Study On Microbial Remediation Of Typical Nitrogen-containing Organic Matter-vanadate Combined Polluted Groundwater

With the rapid development of economy,an increasing amount of toxic substances produced by production and living activities enter the groundwater environment,resulting the aquifer pollution include organic and heavy metal contamination.In situ bioremediation is an attracting method due to its characters of simplicity,environmentally friendly and economy among such technologies.Co-metabolism and appropriate electrical stimulation can promote the efficient and synergistic removal of organic pollutants and heavy metals by microorganisms.In this study,aiming at the combined pollution of nitrogen-containing organic matter and heavy metal vanadate[V(V)],the removal of nitrogen-containing organic matter and V(V)in groundwater was studied by microbial method.First,the performance of polyculture microorganisms to remove pyridine(Pyr)and V(V)was studied.Different co-substrate carbon sources are preferred for the removal of Pyr and V(V).The results show that the removal rate of Pyr and V(V)in 72 h was higher than other co-substrate carbon sources with glucose as the co-substrate material,so glucose was selected as the best co-matrix substrate.After 72 h of continuous operation,the total organic carbon concentration in the Pyr-V system showed a downward trend,and Pyr was degraded to produce NH₄⁺-N.The removal rates of total vanadium in Pyr-V,Pyr-V-G and V-G were 59.6±0.49%,94.1±0.11%and 98.9±0.17%,respectively.The reduction product of V(V)was V(IV),Bacillus and Pseudomonas could realize Pyr oxidation coupled vanadate reduction.Secondly,we explored different voltage stimulations to enhance the removal of nitrobenzene(NB)and V(V)by microorganisms.The study found that under the stimulation of0.6 V voltage,the removal rate of NB and V(V)in 48 h was higher than that of reactors with other voltages,so 0.6 V was chosen as the best voltage.After the end of the experiment,the reaction products were characterized and analyzed.NB was reduced to AN at the cathode and further mineralized at the anode.V(V)was reduced to V(IV).Methanosarcina and Clostridium were the main functional microorganisms of the anode and cathode.In this study,under anaerobic conditions,the synergistic removal of Pyr,NB and V(V)was realized by using mixed microbial remediation and electrical stimulation to strengthen microorganisms,which provided unique research ideas and insights for the synergistic treatment of the co-exit of nitrogen-containing organic matter and heavy metals.