Effect of Media Design on the Performance of Fixed-Bed Anaerobic Reactors

Abstract

Investigations were conducted using four different media in large laboratory-scale anaerobic filters to show the importance of media type, size, and shape on waste treatment performance. These tests have shown that a majority of the waste treatment takes place in the lower filter heights and is associated to a large extent with the biological solids that are held loosely within the interstitial void spaces within the media matrix. Therefore, the ability of the media to retain high concentrations of biological solids either as suspended growth or by attachment to the media surfaces is an important design consideration. This solids retention characteristic seems to be as closely related to media shape and void size as to unit surface area. Media selected for full-scale anaerobic filters should permit withdrawal of biological solids to prevent accumulations that can contribute to short-circuiting and loss of treatment efficiency.