title: Nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.
abstract: Anaerobically digested swine wastewater contains high concentrations of phosphorus (P) and nitrogen (N). A pilot-scale experiment was carried out for nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization. In the pilot plant, a sequencing batch reactor (SBR) and a continuous-flow reactor with struvite accumulation devices were designed and employed. The wastewater pH value was increased by CO(2) stripping, and the struvite crystallization process was performed without alkali and Mg(2+) additions. Results of the long-term operation of the system showed that, both reactors provided up to 85% P removal and recovery over wide ranges of aeration times (1.0-4.0 h), hydraulic retention times (HRT) (6.0-15.0 h) and temperatures (0-29.5°C) for an extended period of 247 d, in which approximate 30% of P was recovered by the struvite accumulation devices. However, 40-90% of NH(4)(+)-N removed was through air stripping instead of being immobilized in the recovered solids. The recovered products were detected and analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and chemical methods, which were proved to be struvite with purity of more than 90%. This work demonstrated the feasibility and effects of nutrients removal and recovery from anaerobically digested swine wastewater by struvite crystallization without chemical additions.
authors: Chinese Research Academy of Environmental Sciences, Dayangfang 8, Anwai Beiyuan, Beijing 100012, China. songyh@craes.org.cn
authors: Yong-Hui
authors: YH
authors: Song
authors: Guang-Lei
authors: GL
authors: Qiu
authors: Peng
authors: P
authors: Yuan
authors: Xiao-Yu
authors: XY
authors: Cui
authors: Jian-Feng
authors: JF
authors: Peng
authors: Ping
authors: P
authors: Zeng
authors: Liang
authors: L
authors: Duan
authors: Lian-Cheng
authors: LC
authors: Xiang
authors: Feng
authors: F
authors: Qian
mesh_terms: D000383:Agriculture / Q000379:methods*; D000693:Anaerobiosis; D000818:Animals; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D019149:Bioreactors; D003460:Crystallization; D005502:Food; D007220:Industrial Waste; D017616:Magnesium Compounds / Q000737:chemistry*; D009584:Nitrogen / Q000302:isolation & purification / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry*; D010758:Phosphorus / Q000302:isolation & purification / Q000378:metabolism; D000069877:Struvite; D013552:Swine
chemical_list: D007220:Industrial Waste; D017616:Magnesium Compounds; D010710:Phosphates; D010758:Phosphorus; D000069877:Struvite; D009584:Nitrogen