Study On The Simultaneous Nitrogen And Phosphorus Removal And Removal Of Phthalate Esters By Three-dimensional Biofilm-electrode Coupled With Iron/Sulfur Reactor

Urban reclaimed water is widely used as urban miscellaneous water, landscape water, industrial cooling water and so on with the increasing of water resources crisis. Due to the technical limitations of sewage treatment, the traditional process often cannot guarantee good removal effect of nitrogen and phosphorus, total nitrogen and total phosphorus in a partial of reclaimed water in are not stable to the "urban wastewater reclamation and reuse of landscape and environmental water quality " requirements,TN?15mg/L,TP?0.5mg/L.At the same time, the vast majority of China’s urban sewage treatment plants do not have a clear requirement for endocrine disrupting substances, which makes the water contains a higher phthalate esters. Phthalate esters were found t in the tail water of water plants in our country. Therefore, a new process to achieve simultaneous nitrogen and phosphorus removal and the removal of phthalate esters is necessary to be found.To realize deep nitrogen and phosphorus removal in tail water of low C/N, Three-dimensional biofilm-electrode and iron/sulfur autotrophic system, which is added a certain proportion of iron and sulfur particles in 3DBER,forming "heterotrophic+hydrogen autotrophic+ sulfur autotrophic + micro electro coagulation" simultaneous denitrification and phosphorus removal system.Nitrogen and phosphorus can be highly removed and it can also achieve a effective PAEs treatment in this system with physical adsorption of the filler, electrochemical action of the current and the biological degradation of the biofilm. The removal of nitrogen and phosphorus and PAEs was studied in the condition of low C/N wastewater.Firstly, a DSPE pretreatment method was established, the various conditions which affect the extraction efficiency were optimized and the optimum extraction conditions were determined; secondly, the operating characteristics of 3DBER-S-Fe were studied at different HRT, current intensity, C/N ratio and the inlet concentration of PAEs; the composition of microorganism in the system were analysied by miseq technology, finally, the removal mechanism of nitrogen and phosphorus and PAEs in 3DBER-S-Fe reactor was analyzed. The Mechanism of nitrogen and phosphorus and PAEs removal were analyzed from the view of macro operation and microorganism in this study, which provided a reference for the actual operation of wastewater treatment plant.3DBER-S-Fe have a better removal capacity of nitrogen and phosphorus and PAEs removal under different conditions, DBP removal rate was 97%, DEHP was 84%, NO3--N was 98% and TN was 83% and the phosphorus was 70% in the condition of C/N(TOC/TN) = 0.4, ρ(DBP, DEHP) = 500 μg / L, HRT = 6h, I = 300 m A. A variety of denitrifying bacteria existed in 3DBER-S-Fe system and the Thiobacilluswere the predominant bacteria, other kinds bacteria of phosphorus removal and microbial degradation were also found by miseq technology.The special filling material and structure of 3DBER-S-Fe reactor makes it able to deeply remove nitrogen, phosphorus and PAEs. Heterotrophic denitrification, sulfur autotrophic denitrification, hydrogen autotrophic anti nitrification and iron autotrophic denitrification exists in this system. Denitrification was strengthened by sulfur autotrophic denitrification process in which electron donor was provided by elemental sulfur.Sponge iron filled in 3DBER-S-Fe system can produce more H2 and provides electron donor for iron autotrophic denitrification, phosphorus can also be removed in the process of flocculation and sedimentation which were caused by of iron dissolution.PAEs can be adsorbed by the large number of activated carbon and degraded by microorganisms in 3DBER-S-Fe system. Combined with physical adsorption of the filler, electrochemical action of the current and biological degradation of the biofilm, 3DBER-S-Fe reactor can remove the PAEs pollution at the same time with the high efficiency of nitrogen and phosphorus removal.This study has a important significance for promoting the process of sewage resources, improving the situation of high nitrogen and phosphorus and PAEs in the sewage treatment plant, and improving the quality of reclaimed water.