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

The treatment technologies, such as the anaerobic digestion process, have been used in many developing countries that should not only reduce the pollution load but could also be able to assist in solving the energy problems (biogas production). With respect to several sugary mills in Pakistan with discharging organic-rich wastes without any proper treatment, this study evaluated the start-up of the UASB reactor using actual sugar mill effluent at constant pH and temperature. The results showed at an organic loading rate of 2.1 kgCOD/m3/day and a hydraulic retention time of 16 h, more than 70% of COD could be reduced. It also showed that in terms of COD decreasing, the longer retention time appeared to be more encouraging and vice-versa. The average VFAs and biogas generation was measured 340 mg/L and 0.30 L/gCOD/day, respectively (58-59% composition of methane was found there). According to the results, 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.