复合自养反硝化材料处理低碳氮比硝酸盐污水

作为一种典型的硝酸盐污水,低碳氮比硝酸盐污水的存在具有广泛性,且对生态环境和居民健康带来的危害日益突出。本研究构建了复合硫自养反硝化(CSAD)体系,基于硫-碳酸钙型复合材料与微生物,进行低碳氮比硝酸盐污水的深度处理,分析了材料投加量、粒径以及进水硝酸盐浓度对CSAD的影响,并探究了硝酸盐去除的动力学行为。结果表明,体系中NO₃^--N去除率为52.7%—99.9%,NO₂^--N在NO₃^--N浓度降低至5 mg·L^-1左右时由积累转变为迅速下降;复合材料投加量较低(1 g·L^-1)时,自养阶段体系内电子供体数量不能满足微生物反硝化需求;增大投加量可提高NO₃^--N去除速率并降低反应过程中NO₂^--N积累量。当粒径大于2.5 mm时,复合材料利用效率显著降低。Michaelis-Menten方程拟合表明,投加量增大提高了酶与底物亲和力,促进V_max增大,粒径减小增大了亲和力,但V_max却减小。进水NO₃^--N浓度增大至50 mg·L^-1时,亲和力显著降低,但V_max增大可能与微生物数量增多有关。本研究从动力学角度上揭示了不同工艺参数对复合材料反硝化过程的影响,同时也为基于复合自养反硝化材料的低碳氮比污水深度处理的实际工程应用提供参考。

Research on the treatment of low C/N ratio nitrate sewage by composite autotrophic denitrification material

As a typical nitrate sewage,the existence of low C/N nitrate sewage is widespread and the harm to ecological environment and residents'health is becoming increasingly prominent.In this study,we constructed a composite sulfur autotrophic denitrification(CSAD)system based on sulfur-calcium carbonate composite material and microorganism for the advanced treatment of nitrate sewage with low C/N.The effects of material dosage,particle size and influent nitrate concentration on CSAD were analyzed,and the kinetic behavior of nitrate removal was explored.The results showed that the NO₃^--N removal rate of CSAD was between 52.7%and 99.9%,and NO₂^--N changed from accumulation to rapid decrease when NO₃^--N concentration decreased to around 5 mg·L^-1.When the dosage of composite material was low(1 g·L^-1),the number of electron donors in the autotrophic system can not meet the demand of microbial denitrification.Increasing the dosage of composite materials can increase the NO₃^--N removal rate and reduce the NO₂^--N accumulation in the process.The utilization efficiency of the composite materials decreased significantly when the particle size was larger than 2.5 mm.The fitting of the Michaelis-Menten equation showed that the increase in dosage increased the affinity of the enzyme and the substrate,thus it promoted the increase of V_max.The decrease of particle size enhanced the affinity,but the V_max decreased.When the influent NO₃^--N concentration increased to 50 mg·L^-1,the affinity decreased significantly.However,the increase of V_max may be related to the increase in the number of microorganisms.This study revealed the influence of different composite materials parameters on the denitrification process from the perspective of dynamics,and also provided a reference for the practical engineering application of advanced treatment of low C/N sewage based on composite autotrophic denitrification materials.