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Photovoltaic and disinfection performance study of a hybrid photovoltaic-solar water disinfection system
No full textFouling prevention, preparing for re-use and membrane recycling. Towards circular economy in RO desalination
No full textReverse osmosis (RO) is the most employed technology for water desalination. Energy consumption and membrane fouling represent some of the major concerns in membrane technology because they increase the costs associated with treated water. Membrane lifespan is mainly correlated to the quality of the water and the operation condition and it is estimated that often membrane lifespan is 5 to 10 years. Remarkable advances have been made improving the reverse osmosis desalination by integrating pretreatment and cleaning processes. Attending to the membrane active layer, substantial research efforts have been conducted in preparing new antifouling RO membranes to i) enhance antifouling properties, ii) obtain high recovery flux and iii) have low energy requirements. However, scarce research has been detected in literature regarding end-of-life membrane management. This review summarizes the most representative research activities conducted to prevent membrane fouling. In addition, it highlights alternative routes to discarded end-of-life-membranes in order to prevent the uncontrolled disposal of fouled membranes in landfills. In this way, this review aims at summarizing research efforts found in literature in order to approach a more circular economy society, covering the whole life cycle of RO membranes: from the new development of antifouling membranes to the membrane waste management
Risk assessment of pesticides used in rice-prawn concurrent systems in Bangladesh
No full textThe objectives of the current study were to determine the occupational health hazards posed by the application of pesticides in rice-prawn concurrent systems of south-west Bangladesh and to assess their potential risks for the aquatic ecosystems that support the culture of freshwater prawns (Macrobrachium rosenbergii). Information on pesticide use in rice-prawn farming was collected through structured interviews with 38 farm owners held between January and May of 2012. The risks of the pesticide use to human health were assessed through structured interviews. The TOXSWA model was used to calculate pesticide exposure (peak and time-weighted average concentrations) in surface waters of rice-prawn systems for different spray drift scenarios and a simple first tier risk assessment based on threshold concentrations derived from single species toxicity tests were used to assess the ecological risk in the form of risk quotients. The PERPEST model was used to refine the ecological risks when the first tier assessment indicated a possible risk. Eleven synthetic insecticides and one fungicide (sulphur) were recorded as part of this investigation. The most commonly reported pesticide was sulphur (used by 29% of the interviewed farmers), followed by thiamethoxam, chlorantraniliprole, and phenthoate (21%). A large portion of the interviewed farmers described negative health symptoms after pesticide applications, including vomiting (51%), headache (18%) and eye irritation (12%). The results of the first tier risk assessment indicated that chlorpyrifos, cypermethrin, alpha-cypermethrin, and malathion may pose a high to moderate acute and chronic risks for invertebrates and fish in all evaluated spray drift scenarios. The higher tier assessment using the PERPEST model confirmed the high risk of cypermethrin, alpha-cypermethrin, and chlorpyrifos for insects and macro- and micro-crustaceans thus indicating that these pesticides may have severe adverse consequences for the prawn production yields
Cleaning-up atrazine-polluted soil by using Microbial Electroremediating Cells
No full textBiodegradation of pollutants in soil is greatly limited by the availability of terminal electron acceptors required for supporting microbial respiration. Such limitation can be overcome if soil-buried electrodes accept the electrons released in the microbial metabolism. We propose the term bioelectroventing for such a environmental treatment. The process would be performed in a device so-called Microbial Electroremediating Cell. Indeed, our studies demonstrate that the presence of electrodes as electron acceptors effectively stimulated by 5-fold the biodegradation rate of the herbicide atrazine (2-chloro-4-ethylamino-6-isopropyl amino-1,3,5-triazine) in comparison with soil natural attenuation. Furthermore, a different set of toxicological test using Pseudokirchneriella subcapitata green alga e, Salmonella typhimorium bacteria and Sorghum saccharatum plant seeds respectively, confirm that atrazine-polluted soil can be effectively cleaned-up in short time by the use of MERCs
Preparation of loose polypiperazine amide membranes. Effect of the nanocomposite sublayer on the NF process performance
No full textAn insight into the drinking-water access in the health institutions at the Saharawi refugee camps in Tindouf (Algeria) after 40years of conflict
No full textAfección a las aguas subterráneas como consecuencia del uso de aguas regeneradas para riego en Gran Canaria
