Microbial denitrification can be impaired by the co-existence of organic chelating pollutants; however, information on the potential impacts of nitrate reduction efficiency in response to such pollutants is limited. Herein, 1-hydroxyethane-(1,1-bisphosphonic acid) (HEDP) was selected as a typical pollutant to investigate effects on biological denitrification in an expanded granular sludge blanket (EGSB) reactor. Results showed that 99.5%–99.9% of nitrate was removed after sludge exposure to HEDP (1.5–30 mM). This was due to the protection of microbial cells by an increase in the secretion of extra polymeric substances (EPS) in response to HEDP stress. However, nitrate removal efficiency decreased to 55% with the accumulation of 470 mg L^-1 nitrite under 40 mM HEDP. This was due to the dissolution of EPSs, as evidenced by the appearance of humic acid-like substances in the three-dimensional excitation-emission matrix. Furthermore, the removal of 48% of HEDP after exposure of sludge to 5.5 mM HEDP and accumulation of PO₄^3--P in the presence of 8.5–22.5 mM HEDP indicated the adsorption and biodegradation of HEDP in the sludge. Besides, the abundance of genus Desulfurispirillum remained dominant with HEDP concentration. Metagenomic assembly of genomes revealed that the denitrification under HEDP stress was accompanied by an increase in the abundance of Halomonas, containing functional genes (R = 0.97–0.98, P < 0.05). Moreover, the qRT-PCR results demonstrated the up-regulation the narG, nirK, and nosZ genes with HEDP concentration, thus suggesting their major role in the reduction of nitrate.

有机螯合污染物的共存会损害微生物的反硝化作用。但是，有关硝酸盐还原效率对此类污染物的潜在影响的信息有限。在此，选择1-羟基乙烷-（1,1-双膦酸）（HEDP）作为典型污染物，以研究其对膨胀颗粒污泥床（EGSB）反应器中生物反硝化的影响。结果表明，污泥暴露于HEDP（1.5–30 mM）后，硝酸盐被去除了99.5％〜99.9％。这是由于响应HEDP应激而增加了多余的聚合物质（EPS）的分泌，从而保护了微生物细胞。但是，随着470 mg L ^-1的累积，硝酸盐去除效率降低到55％。40 mM HEDP下的亚硝酸盐。这是由于EPS的溶解所致，正如三维激发-发射矩阵中腐殖酸样物质的出现所证明的那样。此外，在污泥暴露于5.5 mM HEDP后去除48％的HEDP以及在8.5–22.5 mM HEDP存在下PO ₄ ^3- -P积累表明污泥中HEDP的吸附和生物降解。此外，脱硫螺旋藻属的丰富度仍然与HEDP浓度有关。基因组的元基因组组装显示，HEDP胁迫下的反硝化作用伴随着含有功能基因的Halomonas的丰度增加（R = 0.97–0.98，P <0.05）。而且，qRT-PCR结果表明，HEDP浓度上调了narG，nirK和nosZ基因，从而暗示了它们在减少硝酸盐中的重要作用。