Study On The Treatment Of Low Strength Wastewater Using Anaerobic Baffled Reactor

This thesis mainly studied the performance of two anaerobic baffled reactors(ABR, NO.A and NO.B) treating low strength wastewater(<2000mgCOD/L) under different conditions of influent COD, hydraulic retention time(HRT), temperature and alkalinity. Systemly measured COD, VFA, pH and alkalinity of effluent and each compartment, calculated COD removal rate and volume loading and hydraulic loading, studied the running rule of ABR and its compartmenrts.The study results of this thesis indicated:(1) NO.A anaerobic baffled reactor was used to treat low strength synthetic wastewater at normal temperature (17℃~25℃). Under the conditions of 24h HRT and influent COD of about 500mg/L～1500mg/L, COD removals was more than 87%. When the HRT was reduced to 12 h and 8 h with influent COD of about 500mg/L, all HRTs tested resulted in more than 83% COD removal.The sludge characteristics such as sludge concentration, particle size distribution and specific methanogenic activity showed that the sludge in the last compartment was more sensitive to the low strength than the other three compartments.The microbial composition of anaerobic granular sludge in each compartment was observed by using scanning electron microscope. The results indicated that Methanococcus was predominant in interior of granular sludge in compartment 1. As for compartment 2, there were no absolutely predominant bacteria. In interior of granular sludge of compartment 3 and 4, Methanothrix soehngenii were predominant.(2) While the experiment that described above carried out, NO.B anaerobic baffled reactor was used to treat low strength synthetic wastewater but the temperature was about 35℃. Under the conditions of 24h HRT and influent COD of about 500mg/L～1500mg/L, COD removal was 88%. Compared the results achieved at normal temperature with that achieved at mesophilic temperature , we can conclude that ABR have potential advantage when treating low strength wastewater at normal temperature because of heating substantially increase the costs of treating low...