The nature and behavior of the microbial population developed on a synthetic waste containing salts and sorbitol are compared to that of a treatment-plant activated sludge. The population of the adapted sludge developed on the synthetic waste consisted approximately of only six kinds of bacteria. Experiments with radioactive sorbitol indicate that the microbial population developed on the synth...

The effect of polyelectrolytes; cationic and anionic charges and coagulants have been investigated for fresh activated sludge at different concentrations and pH values in a comparative fashion. The results from the experiments indicate that the cationic polyelectrolytes have a significant effluence on the sludge characteristic, degree of flocculation and water quality such as turbidity and SVI....

Physicochemical studies on wastewater quality and microscopic analyses of activated sludge are necessary to properly evaluate the condition of activated sludge. The aim of this study was to evaluate the application of the sludge biotic index to determine when a change in treatment quality is short-lived, caused by, e.g., a change in influent quality or quantity, and when it indicates adverse ch...

In this paper a new model, tailor-made for nutrient deficient aerobic COD removal, is presented. The Activated Sludge Model No. 1 is chosen as a basis for model development. The original model is extended to include (1) phosphorus state variables; (2) phosphorus and nitrogen limited heterotrophic growth and (3) an additional active biomass component to model predation by higher-order organisms,...

background sewage sludge (biosolids) is a byproduct of wastewater treatment that accumulates in large quantities. effective stabilization and disinfection of sewage sludge prior to land application are necessary to not only protect human health, but also to induce the public its benefits and safety. currently, many wastewater treatment plants in iran dispose great amounts of untreated sewage sl...

Seeding of nitrifying bacteria into the activated sludge process was studied both theoretically and experimentally. A simple model was developed for prediction of the effects of seeding of nitrifying bacteria from a separate stage into the activated sludge process. The purpose of seeding is to improve the treatment results and the process stability as well as to decrease the volume requirements...

Disintegration by hydrodynamic cavitation has a positive effect on the degree and rate of sludge anaerobic digestion. By applying hydrodynamic disintegration the lysis of cells occurs in minutes instead of days. The intracellular and extracellular components are set free and are immediately available for biological degradation which leads to an improvement of the subsequent anaerobic process. H...

This study evaluates the application of an anoxic side-stream reactor in the sludge return line of a conventional activated sludge system for the reduction of biomass production. The oxidation-reduction potential was maintained at -150 mV while the applied sludge loading rate was modified by changing the percentage of return sludge treated in this reactor. The observed yield from the convention...

Municipal biosolids produced during activated sludge treatment applied in wastewater treatment plants, are significant reservoirs of antibiotic resistance, since they assemble both natural and fecal microbiota, as well as residual concentrations of antibiotic compounds. This raises major concerns regarding the environmental and epidemiological consequences of using them as fertilizers for crops...

Background Aerobic granular sludge has become an attractive alternative to the conventional activated sludge due to its high settling velocity, compact structure, and higher tolerance to toxic substances and adverse conditions. Aerobic granular sludge process has been studied intensively in the treatment of municipal and industrial wastewater. However, information on leachate treatment using ae...