Review of experimental biodegradation data on pharmaceuticals and comparison with predictive BIOWIN models.

In this study the experimental data on the biodegradation of 16 pharmaceuticals in activated sludge were reviewed and also the theoretical biodegradation of these pharmaceuticals was calculated using BIOWIN models. The main aim was to show the similarities or discrepancies between the two. Experimental data were critically reviewed considering biodegradation rates, biodegradation mechanisms and biosorption of pharmaceuticals.

Exposure of activated sludge to nanosilver and silver ion: Inhibitory effects and binding to the fractions of extracellular polymeric substances.

The main aim of the study was to determine the inhibitory effects of Ag(+) and AgNP (commercial and synthesized) on activated sludge by using respirometry. Along with this aim, also the changes taking place in extracellular polymeric substances (EPS) were studied. Additionally, the binding of Ag(+) or AgNP to the different fractions in EPS was assessed using voltammetry.

Extracellular polymeric substances (EPS) and surface properties of activated sludges: effect of organic carbon sources.

The study aims to clarify how the type of organic substrate in a wastewater affects the production and composition of extracellular polymeric substances (EPS) and hydrophobicity and surface charge of activated sludges. For this purpose, three activated sludge reactors were operated in parallel with feeds composed of the organics (i) peptone, glucose, and acetate and (ii) peptone and (iii) glucose. EPS extracted from sludges were fractionated into very loosely bound, loosely bound, and tightly bound fractions and analyzed for protein and polysaccharide.

Inhibition of respiration and distribution of Cd, Pb, Hg, Ag and Cr species in a nitrifying sludge.

The study investigated the inhibitory effects of the heavy metals Cd, Pb, Hg, Ag and Cr (as Cr(3+) and Cr(6+)) on a nitrifying sludge. The aim was to assess the IC(50) concentrations leading to 50% inhibition. The method is based on respiration of nitrifying sludge in the presence of these metals.

Adsorption and cometabolic bioregeneration in activated carbon treatment of 2-nitrophenol.

The extent of cometabolic bioregeneration of activated carbons loaded with 2-nitrophenol was investigated in lab-scale batch activated sludge reactors. Bioregeneration was quantified by measuring the deterioration in adsorption capacity of a fresh activated carbon after a pre-loading and a subsequent bioregeneration sequence. Activated carbons loaded with 2-nitrophenol could be partially bioregenerated cometabolically in the presence of phenol as the growth substrate.

Cometabolic bioregeneration of activated carbons loaded with 2-chlorophenol.

Thermally and chemically activated carbons were used to investigate the extent of cometabolic bioregeneration in laboratory scale activated sludge reactors. Bioregeneration was determined and quantified by measuring the substrate and chloride concentrations, oxygen uptake rates, and deterioration in adsorption capacities. Activated carbons loaded with 2-chlorophenol could be partially bioregenerated in the presence of phenol as the growth substrate.

Effect of continuous Cd feeding on the performance of a nitrification reactor.

The inhibitory effect of Cd on nitrification was investigated in a continuous-flow system with enriched nitrifying bacteria. The maximum specific ammonium utilization rate and the half-saturation constant were found as 671 mg NH(4)-N/g VSS day and 0.48 mg/l, respectively.

Monitoring of population shifts in an enriched nitrifying system under gradually increased cadmium loading.

The changes in nitrifying bacterial population under cadmium loading were monitored and evaluated in a laboratory scale continuous-flow enriched nitrification system. For this purpose, the following molecular microbiological methods were used: slot-blot hybridization, denaturing gradient gel electrophoresis (DGGE), real-time PCR followed by melting curve analysis, cloning and sequence analysis. The initial cadmium concentration was incrementally increased from 1 to 10mg/l which led to a drop in ammonia removal efficiency from 99 to 10%.

Importance of cadmium speciation in nitrification inhibition.

In this study, the influence of Cd speciation on nitrification inhibition was investigated in batch suspended growth activated sludge systems which contain biomass enriched in terms of nitrifiers. For this purpose, parallel measurements of specific oxygen uptake rates (SOUR), ammonium utilization rates [Formula: see text] and Cd uptake were carried out. Cd speciation was adjusted with a strong complexing agent, ethylenediaminetetraacetic acid (EDTA).

Adsorption, desorption and bioregeneration in the treatment of 2-chlorophenol with activated carbon.

This study aims to clarify the effect of activated carbon type on the extent of adsorbability, desorbability, and bioregenerability in the treatment of 2-chlorophenol. Four different activated carbon types; thermally activated and chemically activated powdered carbons (PAC), and their granular countertypes (GAC) with similar physical characteristics were used. Thermally activated carbons adsorbed 2-chlorophenol much better than chemically activated ones.

Kinetic analysis of the inhibitory effect of trichloroethylene (TCE) on nitrification in cometabolic degradation.

In this study, the inhibitory effect of TCE on nitrification process was investigated with an enriched nitrifier culture. TCE was found to be a competitive inhibitor of ammonia oxidation and the inhibition constant (K(I)) was determined as 666-802 microg/l. The TCE affinity for the AMO enzyme was significantly higher than ammonium.

Cometabolic degradation of TCE in enriched nitrifying batch systems.

The aim of this study was to evaluate the effect of the trace pollutant trichloroethylene (TCE) on the nitrification process and to assess its cometabolic degradation. Nitrification was accomplished in batch suspended growth systems containing an enriched nitrifier culture. The presence of TCE resulted in both the inhibition of specific oxygen uptake rate (SOUR) and specific ammonium utilization rate (qNH(4)-N).