RESUMEN
Phase separation characteristics of anaerobic baffled reactor (ABR) treating organic wastewater containing sulphate were investigated in a 5-compartment ABR with an effective volume of 32 L. During a start-up experiments of 132 days, the chemical oxygen demand (COD) and sulphate (SO4(2-)) removal efficiency, volatile fatty acid (VFA) and sulfide (S2-) distribution in each compartment were measured. The microbiology communities of granular sludge were also investigated by scanning electronic microscope (SEM). The experimental results showed that low influent loading and low increase are the keys to start-up of ABR. The volumetric loading rates of COD and SO4(2-) increased stage and stage from 1.5 kg x (m3 x d)(-1) to 3.3 kg x (m3 x d)(-1) and from 0.07 kg x (m3 x d)(-1) to 0.18 kg x (m3 x d)(-1) for 132d, and achieved a stable state that resulted in 95% COD and 85% SO4(2-) removal. COD had the trend of decreasing with compartments along flow direction, it's removal rate in compartment 1, 4 and 5 took the large proportion in total COD removal rate, and sulphate removal rate in the initial three compartments took the large proportions in the total sulphate removal rate. The VFA and S2- concentrations were high in the initial three compartments and obviously declined in the final two compartments. With the loading rate increase, the proportion of COD and SO4(2-) removal rates in the final room increased, the highest and the lowest point of VFA and S2- concentrations were gradually moved to hind room. The SEM observation indicated microbiology communities of granular sludge in each compartment were cooperative and specific, it showed that the acidogenic phase and methanogenic phase, sulfate-reducing phase and sulfur-producing phase were separated in the ABR.