Wastewater treatment with activated sludge is the most common way of treating wastewater. The process relies on bacteria converting nutrients, BOD and COD into biomass, CO2 and N2. Even though the configuration of activated sludge processes and wastewater treatment plants varies there are common problems which are shared. Filamentous bulking sludge is one problem that is widespread and disturbs...

The operation of an activated sludge process at a paper mill (AIPM) in Hedera, Israel, was often characterized by disturbances. As part of a research and development project, a study on new biological treatment was initiated. The study included the operation of three pilot units: a. anaerobic treatment by upflow anaerobic sludge blanket (UASB); b. aerobic treatment by two pilot units including ...

Large volumes of sludge are produced from onsite sanitation systems in densely populated areas (e.g. slums and emergency settlements) and wastewater treatment facilities that contain high amounts of pathogens. There is a need for technological options which can effectively treat the rapidly accumulating sludge under these conditions. This study explored a pilot-scale microwave (MW) based reacto...

In biological wastewater treatment technologies the majority of systems are based on activated sludge technology. In these systems the population structure and dynamics of the activated sludge microbial community is largely governed by indirect regulatory mechanisms, such as aerated/nonaerated reactors, reactor configurations and sludge recycling ratios. The build-up of activated sludge flocs (...

in this study, the bacterial diversity in the activated sludge system of a full-scale municipalwastewater treatment plant in dubai was monitored over a period of one year using ribosomal rna (rrna)targeted oligonucleotide probes for a defined phylogenetic group of bacteria by the fluorescence in situhybridization (fish) technique. the largest fraction of the bacterial community in the sludge sa...

Oxic-settling-anaerobic process (OSA) was known as a cost-effective way to reduce the excess sludge production with simple upgrade of conventional activated sludge process (CAS). A low oxidation-reduction potential (ORP) level was the key factor to sludge decay and lysis in the sludge holding tank of the OSA process. However, the ORP control with nitrogen purge or chemical dosing in the OSA pro...

A suspension of wastewater and treatment organisms in an aerated tank is known as the activated sludge process. The activated sludge process can be used for onsite wastewater treatment, generally requiring the addition of an air pump to deliver oxygen to the system and provide mixing energy. Suspended growth treatment systems can be secondary only (require supplemental primary treatment) or com...

The bacterial community structures of phosphate- and non-phosphate-removing activated sludges were compared. Sludge samples were obtained from two sequencing batch reactors (SBRs), and 16S rDNA clone libraries of the bacterial sludge populations were established. Community structures were determined by phylogenetic analyses of 97 and 92 partial clone sequences from SBR1 (phosphate-removing slud...

An analytical method has been developed and applied to determine the concentrations of the nonionic alkylphenol polyethoxylate surfactants and their metabolites, alkylphenoxy carboxylates and alkyphenols, in sewage sludges. The compounds were extracted with methanol/acetone (1:1 v/v) from sludge, and concentrated extracts were cleaned by silica solid-phase extraction prior to determination by l...

-An objective index, the Sludge Biotic Index (SBI), based on the microfauna associated with activated-sludge mixed liquor, has been devised to monitor activated-sludge plant performance. The proposed method makes it possible to define the biological quality of the sludge using numerical values (biotic index) of 0-10, and to group SBI values into four quality classes. The method is based on two ...