电流和碳氮的量比对生物电极脱氮速率影响的模拟

研究了脱氮过程中生物膜内的物质运动和反应机理,在已建立的生物电极模型的基础上,对以下3种情况下生物膜内反应物浓度分布以及电流和有机物时脱氮速率的影响进行了研究:只利用水电解产生的氢气作为电子供体;只利用醋酸作为电子供体;氢气和醋酸同时作为电子供体.研究结果表明:增加电流和碳氮的量比都能提高脱氮速率,但只增大电流或碳氮的量比,脱氮速率的提高程度不大,且随着碳氮的量比的增大,出水中硝酸氮浓度不断降低,残留醋酸浓度也随之提高,影响出水水质;当同时通电和添加醋酸时,脱氮速率显著加快;但过大的电流和碳氮的量比反而不利于脱氮的进行,因此,存在碳氮的量比和电流的最佳组合,在此条件下,出水中残留醋酸浓度最低,脱氮速率最高.当碳氮的量比为0.7,电流为100 mA时的脱氮速率比只通电时的脱氮速率增大了约1倍.

Simulating effects of electric current and molar of C to N on denitrification rates in biofilm of bio-electro reactor

The denitrification mechanism and movement of reactants in a biofilm were investigated. On the basis of a previous bio-electro model, the distribution of reactants in the biofilm and the effects of current and organic matter on denitrification rates were discussed when only hydrogen gas produced by electrolysis of water, only acetic acid, both hydrogen gas and acetic acid were used as electron donors, respectively. The results show that the denitrification rates improve with the increasing of current and the molar of carbon to nitrogen, but good effects are hard to (achieve) by simply increasing current or the molar of carbon to nitrogen, especially when the molar of carbon to nitrogen increases, the concentration of residual acetic acid in the effluent water increases, which leads to the deterioration of water quality. When current and acetic acid are (applied) simultaneously, the denitrification rates increases significantly and the best results are (achieved.) The denitrification rate doubles under the condition of the molar of carbon to nitrogen is 0.7 and the current intensity is 100 mA as what only current is applied. However, denitrification is weakened instead when current intensity or the molar of carbon to nitrogen exceeds their optimal values, so a optimal combination of current intensity and the molar of carbon to nitrogen must be found to guarantee the highest denitrification rate and the lowest concentration of effluent acetic acid at the same time.