BENCH-SCALE DETERMINATION OF THE REMOVAL OF ODOR COMPOUNDS WITH BIOLOGICAL TREATMENT

A bench-scale bioreactor was designed to determine the parameters requ ired for kinetic modelling of assimilable organic carbon (AOC) removal . This reactor was then used to attempt to determine the kinetic param eters in modelling the removal of two odorous compounds, (geosmin and 2,4,6-trichloroanisole) with biological treatment. The bench-scale bio reactor column had a volume of 55 ml, contained 2540 x 3 mm glass bead s, and was operated at a feed rate (Q) of at least 2.0 ml/min with a r ecycle rate (Qr) of 50-70 ml/min. At these rates the bioreactor can be regarded as a continuous stirred tank reactor (CSTR). The biofilm was established using filtered river water blended with an acetate soluti on and was maintained with an, inorganic nutrient and buffer solution. A synthetic water containing geosmin and 2,4,6-trichloroanisole (2,4, 6-TCA) was fed to the column after the biofilm had reached steady stat e. Influent concentrations and effluent concentrations were monitored using extraction with a closed-loop stripping apparatus (CLSA) and ana lyses using gas chromatography-mass spectrometry (GC-MS). The bioreact or did not effectively remove the taste and odour compounds being stud ied and these poor removals prevented determination of kinetic paramet ers. A bioreactor which is not, acclimated and which receives an organ ic and hydraulic loading in the range normally experienced by rapid fi lters and granular activated carbon (GAC) contactors could not be reco mmended as a primary treatment process for the removal of these taste and odour compounds.