废水中硝氮和COD浓度对AD-MFC脱氮产电性能的影响

Influence of nitrate and COD concentrations on nitrogen removal and power production performance of AD-MFC

为探明废水中硝氮和COD浓度对阳极反硝化微生物燃料电池(AD-MFC)工作性能的影响,在批式操作下逐步提高进水浓度考察了AD-MFC反硝化速率和产电性能的变化,并以多个动力学模型对此过程进行拟合。结果表明,废水浓度可通过污染物降解速率来影响产电性能,硝氮浓度从50 mg/L升高至2 000 mg/L时,反硝化速率和输出电压逐渐达到最大值((1.26±0.01)kg N/(m3·d)和(1 016.75±4.74)mV),但硝氮浓度继续提高会抑制反硝化速率和产电性能。Han-Levenspiel模型可较好地表征AD-MFC的污染物降解和产电动力学行为,以该模型为基础建立了污染物去除速率、输出电压、功率密度与进水浓度之间的关系,反硝化在NO-3-N高于4 000 mg/L时才能被完全抑制。AD-MFC适用于处理不同浓度的硝酸盐废水,并对高浓度硝酸盐废水具有较好的耐受性。

To investigate the influence of nitrate and COD concentrations on the nitrogen removal and power production performance of AD-MFC,variations of denitrification rate and electricity production were monitored by stepwisely elevating the influent wastewater concentration and the experimental data were fitted with several kinetic models. Power generation was closely related to denitrification rate. Both the denitrification rate and electricity production capacity were enhanced as the initial NO-3-N concentration increased from 50 mg /L to 2 000 mg /L,with a maximum nitrate removal rate of( 1. 26 ± 0. 01) kg N /( m3·d) and maximum voltage output of( 1 016.75 ±4.74) mV. Further increase of influent concentration led to decrease of denitrification rate and electricity production capacity. The kinetic behavior of the AD-MFC could be described well with Han-Levenspiel model,through which the relationships among the substrates removal,power generation and wastewater concentrations were established. Denitrification would be completely inhibited at a NO-3-N concentration more than 4 000 mg /L,which suggested that AD-MFC was suitable to treat various concentrations of nitrate wastewater and tolerant to high nitrate concentration wastewater.