In wastewater treatment plants, nitrifying systems are usually operated with elevated levels of aeration to avoid nitrification failures. This approach contributes significantly to operational costs and the carbon footprint of nitrifying wastewater treatment processes. In this study, we tested the effect of aeration rate on nitrification by correlating ammonia oxidation rates with the structure...

A bench-scale study on swine manure stabilization for odour control was conducted using batch aeration reactors. In trial 1, two aeration lengths, i.e., 0.5 and 4.0 day, were used under uncontrolled ambient temperature that increased gradually over the experimental period. While in trial 2, a 16.0-day aeration scheme was employed under constant 17 degrees C. An airflow rate of 1.2L/s/m(3) was u...

Single-tank simultaneous nitrification and denitrification (SNdN) processes can potentially eliminate the need for separate tanks and for recycling mixed liquor from oxic nitrifying zones to the typically upstream anoxic zones for denitrification. However, the conditions involved are more susceptible to sludge bulking by excessive growth of filamentous bacteria. This study was aimed at identify...

The present study reports the effects of aeration and agitation on growth and production of the cyclosporin A (CyA) in batch fermentor cultures of Tolypocladium inflatum MTCC 557. Dissolved oxygen concentration, pH, dry cell wt, CyA titer and sugar utilization were continuously measured and determined. In the first step, the effect of agitation was evaluated by changing the agitation speed in t...

A newly designed extended surface biofilm reactor (ESBR) with an inner configuration consisting of eight equidistantly spaced polymethylmethacrylate rectangular strips placed radially on a circular disk to provide additional surface area for microbial growth was used for antimicrobials production by the biofilm-forming marine isolate Streptomyces sundarbansensis sp nov.. Antimicrobials producti...

Klebsiella pneumoniae does not fix N(2) under aerobic conditions. The two protein components required for nitrogenase activity were studied during aeration of cells in nitrogen-free media. Component II of nitrogenase was inactivated more slowly in vivo than component I during aeration. The rate of loss of component II was less than the rate of component II synthesis during derepression. No inac...

In this report we describe the results of a study conducted to determine the rates of bacterial aerosol emission from the surfaces of the aeration tanks of the Metropolitan Water Reclamation District of Greater Chicago John E. Egan Water Reclamation Plant. This study was accomplished by conducting test runs in which Andersen six-stage viable samplers were used to collect bacterial aerosol sampl...

Aeration devices are introduced along chute spillways and at bottom outlets to prevent cavitation damage in high velocity flows. Bottom aerators are characterised by large quantities of air entrained along the jet interfaces but also by a strong de-aeration process near the impact of the water jet with the spillway bottom. In this paper, the aeration and de-aeration occurring respectively in th...

a rhamnolipid–type biosurfactant production by pseudomonas aeruginosa mm1011 was studied in a miniaturized shaken bioreactor. the operational parameters, affecting the biosurfactant production in shaken bioreactors, such as shaking frequency (200, 250, 300 rpm), filling volume (50, 75, 100 ml), and aeration rate (0.2, 0.6, 1 vvm), were optimized using response surface methodology. the optimizat...