the effluent quality of a sewage treatment plant using activated sludge process and finally secondary treatment depends on the flocculation efficiency and settling of the flocs. the survey of various treatment processes in water and wastewater treatment shows that temperature and ph are the important factors affecting efficiency of flocculation and settling properties. this study was performed ...

semi-aerobic leachate is characterized by organic matter (cod, bod) which is relatively low in concentration and difficult to biodegrade. in conventional treatment systems, the low biodegradability is attributed to partial stabilization of leachate at the landfill. biological treatment of leachate in malaysia is not well established and any important data for the treatment process is not availa...

hospital wastewater has special importance since having pathogens, radioactive materials, pharmaceutical wastes and heavy metals. removing them into environment without any treatment may cause serious problems for the public health. membrane biological reactor is the combination of the activated sludge and membrane filters. this research has investigated the performance of the nano-filtration i...

This paper presents three new approaches to reduce excess sludge production in activated sludge systems: 1) modification of conventional activated sludge process with insertion of a sludge holding tank in the sludge return line; 2) chlorination of excess sludge so as to minimize excess sludge production; and 3) utilization of a metabolic uncoupler, 3, 3', 4', 5-Tetrachlorosalicylanilide (TCS) t...

Although activated sludge communities are considered stable, the presence of toxic substances, such as Cr(VI), in the influent may induce changes in the activity and the performance of a wastewater treatment plant. The main objective of this study was the determination of Cr(VI) effects on the performance and on the protistan community of an activated sludge. Six laboratory scale activated slud...

Thirty six samples from each (aerobic and anoxic) activated sludge were collected from two wastewater treatment plants with MBRs in Berlin, Germany. The samples were prepared for count and definition of fungal isolates; these isolates were purified by conventional techniques and identified by microscopic examination. Sixty tow species belonging to 28 genera were isolated from activated sludge s...

A bioreactor refers to any manufactured or engineered device that supports a biologically active environment. These kinds of reactors are designed to treat wastewater treatment. Volumetric mass transfer coefficient and the effect of superficial gas velocity, as the most important operational factor on hydrodynamics, in three-phase airlift reactors are investigated in this study. The experiments...

Introduction: Extended aeration activated sludge system has a lower sludge production than other activated sludge processes. Due to its high hydraulic retention time (HRT), the tolerance of this process is higher than the shocks caused by increased organic loading rate. The main objective of this study is to evaluate the performance of the aeration system in removing physicochemical and mi...

Hospital wastewater has special importance since having pathogens, radioactive materials, pharmaceutical wastes and heavy metals. Removing them into environment without any treatment may cause serious problems for the public health. Membrane Biological Reactor is the combination of the activated sludge and membrane filters. This research has investigated the performance of the Nano-Filtration i...