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We combined profiling of the bloom-forming and potentially toxigenic cyanobacterium Planktothrix rubescens using a multiparameter probe equipped with a phycoerythrin sensor (in vivo fluorometry, IVL) in Lake Mondsee, Austria, with flow cytometric live analyses of discrete samples taken from several depths in the upper 20 m of the water column. Results obtained by IVL and acoustic flow cytometry (AFC) were compared to microscopic analyses of integrated (0-21 m) water samples using fixed material. This comparison was made because the integrated samples are used for the Austrian monitoring programme according to the EU Water Framework Directive. We demonstrate that AFC provides quantitative analyses of the filaments of P. rubescens that are significantly correlated to IVF and microscopic analyses, allowing rapid (within hours) and more precise calculation of P. rubescens biomass than estimates derived from IVL. Our analysis shows that vertically integrated water samples provide unreliable information on the concentration of P. rubescens in the upper surface waters and on the peak concentration of P. rubescens within the water column. We conclude that the protocol that we developed is superior to the current monitoring practice.

Abstract The contamination of water bodies by heavy metals is one of the main concerns for environmental protection, due to the intrinsic toxicity and long lifetime of these compounds. Consequently, there is a pressing need to reduce emissions of heavy metals in wastewater, using efficient and cost-effective remediation techniques, which at the same time will not produce toxic residues, e.g. adsorption on activated carbon. The present work deals with the optimal design and operation of adsorption columns for the removal of cadmium and nickel from synthetic aqueous solutions, both in single-compound and binary systems. Thermodynamic experimental tests were carried out on activated carbon samples (GAC), produced starting from a commercial carbon by chemical oxidation with either nitric acid or hydrogen peroxide, to support the dynamic study and to identify the sample with higher adsorption capacity. Subsequently, the dynamic behavior of Cd and Ni adsorption was studied by means of software simulations in order to attain an optimized column design. Several working configurations were explored, investigating the effects of GAC physical and chemical properties, pollutant concentration and flow rate, for a wide application in process operations. Moreover, the intertwining between thermodynamic and dynamic parameters in the performance of a fixed-bed was highlighted. All the transport phenomena that can affect the overall performance, i.e. axial dispersion, external film diffusion and intraparticle mass transport were considered. In particular, for the internal transport, both pore and surface diffusions were taken into account and considered to occur in parallel; moreover the contribution of pollutant surface diffusivity, which is usually neglected in the commonly adopted model because difficult to estimate, was isolated and its influence on the overall adsorption rate was elucidated. The general formulation of the kinetic model allowed estimating the contribution of each adsorption rate controlling parameter and the effect exerted by the main fluid dynamic parameters, hence representing a fundamental tool for the design and optimization of an adsorption column.

The Biohydrogen Potential (BHP) of six different types of waste biomass typical for the Campania Region (Italy) was investigated. Anaerobic sludge pre-treated with the specific methanogenic inhibitor sodium 2-bromoethanesulfonic acid (BESA) was used as seed inoculum. The BESA pre-treatment yielded the highest BHP in BHP tests carried out with pre-treated anaerobic sludge using potato and pumpkin waste as the substrates, in comparison with aeration or heat shock pre-treatment. The BHP tests carried out with different complex waste biomass showed average BHP values in a decreasing order from potato and pumpkin wastes (171.1 ± 7.3 ml H2/g VS) to buffalo manure (135.6 ± 4.1 ml H2/g VS), dried blood (slaughter house waste, 87.6 ± 4.1 ml H2/g VS), fennel waste (58.1 ± 29.8 ml H2/g VS), olive pomace (54.9 ± 5.4 ml H2/g VS) and olive mill wastewater (46.0 ± 15.6 ml H2/g VS). The digestate was analyzed for major soluble metabolites to elucidate the different biochemical pathways in the BHP tests. These showed the H2 was produced via mixed type fermentation pathways.

