The Treatment Of High Concentrations Of Sulfate And Organic Wastewater By Photosynthetic Bacteria

Many wastewaters contain high concentrations of sulfate and organic matter. The application of anaerobic digestion technology to the wastewaters frequently presents problems:the competition reactions between different bacteria and toxic effect of sulfide. Base on the different niche characteristics of sulfate-reducing bacteria (SRB), acidogenic bacteria (AB), photosynthetic bacteria(PSB)and methane-producing bacteria (MPB), this experiment used anaerote reactor. The effect of pH Temperature SO42-ratioel sulfate luminous flux concentration on sulfate reduction, COD removal and methanogenesis. The main conclusions of the thesis as follows:(1)We successfully select a photosynthetic bacteria (PSB), under certain conditions, which can metabolite of sulfide to sulfur. The successful selection of SRB1, SRB2 make it possibility that sulfate can be removed into sulfide to provide the substrate for the PSB. In the anaerobic reactor, there is a "SO42--S2--S0"metabolic processes. Through this processes, all the needed biological bacteria were selected.(2)The selected photosynthetic bacterium will be inoculated in reactor, mixing with AB which can remove COD, to form a manual microbial systems to research the relationship between the photosynthetic bacterium and acidogenic bacteria (AB), the microbial and the conditions of the reactor.(3)Various species in the Reactor needs suitable conditions to efficiently grow and metabolize, the experiment shows that the optimum pH is between 6.8-7.5, the best reaction temperature at 30±2℃, the luminous flux provided for the photosynthetic bacteria needed to be controlled 6001ux above.(4)The ratio of COD/SO42- is an important parameter in the reactor. Under the different ratio of COD/SO42-, the efficiency of the reactor is very different. When the ratio of COD/SO42- is 2.67, COD removal rate and SO42- reduction rates reach their high efficiency, while the majority of COD is converted by methane bacteria.(5)The presence of photosynthetic bacteria in the reaction system greatly improve the tolerance of sulfate, when the concentration is more than 4500mg/L, sulfate can significantly inhibite the system, this value is much higher than 2000mg/L--the tolerance of MPB to sulfate.