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...

Activated sludge used for wastewater treatment globally is composed of a high-density microbial community of great biotechnological significance. In this study the presence and purpose of quorum sensing via N-acylated-l-homoserine lactones (AHLs) in activated sludge was explored. The presence of N-heptanoyl-l-homoserine lactone in organic extracts of sludge was demonstrated along with activatio...

Activated sludge is a complex ecosystem constituted mainly of bacteria and protozoa. Filamentous bulking, a phenomenon when the filamentous organisms dominate the activated sludge is still a widespread problem in the operation of activated sludge processes. Image analysis offers promising perspectives for early detection of filamentous bulking because the morphology parameters of the activated ...

Phenolic compounds are considered as priority pollutants because of their high toxicity at low concentration. In the present study, the sorption of p-chlorophenol (p-CP) by dried activated sludge was investigated. Activated sludge was collected as slurry from the sludge return line of a municipal wastewater treatment plant. Sorption experiments were carried out in batch mode. In order to invest...

The macromolecular composition of activated sludge (lipids, intracellular proteins and intracellular polysaccharides) was studied together with its capacity to store macromolecules such as polyhydroxybutyrate (PHB) in a conventional activated sludge system fed with synthetic sewage water at an organic load rate of 1.0 kg COD/(m(3)·d), varying the dissolved oxygen (DO) and temperature. Six DO co...

the activated sludge process is the most widely used biological wastewater treatment for both domestic and industrial plants in the world. one of the drawbacks of conventional activated sludge (cas) processes is high sludge production. excess sludge treatment and disposal currently represents a rising challenge for wastewater treatment plants (wwtps) due to economic, environmental and regulatio...

Enzymes are important in biological wastewater treatment systems, since they are responsible for breakdown of macro- and micropollutants, thereby making the pollutants available for metabolism. Enzyme activity has been investigated in particular in activated sludge processes, since the activated sludge technology is the most important and widely spread wastewater treatment technology used today...

The purpose of this work was to examine the settling properties of activated sludge from a sequencing batch reactor (SBR). The experiments were carried out in a bench-scale reactor, fed with wastewater from the University of Olsztyn treatment plant. Concentrations of the examined activated sludge varied between 2.5 and 6.0 kg SS m. Laboratory analyses of the sludge comprised: sludge concentrati...