Accurate estimates for the fall speed of natural hydrometeors are vital if their evolution in clouds is to be understood quantitatively. In this study, laboratory measurements of the terminal velocity yt for a variety of ice particle models settling in viscous fluids, along with wind-tunnel and field measurements of ice particles settling in air, have been analyzed and compared to common method...

The most meaningful parameter to determine the treatment efficiency of large scale sedimentation tanks is the settling velocity of suspended solids. However it is difficult to measured representative settling velocity because of the instability of suspended solids. A water elutriation system was tested to assess the treatment efficiency of sedimentation tanks. In laboratory tests the flow condi...

The fate of coliphage in a wastewater treatment plant in the central part of Japan was investigated from March to December 2001. A relative abundance of coliphage, 1000-10,000 PFU/ml determined with three different Escherichia coli strains, was detected in the influent. But, no remarkable seasonal change in the phage concentration in the influent was observed during the ten-month test period. A...

In this paper based on the conception of evolution, the Genetic Algorithm (GA) is applied to parameters optimization of proportional-integral-derivative (PID) controller for continuous stirred tank reactor (CSTR).The mathematical model of experimental system had been approximated near the operating point for the GA algorithm to adjust PID parameter for the minimum integral of time multiplied by...

Activated sludge systems are biological processes greatly used in wastewater treatment plants (WWTPs). These systems are composed of an aerated tank where the biochemical phase occurs and a settler where the physical phase takes place. Solid-liquid separation is one of the most critical steps in activated sludge processes. This stage presents three main objectives: sludge thickening, effluent c...

In the past years, lamella settlers have been used as devices for treatment by sedimentation also for storm water. Instead of just equipping a sedimentation basin with numerous lamella modules, an innovative approach for traditional separate systems is proposed. Basically, storm water is stored in a basin or tank during a rain event, while treatment is done in a small but continuously operated ...

Abstract Appropriately used, computational fluid dynamics models are powerful tools to design and optimize primary settling tanks (PSTs). This paper uses a Fluent-based 3D model identify the possible causes for underperformance of circular PSTs at Cali waste-water treatment plant, Colombia, propose modifications improve performance. A new configuration center well (CW) is proposed evaluated. Th...

A series of pilot-scale tests were conducted with a continuous system composed of a stirring tank reactor, settling tank, and sand filter. In order to treat acidic drainage from a Pb-Zn mine containing high levels of heavy metals, the potential use of coal-mine drainage sludge (CMDS) was examined. The pilot-scale tests showed that CMDS could effectively neutralize the acidic drainage due to its...

The word "electrocoagulation" (EC) will be sometimes used with "electroflotation" (EF) and can be considered as the electrocoagulation/flotation (ECF) process. Through the process of electrolysis, coagulating agents such as metal hydroxides are produced. When aluminium electrodes are used, the aluminium dissolves at the anode and hydrogen gas is released at the cathode. The coagulating agent co...