Fate and biodegradability potential of an emerging micropollutant diclofenac in subsurface environment

The present study deals with the assessment of the fate of an emerging contaminant (diclofenac), present in the subsurface environment at specific concentration levels, and its biodegradation potential under different environmental configurations. Diclofenac is a widely consumed nonsteroidal anti-inflammatory drug used as a painkiller prescribed as pills or ointments and among the most frequently detected pharmaceuticals in wastewater treatment plants' effluents. Fermentative/methanogenic cultures were enriched from previously contaminated sediment samples. Although partial biodegradation was achieved in all enrichment cultures, complete degradation was not observed. The results reflected that less than 6% of the diclofenac sorbed on the solid phase and the rest was either biotransformed (25-40%) or remained in the liquid phase (55-70%) at the end of 45-day incubation period. Although partial cometabolic degradation of diclofenac occurred in the presence of glucose, biodegradation was not observed in the presence of readily biodegradable carbon source (i.e., acetate). Diclofenac concentration up to 1000 mu g/L did not affect the methanogenic activity of the enriched culture. The results of this study will have a significant impact in the designation of the permitted concentration limits of diclofenac before the discharge through wastewater treatment plants

Integrated watershed management efforts: case study from Melen Watershed experiencing interbasin water transfer

Istanbul is a megacity with a population of over 13 million. Due to experienced droughts and population growth in the city, interbasin water transfer from Melen Watershed was considered as the most feasible alternative to supply water that can compensate for water demand in the future. This decision changed the beneficial use of the Melen Watershed from irrigation water supply to drinking water supply and necessitated extensive pollution prevention measures to comply with the new water quality requirements. A Watershed Protection Action Plan was developed for the sustainable management of Melen Watershed. The action plan included measures concerning wastewater management, diffuse pollution management, solid waste management and water quality monitoring. In this paper, proposed protection actions in the plan are provided together with the activities realized so far. In addition, the changes made by the authorities during implementation of the plan are presented. The proposed Watershed Protection Action Plan as approved by the government is one of the first examples in Turkey, where watershed-based planning of water resources is implemented instead of administrative boundary-based management

Regulatory Framework in Sludge Management: Examples from Around the World

Treatment and disposal/beneficial use are the most important aspects of municipal sludge management. Particularly, the application guidelines and limit values for treatment systems and the major disposal routes including landfilling, land application and incineration are covered in the legislations. This study aims to review the legislations about municipal sludge treatment and disposal from different counties such as Turkey, USA, EU, Canada and South Africa. Evaluations show that the current legislations place a greater emphasis on the beneficial use of sludge, rather than the mere disposal. The specifics of regulations related to combustion changes between different countries such that in some countries separate regulation for sludge combustion is implemented, whereas in others sludge is not specifically mentioned but included among the big group of wastes to be combusted. Similarly, some countries have particular regulations for landfilling of sludge, whereas the others consider sludge within the greater category of biodegradable wastes together with the organic fraction of solid wastes. This study compares and contrasts these issues and current legislations of the aforementioned countries

Application of an optimized total N-nitrosamine (TONO) assay to pools: placing N-nitrosodimethylamine (NDMA) determinations into perspective

Although N-nitrosodimethylamine (NDMA) has been the most prevalent N-nitrosamine detected in disinfected waters, it remains unclear whether NDMA is indeed the most significant N-nitrosamine or just one representative of a larger pool of N-nitrosamines. A widely used assay applied to quantify nitrite, S-nitrosothiols, and N-nitrosamines in biological samples involves their reduction to nitric oxide by acidic tri-iodide, followed by chemiluminescent detection of the evolved nitric oxide in the gas phase. We here describe an adaptation of this method for analyzing total N-nitrosamine (TONO) concentrations in disinfected pools. Optimal sensitivity for N-nitrosamines was obtained using a reduction solution containing 13.5 lit glacial acetic acid and 1 mL of an aqueous 540 g/L iodide and 114 g/L iodine solution held at 80 degrees C. The method detection limit for N-nitrosamines was 110 nM using 100 mu L sample injections and NDMA as a standard. N-nitrosamines featuring a range of polarities were converted to nitric oxide with 75-103% efficiency compared to NDMA. Evaluation of potential interfering species indicated that only nitrite and S-nitrosothiols were a concern, but both interferences were effectively eliminated using group-specific sample pretreatments previously employed for biological samples. To evaluate the low TONO concentrations anticipated for pools, 1 L samples were extracted by continuous liquid-liquid extraction with ethyl acetate for 24 h, and concentrated to 1 mL. N-nitrosamine recovery during extraction ranged from 37-75%, and there was a potential for artifactual nitrosation of amines during solvent reflux in the presence of significant nitrite concentrations, but not at the low nitrite concentrations prevalent in most pools. Using the 1000-fold concentration factor and 56% average extraction efficiency, the method detection limit would be 62 pM (5 ng/L as NDMA). The TONO assay was applied to six pools and their common tap water source in conjunction with analysis for specific nitrosamines. Even accounting for the range of N-nitrosamine extraction recoveries, NDMA accounted for an average of only 13% (range 3-46%) of the total nitrosamine pool