ABSTRACT: Laboratory-scale fluidized bed reactors (FBRs) containing either sand or granular activated carbon (GAC) as biocarriers for immobilized bacteria were evaluated for biotreatment of chemical industry wastes. The FBRs were fed high levels of a synthetic waste stream
containing aniline (ANL), methyl ethyl ketone (MEK), p-nitrophenol (PNP) and sodium formate (FRM) at concentrations increasing from approximately 3 600 mg/L total chemical oxygen demand (COD) up to 17 000 mg/L COD. Microbial biomass attached to the GAC increased from 15 000 mg/L at a COD loading
of 3.2 Kg COD m-3 d-1 to over 40 000 mg/L at a maximum COD loading of 16.0 Kg COD m-3 d-1. The sand was colonized slower during start-up but supported biomass levels of 2 600 to 20 000 mg/L at COD loadings up to 9.6 COD m-3 d-3.
Scanning electron microscopy confirmed biomass measurements and showed that high levels of bacteria were retained on GAC after a toxic surge in COD loading, but were significantly reduced in the sand reactor resulting in diminished performance. Specific chemical analyses showed over 99%
removal of organic feed components by both reactors throughout the study. The sand reactor study was terminated early due to its inability to handle an accidental surge in COD loading. Biological solids production from the GAC reactor ranged from 0.056 to 0.184 g solids/g COD removed. The
GAC reactor demonstrated a greater ability to handle rapid increases in COD loading (for adsorbable chemicals) than the sand reactor. This study has increased fundamental understanding of the operation and performance of FBRs treating a representative chemical industry waste stream and has
demonstrated some advantages of GAC over sand as a biocarrier.
Water Environment Research® (WER®) publishes peer-reviewed research papers, research notes, state-of-the-art and critical reviews on original, fundamental and applied research in all scientific and technical areas related to water quality, pollution control, and management. An annual Literature Review provides a review of published books and articles on water quality topics from the previous year. Published as: Sewage Works Journal, 1928 - 1949; Sewage and Industrial Wastes, 1950 - 1959; Journal Water Pollution Control Federation, 1959 - Oct 1989; Research Journal Water Pollution Control Federation, Nov 1989 - 1991; Water Environment Research, 1992 - present.