Study On The Low Strength Municipal Wastewater And Semi-artificial Greywater Treatment Of IMBBR And BAF

Based on the new concept of "Semi-centralized Treatment System", In this study, IMBBR (Integrated Moving Bed Biofilm Reactor) and BAF(BiologicaI Aerated Filter)were used as greywater treatment technology in the system, and firstly experiments were designed to investigate the removal efficiency and the optimization of process parameters when treating the municipal wastewater of low COD_Cr and high NH₃-N; secondly, pilot experiments were fulfilled to observe the feasibility of main comtaminants removal efficiencies of IMBBR and BAF when treating the semi- artificial greywater by adding LAS to the municipal wastewater; Finally, the technical and economical evaluation of two technologies were finished when treating greywater.It is showed that, to meet the Urban Reused Water Standard, when treating low strength municipal wastewater, the suitable parameters of IMBBR are: HRT=3-4h, DO is 4mg/L, the backwashing cycle of suspended carrier separating is 10d; and the suitable parameters of BAF are: specific surface loading rate is 3.1-3.8m³/m².h, DO is about 4mg/L, backwashing cycle of BAF is 24h without any pretreatment of influent., under the optimal situation, both two technologies had good removal efficiency of COD,NH₃-N,LAS,SS,Turbidity of semiartificial greywater, and the quality of the effluent can next to the Urban Reused Water Standard.Then in order to calculate the investment and operation costs for IMBBR and BAF, the two technologies were applied in the greywater treatment in Semi-centralized system under their optimal situations, and the influent is 3000m³/d. The investment for the two technologies were 1539 yuan/(m³ .d^-1 )and 1472 yuan/(m³.d^-1) respectively, and the operation cost were 0.587 yuan/m³å’Œ0.618 yuan/m³ respectivly. Results showed that IMBBR and BAF both had low costs and short recycle time.Finally, it was concluded that IMBBR and BAF were both suitable for the greywater treatment in Semi-Centralized system technically and economically. IMBBR has long cycles, good effluent quality, and just needs simple operation and management; and BAF has high surface loads, low occupation, good effluent quality,but needs frequent backwash.