Denitrification of drinking water in a two-stage biofilm membrane bioreactor

A two-stage biofilm membrane bioreactor (BMBR) using a commercially available biocarrier material for treating nitrate-contaminated groundwater was developed. The performance of the anoxic stage (denitrification) and oxic stage (total organic carbon removal) in the pilot BMBR system was evaluated and compared with the performance of other membrane bioreactor systems. With a residence time of 2.6h, a nitrate concentration in treated water of below 1mg/L could be achieved in the system without any formation of intermediate nitrite ions. At the same time, the use of biocarriers with specific mechanical properties significantly increases the operational period of the membranes.