This study combines a two-phase biological treatment system of activated sludge/contact aeration process by adding biological contact filters into the rear sector of the activated sludge aeration tank of the slaughterhouse wastewater treatment plant. This system keeps the advantages of complete mixing of substrates and microorganisms and flexible operation of the activated sludge process, and i...

Aerated treatment wetlands have become an increasingly recognized technology for treating wastewaters from domestic and various industrial origins. To date, treatment wetland aeration is provided by air pumps which require access to the energy grid. The requirement for electricity increases the ecological footprint of an aerated wetland and limits the application of this technology to areas wit...

Environment Canada methods for acute toxicity tests with rainbow trout require continuous aeration of test solutions during exposure. Depending on the sample, this procedure can result in an increase in pH as dissolved carbon dioxide (CO2) is stripped from solution as a result of aeration. In samples that contain ammonia, the pH may increase to the point where the unionized fraction results in ...

Despite the fact that there are wastewater treatment plants (WWTPs) currently operational across Iran and great advances have been made in this area, there are still problems in the design, construction, and operation of WWTPs with large nonlinear systems, varying flow rates, and pollution charges. The objective of this study was to investigate the effect of operating parameters including the r...

An experiment was developed using aeration of water for demonstrating the phenomenon of mass transfer. The demonstration was designed to provide both conceptual and practical insight of the mass transfer process. A bubble column fitted with a sieve tray was used to carry out the experiment. The air flow rate and hole size of the sieve tray were varied. Mass transfer coefficient was obtained fro...

Yields of from 200 to 300 mg per liter of aflatoxins B(1) and G(1) were produced by two strains of Aspergillus flavus in 20-liter fermentors under proper conditions of inoculum (well-dispersed growth) and aeration (0.5 volume per volume per min of air, 300 rev/min, 30 psi back pressure, baffles). Peak yields were usually attained in 72 hr, after which the aflatoxin concentration declined rapidl...

In this work the behavior of the growth of Candida guilliermondii FTI 20037 in sugar cane bagasse hemicellulosic hydrolysate on various oxygen transfer rates was investigated. The yeast was able to grow and produced xylitol at different performance levels. At 1.0 vvm (volume of air per volume of medium per minute) the highest growth with 24.4 g/l was observed, but no xylitol was produced. At ae...

Biofixation of CO2 by microalgae has been recognized as an attractive approach to CO2 mitigation. The main objective of this work was to maximize the rate of CO2 fixation ( [Formula: see text] ) by the green microalga Chlorella vulgaris P12 cultivated photoautotrophically in bubble column photobioreactors under different CO2 concentrations (ranging from 2% to 10%) and aeration rates (ranging fr...

Petroleum refining industries produce large amounts of toxic effluents, causing environmental pollution. Iran is an oil-rich country that encounters oil pollution in its soil and water. Bioremediation of these pollutants is an appropriate solution to tackle them, compared to physical and chemical remediation methods. There are some factors that increase the rate of biodegradation; therefore, th...