Exploring the current state of play for cost-effective water treatment by membranes

This article presents a perspective on the current development and application of membranes for the treatment of water. We examine how membranes contribute to the global challenge of sustainable supply of clean water. The main theme is on desalination and how innovative science and emerging technology is being applied. Thus, we appraise how techniques such as advanced membrane materials, biomimetic membranes, hybrid systems, forward osmosis, and membrane distillation are being used to improve production to meet the increasing global demand for water

Improving the performance of trays solar still by using sand beds and reflectors

In order to maintain access to freshwater resources in water-stressed regions, it is important to improve the performance of solar-powered desalination systems with lower cost units like solar stills (SS). However, the SS produces low productivity especially through the rainy or cloudy days due to the indirect diffused beams. Therefore, the main aim of this study is to increase the yield from brackish/seawater via a solar still operating with renewable energy sources. The water depth was lowered, and thermal storage materials with different sand beds trays solar still (TSS) are used to augment the amount of yield from a SS. The effects of sandy bed height, and sand type (black and yellow) on the performance of TSS were investigated. Also, the effect of internal reflectors on the sand TSS performance was investigated. Experimental results revealed that the sandy layer (storage beds) improves the TSS production. The maximum increase in accumulated production of sandy TSS with internal reflectors was reached at sand beds height of 1 cm and black sand. In this case, the freshwater was heightened by 105 % over CSS

Maternal parenting style and body mass index among 6–12-year-old girls in Saudi Arabia: A pilot study

Background: An increasingly high prevalence of overweight and obesity exists among Saudi children. Parenting style may serve as a potential predictor in overweight and obesity. Aim: This study examines parenting style as a potential predictor relationship in overweight and obesity among Saudi children. Methods A cross-sectional study involving 92 paired girls and mothers was conducted to determine the association between maternal parenting styles and Saudi girls’ BMI. Findings: The results indicated that the most prevalent parenting style was the authoritative. Majority of students have a moderate obesogenic environment. However, it was not significantly correlated with students BMI. Also, parenting styles were not significantly correlated with an obesogenic environment. Conclusions: Factors other than maternal parenting styles such as environmental factors, families’ socioeconomic status, or cultural factors might be stronger contributors to an obesogenic environment. Larger heterogenous studies are warranted to explore children's BMI and parenting styles associations in Saudi Arabia

Comparative studies of different membrane distillation configurations and membranes for potential use on board cruise vessels

Cruise tourism industry is expanding worldwide. An average cruise ship produces over 1000 m3 per day of fresh water. To date, multi-stage flash distillation (MSF) and seawater reverse osmosis (SWRO) are the most used desalination technologies on board. However, their application has some drawbacks: a great volume needed on board (MSF), increases of fuel consumptions (SWRO), carbon dioxide emissions and total costs. In this way, membrane distillation (MD) is proposed to overcome limitations of existing conventional technologies. Different configurations (DCMD, AGMD and WGMD) and two membranes (0.45 and 0.20 μm) were tested and compared with each other in order to study potential use of MD on board cruise ships, taking advantage of waste heat generated in the engine cooling system. Operational conditions were established based on an approximation of real conditions encountered in a cruise vessel. Results obtained for simulated and real seawater tests showed advantages for WGMD configuration using PTFE 0.45 μm pore size membrane, reaching a high permeate quality (99.99% of salt rejection) and average fluxes around 13 L m− 2 h− 1, being these similar to those produced by SWRO. In conclusion, use of MD, in the cruise industry, can be a sustainable water production choice that should be considered.MINECO. Proyecto: AVANTE, ref.: CTM2014-52116-R, 201