Experimental comparison between MBBR and activated sludge system for the treatment of municipal wastewater

The aim of the described experimentation was the comparison of a low cost M BBR and an activated sludge system (AS). The MBBR applied system consists o f the FLOCOR-RM(R) plastic media with a specific surface area of about 160 m(2)/m(3) (internal surface only). The comparison with activated sludge (AS ) was performed by two parallel treatment lines. Organic substance removal and nitrification were investigated over a 1-year period. Comparing the res ults obtained with the two lines, it can be observed AS totCOD removal effi ciencies were higher than MBBR ones; the average efficiencies for totCOD re moval were 76% for MBBR and 84% for AS. On the contrary, the solCOD removal s resulted alike (71% for both systems). In spite of the remarkable variations of wastewater temperature, mainly in winter (range of 5-21 degrees C), the average ammonium removal efficiency r esulted 92% for MBBR and 98% for AS. With an ammonium loads up to 1.0 g m(- 2) d(-1) (up to 0.12 kg m(-3) d(-1)), nitrification efficiencies in MBBR we re more than 98%. At higher loads decrease in the MBBR efficiency was regis tered; that is related to the increase in the applied COD load.