Within the limits of this study, it was found that 5 ppm of cobalt was adequate to give good levels of vitamin B(12). The vitamin B(12) precursor 5,6-dimethylbenzimidazole was found to be adequate at 10 ppm in the absence of aeration. In the presence of aeration, a zero level of precursor was found to be most desirable. The analysis of variance showed aeration to be highly significant, and the ...

−Bacterial cellulose (BC) was produced by Acetobacter xylinum KJ1 in a modified airlift-type bubble column bioreactor, which had a low shear stress and high oxygen transfer rate (kLa). Saccharified food wastes (SFW) were used as the BC production medium due to its low cost. An aeration rate of 1.2 vvm (6 L/min) was tentatively determined as the optimal aeration condition in a 10 L spherical typ...

A laboratory scale aeration treatment system was built to study the fate of nitrogen during aeration of pig slurry. For each run evaluated, the nitrogen mass balance was determined including measurement of the nitrous oxide gas emissions. Intermittent aeration led to a nitrogen removal of about 53% of the total nitrogen content of the raw slurry. About 18% of the total nitrogen content of the r...

with its well-known biological toxicity, the excessive concentrations of sulfide in tannery wastewaters may upset the biological treatment processes, thus leading to a substantial decrease in the efficiency of treatment plants. the presence of sulfide in wastewaters may dramatically interfere with microbial activities and consequently disturb the function of the system as a whole. in this study...

This study evaluated the effects of aeration (constant aeration, intermittent aeration and a lack of aeration) and hydraulic retention time (HRT) (2, 3 and 4 days) on a continuous process with cell recycling, using chitosan as a natural coagulant for the sedimentation of a C1 mixed culture. This culture was used for the biodegradation of hydrocarbons present in the effluent contaminated with di...

considering the water scarcity in iran and the importance of environmental protection, it is approperiate to investigate the environmental management of siah-rud river. it is a small river being utilized as discharge channel by factories located in the vicinity of the river. the physico-chemical characteristics of river water at 10 different sampling locations 'along with coefficient of ae...

A model of the concentrations of suspended solids (SS) in the aeration tanks and in the effluent from these during Aeration tank settling (ATS) operation is established. The model is based on simple SS mass balances, a model of the sludge settling and a simple model of how the SS concentration in the effluent from the aeration tanks depends on the actual concentrations in the tanks and the slud...

BACKGROUND It is not well known what is the main mechanism causing lung heterogeneity in healthy lungs under mechanical ventilation. We aimed to investigate the mechanisms causing heterogeneity of regional ventilation and parenchymal densities in healthy lungs under anesthesia and mechanical ventilation. METHODS In a small animal model, synchrotron imaging was used to measure lung aeration an...

A full scale swine (300 pigs) waste treatment system, including a solid/liquid separation unit (3 m) with a solids holding tank (1.2 m) and a liquid holding tank (20 m), two anaerobic reactors (10 m each) in series, an intermittent aeration unit (20 m), a sedimentation/polishing unit (20 m) and a sludge dewatering bed (17 m), was used to investigate the impact of integrating an intermittent aer...