The operating condition of a submerged propeller has a significant impact on flow field and energy consumption of the oxidation ditch. An experimentally validated numerical model, based on the computational fluid dynamics (CFD) tool, is presented to optimize the operating condition by considering two important factors: flow field and energy consumption. Performance demonstration and comparison of different operating conditions were carried out in a Carrousel oxidation ditch at the Yingtang wastewater treatment plants in Anhui Province, China. By adjusting the position and rotating speed together with the number of submerged propellers, problems of sludge deposit and the low velocity in the bend could be solved in a most cost-effective way. The simulated results were acceptable compared with the experimental data and the following results were obtained. The CFD model characterized flow pattern and energy consumption in the full-scale oxidation ditch. The predicted flow field values were within −1.28 ± 7.14% difference from the measured values. By determining three sets of propellers under the rotating speed of 6.50 rad/s with one located 5 m from the first curved wall, after numerical simulation and actual measurement, not only the least power density but also the requirement of the flow pattern could be realized.
- IWA Publishing
- Optimization design of submerged propeller in oxidation ditch by ...
Eliminating sludge islands in your wastewater lagoon
Old municipal and industrial wastewater lagoons have the tendency to build islands of sludge at various locations around the lagoon. It is most common for older lagoons to build such islands wherever wastewater enters the lagoons. Of course, this is because the solids entering the lagoon have enough weight to fall out of the water as flow velocity is reduced, so the solids pile up just after entering the lagoon. Sometimes these sludge islands will build very near a surface aerator, because the violence of the...
Revitalizing a hog waste lagoon
A North Carolina hog grower with a brood barn of 200 full grown sows contacted Reliant Water Technologies to see if we could assist him with one of his waste lagoons. All of his lagoons were identical, measuring only .05 acres in size, and designed to be 8 feet deep. When we arrived at the farm all of the lagoons looked like the one in Figure 1.The lagoon that he chose for us to work with was located closest to the barn, and his goal was to use the water on the surface of the lagoon as wash-down water for the...
Aeration System Upgrade Increases Flow Capacity and Reclaimed Water Availability
Read the full Case Study:Replacing Brush Rotors with Aire-O2 Tritons® Increases Flow Capacity and Reclaimed Water Availability Overview: In 2012, the Middlebury, Indiana Wastewater Treatment Plant (WWTP) was faced with aging brush rotors and higher loads in their oxidation ditch system. When Mick Reese was hired as Plant Superintendent, the upgrade design was about 90% complete. The full system upgrade included adding an outer ring to the existing oxidation oval, construction of a new clarifier, controls...
Sludge Blanket Level Detection – making new process opportunities possible
Much Pulsar`s Self-Cleaning Viper Sludge Sensor of the demonstrating the effective maintenance-free solution. discussion around the way we deal with sewage sludge – the way it is moved around the process, the bellmouth valves and decant processes, the downstream treatment of the liquors, important issues around TOTEX and discharge Compliance, plus more recently the green energy benefits of on-site power generation – depends in large part on the accurate and reliable measurement of the strata of the...
Which plants are needed for a French vertical-flow constructed wetland under a tropical climate?
Plants are essential in the functioning of constructed wetlands. When setting up systems in tropical areas, Phragmites australis is not always a good choice because of its invasiveness. In vertical-flow constructed wetlands (VFCWs) fed with raw wastewater, the main role of plants is their mechanical action, which helps prevent clogging of the deposited organic matter. Various species have already been used in some tropical climate studies, but generally not for such systems, and no attempt has been made to screen...