The objective of this study is to upgrade the operation of conventional activated sludge treatment plants for the purpose of saving aeration energy and at the same time providing better utilization of existing plant capacity for nutrient removal without major investment. In this study, pilot-scale experiments of the single stage activated sludge process (ASP), as operated in existing ASP in sou...

A highly efficient transition-metal-free catalytic system Br2/NaNO2/H2O has been developed for a robust and economic acid-free aerobic oxidation of sulfides. It is noteworthy that the sulfide function reacts under mild conditions without over-oxidation to sulfone. The role of NaNO2as an efficient NO equivalent for the activation of molecular oxygen was identified. Under the optimal conditions, ...

Changes in the fractions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria in two laboratory-scale reactors were investigated using 16S rRNA probe hybridizations. The reactors were operated in intermittent aeration mode and different aeration cycles to treat anaerobically digested swine wastewater with ammonia concentrations up to 175 mg NH(3)-N/L. High ammonia removals (>98.8%) were...

The impacts of four simulated hazardous events, namely, aeration failure, power loss, and chemical shocks (ammonia or bleach) on the performance of an anoxic-aerobic membrane bioreactor (MBR) receiving real wastewater were investigated. Hazardous events could alter pH and/or oxidation reduction potential of the mixed liquor and inhibit biomass growth, thus affecting the removal of bulk organics...

Copper manganese oxide spinels and related (multiphase) materials with the formula CuxMn3−xO4 are active catalysts in a wide variety of industrially important processes due to their great diversity phase relations, metal ion valence/site distribution, chemical properties. In this review, we summarize preparation methods effects on composition, properties, catalytic properties various Cu/Mn rati...

An activated sludge aeration tank (W × L × H = 40 × 40 × 300 cm) with a set of 2 mm orifice air spargers was utilized to treat gas-borne volatile organic compounds (VOCs, toluene, p-xylene, and dichloromethane) in air streams. Effects of liquid depth, aeration intensity (G/A), overall mass transfer coefficient of oxygen in clean water (KLaO2), dimensionless Henry’s law coefficient of the tested...

Syed, M., Soreanu, G., Falletta, P. and Béland M. 2006. Removal of hydrogen sulfide from gas streams using biological processes A review. Canadian Biosystems Engineering/Le génie des biosystèmes au Canada 48: 2.1 2.14. Hydrogen sulfide (H2S) is a toxic and odorous compound present in biogas produced by the anaerobic digestion of biosolids and other organic materials. Due to its corrosive nature...

The effectiveness of chemical and biogenic sulfide in decolorizing three sulfonated azo dyes and the robustness of a sulfate-reducing process for simultaneous decolorization and sulfate removal were evaluated. The results demonstrated that decolorization of azo dyes assisted by chemical sulfide and anthraquinone-2,6-disulfonate (AQDS) was effective. In the absence of AQDS, biogenic sulfide was ...

Catalytic oxidation of spent sulfidic caustic consist SH- ion or NaHS compound by H 2 O2 in neutral acidic solution to elemental sulphur may provide a convenient and economical method for the control sulphide wastes their associated odors at pulp, paper textile industry. Oxidation sulfide rayon waste hydrogen peroxide was investigated presence ferric sulfate catalyst. Kinetic equations activati...