Study On Phosphorus Occurrence Forms And Phosphorus Removal Mechanism In Moving Bed Biofilm Reactor

As a biofilm treatment process,the moving bed biofilm reactor(MBBR)has many advantages compared with the traditional activated sludge process,such as small head loss,strong impact load,and wide application,so it has attracted much attention.The MBBR system can effectively remove organic pollutants and remove nitrogen and also hasa certain effect on phosphorus removal,but its phosphorus removal effect is unstable and the phosphorus removal mechanism is unclear.Therefore,this topic mainly uses MBBR reactors to treat municipal wastewater and explores the ratio of carbon to phosphorus.C/P and the effect of carbon source type changes on the phosphorus removal performance of the system and the occurrence and content of phosphorus.At the same time,combining microbial metabolism characteristics and community structure and other microscopic perspectives,the mechanism of phosphorus removal in the reactor is forther clarified,which is a moving bed The biofilm reactor provides a reference basis and theoretical analysis for improving the phosphorus removal effect in actual sewage treatment applications.More about this source textSource text required for additional translation information The main findings are as follows:(1)When C/P is 109,MBBR has the best removal effect on TP and PO43-in sewage,and the treatment efficiency is 72.4%and 69.0%,respectively.With the increase of C/P,the content of TP in biofilm and suspended sludge gradually increases,and The phosphorus content of various forms in the biofilm is higher than that of suspended sludge.Inorganic phosphorus(IP)in sludge flocs is the main form of phosphorus.IP accounts for 75.4%～92.7%of TP content,and non-apatite inorganic phosphorus(NAIP)content is 6.62～12.60 mg/g,accounting for 44.9%～65.7%of TP.(2)The system with sodium propionate as a carbon source has the best removal effect on pollutants in sewage.The removal rates of COD,ammonia nitrogen,TP and PO43-are 91.4%,88.5%,74.1%and 72.1%,respectively.In addition to organic phosphorus(OP)In addition,the sludge is the highest.Among them,NAIP accounts for about 52.2%～60.8%of TP in biofilm,and about 50.7%～59.3%of TP in suspended sludge,AP is not affected by changes in carbon source types.(3)The distribution ratio of phosphorus in biofilm and suspended sludge in the three EPS structures varies with C/P and carbon source types.The higher the content of protein(PN)and polysaccharides(PS)in EPS,the more phosphorus is saved.The stronger the ability.The higher the C/P,the more glycogen synthesized by microorganisms,the better the phosphorus removal effect,while PHA has little change.When sodium propionate and starch are used as carbon sources,the absorption and release of phosphorus in sewage are obvious.PHA and glycogen are accumulated and degraded in all three reactors,and PHA has priority over glycogen decomposition.(4)C/P and carbon source types have significant effects on the bacterial community structure in the biofilm.The bacterial phyla with higher relative abundance are:Proteobacteria,Actinobacteria,Bacteroides,Patescibacteria,Verrucomicrobia,Thick-walled For bacteria,the higher the phosphorus treatment efficiency,the greater the relative abundance of actinomycetes in the system.