Screen-printed electrode based electrochemical detector coupled with ionic liquid dispersive liquid–liquid microextraction and microvolume back-extraction for determination of mercury in water samples

A novel approach is presented, whereby gold nanostructured screen-printed carbon electrodes (SPCnAuEs) are combined with in-situ ionic liquid formation dispersive liquid–liquid microextraction (in-situ IL-DLLME) and microvolume back-extraction for the determination of mercury in water samples. In-situ IL-DLLME is based on a simple metathesis reaction between a water-miscible IL and a salt to form a water-immiscible IL into sample solution. Mercury complex with ammonium pyrrolidinedithiocarbamate is extracted from sample solution into the water-immiscible IL formed in-situ. Then, an ultrasound-assisted procedure is employed to back-extract the mercury into 10 µL of a 4 M HCl aqueous solution, which is finally analyzed using SPCnAuEs. Sample preparation methodology was optimized using a multivariate optimization strategy. Under optimized conditions, a linear range between 0.5 and 10 µg L−1 was obtained with a correlation coefficient of 0.997 for six calibration points. The limit of detection obtained was 0.2 µg L−1, which is lower than the threshold value established by the Environmental Protection Agency and European Union (i.e., 2 µg L−1 and 1 µg L−1, respectively). The repeatability of the proposed method was evaluated at two different spiking levels (3 and 10 µg L−1) and a coefficient of variation of 13% was obtained in both cases. The performance of the proposed methodology was evaluated in real-world water samples including tap water, bottled water, river water and industrial wastewater. Relative recoveries between 95% and 108% were obtained.

Water reduction in waste-activated sludge by resettling and filtration in batch. Phase (1): pilot-scale experiments to optimize performance

This article describes an effective procedure for reducing the water content of excess sludge production from a wastewater treatment plant by increasing its concentration and, as a consequence, minimizing the volume of sludge to be managed. It consists of a pre-dewatering sludge process, which is used as a preliminary step or alternative to the thickening. It is made up of two discontinuous sequential stages: the first is resettling and the second, filtration through a porous medium. The process is strictly physical, without any chemical additives or electromechanical equipment intervening. The experiment was carried out in a pilot-scale system, consisting of a column of sedimentation that incorporates a filter medium. Different sludge heights were tested over the filter to verify the influence of hydrostatic pressure on the various final concentrations of each stage. The results show that the initial sludge concentration may increase by more than 570% by the end of the process with the final volume of sludge being reduced in similar proportions and hydrostatic pressure having a limited effect on this final concentration. Moreover, the value of the hydrostatic pressure at which critical specific cake resistance is reached is established.

Brackish groundwater desalination by reverse osmosis in southeastern Spain. Presence of emerging contaminants and potential impacts on soil-aquifer media

Desalinated brackish groundwater is becoming a new source of water supply to comply with growing water demands, especially in (semi-) arid countries. Recent publications show that some chemical compounds may persist in an unaltered form after the desalination processes and that there is an associated risk of mixing waters with different salinity for irrigation. At the university of Alicante campus (Spain), a mix of desalinated brackish groundwater and water from the existing aquifer is currently applied for landscape irrigation. The presence of 209 emerging compounds, surfactants, priority substances according to the 2008/105/EC Directive, 11 heavy metals and microbiological organisms in blended water and aquifer samples was investigated. Thirty-five compounds were detected (pesticides, pharmaceuticals and surfactants) among them two priority substances α-endosulfan and Ni were found above the permitted maximum concentration. Blended water used for landscape irrigation during the summer period is supersaturated with respect to carbonates, which may ultimately lead to mineral precipitation in the soil-aquifer media and changes in hydraulic parameters.

Conditional Order-m Efficiency of Wastewater Treatment Plants: The Role of Environmental Factors

The growing economic and environmental importance of managing water resources at a global level also entails greater efforts and interest in improving the functioning and efficiency of the increasingly more numerous wastewater treatment plants (WWTPs). In this context, this study analyzes the efficiency of a uniform sample of plants of this type located in the region of Valencia (Spain). The type of efficiency measure used for this (conditional order-m efficiency) allows continuous and discrete contextual variables to be directly involved in the analysis and enables the assessment of their statistical significance and effect (positive or negative). The main findings of the study showed that the quality of the influent water and also the size and age of the plants had a significant influence on their efficiency levels. In particular, as regards the effect of such variables, the findings pointed to the existence of an inverse relationship between the quality of the influent water and the efficiency of the WWTPs. Also, a lower annual volume of treated water and more modern installations showed a positive influence. Additionally, the average efficiency levels observed turned out to be higher than those reported in previous studies.

