Operational results and experience with submerged fixed-film reactors in the pretreatment of industrial effluents

Submersed fixed-film reactors are ideal for the pretreatment of industrial effluents. The advantages lie not only in the investment costs, but also in the operating costs. The pretreatment plants can be subject to higher load s than are possible with the activated sludge process. Consequently, consid erably less space is required. And, last but not least, it is also possible to treat normally non-degradable industrial effluents. The prerequisites a re that system related general structural requirements are fulfilled and su itable materials are used for the fixed-film reactor. They also offer considerable advantages in terms of operation compared to t he activated sludge process, since both a higher oxygen transfer rate and y ield are achieved, less sludge is produced and fewer personnel are required . All in all, the upstream submerged fixed-film reactor has proven to be an extremely reliable process, requiring little maintenance, that can cope, t o a far-reaching degree, with load fluctuations of all types and reduce the se. As a result, the operation of downstream treatment stages is also stabi lized.