Anaerobic domestic wastewater treatment with bamboo carrier anaerobic baffled reactor

The carrier anaerobic baffled reactor (CABR) was developed to treat sewage at 28 ± 1 °C. The performance during start-up, mechanism of pollutant removal and its potential to remove pathogenic microorganisms were investigated. The success of start-up was indicated by total chemical oxygen demand (TCOD), removal efficiency and the varying pH curve and/or alkalinity along the on site flow measurement. The TCOD removal efficiency decreased from 79% at a hydraulic retention time (HRT) of 48 h to 69% at 18 h due to washed-out biomass while soluble chemical oxygen demand (SCOD) removal efficiency was nearly constant. The total nitrogen to total phosphorus removal ratio that ranged from 3.5 to 6.5 in CABR was less than the average nitrogen to phosphorus ratio in living cells (5–7) due to partial phosphorus adsorption by biomass. About 63% of substrate was used for cell synthesis during the start-up phase, whereas only 20% substrate was consumed during the steady state operation. The reactor had certain effect on the removal of pathogenic species, but it was necessary to adopt appropriate post-disinfection measures to guarantee the effluent safety. CABR is a suitable technology for decentralized domestic sewage treatment from rural areas of China.