Assessment of the effectiveness of a solar system heating an anaerobic bioreactor

The performance of a solar system designed to heat a packed bed reactor for anaerobic treatment of municipal wastewater was evaluated, and the feasibility of employing low-scale solar reactors in small settlements or enterprises was investigated. An energy balance was performed using a simple reactor model previously proposed byYiannopoulos et al. (Bioresource Technology 99:7742-7749, 2008) to estimate the size of a solar system in Patras, Greece. The main objective is to feed the reactor with warm water produced by solar energy and achieve an increase of temperature close to 35°C for the majority of the year. Model simulations indicated that the heat demand of the reactor could be balanced practically by a number of flat plate solar collectors supplying warm water at above 20°C for over 95% of the year. Therefore, the proposed system can offer a viable alternative to enhancing anaerobic treatment in wastewater facilities.