LAUSR

Abstract Anaerobic sewage treatment has been proposed as sustainable sanitation technology with the potential to be energy positive. However, there are very few works dealing with anaerobic degradability (i.e. biomethane potential – BMP) of sewage. Until now, no authors systematically studied anaerobic psychrophilic degradation of sewage in sufficient detail, i.e. in batch experiments. In this study, six sewage samples of various origin and quality were tested via BMP experiments with three different samples of inoculum (both adapted and non-adapted), to elucidate the principle kinetics and obtain fundamental engineering data. The anaerobic biodegradability of sewage at 15 °C varied from 50 to 75%, with the average methane yield 0.22 ± 0.03 m3 kg−1 (CH4, CODadded). According to Monod-based calculations, all sewage samples behaved as two component substrate, while no correlation of biodegradability with different raw sewage quality was observed. The same rate constant (rmax) was found for all tested sewage samples. But, rmax was greatly dependent on inoculum source. This study provides a fundamental dataset to understand and predict psychrophilic anaerobic sewage utilization. With this knowledge, novel wastewater treatment plant layouts can be designed even in mild/cold climates as well as already existing facilities intensified in terms of energy optimization and recovery.