With the re-evaluation and revision of a number of design floods, several embankment overtopping protection systems have been developed and a common technique is the construction of a stepped spillway on the downstream slope. For such moderate slope stepped channels, detailed air–water flow measurements were performed in a large facility with a focus on the rate of energy dissipation, flow resi...

The variation of moisture during sewage sludge bio-drying was investigated. In situ measurements were conducted to monitor the bulk moisture and water vapor, while the moisture content, water generation, water evaporation and aeration water input of the bio-drying bulk were calculated based on the water mass balance. The moisture in the sewage sludge bio-drying material decreased from 66% to 54...

Heavily polluted sediment is becoming an important part of water pollution, and this situation is particularly acute in developing countries. Sediment has gradually changed from being the pollution adsorbent to the release source and has influenced the water environment and public health. In this study, we evaluated the pollutant distribution in sediment in a heavily polluted river and agitated...

The aims of these experiments were treating tapioca processing waste water to produce polyhydroxyalkanoates (PHAs) and removal of chemical oxygen demand (COD). The experiments were conducted in a sequencing batch reactor with a volume of 6 L. The entire experimental condition was anaerobic-aerobic-anaerobic. Experiment 1, 2 and 3 had the first 2 h for feeding time while Experiment 4 had 3 h. Th...

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...

geosmin and mib are the common factors causing odor in the water. water treatment plants usually employ the conventional processes such as aeration, coagulation, flocculation, chlorination or ozonation and adsorption as preventive measures to reduce water odor. but each of these processes alone cannot completely remove the smell. the smell of fish, grass and mud greatly depends on the excessive...

Environment Canada methods for acute toxicity tests with rainbow trout require continuous aeration of test solutions during exposure. Depending on the sample, this procedure can result in an increase in pH as dissolved carbon dioxide (CO2) is stripped from solution as a result of aeration. In samples that contain ammonia, the pH may increase to the point where the unionized fraction results in ...

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...

M ixing behavior of three geometrically equivalent 0.06 m bubble column and airlift photobioreactors was compared for use in microalgal culture. Mixing was characterized in terms of the axial dispersion coefficient, mixing time, circulation time and Bodenstein number. Measurements were reported in tap water and sea water, as used in growing microalgal biomass. Compared with the two airlift reac...

Using bottom outlets for drain and regulation of water level in reservior has significant importance in performance mahagment of dam. Amount of service and emergency gates opening have important role in pressure, velocity and discharge coefficient variations and finally dam performance. In the present research, flow aeration between emergency and service gates was studied with different hydraul...