摘要
采用蒸发法浓缩处理沼液,研究了低温蒸发、常压蒸发和减压蒸发过程对沼液浓缩的影响。结果表明:不同温度下(常温、25℃、35℃、45℃、55℃、65℃、75℃、85℃)低温蒸发对浓缩沼液的氨氮质量浓度有较大影响,氨氮在蒸发过程中几乎全部损失(98%),对浓缩液营养物质的回收不利。沼液在不同p H值(2、3、4、5、6、7)的常压蒸发研究表明,当初始p H值小于等于4时,冷凝水的氨氮质量浓度低于41.0 mg/L,水质可以满足GB 18596—2001《畜禽养殖业污染物排放标准》。减压蒸发试验结果表明,相对真空度-0.03^-0.08 MPa对沼液蒸发过程影响不大。沼液不同初始p H值的减压试验结果表明,与常压蒸发相比,减压蒸发可以降低冷凝水中的氨氮质量浓度和化学需氧量(COD),提高冷凝水水质。减压蒸发在沼液初始p H值小于等于5时,冷凝水氨氮质量浓度在61.8 mg/L以下,可满足排放标准。因此,真空蒸发对整个系统的运行最为有利。
Evaporation was applied to concentrate biogas slurry. The effects of low temperature evaporation, atmospheric evaporation and vacuum evaporation on biogas slurry concentration were investigated. Results showed that the low temperature evaporation （room temperature, 25℃, 35℃, 45℃ , 55℃ , 65℃ , 75℃ , 85℃ ） had a great impact on the ammonia nitrogen concentration of biogas slurry, and almost all ammonia （98%） were lost, which has disadvantages on the recovery of nutrients. It showed that when the initial pH value was less than 4 in atmospheric evaporation, the water quality of the effluent （ammonia is lower than 41.0 rag/L） could meet the demand of Discharge Standard of Pollutants for Livestock and Poultry Breeding （GB 18596--2001 ）. Experimental results of the vacuum evaporation showed that vacuum degree （ -0. 03 - -0.08 MPa ） had little influence on evaporation results. Vacuum evaporation of biogas slurry with different initial pH value showed that compared with the atmospheric evaporation, vacuum evaporation could reduce the content of ammonia nitrogen and chemical oxygen demand （COD） in effluent and improve quality of effluent. When the initial pH value of biogas slurry in vacuum evaporation process was less than 5, the effluent （ammonia is lower than 61.8 mg/L） could meet the discharge standard. Therefore, the most effective operation for the whole system is vacuum evaporation.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2015年第5期164-170,共7页
Transactions of the Chinese Society for Agricultural Machinery
基金
国家国际科技合作项目(2013DFG92620)
中央高校基本科研业务费专项资金资助项目(2302013FRF-MP-13-001B)
关键词
沼液
蒸发
浓缩
减压
营养物质回收
Biogas slurry Evaporation Concentration Vacuum Nutrient recycling