Abstract This paper presents the integration of the evacuated tube solar collectors into a novel solar polygeneration plant. The analysis is performed by evaluating the energy and economic performance of the plant, coupled to a multi-effect distillation unit for seawater desalination, a single effect water lithium bromide absorption chiller, a biomass auxiliary heater, heat exchangers, tanks and balance-of-plant devices. Solar collectors produce heat, at about 90 °C, used for space heating and domestic hot water production, driving the absorption chiller (used for space cooling). Solar heat, combined the heat produced by the biomass auxiliary heater, also drives the multi-effect distillation unit producing desalinated water. The plant is simulated by means of a zero-dimensional dynamic model, developed in TRNSYS environment, which considers several control strategies, for the plant management. The economic analysis shows that the economic profitability significantly improves in case of feed-in tariffs, achieving a payback period of about 3.5 years. The optimization procedure performed by using the Design of Experiment method, returned a payback period of 2.4 years, by selecting the solar field area equal to 1200 m2, the tank dead band temperature to 2 °C, the summer/winter outlet set point temperature from the solar field equal to 95 °C/50 °C.

Effects of anthropogenic and environmental stressors on freshwater communities can propagate to ecosystem functions and may in turn impede ecosystem services. We investigated potential shifts in ecosystem functions that provide energy for freshwater ecosystems due to pesticides and salinity in 24 sites in streams of southeast Australia. First, effects on allochthonous organic matter (AOM) breakdown using three different substrates (leaves, cotton strips, wood sticks) in coarse and fine bags were investigated. Second, we examined effects on stream metabolism that delivers information on the ecosystem functions of gross primary production and ecosystem respiration. We found up to a fourfold reduction in AOM breakdown due to exposure to pesticides and salinity, where both stressors contributed approximately equally to the reduction. The effect was additive as, no interaction or correlation between the two stressors was found. Leaf breakdown responded strongly and exclusively to exposure to pesticides and salinity, whereas cotton strip breakdown was less sensitive and responded also to other stressors such as nutrients. No functional redundancy for the effects of pesticides and salinity on leaf breakdown was observed. For wood stick breakdown, no relationship to environmental gradients was found, however, the sample size was lower. We did not detect effects of pesticides or salinity on gross primary production or ecosystem respiration. A reduction in AOM breakdown by pesticides and salinity may impair the ecosystem services of food provision and possibly water purification. Hence, future studies should examine the spatial extent of these effects.

Cement production is an energy-intensive manufacturing process with potentially large environmental burdens. Among the others, it is one of the largest industrial sources of CO2 emission. Limestone calcination is the stage responsible for most of CO2 emissions and energy requirement. This article aims at supporting the use of solar energy as non-carbogenic renewable source to sustain limestone calcination, with advantages on both the economic and environmental aspects of the process. A directly irradiated Fluidised Bed (FB) reactor was used as limestone precalciner for clinker production. Concentrated solar radiation was simulated with an array of three short-arc Xe-lamps of 4 kWel each, coupled with elliptical reflectors, capable of producing a peak flux of about 3 MW m-2 at the centre of the reactor. The total irradiated power is of approximately 3.2 kWth. Thermocouples and an IR camera were used for the analysis of the FB thermal profiles. Calcination was carried out at a nominal bulk bed temperature of 950 °C, in an atmosphere containing about 70% CO2. The reactivity of lime generated by the solar-driven calcination process has been characterised. Lime produced by the solar-driven process was used together with commercial clay as kiln feed components for the formulation of Portland cement samples. A binary mixture composed by fresh limestone and the same clay as above was employed as a reference. The key focus of the investigation was the assessment of the reactivity of the solar-generated lime toward the main clay components in the clinker production process, as compared to lime from ordinary calcination. An aspect that is specifically scrutinised is whether the different, and possibly more severe, thermal history to which limestone particles undergo during solar-driven calcination in directly irradiated FB reactors may compromise lime reactivity. Portland clinkers were produced by burning the raw meals at 1500 °C for 15 min. Clinkers were mixed with 5% natural gypsum to prepare the related Portland cements, which were then paste hydrated for times ranging from 2 to 28 days (water/cement mass ratio = 0.5, 20 °C, 95% relative humidity). Parameters as lime saturation factor, burnability, phase composition of clinkers and hydration behaviour of cement pastes were taken into consideration. Techniques as X-ray fluorescence and diffraction, and simultaneous differential thermal-thermogravimetry were used to study the materials.

