• Energy Research
• 6. Clean water close
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• Polytechnic University of Turin close

The development of new methods for the correct disposal of waste is unavoidable for any city that aims to become eco-friendly. Waste management is no exception. In the modern era, the treatment and disposal of infectious waste should be seen as an opportunity to generate renewable energy, resource efficiency, and, above all, to improve the population’s quality of life. Northern Italy currently produces 66,600 tons/year of infectious waste, mostly treated through incineration plants. This research aims to explore a more ecological and sustainable solution, thereby contributing one more step toward achieving better cities for all. Particularly, this paper presents a conceptual design of the main sterilization chamber for infectious waste. The methodology selected was Design Thinking (DT), since it has a user-centered approach which allows for co-design and the inclusion of the target population. This study demonstrates to the possibility of obtaining feasible results based on the user’s needs through the application of DT as a framework for engineering design.

This work has as main objective the analysis of waste from electric and electronic equipment (WEEE or e-waste) management through material flow analysis and life cycle assessment of a full-scale Italian facility that is significant about the e-waste flows treated (9900 t/y) and representative of a developed EU country about the industrial process outline, based on manual dismantling phases and physic-mechanical automatic processes. Three WEEE categories (i.e. R1-Cooling equipment, R2-Large household appliances and R3- TVs and screens) have been chosen with the reason that they are the most abundant in EU. The methodology was based on two end-of-life scenarios: S0-partial recycling of valuable fractions and landfilling of the rest, which is conventional e-waste processing in Italian facilities; S1-complete recycling of valuable fractions, limited incineration and landfilling of the rest, which describes what happens in the considered case study. Mass balance of the three treatment lines showed recycling rate (RR) values equal to: for R1 40% for S0 and 80% for S1; for R2 65% for S0 and 99% for S1; for R3 86% for S0 and 91% for S1, with significant fractions incinerated or landfilled only for R1 treatment line. Life cycle assessment considered transport (post-consumer collection), treatment, recycling, incineration and disposal. As main results, eco-toxicity aquatic potentials referring to marine and fresh water were the most relevant impact categories. In conclusion, recycling (mostly of metals) played a crucial role for environmental benefits, and transport and polyurethane plus rubber incineration for the environmental impacts.

The incremental oil recovery has been investigated and approved by many laboratory and field projects using water flooding in tertiary stage. The salinity of the injected water is an important factor observed by many researchers. The more salinity decreases the more oil recovery obtained. The investigations on the hot low salinity water flooding have been conducted by many researchers and they found out that it is useful for increasing oil recovery especially heavy oil due to reducing oil viscosity and make it easy to produce to the surface. The thermal expansion of water plays an important role in the incremental oil recovery mechanism, reducing the density of the injected water relative to the aquifer water. This reduces mixing; minimizing thermal loses to the aquifer. Hot water flooding may also increase the economic life of individual wells by as much as a factor of two. Smart water was also used to alter the reservoir wettability and increase oil recovery by manipulating the divalent cations in the injected water. In this study, we used hot and cold smart water and injected both into the sandstone saturated with crude oil in order to investigate the important role of smart water itself and hot smart water. The systematic results showed that changing some cations in the injected brines was better than to spend more money to heat the smart water. The divalent cations Ca2+ and Mg2+ were the most effective component in the smart water. In this study, we also studied the pH effect of the cold/hot smart water effluent smart water EOR.

Performances of mechanical and low-temperature (<100°C) thermal pre-treatments were investigated to improve the present efficiency of anaerobic digestion (AD) carried out on waste activated sludge (WAS) in the largest Italian wastewater treatment plant (2,300,000p.e.). Thermal pre-treatments returned disintegration rates of one order of magnitude higher than mechanical ones (about 25% vs. 1.5%). The methane specific production increased by 21% and 31%, with respect to untreated samples, for treatment conditions of respectively 70 and 90°C, 3h. Thermal pre-treatments also decreased WAS viscosity. Preliminary energy and economic assessments demonstrated that a WAS final total solid content of 5% was enough to avoid the employment of auxiliary methane for the pre-treatment at 90°C and the subsequent AD process, provided that all the heat generated was transferred to WAS through heat exchangers. Moreover, the total revenues from sale of the electricity produced from biogas increased by 10% with respect to the present scenario.