The effect of electricity tariffs over the operating costs of the Spanish wastewater treatments plants

Given the complex structure of electricity tariffs and their steady growth in Spanish, we've studied its effect over the operating costs of the wastewater treatment plants (WWTP), concluding that in the last three years the revisions of electricity rates have meant increases in electricity costs of 64.5% in the rate 3.1.A and 79.1% in the rate 6.1. This has caused the cost of electricity, which was the most important, has increased from a 44% of total operating costs in the year 2009, to more than a 56% in the year 2012.

Evolution of extracellular polymeric substances produced in two submerged membrane bioreactors working at high sludge age

This research paper deals with the evolution of the extracellular polymeric substances (EPS) produced in the mixed liquor of two 25 L bench-scale membrane bioreactors (MBRs), with micro (MF-MBR) and ultrafiltration (UF-MBR) submerged membranes. The conclusion focuses on the relationship between the operation and how EPS respond, demonstrating that significant changes in EPS concentration were commonly observed when abrupt changes in the operational conditions took place. Bound EPS (EPSb) showed moderate positive statistical correlations with sludge age and MLSS for the two MBRs. Soluble EPS (EPSs), on the other hand, showed a moderate negative statistical correlation between EPSs with the two parameters analyzed for MF-MBR and no correlation with the UF-MBR was found. With respect to the composition of EPS, EPSb were mostly made up of proteins (44–46%) whereas in EPSs, the three components (proteins, carbohydrates, and humic substances) appeared in approximately the same proportion. The statistical analysis exhibited strong positive correlations between EPSb and their constituents, however for EPSs, the correlation was strong only with carbohydrates and moderate with humic substances.

Influence of sludge retention time on filtration performance and biomass characteristics in a hollow fiber membrane bioreactor

In this study, the filtration process and the biomass characteristics in a laboratory-scale submerged membrane bioreactor (MBR) equipped with a hollow fiber (HF) microfiltration membrane were studied at different solid retention times (SRT). The MBR was fed by synthetic wastewater and the organic loading rate (OLR) was 0.5, 0.2, 0.1, and 0.08 kg COD kg VSS−1 d−1 for 10, 30, 60, and 90 days of SRT, respectively. The hydraulic retention time was 8.4 h and the permeate flux was 6 L m−2 h−1(LMH). Data analysis confirmed that at all the studied SRTs, the HF-MBR operated very good obtaining of high quality permeates. Chemical Oxygen Demand (COD) removal efficiencies were higher than 95%. The best filtration performance was reached at SRT of 30 d. On the other hand, the respirometric analysis showed that biomass was more active and there was more biomass production at low SRTs. The concentration of soluble extracellular polymeric substances (EPS) decreased with increasing SRT. A decrease of soluble EPS caused a decrease of membrane fouling rate, decreasing the frequency of chemical cleanings. The floc size decreased with SRT increasing. At high SRTs, there was more friction among particles due to the increase of the cellular density and the flocs broke decreasing their size.

A hydrological–economic model for sustainable groundwater use in sparse-data drylands: Application to the Amtoudi Oasis in southern Morocco, northern Sahara

A hydrological–economic model is introduced to describe the dynamics of groundwater-dependent economics (agriculture and tourism) for sustainable use in sparse-data drylands. The Amtoudi Oasis, a remote area in southern Morocco, in the northern Sahara attractive for tourism and with evidence of groundwater degradation, was chosen to show the model operation. Governing system variables were identified and put into action through System Dynamics (SD) modeling causal diagrams to program basic formulations into a model having two modules coupled by the nexus ‘pumping’: (1) the hydrological module represents the net groundwater balance (G) dynamics; and (2) the economic module reproduces the variation in the consumers of water, both the population and tourists. The model was operated under similar influx of tourists and different scenarios of water availability, such as the wet 2009–2010 and the average 2010–2011 hydrological years. The rise in international tourism is identified as the main driving force reducing emigration and introducing new social habits in the population, in particular concerning water consumption. Urban water allotment (PU) was doubled for less than a 100-inhabitant net increase in recent decades. The water allocation for agriculture (PI), the largest consumer of water, had remained constant for decades. Despite that the 2-year monitoring period is not long enough to draw long-term conclusions, groundwater imbalance was reflected by net aquifer recharge (R) less than PI + PU (G < 0) in the average year 2010–2011, with net lateral inflow from adjacent Cambrian formations being the largest recharge component. R is expected to be much less than PI + PU in recurrent dry spells. Some low-technology actions are tentatively proposed to mitigate groundwater degradation, such as: wastewater capture, treatment, and reuse for irrigation; storm-water harvesting for irrigation; and active maintenance of the irrigation system to improve its efficiency.

