in this study, activated sludge process for wastewater treatment in a refinery was investigated. for such purpose, a laboratory scale rig was built. the effect of several parameters such as temperature, residence time, effect of leca (filling-in percentage of the reactor by leca) and uv radiation on cod removal efficiency were experimentally examined. maximum cod removal efficiency was obtained...

Activated sludge treatment is one of the most popular biological processes for wastewater treatment. Detection of activated sludge structures from complex substrates such as soil and water is not easy. A rapid and effective method for extracting high molecular weight amplifiable DNA from activated sludge was modified. Five nanogram quantities of DNA per milligram activated sludge were recovered...

Activated sludge process has been widely adopted to remove pollutants in wastewater treatment plants (WWTPs). However, stable operation of activated sludge process is often compromised by the occurrence of filamentous bulking. The aim of this study is to build a proper model for timely diagnosis and prediction of filamentous sludge bulking in an activated sludge process. This study developed a ...

A significant nutrient load can be generated internally by publicly owned treatment works (POTWs). These nutrients can be found in the reject water, also known as side streams, of many municipal wastewater and sewage sludge treatment processes. These side streams include the reject stream from membranes, supernatant liquid from sludge digesters, and the centrate/filtrate return stream from sewa...

This work deals with the effect of combined microwave-ultrasonic pretreatment on the anaerobic biodegradability of primary, excess activated and mixed sludge. The characteristics, biodegradability and anaerobic digester performance for untreated primary, excess activated and mixed sludge were compared to combined microwave-ultrasonic pretreated primary, excess activated and mixed sludge. All sl...

The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis (DGGE) of nested polymerase chain reaction (nested PCR) amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated ...

Microbial activity measurements (oxygen transfer rate, OTR, carbon dioxide transfer rate CTR and respiratory quotient, RQ) are used to monitor and control biological processes. In this study, the digestion of activated sludge in microaerobic conditions was evaluated. The changes of biological activity during digestion were monitored by respiration activity. The sludge mixtures used were primary...

The activated sludge biodegradability of 12 commercial phthalate esters was evaluated in two test systems: (i) a semicontinuous activated sludge test and (ii) an acclimated 19-day die-away procedure. Both procedures demonstrated that phthalate esters are rapidly biodegraded under activated sludge conditions when loss of the parent phthalate ester (primary degradation) is measured.

Activated sludge gains xenobiotic degradation capability through acclimation to the target. Acclimated activated sludge contains a two-part biomass of non-degrader and degrader, abundance of the latter being most important for activated sludge to successfully treat the inflow of xenobiotic pollutants. For the purposes of understanding and also possible improvement of xenobiotic treatment, xenob...