DO浓度和pH对沼液废水短程硝化反应的影响

目的]研究溶解氧(DO)浓度和p H对沼液废水短程硝化反应的影响。方法]采用自制的SBR反应器,针对DO浓度和p H 2个影响因子进行单因素试验,考察其对亚硝酸盐积累的影响。结果]在温度(25±2)℃,进水氨氮(NH_4~+-N)浓度550~600 mg/L、化学需氧量(COD)1 600~1 700 mg/L、p H 7.5,水力停留时间(HRT)为1 d的条件下,DO浓度在1.1~1.5 mg/L时,出水亚硝氮(NO_2~--N)/总硝氮(NO_x~--N)可达到0.85,NO_2~--N/NH_4~+-N接近于1。在温度为(25±2)℃、DO为1.3 mg/L和进水NH_4~+-N浓度为600 mg/L时,将p H控制在7.3~7.8,亚硝酸菌整体活性最高。结论]DO浓度会显著影响亚硝酸盐的积累和转化,p H直接影响亚硝酸菌的生长,过高的p H会导致高NH_4~+-N沼液废水中游离氨的浓度升高,从而抑制亚硝酸菌的活性。

Effect of DO and pH on Short-cut Nitrification for Biogas Slurry Wastewater

Objective] To study the effect of DO concentration and pH on short-cut nitrification of biogas wastewater.Method] A single factor experiment was conducted to investigate the effects of two factors,DO and pH,on nitrite accumulation in a SBR reactor.Result] The NO2--N/NOx-N could reach 0.85 in effluent and NO2--N/NH4+-N was close to 1 under the following conditions:(25 ±2) ℃,the concentration of NH4+-N and COD in influent was 550-600 and 1 600-1 700 mg/L,pH was 7.0-7.5,HRT was 1 d,and the concentration of DO was 1.1-1.5 mg/L.It has the highest activity of nitrosomas under the control of pH within 7.3-7.8 with the following conditions:(25 ±2) ℃,the concentration of NH4+-N in irfluent was 600 mg/L,and the pH was controlled within 7.3-7.8.Conclusion] The concentration of DO significantly affects the accumulation and transformation of nitrite,and the level of pH will directly affect the growth of nitrite bacteria.The excessive pH will lead to the increase of ammonia concentration in the biogas slurry wasterwater with high ammonia nitrogen,thus inhibiting the activity of nitrosomas.