硫氮比对厌氧生物同步脱氮除硫工艺性能的影响

研究了硫氮摩尔比对厌氧生物同步脱氮除硫工艺高效性、稳定性和选择性的影响.单质硫型厌氧生物同步脱氮除硫反应(硫氮摩尔比为5:2)的硫化物和硝酸盐容积去除速率高达4.86 kg·m-3.d-1和0.99 kg·m-3.d-1工艺效能明显高于混合型和硫酸盐型(硫氮摩尔比分别为5:5和5:8).单质硫型厌氧生物同步脱氮除硫反应各项出水指标的波动相对较小,但当进水硫化物浓度超过临界值时,工效失稳,其主要原因是pH无法维持在所需范围.在所试的3种进水硫氮摩尔比下,实际反应的硫氮摩尔比有靠拢5:2的趋势.将硫氮摩尔比调控在较高水平(硫氮摩尔比为5:2),可提高同步厌氧生物同步脱氮除硫反应对单质硫和氮气的选择性.对不同硫氮比时反应物之间的电子得失情况进行了分析.

The effect of sulfide to nitrate ratio on the performance of a simultaneous anaerobic sulfide and nitrate removal process

The effect of sulfide to nitrate (S/N) ratio on the performance of a simultaneous anaerobic sulfide and nitrate removal process was investigated on the basis of capacity,stability and selectivity. The volumetric sulfide-sulfur and nitrate-nitrogen removal rates at a molar S/N ratio of 5:2 were 4.86 kg·m^-3·d^-1 and 0.99 kg·m^-3·d^-1,respectively,which were higher than those at molar S/N ratios of 5:5 and 5:8. Moreover,the effluent fluctuation at a S/N ratio of 5:2 was less than at the other two ratios. During operation,the ratio of converted sulfide to converted nitrate tended to approach 5:2. The selectivity for elemental sulfur and dinitrogen was improved when the molar S/N ratio was set at 5:2 rather than 5:8 or 5:5. The process became unstable if the influent sulfide surpassed its critical concentration. The electron balance between the reactants was measured at each of the different molar S/N ratios.