Experimental Study On The Treatment Of Municipal Domestic Sewage By FBBR Based On Waste Non-woven Fabric And Coral Sand

The packing is the core of biofilm reactor.It is a hot spot to find the economical and durable packing which is easy to form membrane.Non-woven fabrics are widely used in many fields,resulting in a large amount of waste non-woven fabrics;The traditional disposal methods of waste non-woven fabrics not only waste resources,but also produce secondary pollution.As a natural seabed material,coral sand has rough surface and good microbial affinity,which can improve water quality.In this study,single waste non-woven fabric（NWF）and combined waste non-woven fabric and coral sand（NWF-CS）were used as biofilm carriers to construct single waste non-woven fabric biofilm reactor（NWF-FBBR）and combined waste non-woven fabric and coral sand biofilm reactor（NWF-CS-FBBR）;The membrane forming effect of the two fillers and the wastewater treatment effect of NWF-FBBR and NWF-CS-FBBR systems were compared;NWF-CS-FBBR,which has good membrane forming effect and effluent quality,was used to treat simulated urban domestic sewage.Single factor test and orthogonal test were carried out to explore the influence of main factors on sewage treatment effect and determine the optimal process parameters of NWF-CS-FBBR;Then,NWF-CS-FBBR was used to treat the actual urban domestic sewage,and the removal effect of pollutants in the sewage was analyzed,and the mechanism was analyzed.The main conclusions are as follows:（1）The p H value of NWF-CS-FBBR system with coral sand is higher than that of NWF-FBBR system,and can be kept in a relatively stable range,which plays a good role in promoting the membrane hanging of fillers.In stable operation,the removal rates of COD,NH₄⁺-N and TP of NWF-CS-FBBR were higher than those of NEF-FBBR;The amount of biofilm per unit mass of composite filler is higher than that of single waste non-woven fabric filler.（2）When NWF-CS-FBBR was used to treat simulated municipal wastewater,HRT,DO,influent cod,coral sand additive amount and filling rate all had certain effects on the removal efficiency of COD,NH₄⁺-N and TP.The results of orthogonal test showed that the best combination of conditions for COD treatment by NWF-CS-FBBR system was HRT 8h,DO3.0mg/l,filling rate 4g/L and coral sand additive amount 12.5g.The best combination of NH₄⁺-N treatment conditions of NWF-CS-FBBR system is:HRT 10h,DO 3.0mg/l,filling rate 5g/L,coral sand additive amount 17.5g.The results showed that the optimal conditions for TP treatment by NWF-CS-FBBR system were HRT 8h,DO 3.0mg/l,filling rate 6g/L and coral sand additive amount 17.5g.（3）When the NWF-CS-FBBR was used to treat the actual urban domestic sewage,the removal rate of COD,NH₄⁺-N and TP was about 88.1%,68.4%and 59.3%respectively,and the system had strong anti shock load capacity.（4）The mechanism analysis shows that the composite fillers of coral sand and waste non-woven fabrics have good hydrophilic properties,and the surface has hydrophilic groups such as aldehyde group,carboxyl group,hydroxyl group and ketoaldehyde group,which is conducive to the adhesion and biofilm formation of microorganisms;The dehydrogenase activity of microorganism on the surface of the composite packing was 49.91 TFμg/g biofilm·h,significantly higher than that of single waste non-woven fabric filler;Compared with the single waste non-woven fabric filler,the biofilm forming time and renewal cycle of the composite filler are shorter,which indicates that the additive amount of coral sand can improve the growth environment of microorganisms and is conducive to the growth and reproduction of microorganisms.In this study,daily necessities non-woven fabrics and natural material coral sand were selected as biofilm fillers to make FBBR,which was used for urban domestic sewage treatment.It not only effectively treated urban domestic sewage,solved the treatment and disposal of waste non-woven fabrics,but also solved the treatment and disposal of inactive coral,and improved the economy of biofilm reactor fillers FBBR has great promotion value.