A combined anaerobic-aerobic system to treat domestic sewage in coastal areas

This article presents the results for the treatment of raw sewage in an anaerobic-aerobic system at pilot plant level. Experiments were carried out in summer and winter, with different loads and temperatures (19°C and 12°C) to evaluate the potential of this system to be used in touristic-coastal areas. Results show that removal efficiencies are similar in both seasons because temperature balances the excess of the summer load. However, the overall yield coefficient for sludge production is reduced around, compared with reported values for conventional activated sludge processes. Nitrification takes place in Rotating Biological Contactors with good yields at hydraulic loads below 0.13 m3/m2•d.