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Triclosan (TCS) is an antimicrobial agent used in many personal care and cleaning products. It has been detected in most environmental compartments and the main entry pathway is wastewater effluents and biosolids. TCS was analyzed in 300 samples of raw influent, final effluent, and biosolids from 13 wastewater treatment plants (WWTPs) across Canada representing five types of typical wastewater treatment systems. TCS was almost always detected in influent (median 1480 ng/L), effluent (median 107 ng/L), and biosolids (median 8000 ng/g dry weight) samples. Removals of TCS from lagoons as well as secondary and advanced treatment facilities were significantly higher than primary treatment facilities (p < 0.001). TCS removal was strongly correlated with organic nitrogen removal. TCS removals at most lagoons and plants that use biological treatment were higher during summer compared with winter. However, no seasonal or temperature effects were observed at the two primary facilities, likely due to the absence of biological activity. Aerobically digested solids contained the lowest levels (median 555 ng/g) while anaerobically digested primary solids contained the highest levels of TCS (median 22,700 ng/g). The results of this large comprehensive study demonstrate that TCS is consistently present in wastewater and biosolids at relatively high concentrations and that removal from wastewater and levels in biosolids are strongly influenced by the wastewater and solids treatment types. [ABSTRACT FROM AUTHOR]

Abstract: The fate of 14 antidepressants along with their respective N-desmethyl metabolites and the anticonvulsive drug carbamazepine (CBZ) was studied in 5 different sewage treatment plants (STPs) across Canada. Using two validated LC-MS/MS analytical methods, the concentrations of the different compounds were determined in raw influent, final effluent and treated biosolids samples. Out of the 15 compounds investigated, 13 were positively detected in most 24-h composite raw influent samples. Analysis showed that venlafaxine (VEN), its metabolite O-desmethylvenlafaxine (DVEN), citalopram (CIT), and CBZ were detected at the highest concentrations in raw influent (up to 4.3 μg L−1 for DVEN). Cumulated results showed strong evidence that primary treatment and trickling filter/solids contact has limited capacity to remove antidepressants from sewage, while activated sludge, biological aerated filter, and biological nutrient removal processes yielded moderate results (mean removal rates: 30%). The more recalcitrant compounds to be eliminated from secondary STPs were VEN, DVEN and CBZ with mean removal rates close to 12%. Parent compounds were removed to a greater degree than their metabolites. The highest mean concentrations in treated biosolids samples were found for CIT (1033 ng g−1), amitriptyline (768 ng g−1), and VEN (833 ng g−1). Experimental sorption coefficients (K d ) were also determined. The lowest K d values were obtained with VEN, DVEN, and CBZ (67–490 L kg−1). Sorption of these compounds on solids was assumed negligible (log K d  ≤ 2). However, important sorption on solids was observed for sertraline, desmethylsertraline, paroxetine and fluoxetine (log K d  > 4). [Copyright &y& Elsevier]

A full-scale demonstration of an integrated fixed-film activated sludge (IFFAS) process with floating carriers has been conducted in Ontario, Canada, since August 2003. In this study, data collected on-site from July 2005 to December 2006 are analyzed and compared with the performance of a conventional activated sludge train operated in parallel. Both trains received similar loadings and maintained comparable mixed liquor concentrations; however, the IFFAS had 50% more biomass when the attached growth was considered. In the winter, the conventional train operated at the critical solids retention time (SRT) and had fluctuating partial nitrification. The IFFAS nitrified more consistently and had a doubled average capacity. In the summer, the suspended SRT was less limiting, and the benefit of IFFAS for nitrification was marginal. The lessons learned from the operational requirements and challenges of the IFFAS process (air flow, carrier management, and seasonal foaming) are discussed, and design recommendations are proposed for whole plant retrofit. Water Environ. Res., 81, 219 (2009). [ABSTRACT FROM AUTHOR]

Polycyclic and nitro musk (PNM) fragrances in personal care products persist and bioaccumulate in the environment following wastewater discharges and land application of biosolids. Influent and effluent concentrations, seasonal variations, and process removal efficiencies of 11 PNMs were investigated at six wastewater treatment plants representing four typical Canadian treatment processes: lagoon, oxidation ditch, extended aeration, and conventional activated sludge. Influent concentrations were as high as 40 000 ng/L for polycyclic musks and 400 ng/L for nitro musks, and showed some seasonal fluctuation. Effluent concentrations were as high as 4000 ng/L and 150 ng/L for polycyclic and nitro musks, respectively. Lagoon treatment produced the highest percent removal (>95%) and the lowest effluent concentrations of PNMs, with process temperature exerting some influence on removal. Results indicate that simple hydraulic or solids retention time are not strong predictors of PNM removals from wastewater. Effluent PNM concentrations were extrapolated to all treatment plants in the watershed to estimate concentrations along the Grand River and its tributaries. [ABSTRACT FROM AUTHOR]

Patterns of microbial fatty acids (MFAs) from activated sludge samples were analyzed over one year's operation at the Hamilton Woodward municipal wastewater treatment plant in Canada. The objective was to examine community structure dynamics and to consider the potential for interrelationships between the population dynamics and treatment performance. With the exception of a higher than normal solids discharge on one day, the treatment plant operations were otherwise stable during the year. As such, wastewater temperature appeared to be the dominant influence on the observed dynamics of the MFA community structure. MFA monitoring and analysis was demonstrated as a practical diagnostic tool in community structure trend monitoring. While the findings did suggest potential for full-scale treatment process monitoring, further development is required. Advancement in technique and greater insight for the data interpretation will be made with historical data from continued case studies. In future studies, selective sub-sampling of biomass fractions (settling and dispersed fauna), evolution in the compositional analysis methods, and, ideally, complementary genotypic and classical microscopic analyses on select samples are recommended. [ABSTRACT FROM AUTHOR]

Discusses a study that examined aerobic digestion of the phosphorus-laden sludge produced at the Regina Wastewater Treatment Plant in Saskatchewan and the feasibility of land use of sludge combined with dewatered anaerobically digested primary sludge from the plant. Possible use of aerobic digestion for the stabilization of chemical sludge; Advantages of mixed digested sludge; Information on sludge disposal appropriateness of mixed digested sludge.