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High operation and maintenance costs, and 'last-mile' issues for populations not connected to municipal water infrastructure, have limited the utility of centralized reverse osmosis (RO) systems to alleviate water availability issues for rural communities. To address these challenges, a decentralized RO module which employs tubular RO membranes was designed and investigated. The system represents an appropriate technology because it requires minimal pretreatment and it fits in self-contained, low-profile suitcase. This compact desgin also incorporated innovative 3D printed static mixers to minimize salt concentration polarization and to improve performance. Since grid electricity may also be discontinuous in the target use cases, the system was tested with two direct current (DC) power solutions: a photovoltaics-battery configuration and an alternator-battery. The final prototype weighs less than 15 kg and was found to have a production capacity of ∼8 L/h, consuming ∼100 W of pumping power. Experiments of the prototype module revealed a 96% rejection rate of salt from a 1000–2000 ppm synthetic groundwater solution and a >99% rejection coefficient for bovine serum albumin protein and humic acid. From these performance metrics, it was estimated that 36 sets of this decentralized system (with a total CapEx of US$23,400) could provide drinking water for ∼600 rural households at a unit cost of water of 1 LKR/L (0.005 USD/L) in Sri Lanka. Overall, this study demonstrates how computational modeling and 3D printing can be leveraged to develop a compact and cost-effective decentralized RO package that could be rapidly deployed to water-stressed rural areas and in disaster relief applications. [Display omitted] • A plug-and-play, compact DC driven mobile RO desalination system was developed. • Both alternator-battery and solar PV- battery power solutions were designed and tested. • The system is less than 15 kg and can produce 8 L/h of water with 100 W of power. • Rejection of 96% for salt and >99% for both protein and humic acid was observed. • The levelized cost of water of water was found to be < 0.005 USD/L. [ABSTRACT FROM AUTHOR]

Solar thermal electricity generated by concentrated solar power (CSP) plants is increasingly implemented. CSP plants can supply electricity on a fully matched supply-demand basis if equipped with a thermal energy storage. To increase the efficiency and reduce both capital and operating costs, a next generation of CSP concepts is required. Particle suspensions can be applied to meet these targets and can be used throughout the CSP conversion process, as high temperature heat transfer medium in the receiver, for heat storage, and in the power block of the plant. This work presents the novel concept of using particle suspensions as heat carriers, mostly further to initial testing at the CNRS 1 MW solar furnace of Odeillo Font-Romeu (F). Values of the heat transfer coefficient up to 1100 W/m 2 K (bare tubes) and 2200 W/m 2 K (finned tubes) were obtained for operation at low superficial gas velocities of 0.04–0.19 m/s, thus limiting heat losses by the exhaust air. Despite additional costs for particle handling and for an appropriate boiler, the required overall investment and operating costs are expected to be significantly lower than for common equivalent molten salt CSPs, leading to a reduction in Levelized Cost of Electricity (LCOE) from approximately 125 €/MWh to below 100 €/MWh. [ABSTRACT FROM AUTHOR]

The bio-waste slow pyrolysis process is assessed by four indicators to determine its energetic, exergetic, economic and environmental performance. The influence of the pyrolysis temperature (300–800 °C) on these parameters, but also on the biochar, bio-oil and gas production, is analysed. The biochar yield decreased 10.5% and the gas yield increased 17.2% between 300 and 800 °C. The bio-oil yield increased about 2.1% between 300 and 500 °C and decreased about 8% between 500 and 800 °C. Within the temperature range 300–800 °C, the H 2 , CO and CH 4 molar fractions increased 51.4, 6.6 and 0.3%, respectively. CO 2 content decreased about 58.3%. The exergy efficiency varied between 81.16 and 85.33% in this temperature range. The exergy-based economic factor revealed that 15.38–19.16% of the total cost was associated with the exergy destruction. The environmental impact was lower at higher temperatures. The recommended temperature range is 300–400 °C to produce biochar, and temperatures of over 700 °C to produce gas. When the interest focus is on the bio-oil, it is recommended to work close to 500 °C. Image 1 • Thermodynamic equilibrium model was applied to predict biochar, bio-oil and gas yields. • The bio-oil yield showed a maximum at 500 °C. • H 2 , CO and CH 4 contents in the pyrolysis gas increased with the pyrolysis temperature. • The exergy efficiency varied between 81.16 and 85.33%. • 15.38–19.16% of the total cost is associated with exergy destruction. [ABSTRACT FROM AUTHOR]

In this study, ultrasound (US) disintegration was evaluated as a digestate treatment strategy. Digestate treatment is the physical, chemical or biological treatment and recirculation AD of the effluents of the anaerobic digesters (i.e., digestate) to the digester as supplementary feed to increase their utilization potential for energy conversion or green chemical production in post-valorization pathways. In this scope, semi-continuous small pilot scale manure digesters were operated in parallel with various operational settings. One of the digesters was fed by adding disintegrated digestate to an equal volume of fresh manure feed (recycle ratio of 1). The obtained results showed that US-assisted digestate treatment at 1500 kJ/kg TS specific energy input with 30 days of hydraulic retention time increased the methane production rate by 18%. The increased methane production rate was found to be related to the applied specific energy and organic loading rate. A basic cost-benefit analysis showed that the energy demand of the US disintegration at lab scale was higher than the energy that can be recovered from the additional biogas produced. • Ultrasound-assisted digestate treatment increases soluble COD of the digestate. • Higher methane production is correlated with the specific energy input of treatment. • Digestate treatment with lower intensity is favored for increased methane production. • Energy consumption of the US reactor exceeds energy gain from extra produced biogas. [ABSTRACT FROM AUTHOR]