Seawater desalination of arid regions:comparing the policy of the Kingdom of Saudi Arabia and Indonesia

Problems with clean water in coastal areas alongside an increase in population and community economic activities have diversified community activities.Coastal settlements bordering the high seas are characterized as arid areas with a lack of clean water.Here,the use of the range groundwater supply against seawater intrusion means that the water consumed by the community tastes salty and brackish.The availability of abundant seawater,processed through desalination technology,can be used to meet the daily clean water needs of coastal communities.Sustainable development goal(SDG)6 Water and Sanitation is concerned with ensuring that everyone has access to clean water and sanitation.In this regard,desalination technology is considered viable to achieve the SDGs in the environmental sector.Some countries have focused on using desalination technology to achieve target 6.4 by 2030.This goal aims to improve the efficiency of water use to reduce the number of people experiencing clean water scarcity by ensuring a sustainable supply of fresh water.The objective of this study is to examine the application of seawater desalination technology for clean water in the Kingdom of Saudi Arabia(KSA)and Indonesia,and identify the implications of desalination policies in these countries.Comparative studies were conducted using secondary data and literature studies on transforming seawater into clean water with technology.KSA applies seawater desalination technology to meet water needs.However,in Indonesia,policymaking has not holistically examined the potential of using seawater desalination technology for clean water.Until now,unlike in the KSA,Indonesia has not addressed the importance of the use of desalination technology in state policy.

Photothermal-photocatalytic thin-layer flow system for synergistic treatment of wastewater

The integration of the photocatalytic effect into solar steam is highly desirable for addressing freshwater shortages and water pollution.Here,a ternary film structure for the adsorption and photothermal and photocatalytic treatment of wastewater was designed by combining the technique of self-assembled carbon nano paper with a nitrogen composite titanium dioxide(N-TiO_(2))deposited on the surface of carbon nanotubes(CNT)using polyvinylidene fluoride(PVDF)as a substrate.The photogeneration of reactive oxygen species can be promoted by rapid oxygen diffusion at the three-phase interface,whereas the interfacial photothermal effect promotes subsequent free radical reactions for the degradation of rhodamine B(93%).The freshwater evaporation rate is 1.35 kg·m^(-2)·h^(-1)and the solar-to-water evaporation efficiency is 94%.Importantly,the N-TiO_(2)/CNT/PVDF(N-TCP)film not only effectively resists mechanical damage from the environment and maintains structural integrity,but can also be made into a large film for outdoor experiments in a large solar energy conversion device to collect fresh water from polluted water and degrade organic dyes in source water simultaneously,opening the way for applications in energy conversion and storage.

Quantifying Spatiotemporal Change in Landuse and Land Cover and Accessing Water Quality: A Case Study of Missouri Watershed James Sub-Region, North Dakota

Spatial causal effects on water quality are essential in identification of vulnerable watersheds. Modelling landuse variables is an effective method of projecting localized impairment. This study presents an integrated index, designed to gauge the ability of an 8-digit Hydrologic Unit Code watershed in its ability to produce clean water. This index, IAPCW, can be successfully applied on a geospatial platform. In this study we utilized IAPCW to address forest cover dynamics of an impaired watershed, that is, Missouri Watershed James Sub-region in North Dakota. Specific parametric functions were analysed and combined within a customized GIS interface to provide a multi-faceted structured technique to derive IAPCW. These included ambient forest cover, housing density, agricultural land, soil erodibility and road density;it can be lucidly ascertained that where a prevailing forest cover undergoes conversion processes, the secondary effect may spur an exponential increase in water treatment costs. These parameters when projected statistically validated temporal and spatial relations of landuse/land cover dynamics to nutrient concentrations especially those that would be noted at the mouth of the watershed. In this study, we found that the levels of Total Dissolved Solids (TDS) were much higher for the years 2014 to 2016 with a discernible increased alkalizing effect within the watershed. When IAPCW was compared to Annualized Agricultural Nonpoint Source (AnnAGNPS), the spatial distribution generated by the AnnAGNPS study showed that fallow areas produced significant amounts of sediment loads from the sub-watershed. These same locations in this study generated a low IAPCW.

