A small-scale biological trickling filter using activated carbon filter media was seeded with a culture known to degrade MTBE. A mixture of nutrients and MTBE-contaminated tap water was sprayed on the activated carbon. To minimize effluent discharge the reactor was designed as a closed system with a recycling solution. Nutrients and MTBE were replenished as required. Compressed air was used to aerate the filter.

The first goal of the study was to establish a colony of MTBE-degrading organisms on the activated carbon to determine viability of liquid phase treatment with such a system. After two months a biological growth was observed near the top of the filter media. The reactor continued to run while the biological growth spread throughout the activated carbon. A bottle test was performed using some of the activated carbon from the reactor. The bottle test indicated that the culture populating the activated carbon biodegrades MTBE. Tests performed on the reactor influent and effluent MTBE concentrations also indicated the biological trickling filter was removing MTBE from the liquid phase.

After establishing an active MTBE-degrading culture, the second goal is to perform tests to determine the optimal filter loading rates. Loading rates will be used to determine the size of biological trickling filters required to remove MTBE from contaminated water containing varying level of MTBE. Based upon the physical size of the filters required to remove MTBE a more accurate removal cost can be estimated.