Combined System UASB+MBR for the Biological Elimination of Emerging Contaminants, Organic Matter and Nutrients in Urban Waste Water

Conventional purification systems can achieve low efficiency in the removal and/or degradation of emerging contaminants (ECs) which are present in urban waste waters. Although biological aerobic technologies such as membrane bioreactors (MBR) have shown high effectiveness, some compounds are eliminated in a higher degree using anaerobic biological systems. This research is aimed at the study of a system which has all the advantages of both the aerobic and anaerobic biological cleansing, in order to optimize ECs, organic matter and nutrient elimination. To this end, a pilot plant operation has been analyzed, integrated by an Upflow Anaerobic Sludge Blanket reactor (UASB) followed by a MBR with an external submerged configuration. The first phase of this research has been performed with the aerobic biomass in suspension and the second phase with supported biomass. Results confirm the synergic effect of both systems, due to the achievement of a high removal performance of the more persistent contaminants, such as carbamazepine, diclofenac, simazine, atrazine, linuron and terbuthylazine. Regarding organic matter, nitrogen and phosphorus elimination, global yields were close to 98%, 45% y 35% respectively, with a particularly high performance in the supported biomass phase.