理化因素对脱氮硫杆菌自养反硝化的影响

从连续运行的UASB反应器厌氧污泥中分离得到一株脱氮硫杆菌T.d.a,采用分批摇床试验,采用脱氮硫杆菌标准培养基,以硫代硫酸钠为硫源,研究pH值、温度、氮源(NO3--N,NH4+-N)、能源(S2O32-)、碳源(HCO3-)、葡萄糖、无机盐(P,Mg2+,Fe2+)对该菌株自养反硝化的影响.结果表明,在pH6.5～8.0,温度20～35℃的范围内,T.d.a对NO3--N均有较高的去除速率,其最佳反硝化pH值为7.04,温度为27.40℃.T.d.a对416mg/L的NO3--N有较好的适应性,554mg/L的NO3--N对T.d.a有一定的抑制作用;T.d.a反硝化所需NH4+-N的限制浓度为2.62mg/L;S2O32-浓度对T.d.a反硝化的影响主要取决于其与NO3-的比例关系,在NO3-过量的情况下,NO3--N去除率与加入的S2O32-量成近似的正比关系.T.d.a以HCO3-作为无机碳源时其限制浓度为29.05mg/L;0～2000mg/L的葡萄糖对NO3--N去除率没有明显影响.P和Mg2+的限制浓度分别为0.034,0.059mg/L,Fe2+的限制浓度低于0.058mg/L.

Effects of the physicochemical factors on autotrophic denitrification by Thiobacillus denitrificans

A strain of Thiobacillus denitrificans (T.d.a) was isolated from anaerobic sludge of consecutive running UASB reactor. Based on culture media of Thiobacillus denitrificans, the effects of pH, temperature, NO_3 -N, NH_4~+-N,S_2O_3~(2-), HCO_3, C_6H_(12)O_6, P, Mg~(2+) and Fe~(2+) on the denitrification by T.d.a were studied in batch experiments using sodium thiosulphate as sulfur source. The nitrate removal velocities were high at pH 6.5～8.0 and temperature 20～35℃. The optimal conditions were pH 7.04 and 27.40℃. T.d.a exhibited a good adaptation when the concentration of NO_3-N was below 416mg/L. At 554mg/L or above, however, the nitrate removal was markedly inhibited. The denitrification needed NH_4~+-N and its limiting concentration was 2.62mg/L. The effect of the concentration of S_2O_3~(2-) on the denitrificaion depended on different sulfur to nitrogen ratios. When NO_3 was enough, the NO_3-N removal efficiency was in similar direct proportion to the S_2O_3~(2-) added0]. Using HCO_3 as sole carbon source, its limiting concentration was 29.05mg/L. The presence of glucose up to 2000mg/L didn't significantly affect the nitrate removal efficiency. The limiting concentrations of P and Mg~(2+) were 0.034mg/L and 0.059mg/L respectively. The limiting concentration of Fe~(2+) was below 0.058mg/L.