title: Effect of organic matter on phosphorus recovery from sewage sludge subjected to microwave hybrid pretreatment.
abstract: Microwave (MW) hybrid processes are able to disrupt the flocculent structure of complex waste activated sludge, and help promote the recovery of phosphorus as struvite. In this study, to optimize struvite yield, (1) the characteristics of matter released in MW-hybrid treatments were compared, including MW, MW-acid, MW-alkali, MW-H2O2, and MW-H2O2-alkali. The results showed that selective release of carbon, nitrogen, phosphorus, Ca(2+), and Mg(2+) achieved by sludge pretreatment using MW-hybrid processes. MW-H2O2 is the recommended sludge pretreatment process for phosphorus recovery in the form of struvite. The ratio of Mg(2+):NH4(+)-N:PO4(3-)-P was 1.2:2.9:1 in the supernatant. (2) To clarify the effects of organic matter on struvite recovery, the composition and molecular weight distribution of organic matters were analyzed. Low molecular weight COD was found to facilitate the removal rate of NH4(+)-N and PO4(3)-P via crystallization, and the amorphous struvite crystals (<1kDa) from the filtered solutions had high purity. Therefore, the present study reveals the necessity of taking into consideration the interference effect of high molecular weight organic matters during struvite crystallization from sewage sludge.
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China; CSD IDEA (Beijing) Environmental Test& Analysis Co. Ltd., Beijing 100192, China.
authors.forename: Qingcong
authors.initials: Q
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhong
authors.affiliation: School of Environment and Natural Resources, Renmin University of China, Beijing 100872, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Environmental Aquatic Chemistry, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: yswei@rcees.ac.cn.
authors.forename: Yuansong
authors.initials: Y
authors.lastname: Wei
mesh_terms: D002118:Calcium / Q000737:chemistry; D005427:Flocculation; D008274:Magnesium / Q000737:chemistry; D008872:Microwaves; D008970:Molecular Weight; D009584:Nitrogen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry*; D000069877:Struvite / Q000737:chemistry*
chemical_list: D012722:Sewage; D010758:Phosphorus; D000069877:Struvite; D008274:Magnesium; D009584:Nitrogen; D002118:Calcium
keywords: Microwave pretreatment; Molecular weight distribution; Phosphorus recovery; Sewage sludge; Struvite