title: Biological treatment of mixed industrial wastewaters in a fluidised bed reactor.
abstract: A study has been carried out on the operating parameters that influence the biodegradation of petroleum and brewery wastewaters, with a low-density biomass support. The biodegradation rate of a mixture of two wastes was compared with that of the separate wastes. A low aspect ratio reactor was employed, and this made it possible to operate at low superficial gas and liquid velocities. The gas distributor used created a fluid flow pattern similar to that of a draft tube, which enhanced axial mixing. At a particles loading of 12% (v/v), the optimum superficial gas velocity was 2.5 cm/s for the mixture. The interstice structure of the biomass-support particles, improved microbial attachment due to the resulting large surface area. There was a low biomass concentration when petroleum wastewater was treated alone, however, for a mixture of petroleum and brewery wastewaters, an increase in the concentration was observed. There was a higher gas hold up in the mixture than in the petroleum wastewater, but lower than in the brewery wastewater. An improved biodegradation was achieved when a mixture of brewery and petroleum wastewaters was treated, and this gave an indication that nutrient deficient wastes can be treated together with phosphate and nitrate rich food industry wastewaters.
authors.affiliation: Chemical and Process Engineering Department, Moi University, P.O. Box 3900, Edoret, Kenya. aoyio@yahoo.com
authors.forename: Aoyi
authors.initials: A
authors.lastname: Ochieng
authors.forename: John O
authors.initials: JO
authors.lastname: Odiyo
authors.forename: Mukayi
authors.initials: M
authors.lastname: Mutsago
mesh_terms: D001419:Bacteria; D001515:Beer; D001673:Biodegradation, Environmental; D019149:Bioreactors; D004867:Equipment Design; D010578:Petroleum; D014865:Waste Disposal, Fluid / Q000295:instrumentation*
chemical_list: D010578:Petroleum