Pilot plant investigation on the start-up of a USAB reactor using sugar mill effluent

The existing pollution in the environmental system is adversely deteriorated by the disposal of untreated domestic and industrial effluent. Moreover, in developing countries, the current and emerging energy crises compel to work out the treatment technologies that should not only reduce the pollution load but could also be able to assist in solving the energy problems. The anaerobic digestion process not only reduces the high strength pollution load but it also converts the wastes into biogas. Since in Pakistan, some sugary mills are discharging their organic-rich wastes without any proper treatment or utilization, therefore, using actual sugar mill effluent at constant pH and temperature this study was designed to evaluate and study the start-up of the UASB reactor. It was noticed during the study that at an organic loading rate of 2.1 kg-COD/m3-day and a hydraulic retention time of 16 hours, more than 70% of COD could be reduced. It was observed that in terms of COD decreasing the longer retention time appears to be more encouraging and vice-versa. The average VFAs 340 mg/L and biogas generation 0.30 L/g-CODrem-d was observed, respectively. an‎d 58-59% composition of methane was found there. The results of this study insinuate that to reduce the pollution load of sugar mills outflow, the use of the UASB reactor at neutral pH and mesophilic range of temperature is a quite achievable and viable option.