Efficiency Of The SBR-microalgae Bioreactor For The Treatment Of Domestic Sewage

Eutrophication is the main manifestation of polluted water in China.The eutrophication is related to the discharge of sewage.The effluent of sewage treatment plant is discharged into the natural water body.The removal of nitrogen and phosphorus in the existing sewage treatment process is based on the concentration standard required by the first class A in the current sewage discharge standard,but the treatment efficiency is still not enough.The concentration of nitrogen and phosphorus in the effluent can still cause the eutrophication of the receiving water.Therefore,in order to alleviate the eutrophication,we need to further reduce the concentration of nitrogen and phosphorus in the effluent of the sewage treatment plant.In this paper,the traditional SBR reactor and microalgae bioreactor are combined to treat sewage,in order to develop an economic wastewater treatment process with high removal efficiency of nitrogen,phosphorus in sewage.This paper mainly studied the effects of algae species,residual bacteria,insoluble substances in influent and the algal culture conditions on the treatment effect of microalgae bioreactor.The experimental result indicated that the effect of Chlorella vulgaris on the treatment of SBR secondary effluent is the best.The residual bacteria and insoluble substances in SBR effluent had no obvious effects on algae growth and water purification.The microalgae bioreactor with Chlorella vulgaris had the best effect on the treatment of unpretreated secondary effluent,when the environment temperature is 30?,light intensity is 4000 lux,light /dark ratio is14h:10h.The effect of SBR operation mode on water quality of series system is studied.The results showed that the different running time of SBR will cause different effluent quality.When the SBR reactor operated in the mode of "instantaneous influentanaerobic reaction 2h-aerobic reaction 2h+50min-anoxic reaction 2h-aerobic reaction 10min-precipitation 1h-drainage 20min-idle 4min",the secondary effluent was best treated with the microalgae bioreactor that uses Chlorella vulgaris as the functional algal species.The effects of microalgae bioreactor treated sewage under different hydraulic retention time of SBR secondary effluent was investigated.The treatment effect of SBR-microalgae bioreactor was negatively correlated with the hydraulic retention time of SBR secondary effluent in the microalgae reactor.When the hydraulic retention time is 2 days and the algae density in the microalgae reactor is 9.33×106 per/m L,the best effluent quality are obtained.This paper studied the effectiveness of bacteria-microalgae tandem bioreactor treating domestic sewage.The SBR-microalgae bioreactor operated at the optimal operating point was very effective in treating domestic sewage.The concentration of COD in the effluent is 6~8.5mg/L,TP concentration is 0.10~0.15mg/L,ammonia nitrogen is 1.4~3.0mg/L,nitrate nitrogen is 3.5~4.5mg/L,TN is 6.0~8.5 mg/L.They are far below the concentration required by the first grade A standards,which greatly reduces the adverse effects of treated water on natural water.