Environmental applications of fine bubble generating apparatus with low energy and high treatment efficiency

A fine bubble generating equipment maintaining 12 mg L^–1 of dissolved oxygen concentration with low energy consumption was developed, on a trial basis, to solve various kinds of environmental problems such as heavy metals, high concentration of T-N, malodor and hydrogen sulfide from the sewage treatment plant. Such heavy metals as Fe, As of acid mine drainage from stormwater runoff were effectively oxidized depending on aeration period. Almost 90% of T-N removal efficiency was obtained at around 10,000 mg L^–1 concentration. On average, 55.6% removal efficiency for hydrogen sulfide was achieved in the reactor. The development of a novel reactor generating fine bubbles may be of use not only to protect water qualities polluted but also to keep clean air qualities.