In Mediterranean climates, high temperatures and vapour pressure deficits are currently observed in greenhouses during summer. These conditions are responsible for a high transpiration rate leading to greater water consumption. Measuring and modelling transpiration can be useful for efficient irrigation management by allowing prediction of short-term water demand. The rate of transpiration of zucchini crops (Cucurbita pepo L.) grown in soilless culture was measured in a greenhouse located at Viterbo, central Italy, during spring–summer 2002. The Penman-Monteith equation was used to predict the potential transpiration of the plants averaged over 30-min intervals using different approaches in the calculation of aerodynamic resistance. The values obtained were compared with transpiration measured by a gravimetric method by weighing plants on an electronic balance. Leaf temperature was lower (up to 5°C) than air temperature on clear summer days owing to high transpiration rates. Stomatal resistance was computed and found to be exponentially related to solar radiation. The best fit in transpiration between the Penman-Monteith calculated and those measured was achieved when the heat transfer in the former was obtained as a process of mixed convection, where the slope of the regression was 1, and there was improvement of the coefficient of determination (R2 = 0.96). A simplified model of daytime transpiration based on easily measured variables (solar radiation and vapour pressure deficit) was developed and produced strong agreement with the gravimetric method (R2 = 0.93).

Abstract The technological concept ensuring highly efficient co-digestion of by-products from the production of biodiesel and sewage sludge was examined. Rapeseed cakes (RC) 1–5% addition to waste activated sludge (WAS) 95–99% in digesters, positively influenced the degree of biodegradation of organic matter and the quantity and quality of the biogas produced. Under the optimal conditions (HRT = 20–22 days), the co-digestion mixtures (WAS + microwave disintegration + RC) generated double the amount of biogas, containing approximately 10–12% more CH4, than the samples which had the sewage sludge only. Under these conditions, the biogas yield increased by approximately 48–82% depending on the co-substrate used and was further improved via the introduction of microwave pre-treatment. After testing at the pilot scale, this method could be considered as a sustainable alternative to conventional methods for WAS and RC treatment.

This study uses five years of panel data (2009-2013) for Northern Kenya's Marsabit district to analyze the levels and extent of malnutrition among children aged five and under in that area. We measure drought based on the standardized normalized difference vegetation index (NDVI) and assess its effect on child health using mid-upper arm circumference (MUAC). The results show that approximately 20 percent of the children in the study area are malnourished and a one standard deviation increase in NDVI z-score decreases the probability of child malnourishment by 12-16 percent. These findings suggest that remote sensing data can be usefully applied to develop and evaluate new interventions to reduce drought effects on child malnutrition, including better coping strategies and improved targeting of food aid.

The effect of cultivar and nutrient solution macrocation proportions (SK, SCa, SMg) on the bioactive content of hydroponically cultivated lettuce was evaluated on two lettuce cultivars (red and green-pigmented Salanova®) grown in a fully controlled Fitotron® chamber. Fresh weight and color attributes were superior in green Salanova and in SK-treated plants, while elevated macrocation proportions (SK, SCa, and SMg) affected the corresponding minerals, P and Na content. SCa and SMg treatments raised ascorbate concentration and reduced nitrate levels in treated plants. Chicoric and chlorogenic acids were higher in red over green Salanova. Chlorogenic acid was higher in SCa and SMg plants and chicoric acid levels were SMg > SCa > SK. The SMg-treated red Salanova contained higher concentrations of target carotenoids. In conclusion, nutrient solution management constitutes an effective cultural practice to increase bioactive properties and functional quality of hydroponically grown lettuce.