Study On The Treatment Of Municipal Wastewater Using Sequencing Batch Biofilm Reactor With Luffa Cylindrical Sponge As Fillers

The speed of urbanization development in our country became faster and faster,the discharge of municipal wastewater increased substantially.The treatment of municipal wastewater was becoming an important point of achieving energy conservation and emissions reduction targets.For the problem of SBBR process in filler selection and operation condition optimization,SBBR process which had simple structure and could simultaneously remove nitrogen and phosphorus was applied in this study,the treatment effect of municipal wastewater under different conditions was discussed to provided a more comprehensive theoretical basis for the practical application of SBBR process.Municipal wastewater was the research object and two identical SBBR reactors were built.The start-up effect of two SBBR systems were studied by pilot test which added polypropylene fillers and luffa cylindrical sponge fillers respectively,and then chose a better filler.The operation condition of SBBR with luffa cylindrical sponge fillers on ananerbic/aerobic conditions was determined.The influence of four factors on the treatment effect was discussed,these factors included temperature,influent C/P,influent ammonia nitrogen concentration and elements released by luffa cylindrical sponge.The influence of different water intake modes on nitrogen and phosphorus removal was compared.The start-up speed and biofilm culturing effect in 2#SBBR with luffa cylindrical sponge fillers were better than that in 1#SBBR with polypropylene fillers.The removal rate of COD,TP,TN during starting period was 86.38%,81.72%and 79.15%,respectively.It proved that natural dense mesh structure and hydrophily property of luffa cylindrical sponge could provide suitable growing environment for microorganisms.Luffa cylindrical sponge was chosen as the test fillers.Taking an overall consideration of the removal effect of COD,TP,ammonia nitrogen,the operation condition was determined:water intake 10min→anaerobic phase 2.5h→aerobic phase 6h→precipitation 45min→drainage phase 20min→idle time 135min.The aeration rate was set as 120L/h.Sludge discharge took 12 days.After studying the influence of temperature,influent C/P,influent ammonia nitrogen and release elements of luffa cylindrical sponge on treatment effect of SBBR system,the results showed that the temperature change of system had influence on microganisms growth and the nitrogen,phosphorus removal reaction.When temperature was between 20℃ and 30℃,SBBR system reached good treatment effect;The change of TP removal rate had positive correlation with the increased influent C/P,y=81.5 73 x0.0656,R2=0.9612.A large number of free ammonia nitrogen inhibited the activity of nitrifying bacteria and denitrifying bacteria and affected the nitrogen removal effect.A small quantity of nitrogen and phosphorus released by luffa cylindrical sponge had little influence on the treatment effect.The property of gradually releasing COD made luffa cylindrical sponge a solid slow release carbon source.On the optimal conditions:25 ℃,influent C/P in 40.79～61.40,influent ammonia nitrogen concentration in 10.80～59.52mg/L,when SBBR system was stably operating,the average removal rate of COD,TP,TN was 91.81%,91.04%,80.37%,respectively.The effluent concentration of COD,ammonia nitrogen could stably achieve national level A discharge standard,the effluent concentration of TN,TP could not stably achieve national level A discharge standard.It was found that the disperse water intake mode could improve nitrogen removal performance.The TN removal rate under two stages and three stages water intake mode were 3.57%and 8.40%higher than it under one stage water intake mode.The effluent TN concentration stably reached the national level A discharge standard.Due to the simultaneous nitrogen and phosphorus removal in SBBR system and limited organic carbon source,the phosphorus removal efficiency was reduced.The removal efficiency of COD had no obvious change.Natural dense mesh structure and hydrophily property of luffa cylindrical sponge could improve the biofilm attachment effect.The optimal operation conditions could improve the treatment effect of SBBR system.The disperse water intake mode improved the nitrogen removal performance.SBBR treatment with luffa cylindrical sponge fillers had broad application prospect in municipal wastewater treatment.