城镇污泥蚯蚓堆肥硝化进程及其影响因素

Nitrification process and its influencing factors in vermicomposting of sewage sludge

硝化是城镇污泥蚯蚓堆肥稳定化的最后一个阶段,研究硝化进程及其影响因素对减少蚯蚓堆肥过程中的NH_4^+积累、氮素损失和加快蚯蚓堆肥稳定化过程具有重要意义.文章考察了蚯蚓生物量、环境温度以及好氧条件对蚯蚓堆肥NH_4^+、NO_3^-变化的影响.结果发现,蚯蚓生物量对NH_4^+、NO_3^-含量变化影响较大,并存在显著的跃变特点,即当蚯蚓生物量超过一定数量时,会显著加快氨化和硝化速率.环境温度显著影响堆肥氨化作用,影响大小顺序为25℃>20℃>15℃;环境温度仅对蚯蚓堆肥硝化速率产生影响,但不改变堆肥的硝化进程.蚯蚓堆肥好氧条件对硝化影响大于对氨化的影响,好氧条件优劣不但影响硝化进程还影响硝化速率,氧环境条件好的蚯蚓堆肥硝化进程启动早,硝化速率高.

Nitrification is the last essential stage of the vermicomposting stabilization process of sewage sludge.It is therefore of great significance to investigate the nitrification process and its influencing factors in order to reduce the accumulation of NH4~＋ and nitrogen loss and speed up the stabilization process during vermicomposting process.Changes of NH4~＋ and NO3^- in response to different earthworm biomasses,environmental temperatures and aerobiotic conditions were examined.The results show that the earthworm biomass plays an important role in the changes of NH4~＋ and NO3^-,and this influence has a significant saltation,i.e.when the earthworm biomass exceeds a certain number,the ammonification and nitrification rate will be significantly accelerated.Environmental temperature significantly affects ammoniation with the influence order of 25℃〉20℃〉15℃.Environmental temperature affects vermicomposting nitrification rate only but not the nitrification process.In comparison,aerobiotic condition has a greater influence on nitrification than ammoniation,and it can affect both nitrification process and nitrification rate.The better the aerobiotic condition is,the earlier the vermicomposting nitrification starts and the higher the nitrification rate can reach.