排水管道沉淀物氮释放特性的研究

利用室内模拟的方法探讨了排水管道沉淀物在水土比、p H值、温度以及扰动这4个环境因子影响下的氮素转化规律.4个影响因子下的实验结果表明,沉淀物中氮素主要以氨氮的形式向上覆水中释放,各组上覆水中氨氮呈先升高后降低的两阶段变化趋势,在第4~6 d达到释放峰值,随后质量浓度逐渐下降,而总硝态氮的变化趋势与氨氮相反.4个影响因子中p H对氨氮释放的影响最大,其次为搅动、水土比,温度的影响最小,其中不同初始p H条件下氨氮的最大释放量从大到小排序为p H 6.3p H 8.0p H 9.6,释放量最大值分别为54.0、30.9、26.7 mg·L-1.实验中水土比越大,氨氮的释放量越大,在相同的速率下对上覆水搅动时间越长,氨氮的释放量越大.温度的升高促进了上覆水中的氨氮向硝态氮的转化,加快了上覆水中总氮质量浓度的下降.

Nitrogen Release Performance of Sediments in Drainage Pipeline

The effects of soil and water ratio, pH, temperature and rotation on the nitrogen transformation of sediment in drainage pipeline were investigated in this study. The experimental results for the four impact factors indicated that ammonia nitrogen was the main existing form for nitrogen release from the sediment to the overlying water, the concentration of ammonia nitrogen was uptrend, reaching the maximum in four to six days, and it went down till to the end of experiments. While the variation trend of nitrate nitrogen concentration was opposite to that of ammonia nitrogen. The factor of pH influenced most in the release of ammonia nitrogen among the four factors, then was the disturbance, and the temperature had a minimal impact. The release of ammonia nitrogen followed the descending order of pH 6.3>pH 8.0>pH 9.6, and the maximum concentrations were 54.0, 30.9 and 26.7 mg·L^-1 respectively. The higher soil and water ratio and the longer agitation time under the same agitation speed were, the higher ammonia nitrogen concentration was obtained. An increase in temperature promoted the conversion of ammonia nitrogen to the nitrate nitrogen, and speeded up the decrease of total nitrogen in the overlying water.