基于结构改进的生物滴滤塔对鸡舍NH_(3)和H_(2)S的处理效果

Study on the Treatment Effect of NH_(3) and H_(2)S in Chicken Coop by Biotrickling Filter Tower Based on Improved Structure

围绕提升生物滴滤塔NH_(3)和H_(2)S的处理效率,并解决受循环液中氧气供应量不足而导致二次污染物累积的问题,设计了一种结构改进型生物滴滤塔。该塔自循环液进气,增大了传质效率并为循环液提供曝气,将其与目前研究中常用的普通生物滴滤塔进行对比试验。结果表明:针对气态NH_(3)和H_(2)S,改进型生物滴滤塔在低停留时间、低进气浓度条件下处理效率更高。在低停留时间(10 s)条件下,改进型生物滴滤塔NH_(3)和H_(2)S的平均处理效率分别为86.90%和80.79%,分别比普通型提高10.52和10.68个百分点。与普通型相比,改进型生物滴滤塔在更低的停留时间条件下能实现高效处理,对应所需的装置体积更小,建设和运行成本更低。在低进气浓度(NH_(3),体积分数为5×10^(-6);H_(2)S,体积分数为1×10^(-6))条件下,改进型生物滴滤塔对NH_(3)和H_(2)S的平均处理效率分别为93.98%和87.73%,分别比普通型高10.74和17.47个百分点。与普通型相比,改进型生物滴滤塔能实现高效处理的适用浓度范围更广,可适用于不同排放水平的鸡舍。针对循环液中累积污染物,改进型生物滴滤塔的去除效率更高。在试验最后1个周期,改进型生物滴滤塔循环液中NH_(4)^(+)、NO_(2)^(-)最终累积质量浓度分别为5.77和1.99 mg·L^(-1),比普通型分别减少70.81%和76.49%;稳定终产物NO_(3)^(-)和SO_(4)^(2-)(均非国家现行的养殖场废水排放标准中的指标物)最终累积质量浓度分别为70.69和13.78 mg·L^(-1),分别比普通型增加56.29%和29.21%。

A structure⁃improved biological filter tower(BFT)was designed to improve its NH_(3) and H_(2)S removal efficien⁃cy,so as to avoid the secondary contaminant accumulation due to insufficient oxygen in the circulating liquid.The im⁃proved BFT can increase mass transfer efficiency and provide aeration for the circulating liquid.The results of the compa⁃ring study of the improved BFT and ordinary BFT show that the improved BFT has the following advantages:It brings high treatment efficiency under the condition of short residence time and low intake gas concentrations.Under short residence time(i.e.10 s),the average efficiency of the improved BFT in removing NH3 and H2 S was 86.90%and 80.79%,re⁃spectively,10.52 and 10.68 percentage point higher than that of the ordinary one,respectively.Compared with the ordi⁃nary BFT,the improved BFT can achieve efficient treatment under the condition of lower residence time,resulting in smal⁃ler device size and lower construction and operation costs.Under low intake gas concentrations(i.e.NH_(3),5×10^(-6);H_(2)S,1×10^(-6)),the average efficiency of the improved BFT in removing NH3 and H2S was 93.98%and 87.73%,respectively,10.74 and 17.47 percentage point higher than that of the ordinary one,respectively.Compared with the ordinary BFT,the improved BFT can realize the efficient treatment of a wider range of applicable concentration,and can be applied to differ⁃ent emission levels of chicken house.It brings high efficiency in removing the accumulated pollutants in circulating liquid.In the last period of the experiment,the concentration of NH4+and NO_(2)^(-)in circulating liquid from the improved BFT was 5.77 and 1.99 mg·L^(-1),respectively,70.81%and 76.49% lower than that in the circulating liquid from ordinary BFT.The concentration of the stable end⁃products,NO3-and SO_(4)^(2-)(both not being indicators in the current national wastewater discharge standards for livestock farms),from the improved BFT,was 70.69 and 13.78 mg·L^(-1),respectively,56.29% and 29.21% higher than that in the circulating liquid from the ordinary BFT.