Korea. Electronic address: dongjin@hallym.ac.kr.
authors.forename: Dong-Jin
authors.initials: DJ
authors.lastname: Kim
mesh_terms: D000468:Alkalies / Q000737:chemistry; D057919:Biological Oxygen Demand Analysis; D006361:Heating / Q000379:methods*; D007220:Industrial Waste / Q000517:prevention & control; D007700:Kinetics; D009584:Nitrogen / Q000737:chemistry / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D012722:Sewage / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods
chemical_list: D000468:Alkalies; D007220:Industrial Waste; D012722:Sewage; D014874:Water Pollutants, Chemical; D010758:Phosphorus; D012972:Sodium Hydroxide; D009584:Nitrogen
keywords: Alkali treatment; Phosphorus recovery; Phosphorus release; Thermal treatment; Waste activated sludge