Toxic compounds in sewage or industrial wastewater may inhibit the biological activity of activated sludge impairing the treatment process. This paper evaluates the Inhibition Capacity Index (ICI) for the assessment of activated sludge in the presence of toxicants. In this study, activated sludge was obtained from industrial treatment plants and was also synthetically produced. Continuous respi...

Over 99% of phenol was effectively degraded in an upflow anaerobic sludge blanket (UASB) reactor at 55 degrees C with 40 h of hydraulic retention time (HRT) for a wastewater containing 630 mg/L of phenol, corresponding to 1500 mg/L of chemical oxygen demand (COD) and a loading rate of 0.9 g-COD/L/d. The maximum specific methanogenic activity (SMA) of the phenol-degrading sludge was 0.09 g-CH4-C...

Biomarkers (respiratory quinones and cellular fatty acids) and denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA genes were used to characterize the microbial community structure of lab-scale enhanced biological phosphate-removal (EBPR) systems in response to altering sludge phosphorus (P) content. All the data suggest that the microbial community structures of sludge sam...

The agent in wastewater sludge previously shown to reduce the heat required to inactivate reovirus (R. L. Ward and C. S. Ashley, Appl. Environ. Microbiol. 34:681--688, 1977) was "separated" from other sludge components and analyzed by infrared spectroscopy. The infrared spectrum of this material was quite similar to the spectra of commercial anionic detergents, and subsequent analyses of the fr...

The effects of agricultural-improvement treatments on the chitinolytic activity and diversity of a microbial community were investigated within an upland pasture. The treatments of interest were lime and treated sewage sludge, both commonly applied to pasture land to improve fertility. Burial of chitin-containing litter bags at the field site resulted in enrichment of bacteria according to 16S ...

Accumulation of substrate onto the biomass was quantified under steady-state and shock conditions in a fixed bed reactor fed with an oleic acid-based synthetic effluent. The accumulation of substrate onto the sludge was more dependent on oleic acid concentration than on oleic acid loading rate and decreased the acetogenic, acetoclastic and hydrogenophilic activity. However, even when the methan...

Cadmium has a toxic effect on soil microbial activity which plays an important role in nutrient cycling and, therefore, in maintaining soil fertility. In addition, the mobility of this heavy metal in soil is affected by the addition of urban wastes such as sewage sludge. This study was conducted to determine the effect of sewage sludge amendment of a semiarid soil, previously polluted with Cd, ...

This paper deals with thermal drying of wastewater sludges, whose management will become crucial in the forthcoming years. Sludges collected after mechanical dewatering in 5 different WWTPs are submitted to the same convective drying treatment in order to try finding some relations between the drying behaviours, the type of effluent and wastewater treatments. Results show dearly sludge drying r...

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...