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研究报告

Effect of long-term operation of biofilters on biological removal of ammonia

摘要：针对含氨恶臭气体的处理,选用堆肥和污泥颗粒作为填料,研究了生物滤塔长期运行(210d)处理氨的效果.结果表明,运行初期在低负荷(NH₃浓度<110mg·m^-3)条件下,生物滤塔对氨的去除能力均保持在较高水平,氨去除效率达到99%以上;随着负荷的不断增加,到实验后期,当进气浓度大于190mg·m^-3时,氨去除效率下降到了50%左右.生物滤塔BG1和BG2对氨的最大去除能力分别为288g·m^-3·d^-1和243g·m^-3·d^-1(以NH₃计).氨的去除主要发生在生物滤塔的底层,氨的转化产物以硝酸盐为主.长期运行及高负荷(NH₃浓度>110mg·m^-3)条件下,两生物滤塔均出现了失活现象.通过对填料中代谢产物的分析和氮平衡计算,发现生物滤塔失活的原因主要有两个:①由于进气中氨的浓度不断升高,导致填料所吸附的氨不断增加并大量积累,高浓度的游离氨会抑制硝化细菌的活性,造成系统硝化速率降低;②由于氨氮和产物积累造成盐浓度过高,引起渗透压效应,抑制了硝化细菌的活性.

Abstract：Long-term operation of biofilters for biological removal of ammonia was investigated using compost (BG1) and sludge (BG2) as packing materials. At the beginning of the experiment,during the low ammonia load period,the elimination capacities of both biofilters were high and the ammonia removal efficiencies could reach more than 99%. With the increase of ammonia load,at the end of the experiment when the inlet concentration of ammonia was higher than 190mg·m^-3,the removal efficiencies of both biofilters decreased to 50%. The maximum elimination capacities of BG1 and BG2 were 288 and 243 g (NH₃)·m^-3·d^-1,respectively. Most of the NH₃ removal was performed in the bottom layers of the reactors. Ammonia was mainly oxidized to nitrate. After long time operation and high load of ammonia,deactivation occurred in both biofilters. There are two possible reasons:First,with the increase of the inlet concentration of ammonia,large amounts of ammonium were adsorbed and accumulated in the packed bed,thus causing inhibition of nitrifying bacteria due to free ammonia accumulation. Second,the accumulation of ammonium and its products caused high salt concentrations,and the increased osmotic pressure due to the high salt concentration inhibited the activity of nitrifying bacteria.