Study On Treatment Of High Chlorine Wastewater In Polysilicon Production

In recent years,new energy and new materials industrial parks have gathered,and industrial wastewater treatment in the park has become a problem of concern.Polycrystalline silicon is the main raw material for the production of solar photovoltaic cells.In the production process,a large amount of high-salt and high-acid wastewater,especially high chloride ion content will be generated,which will affect the use of enterprise equipment and inhibit subsequent biological treatment.Excessive emissions will also cause bad influence of ecological environment.In this study,the traditional activated sludge method was used to cultivate domesticated salt-tolerant sludge.The organic matter and ammonia nitrogen in the polysilicon wastewater achieved good removal effect.With the increase of salinity,the removal rate and degradation rate of organic matter and ammonia nitrogen are inhibited,and the nitrification of sludge is inhibited.The inhibition is more obvious.Mud has limited tolerance to salinity shocks and requires regular monitoring of the effects of salinity shock on biological treatment.Operating at 25-30?,pH 6-8 and suitable load is conducive to the efficient removal of pollutants in the reaction system,and the sludge has limited tolerance to salinity shocks.It is necessary to monitor and pay attention to the impact of salinity shocks on biological treatment regularly.At the same time,through microscopic microscopy and high-throughput sequencing,it is observed that the sedimentation performance of the sludge acclimation is enhanced,thefloc structure is smaller,the bacterial gum mass is tighter,and the salinity is increased,so that the microbial species in the sludge are reduced,and the protozoa are tired.Branches and insects showed stronger adaptability,and the diversity index decreased.The decrease in the abundance of dominant bacteria such as Proteobacteria and Bacteroidetes in sewage treatment indicates that acclimated sludge requires a long reaction time to achieve the same removal rate.The decrease in the abundance of the main flora of the sludge,which is caused by the expansion of the sludge,further confirms that the increase in salinity reduces the filamentous bacteria in the sludge and the possibility of sludge swelling decreases.Compared with the inoculated sludge,the acclimation of the sludge in a high salt environment enriched a certain proportion of salt-tolerant and halophilic bacteria,and the microbial community structure changed.Considering that the salt tolerance of domesticated sludge is limited,and the effluent still contains excessive amounts of chloride ions after biological treatment,the chloride ion can be removed by the ultra-high lime aluminum method,which can be combined with biological treatment to better treat polysilicon wastewater.The removal rate of chloride ions increases with the increase of initial chloride ion concentration.The experimental results showed that the optimal dosage parameters were Ca²⁺:Al³⁺:Cl^—,the ratio was 10:4:1,and the drug was added in two wet methods at 0.4:0.6.The chloride ion removal rate is up to 90.5%.The above research results provide certain technical support for the treatment of polysilicon industrial wastewater,which has important practical significance.