Treatment Of Acid Wastewater Containing Heavy Metal With Sulfate Reducing Bacteria And Fe～0

Acid wastewater containing heavy metal is a kind of industrial wastewater,which can induce the most serious environment pollution and do great harm to humanbeings. It is a new technique to treat this kind of wastewater with microbialmetabolism and sulfur cycle principle. In order to intensify the metabolism activitiesof microorganism in wastewater and improve the treatment efficiency, the followingworks have been done in this research. Function and mechanism of different factorson the reaction have been analyzed by comparing the reaction effects of SRB andSRB+Fe~0 system. Intensified function and mechanism of Fe~0 on biological sulfatereducing metabolism and the removing of the heavy metal have been studied onemphasis. On this basis, the treatment effect of mining drainage in SRB+Fe~0 systemwas researched.Firstly, the effect of temperature, pH and substrate concentration on SRBreducing metabolism and intensify function of Fe~0 under different conditions werestudied by intermittent experiments. It is shown that Fe~0 has functions of reducingactivation energy of reaction, enhancing the endurance capability of system to lowtemperature and eliminating the infection of pH variety on sulfate reducing rate, andintensifying the metabolism capability of microorganism under acidity condition. Inaddition, Fe~0 can enhance the appetency of bacteria with substrate by adjusting theactivity of enzymes. Substrate dosage needed in SRB+Fe~0 system is 75% that of SRBsystem under the same treatment capability. On this basis, sulfate reducing kinetics ofSRB and SRB+Fe~0 system were studied, and a series of experiential equations ofsulfate reducing rate were deduced.Secondly, toxicity of heavy metal on SRB metabolism, removing mechanism ofheavy metal and intensified function of Fe~0 in process were studied. Mathematicsmodel describing the relationship of metal concentration with sulfate reducing rateand reducing percent was proposed, in which toxicity coefficientβand metalconcentration Ic that restraining 50% metabolism activities were included as criterionsto evaluate the inhibition of metal to SRB activities. Toxicity order of different metalions is Cr6+>Cu2+>Mn+>Mn2+>Zn2+and toxicity of mixing metal is greater thansum of respective action effect of all metals. Removing mechanism and mode ofdifferent metals were specified. Mechanisms of Fe0 eliminating the toxicity andenhancing the removing effect of heavy metal were studied on emphasis.Lastly, treatment performance of acid wastewater containing heavy metal byup-flow multiple bed bioreactor was studied. It is shown that the toxicity of heavymetal in continuous reactor is weakened greatly and metal concentration standed bycontinuous reactor is 2~6 times that of intermittent reactor under the same treatmentcapability. Acid mining drainage is perfectly treated in SRB+Fe0 system under 25℃.Sulfate reducing percent is 61%, pH rises from 2.75 to 6.20 and concentrate of Cu2+drops to 0.2mg?L-1,which achieve the wastewater discharge standard. The removingof Mn2+ is not satisfied with removing percent is only 53%.