LABORATORY STUDY OF URINE HYDROLYSIS AND PRECIPITATION FOR N-AND P-RECOVERY ENHANCED BY ACTIVATED SLUDGE
1.INTRODUCTION The conversion from urine to ammonia is an important step for the N- and P-recovery when using the struvite method. In this study, activated sludge was employed to enhance this process and the efficiency of N- and P-recovery was evaluated. Results demonstrate that the dosing of activated sludge (AS) to urine was effective to improve the hydrolysis of urine. The dosage of AS only affected the rate of hydrolysis but did not change its equilibrium of the hydrolysis, suggesting the urease may be introduced, which was excreted by the microorganisms in the AS. With the dosage of 50g /I AS in urine, the hydrolysis efficiency was approximately 85％ after 2 days reaction, which was equivalent to the dosage of 50mg /I urease in the urine. The hydrolyzed urine was filtered to remove the residual of AS and the nutrient in the filtrate was recovered using magnesium-ammonium-phosphate (MAP) precipitation by adding MgCI2 and Na2HPO4. When Mg:N:Pwas 1.4:1:1 on a molar base and the pH was 10.5, the efficiency of N- and P-recovery were up to 96.0％ and 96.7％, respectively. Using X-ray diffraction analysis, the main phase of precipitates was identified as NH4MgPO4·6H2O comprised of 70％ of the precipitate. This study shows that the dosing of AS in urine could effectively increase the rate of hydrolysis and the followed MAP precipitation method with external P-source dosing was an effective method for the N- and p-recovery in the hydrolyzed urine.
Activated sludge Urine Urease Magnesium-ammonium-phosphate (MAP) precipitation N recovery P recovery
Xiaochang WANG Chenggang LIANG Pengkang JIN Zhihua LI Naoyuki FUNAMIZU
School of Environmental and Municipal Engineering, Xian University of Architecture and Technology.K Department of Environmental Engineering, Hokkaido University kilal3-nishi 8, Kita-ku, Sapporo-shi, H
国际会议
第七届中日水环境研讨会暨NSFC-JST重大国际合作项目成果交流会
北京
英文
113-118
2007-10-25（万方平台首次上网日期，不代表论文的发表时间）