Six different wastewater treatment plants were monitored in order to identify the main bioaerosol sources and to evaluate the effect of the aeration system used in the biological treatment (air diffusion, horizontal rotors and surface turbine aerators) on the airborne microorganism levels to which workers may be exposed. Air samples were collected by using a single stage impactor. Total count o...

UNLABELLED The emission of particulate matter (PM10 and PM2.5) and ammonia (NH3) by aeration processes at wastewater treatment plants (WWTPs) with and without odor control units was examined. Local concentrations of PM2.5, PM10, and NH3 at the aeration basins were within urban ranges. Emission fluxes of NH3 and PM2.5 for a medium-sized WWTP were determined to be 136 g day(-1) and 43 g day(-1), ...

Minimizing runoff losses from grasslands may benefit the producer and abate potential eutrophication of aquatic systems. This study was conducted to evaluate the effects of fertilizer source and soil aeration on the volume and quality of runoff from grassed plots. Sixteen tall fescue [Festuca arundinacea Schreb.]–bermudagrass [Cynodon dactylon L.] plots were established on Altavista sandy-loam ...

In wetland soils, changes in oxygen (O2) level in the rhizosphere are believed to influence the behaviour of nutrients and their usage by plants. However, the effect of aeration on nitrogen (N) acquisition under different N supply conditions remains largely unknown. In this study, the rice cultivars Yangdao 6 (YD6, with higher root aerenchyma abundance) and Nongken 57 (NK57, with lower root aer...

The discharge rate of coarse powders (mean particle size >500 pm) from bunkers without aeration can be described by both empirical relations and theoretical models. In the case of small particles the discharge rate is largely overestimated. As the powder dilates during flow a negative pressure gradient develops near the hopper outlet, inducing an air flow into the hopper. This extra drag force ...

BACKGROUND The Antarctic fungus Lecanicillium muscarium CCFEE 5003 is one of the most powerful chitinolytic organisms. It can produce high level of chitinolytic enzymes in a wide range of temperatures (5-30°C). Chitinolytic enzymes have lot of applications but their industrial production is still rather limited and no cold-active enzymes are produced. In view of massive production of L. muscari...

Acetaldehyde, ethanol and non-protein bound amino acids were determined in broccoli florets (Brassica oleracea L. var. Italica cv. Marathon) stored for 7 days at 10°C in air or controlled atmospheres (0.125, 0.25, or 0.5% O2 alone or in combination with 20% CO2, or 20% CO2 in N2) followed by 2 days aeration. Floret yellowing was visible at days 7 and 9 in air. Low O2 or low O2 plus high CO2 atm...

Two-level controllers for dissolved oxygen reference trajectory tracking for activated sludge processes is proposed and investigated. Both the nutrient and the phosphorous removal from a wastewater by its biological treatment using an activated sludge technology are considered. Typically, an aeration system itself is a complicated hybrid nonlinear dynamical system with faster dynamics compared ...

The present paper attempts to investigate the prediction of air entrainment rate and aeration efficiency of a free overfall jets issuing from a triangular sharp crested weir by using regression based modelling. The empirical equations, Support vector machine (polynomial and radial basis function) models and the linear regression techniques were applied on the triangular sharp crested weirs rela...

Examination of some previously isolated bile acid-utilizing Pseudomonas strains showed that Pseudomonas sp. ATCC 31752, together with other fluorescent strains, can be assigned to Pseudomonas putida biotype B, whereas Pseudomonas sp. ATCC 31753, like most other nonfluorescent strains, is an unrecognized phenotype. A study was made of the growth of these two species at 25 degrees C and pH 7.0 in...