An Eco-tank system containing microbes and different aquatic plant species for the bioremediation of N,N-dimethylformamide polluted river waters.

An Eco-tank system of 10m was designed to simulate the natural river. It consisted of five tanks sequentially connected containing microbes, biofilm carriers and four species of floating aquatic plants. The purification performance of the system for N,N-dimethylformamide (DMF) polluted river water was evaluated by operating in continuous mode. DMF was completely removed in Tanks 1 and 2 at influent DMF concentrations between 75.42 and 161.05mg L-1. The NH4+-N concentration increased in Tank 1, followed by a gradual decrease in Tanks 2-5. Removal of NH4+-N was enhanced by aeration. The average effluent NH4+-N concentration of Tank 5 decreased to a minimum of 0.89mg L-1, corresponding to a decrease of 84.8% when compared with that before aeration. TN concentration did not decrease significantly as expected after inoculation with denitrifying bacteria. The average effluent TN concentration of the system was determined to be 4.58mg L-1, still unable to satisfy the Class V standard for surface water environmental quality. The results of this study demonstrated that the Eco-tank system is an efficient process in removing DMF, TOC, and NH4+-N from DMF polluted river water. However, if possible, alternative technologies should be adopted for controlling the effluent TN concentration.