Application Research On Nitrogen And Phosphorus Removal By Polyurethane Foam-Metal Filler In Domestic Wastewater

With the eutrophication of water body in China becoming more and more severe, nitrogen and phosphorus removal has turned to be one of the important tasks in the field of wastewater treatment. Traditional nitrogen and phosphorus removal processes such as A/O, A2/O, oxidation ditch, etc. are mainly biological methods. However, most of the processes are complex, difficult to operate and high operating costs. Moreover, it’s difficult to remove nitrogen and phosphorus with high efficient simultaneously by these processes. Phosphorus removal by chemical methods with addition of flocculants increases treating costs further.In this paper, a novel filler with microporous called Polyurethane Foam-Metal Filler (PFMF) wais developed to enhance the performance of phosphorus and nitrogen removal by traditional SBR. The main contents been studied included:the combination mode of PFMF with SBR (mode A and mode B), dosage(A1g/L,A2g/L,A3g/L); influencial factors of nitrogen and phosphorus removal by PFMF-SBR; the performance of nitrogen and phosphorus removal by a long term operated PFMF-SBR reactor under optimal conditions; the effeciency of nitrogen and phosphorus removal by a0.16m3/d PFMF-SBR; the mechanisms of nitrogen and phosphorus removal by PFMF-SBR. The results showed that:(1) The performance of nitrogen removal and the degradation of organic matter of the combined reactor was much better when mode A was employed while performance of phosphorus removal was better when mode B was adopted. From the studies, the overall performance of the combined reactor of mode A was thought to be better by than that of mode B. The optimal dosage of PFMF was A3g/L.(2) The optimized operation of PFMF-SBR was achieved and the performance of pollutants removal was the highest when the operation cycle was6h, pH value was neutral or slightly alkaline, DO about2-4mg/L and the volume load was greater than or equal to1.0kgcoD/m3·d.(3) After PFMF-SBR reactor was operated continuously for a period, the average COD, ammonia, TN and TP in effluent were47mg/L,7.6mg/L,15.4mg/L and0.36mg/L, respectively. The water quality of COD, TN, TP met level A and the water quality of ammonia met level B of Discharge standard of pollutants for municipal wastewater treatment plan, respectively.(4)The average COD, ammonia, TN and TP in effluent of the0.16m3/d PFMF-SBR were24mg/L,0.90mg/L,22.0mg/L and0.5mg/L, respectively. The water quality of COD, ammonia, TP met level A and the water quality of TN met level B of Discharge standard of pollutants for municipal wastewater treatment plan, respectively.(5) PFMF-SBR was cost-efficient and feasible in the application of engineering project due to its simple structure, convenient operation, low running costs and investment saving,.(6) Under the condition of low carbon sources, the degradation rate of phosphorus had a positive correlation with COD during the operating cycle of PFMF-SBR.(7) During the arerobic uptake of phosphorus accumulation organisms, minimum TP concentrations in water was about1.5mg/L while the TP of reactor effluent was below0.5mg/L. As a result, PFMF of metal microporous material played an important role in phosphorus removal in SBR reactor.(8) Phosphorus and iron activeted sludge contained in PFMF-SBR was higher than that in normal SBR. ThereforeThus, the PFMF-SBR had a biological collaborated chemical capability of phosphorus removal.