Treatment Of Anaerobically Digested Swine Wastewater By Rhodobacter Blasticus And Rhodobacter Capsulatus

Digested swine wastewater of pig farm is rich of a variety of organic and inorganic nutrients,if discharged directly without treatment or long-term application for land,it will be easy to cause the secondary pollution of soil and groundwater.Compared with conventional treatment technologies,using photosynthetic bacteria in wastewater treatment have the advantage of no secondary pollution,and the biomass resources of photosynthetic bacteria can be recovered and utilized.Two strains of photosynthetic bacteria,Rhodobacter blasticus and Rhodobacter capsulatus,were used in this work.The mixed culture of Rhodobacter blasticus and Rhodobacter capsulatus in the effect of prompting photosynthetic bacteria proliferation and the environmental factors of different energy sources,and temperature effects on photosynthetic bacteria the proliferation were also studied.The feasibility of using photosynthetic bacteria for the treatment of anaerobically digested swine wastewater and the effects of crucial factors which influence the pollutants removal efficiency were also examined.The experimental results show that the mixing ratio of R.capsulatus in composite photosynthetic bacteria liquid and R.blasticus on biogas slurry COD removal had little difference,but in the mixing conditions,the biomass yield had some changes,which mean the same consumption of COD can produce more biomass.To explore the impact of the initial concentration of wastewater on the treatment effect,found in the lower the initial concentration of wastewater by composite photosynthetic bacteria Mixed-PSB organic matter removal effect is poor,the biomass is lower,so it was more suitable for the growth of photosynthetic bacteria in the slurry concentration,does not need to waste water for dilution.The effects of initial pH on composite photosynthetic bacteria and effect of Mixed-PSB treatment of piggery biogas slurry,the photosynthetic bacteria found in neutral or alkaline conditions the highest activity,and the photosynthetic bacteria release of alkaline substances in the growth process,the final slurry processing system of pH are strongly alkaline,then through regulating pH can reflect the system.To promote the growth of bacteria reached two times.Finally the initial exploration of the competition effect of bacteria on composite photosynthetic bacteria in the Mixed-PSB wastewater treatment process will produce nutrients in photosynthetic bacteria,expand the application process,how to remove the influence of bacteria,photosynthetic bacteria to ensure the dominant position,is the direction of further study.Results showed that anaerobically digested swine wastewater could be treated effectively by photosynthetic bacteria.The treatment efficiency was significantly higher by the mixed photosynthetic bacteria than that by any unitary bacterium.The optimal treatment condition by mixed bacteria was inoculation of 10.0%(v/v)of the two bacteria by 1:1,initial pH of 7.0 and initial chemical oxygen demand of 4800 mg L-1.Under these conditions,the removal rate of chemical oxygen demand was 83.3%,which was 19.3%higher than when using R.blasticus or 10.6%higher than when using R.capsulatus separately.This mixed photosynthetic bacteria achieved high chemical oxygen demand removal and cell yields.The effects of initial pH on the treatment system found that the photosynthetic bacteria in the growth process will eventually release alkaline substances,by adjusting the reaction system of pH bacterial growth can be promoted.