The Italian Merck Case. Research Papers in Law, 1/2007

From the Introduction. Regulation 1768/921 created supplementary protection certificates (hereinafter, ‘SPCs’) for medicinal products (hereinafter, “pharmaceuticals”) protected by patents. SPCs afford the same exclusive rights as those conferred by patents once these expire and may be granted for a maximum of five years.2 Italy enacted similar legislation in 1991, the most salient difference between both texts being that, pursuant to Law No. 349/91,3 holders of Italian patents for pharmaceuticals could be granted supplementary protection for a maximum period of 18 years after the expiration of the patent. Following the enactment of Regulation 1768/92, SPCs granted by the Italian authorities were brought in line with the period provided for in that text. However, pharmaceuticals for which supplementary protection was sought in the lapse between the adoption of Law No. 349/91 and Regulation 1768/92 (around 400 products) continued to enjoy the protection provided for in the former text.4 Several steps were taken by the Italian authorities to progressively reduce the length of protection granted to these products.

The AstraZeneca Case. Research Papers in Law, 4/2007

Introduction. On June 2005, after a five year investigation, the Commission imposed a 60 millions euros fine on AstraZeneca (hereinafter AZ) for having abused its dominant position in several Member States in the market for proton-pump inhibitors (PPI)2. It was alleged that AZ misused the patent system and procedures for marketing pharmaceuticals to block or delay the entry of generic competitors and parallel traders to its ulcer drug Losec3. This decision is a seminal one. The political and legal importance of the CFI judgment that will review the case (and the ECJ appeal that is likely to follow) cannot be understated. On the one hand the incentive to innovate and to undertake R&D is at stake, on the other, the uncertain boundaries between competition and intellectual property law should once again be explored. In contrast to the US, where many cases concerning the abuse of regulatory and governmental procedures have already been dealt with competition authorities and courts, it is the first time in Europe that such conduct is subject to scrutiny through an anti-trust lens. Moreover, following the appeal brought by AZ against the Commission decision, the CFI will be confronted for the first time with an abuse of a dominant position in the pharmaceutical sector, which explains why this judgment is eagerly anticipated4.

Drivers for and against municipal wastewater recycling: a review

The reclamation, treatment and reuse of municipal wastewater can provide important environmental benefits. In this paper, 25 studies on this topic were reviewed and it was found that there are many (\textgreater150) different drivers acting for and against wastewater recycling. To deal with the challenge of comparing studies which entailed different research designs, a framework was developed which allowed the literature to be organized into comparable study contexts. Studies were categorized according to the level of analysis (wastewater recycling scheme, city, water utility, state, country, global) and outcome investigated (development/investment in new schemes, program implementation, percentage of wastewater recycled, percentage of water demand covered by recycled water, multiple outcomes). Findings across comparable case studies were then grouped according to the type (for or against recycling) and category of driver (social, natural, technical, economic, policy or business). The utility of the framework is demonstrated by summarizing the findings from four Australian studies at the city level. The framework offers a unique approach for disentangling the broad range of potential drivers for and against water recycling and to focus on those that seem relevant in specific study contexts. It may offer a valuable starting point for building hypotheses in future work.

Why Do Some Water Utilities Recycle More than Others? A Qualitative Comparative Analysis in New South Wales, Australia

Although the recycling of municipal wastewater can play an important role in water supply security and ecosystem protection, the percentage of wastewater recycled is generally low and strikingly variable. Previous research has employed detailed case studies to examine the factors that contribute to recycling success but usually lacks a comparative perspective across cases. In this study, 25 water utilities in New South Wales, Australia, were compared using fuzzy-set Qualitative Comparative Analysis (fsQCA). This research method applies binary logic and set theory to identify the minimal combinations of conditions that are necessary and/or sufficient for an outcome to occur within the set of cases analyzed. The influence of six factors (rainfall, population density, coastal or inland location, proximity to users; cost recovery and revenue for water supply services) was examined for two outcomes, agricultural use and "heavy" (i.e., commercial/municipal/industrial) use. Each outcome was explained by two different pathways, illustrating that different combinations of conditions are associated with the same outcome. Generally, while economic factors are crucial for heavy use, factors relating to water stress and geographical proximity matter most for agricultural reuse. These results suggest that policies to promote wastewater reuse may be most effective if they target uses that are most feasible for utilities and correspond to the local context. This work also makes a methodological contribution through illustrating the potential utility of fsQCA for understanding the complex drivers of performance in water recycling.

National Conference on Less Costly Wastewater Treatment Systems for Small Communities, U.S. Environmental Protection Agency, Date: April 12, 13, and 14, 1977, Location: Reston, Virginia.

Mode of access: Internet.

Wastewater irrigation at Tallahassee, Florida /

Aug. 1979.

Long-term effects of land application of domestic wastewater : Roswell, New Mexico, slow rate irrigation site /

Mode of access: Internet.