Performance evaluation of anaerobic baffled reactor (ABR) treating pulp and paper wastewater in start-up period

Abstract

This essay outlines the use of an anaerobic baffled reactor (ABR) treating pulp and paper wastewater during its start-up period. For this purpose, a pilot with four chambers and overall volume of 45 liters was fed continuously through the equalization tank of Mazandaran wood and paper wastewater treatment plant, in the north of Iran. The influent was classified as low strength slowly biodegradable wastewater. The average soluble chemical oxygen demand (SCOD) and biochemical oxygen demand (BOD) of the influent were about 1,130 and 320 mg/L, respectively. Results show that the start-up was accomplished in 90 days in which the ABR reached its maximum SCOD removal of 60%. This was achieved at the controlled mesophilic temperature (37 °C) and optimum hydraulic retention time (HRT) of 24 hours. In spite of the influent characteristics, the performance of ABR has not been inhibited and mostly influenced by HRT. The gradual hydrolysis and acidogenesis were observed within the ABR. The majority of chemical oxygen demand (COD) removal takes place in the first chamber. In addition, the concentrations of readily biodegradable organics (BOD to COD ratio) have been increased and doubled through the reactor. Moreover, the total values of pH, volatile fatty acids and alkalinity remained constant. Consequently, this system can be approved for application as a pretreatment unit for paper mill industrial wastewater treatment plants.