Coal fly ash was characterized at first in batch adsorption with acid and basic dyes. Good results of removal were obtained, although strongly dependent on initial dye concentration, ash dosage, and above all on pH of the solution. The maximum adsorption capacities per g of fly ash were 410 mg of Acid Blue 25 and 142 mg of Basic Blue 9, both with an ash dosage of 2 g/L at pH 11 after a contact time of 1 h. However, increasing the ash dosage to 20 g/L and contact time to 24 h, the maximum adsorption capacity of Basic Blue 9 raised 187 mg/g fly ash at pH 11, but this value was lowered to 8.4 mg/g at pH 7. Afterwards, flow experiments were carried out in semi-batch mode with a fixed amount of ash and continuous flow of dye solution in continuous stirred tank reactor, to determine the exhaustion curves of fly ash. The best fit of the results was obtained by a sigmoidal function referable to the breakthrough curve model of Yoon-Nelson. Successively, to reduce the alkali leaching by solution flow, in a semi-pilot scale plant, a continuous stream of dye solution was mixed in stirred tank reactor with a continuous ash slurry supply, and the resulting slurry was decanted in a settling tank to obtain a clarified supernatant stream outlet. In this last equipment, the optimum conditions were investigated to obtain the highest yields of dye removal from solutions at low concentrations (5–20 mg/L) such as those occur in rinsing waters arising from dyeing processes.

Abstract The integration of solid oxide fuel cell (SOFC) systems and micro gas turbines in a reference wastewater treatment plant is proposed. The main scope is to utilize the available biogas in a real wastewater treatment plant (WWTP) to feed both the SOFCs and micro gas turbines (MGTs) to produce electrical power while covering the digester thermal demand of the plant. To do so, two cases namely SOFC-WWTP (in which the SOFC system is the only CHP unit), and SOFC-MGT-WWTP (integration of both SOFCs and microturbine systems) are proposed. Results show that use of microturbines along with the SOFC systems can increase the share of electricity covered by self-generation within the WWTP by up to 15% while keeping stable the coverage of the thermal load. Also, the energy efficiency of the novel system (SOFC-MGT-WWTP) is calculated to be 7% more than that of the SOFC-WWTP. Economic analysis results reveal that using microturbines, the payback time for whole the system could be reduced about 4 years. Also, for the short term scenario, the levelized cost of electricity for the SOFC-MGT-WWTP system is found to be 0.118 $/kWh which is about 12% less than that for the SOFC-WWTP system. However, for the long term scenario, the difference becomes remarkably less.

Abstract This article aims to apply the Energy Sustainability Analysis (ESA) to the process of Anaerobic Digestion (AD), considering five different feedstocks: the organic fraction of municipal solid waste (OFMSW), agro-industrial products (energy crops) such as maize and sorghum silages, and agro-zootechnical wastes (slurry and manure) from cattle and pig livestock. The case study focuses on an AD bioreactor which is fed with a constant flow (50 ton/d) at a fixed total solids (TS) concentration (15% TS w/w). The processing chain is divided into three phases: pre-digestion operations, AD and the cogeneration of biogas, and post-digestion operations. The ESA methodology uses dedicated metrics and considers the entire technology chain from the energy resources up to useful energy. Energy crops present important energy footprints that must be spent for their production, while in the AD process, the pre-digestion and post-digestion phases present different energy costs for each analyzed feedstock. The results indicate that although the produced energy depends on the energy potential of the biomasses, the pre-digestion and post-digestion phase have an important weight in the overall energy sustainability of the system. In addition, in the case of the use of agro-zootechnical wastes and energy crops as feed, the availability of sufficient land to spread digestate on the field is essential to ensure the sustainability of AD technology, in its absence the energy sustainability can be critical as shown for the case of maize silage.

The flow ripple in an internal gear pump was measured by means of a new instantaneous high-pressure flowmeter. The flowmeter consists of two pressure sensors mounted on a piece of the straight steel pump delivery line, and a variable-diameter orifice was installed along such a line, downstream of the flowmeter, to generate a variable load. Three distinct configurations of the high-pressure flowmeter, characterized by a different distance between the pressure transducers, were analyzed. Furthermore, a comprehensive fluid dynamic 3D model of the pump and of its high-pressure delivery line was developed and validated in terms of both the delivery pressure and the flow ripple for different pump working conditions. For the three examined configurations of the flowmeter, the measured flowrate time histories matched the corresponding numerical distributions at the various operating points. Finally, the validated 3D model was applied to predict the incomplete filling working of the interteeth chambers, and the obtained numerical pressure time histories along the delivery line were used, as input data, to assess the reliability of the flowmeter algorithm even in these severe operating conditions.