No full textLos servicios de agua potable y saneamiento, y electricidad son indispensables para la mejora de la salud humana, la reducción de la pobreza y la exclusión social, el bienestar, la alimentación, el crecimiento y desarrollo económico, el cambio climático, entre otros. Así, la equidad, eficiencia y sostenibilidad en el acceso a ambos servicios es un requisito previo para el desarrollo sostenible y la consecución de cada uno de estos objetivos. Sin embargo, el acceso en cantidad, calidad y equidad se ve seriamente condicionado por un conjunto de factores que reducen la eficiencia en la prestación de estos servicios, en especial en países en desarrollo. El estudio desarrollado sobre la prestación de los servicios de agua potable y saneamiento, y electricidad en República Dominicana, ha demostrado que existen una serie de variables que afectan la provisión eficiente de estos servicios en el país. Para ello, se ha descrito el estado de situación de la gestión y prestación de estos servicios en el país mediante una sistematización de datos técnicos e información actualizada y una lectura crítica del funcionamiento de los fragmentarios marcos jurídicos, normativos e institucionales que regulan tales servicios. A su vez, partiendo de esta base, se han identificado y caracterizado los factores relevantes en las dimensiones político-institucionales, económicas y sociales, que más allá del tradicional enfoque técnico, afectan la prestación eficiente de estos servicios. Por lo cual, la presente investigación constituye una base que permitirá a los investigadores y tomadores de decisiones seguir reflexionando sobre cómo mejorar la prestación de estas necesidades básica
Microbial colonisation of transparent glass-like carbon films triggered by a reversible radiation-induced hydrophobic to hydrophilic transition
No full textWe report a reversible wettability hydrophobic to hydrophilic transition in transparent glass-like carbon films under ultraviolet irradiation when the source emitted in the vacuum ultraviolet. The transition occurred at doses below 5 J cm(-2) for devices emitting at 185 nm and was absent when using a 266 nm monochromatic laser source. Hydrophilicity, measured as the water contact angle, was higher when the films were irradiated in air with high relative humidity. Sample hydrophobicity was almost entirely restored over the following 24 h and was completely restored to the initial level when samples were stored for sufficient time under ambient conditions. Our observations were consistent with a transition caused by the dissociative adsorption of water molecules leading to the formation of polar surface groups. Over the few hours in which the surface remained hydrophilic under ambient conditions, a rapid colonisation with Escherichia coli took place with extensive biofilm formation. The percent surface colonised increased from 1.30% +/- 0.4% to a maximum of 51.0% +/- 2.7% for carbon films irradiated in dry air. Irradiation in the presence of water vapour led to surfaces which were more hydrophilic, but less prone to bacterial adhesion. Bacterial colonisation was favoured in films with intermediate hydrophilicity irrespective of the surface charge, measured as the zeta potential. Our study demonstrates that vacuum ultraviolet irradiation induces a wettability transition in glass-like carbon films, and that a relatively short ultraviolet dose of 185 nm irradiation renders their surfaces highly biocompatible
Integrating a microbial electrochemical system into a classical wastewater treatment configuration for removing nitrogen from low COD effluents
No full textThe scaling-up process of microbial electrochemical technologies (METs) may require an initial investment
for constructing completely new infrastructure. In contrast, adapting METs to equipment already present in
wastewater treatment plants (WWTP) can be an attractive alternative to accelerate their implementation. In
this study we evaluated the viability of adapting a classical oxic–anoxic chamber system to a membranefree
microbial electrochemical system in order to remove both nitrogen and organic matter. We simulated
this configuration on a 22 L reactor with two chambers in the absence of any separation membrane. The
working electrode acted as the electron source for denitrifying microorganisms and was placed in the first
chamber. The system was able to support the nitrifying activity without external aeration and at oxygen
levels below 2 mg L−1. The influent, a synthetic medium with ammonium as the sole nitrogen source, was
fed at COD/N ratios from 2 to 4. Up to 19 g NO3
− N m−3 TCC per day were reduced at a COD/N ratio of 4,
with a denitrification efficiency of 93% and a nitrogen removal efficiency of 81%. he system's capacity for nitrifying and denitrifying was strongly dependent on both the COD/N ratio and the working electrode potential. A massive sequencing study revealed the greater abundance of denitrifying genera such as Opitutos,
Methyloversa and Zoogloea at the cathode. Nitrifying genera such as Nitrosomonas and Nitrospira were found in the reactor, the latter being enriched at the anode. In this study we demonstrate that the classical configuration of activated sludge systems can be turned into a MET to treat wastewater. We suggest the mplementation of this air-free hybrid configuration in WWTP as an alternative method to remove nutrients from effluents with low levels of organic matter
Revealing the willingness to pay for income insurance in agriculture
No full textIn spite of its minor and decreasing share in EU GDP, agriculture still plays a fundamental and strategic role in the economy. This is why EU institutions have supported for decades a series of policies to guarantee a stable agricultural income, including insurance. With different degrees of public support, insurance policies covering an increasing number of risks have been developed across the EU. Eventually, EU institutions have started to encourage the development of income insurance. Income insurance covers more risks and has higher uncertainty and costs than conventional single risk or combined yield insurance. Assessing and enhancing the viability of income insurance demands an in depth knowledge of farmers' willingness to pay (WTP) for this product. This study develops a methodology to calculate the WTP for different degrees of income protection using a revealed preference model and the certainty equivalent theory. The methodology is applied in a drought prone area in southeastern Spain. Results show that WTP for income insurance in the area is higher than observed insurance premiums. This may play in favor of the development of more comprehensive income insurance systems