Clean River Water for Thirsty Beijing in Six Years

PLAGUED by frequent floods in its history,Beijing is now suffering a grave water short-age.

Towards a better hydraulic cleaning strategy for ultrafiltration membrane fouling by humic acid: Effect of backwash water composition

As a routine measurement to alleviate membrane fouling, hydraulic cleaning is of great significance for the steady operation of ultrafiltration（UF） systems in water treatment processes. In this work, a comparative study was performed to investigate the effects of the composition of backwash water on the hydraulic cleaning performance of UF membranes fouled by humic acid（HA）. Various types of backwash water, including UF permeate, Milli-Q water, Na Cl solution, CaCl_2 solution and HA solution, were compared in terms of hydraulically irreversible fouling index, total surface tension and residual HA. The results indicated that Milli-Q water backwash was superior to UF permeate backwash in cleaning HA-fouled membranes, and the backwash water containing Na＋or HA outperformed Milli-Q water in alleviating HA fouling. On the contrary, the presence of Ca^（2＋） in backwash water significantly decreased the backwash efficiency. Moreover, Ca^（2＋） played an important role in foulant removal, and the residual HA content closely related to the residual Ca^（2＋） content.Mechanism analysis suggested that the backwash process may involve fouling layer swelling, ion exchange, electric double layer release and competitive complexation. Ion exchange and competitive complexation played significant roles in the efficient hydraulic cleaning associated with Na＋and HA, respectively.

GREEN AGRICULTURE AND BLUE WATER IN CHINA:REINTEGRATING CROP AND LIVESTOCK PRODUCTION FOR CLEAN WATER

Crop and livestock production are essential to maintain food security.In China,crop and livestock production were integrated in the past.Today,small backyard systems are still integrated but the larger livestock farms are landless and largely geographically separated from crop production systems.As a result,there is less recycling of animal manures and there are lower nutrient use efficiencies in the Chinese food production systems.This,in turn,results in considerable losses of nutrients,causing water pollution and harmful algal blooms in Chinese lakes,rivers and seas.To turn the tide,there is a need for agricultural“green”development for food production through reintegrating crop and livestock production.An additional wish is to turn the Chinese water systems“blue”to secure clean water for current and future generations.In this paper,current knowledge is summarized to identify promising interventions for reintegrating crop and livestock production toward clean water.Technical,social,economic,policy and environmental interventions are addressed and examples are given.The paper highlights recommended next steps to achieve“green”agriculture and“blue”water in China.

Bottled Water Not Always As Clean As Advertised

美国是世界上为数不多的可直接饮用自来水的国家之一。美国市场上销售的瓶装饮用水更应该洁净而令消费者放心,可是,本文让读者大吃一惊！

Narrow-bandgap light-absorbing conjugated polybenzobisthiazole:Massive interfacial synthesis,robust solar-thermal evaporation and thermoelectric power generation

Exploiting advanced light-absorbing conjugated polymers is of great significance to achieve the blue dream of low-energy solar steam generation and clean water collection.Herein,an interfacial chemistry strategy is developed to massively synthetize conjugated polybenzobisthiazole(CP)microspheres with a narrow bandgap of 0.274 eV and high solar absorbance of 94.0%.The CP microspheres are combined with the polyvinyl alcohol(PVA)hydrogel to form a Janus evaporator.The evaporation rate and energy efficiency of the CP@PVA solar evaporator reach 2.96 kg m^(-2) h^(-1) and 98.8%with a low coating content of 5 mg cm^(-2).The evaporation performance of the Janus CP@PVA evaporator is applicable to seawater,sewage,and acid/alkali water.The efficient evaporator with portable collector can be simply assembled to produce drinking water from real seawater and sewage.Additionally,the Janus evaporator is also equipped with a thermoelectric module to generate the steam and electricity simultaneously.The power output achieves 1.04 W m^(-2 )in real seawater while the evaporation rate remains 2.23 kg m^(-2) h^(-1) under 1 sun,demonstrating the remarkable capacity to utilize the solar energy.