木醋液酸化处理对奶牛场原水贮存过程中氨挥发的影响

Effects of Acidification on Ammonia Volatilization from Raw Water of Cattle Farm During Storage

为减少奶牛场原水贮存过程中氨气排放引起的二次污染,采用木醋液作为酸化剂对牛场原水进行酸化处理,探究酸化处理对牛场原水贮存过程中氨气排放特征及理化性质的影响。将原水溶液初始pH值调为7.0(T1)和6.3(T2),同时设置对照处理(CK),用通气法对氨挥发进行监测。结果表明,3组处理原水pH值在贮存过程中上升并最终均呈碱性,试验结束时分别达到了8.43、8.24和7.99。贮存过程中原水溶液温度始终与室温保持一致,温度变化范围在24℃~33℃。酸化处理能明显降低原水贮存过程中的氨挥发通量和氨挥发总量,且氨挥发通量和pH值呈显著正相关性(p<0.01)。CK、T1、T2在整个贮存周期内的平均氨挥发通量分别为1338、1025和618 mg·m^(-2)d^(-1),T1、T2分别下降了23.4%和53.8%。不同处理原水贮存过程中氨挥发的变化规律相同,在贮存前15天氨挥发呈波动上升趋势,在16~18天开始下降随后上升直到贮存结束,前期氨挥发波动上升的变化趋势受pH值和温度的共同影响,后期先下降后上升的趋势受温度影响。贮存周期内氨挥发总量分别为26.8、20.5和12.4 g·m^(-2),T1、T2分别下降了23.51%和53.73%。贮存过程中各处理铵态氮浓度呈现先升高后降低的趋势,贮存结束后各处理的铵态氮浓度分别降低了7.24%、5.64%和3.56%。通过添加木醋液,可以显著降低原水贮存过程中的氨挥发通量和总量,提高其铵态氮浓度,进而提升原水经过贮存后还田的肥效,为牛场原水酸化贮存氨减排技术和农田利用提供了理论依据。

This study aimed to reveal the characteristics of ammonia(NH_(3))volatilization and the variation of the chemical properties of raw water treated with acidification during storage.Three experimental groups were set in this study.Two treatments being acidified to pH of 7.0(T1)and 6.3(T2)with wood vinegar,while CK was set with no acidification(pH 7.7).The pH value of the three raw water solutions increased continuously during storage and finally became alkaline.The pH value of CK、T1 and T2 treatment were 8.43,8.24 and 7.99 at the end of the experiment respectively.During the storage process,the temperature of the raw water solution was always consistent with the room temperature,and the temperature varied between 24℃and 33℃acidified treatment reduced ammonia volatilization flux significantly.There was a significant positive correlation between ammonia volatilization flux and pH value.The average ammonia volatilization fluxes of CK,T1 and T2 during the whole storage were 1338,1025 and 618 mg·m^(-2)d^(-1)respectively.Compared with CK treatment the ammonia volatilization flux of T1 and T2 treatment decreased by 23.4%and 53.8%,respectively.Ammonia volatilization of different treatment during storage process had same trend.The ammonia volatilization flux showed a fluctuating upward trend in the first 15 days,it started to decrease at 16 to 18 days and then increase until the end of storage.The change of ammonia volatilization is affected by pH value and temperature before 15 days and by temperature after 15 days.During the storage process,the ammonia volatilization of CK T1 and T2 treatment were 26.8,20.5 and 12.4 g·m^(-2)respectively.Compared with CK treatment the ammonia volatilization of T1 and T2 treatment decreased by 23.51%and 53.73%,respectively.During the storage process,the concentration of ammonium nitrogen increased at first and then decreased.After the storage,the concentration of ammonium nitrogen in each treatment decreased by 7.24%,5.64%and 3.56%respectively.By adding wood vinegar to reduce the pH of raw water solution,ammonia volatilization and concentration of ammonium nitrogen in the raw water storage process was significantly reduced and the fertilizer efficiency of raw water is improved.The results provide a theoretical basis for the reduction technology of ammonia volatilization in raw water acidification storage.