Assessment of carrier materials for biofilm formation and denitrification
The capacity for biofilm attachment and activity of 20 low cost materials with little environmental impact (leftovers, byproducts or reusable waste materials) were investigated using two denitrifying biomarker organisms, Comamonas denitrificans 110 and Brachymonas denitrificans B79, and the non-denitrifying strain E. coli K12. The amount of attached biofilm was indirectly measured by analyzing the denitrification activity. Four materials; LECA, Pumice, Wood chips and Kaldnes K1, performed best and were therefore subjected to further investigation. The result from the second phase showed that wood chips gave the highest average denitrification activity over time while Kaldnes K1 gave the highest peak values. However, considering mechanical properties, cost and energy requirements for production in addition to denitrification activity over time, pumice was considered to be the most promising material.