Artificial shortage of surface water: how can water demand management mitigate the scarcity problem?

Water demand management stresses the crucial roles of water user motivations in balancing actual water availability and competing human needs. This paper shows how the absence of such motivations influences artificial water scarcity, even in resource‐abundant countries, and how slight modifications to economic instruments (surface water charges in particular) might solve the problem. Data from the Czech Republic are used to illustrate the rationale behind the artificial scarcity problem and its solution. A model with feedback based on historical surface water abstraction data is built to simulate the impacts of different payment modification scenarios.     

Hydration of high-calcium quicklime with methanol–water mixtures

In this study, hydration of quicklime was accomplished with different methanol–water mixtures. The greater the percentage of methanol, the more intense was the suppression of the hydration conditions. The reactivity was not greatly affected by the presence of methanol up to 20%, while for hydration mixtures with 30 to 60% methanol a great reduction of reactivity was observed. In all cases of hydration the complete conversion of CaO into Ca(OH)₂ was established by the XRD method. From the SEM study it was ascertained that in a percentage of up to 20% methanol, a normal hydration was observed, expressed by aggregates of hydrated lime grains, whereas the hydration in mixtures of 30–60% methanol, progressively leads to the formation of tabular crystals, the size of which increases with the methanol percentage. What is more important is that the maximum hydration temperature decreases up to 12.5 °C for hydration mixtures up to 20% methanol without the quality of the produced hydrated lime being affected.     

What affects public acceptance of recycled and desalinated water?

This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived.     

Influence of initial dry density and water content on the soil–water characteristic curve and suction stress of a reconstituted loess soil

In the northwest of China, many loess landslides have occurred without clear triggering factors (i.e., rainfall, earthquake, human activities, etc.). To better understand and analyze the hydro-mechanical properties of these slopes and then provide evidence for their stability analysis subjected to matric suction, it is essential to clarify the soil–water characteristic curve (SWCC). In this study, we conducted a set of experimental trials to examine the influences of initial dry density, water content upon the SWCCs of a loess soil taken from a loess landslide area, by using a conventional volumetric pressure plate extractor. Two common SWCC models have been investigated to evaluate which one is better for loess soil. The suction stress characteristic curves (SSCCs) were also estimated and analyzed. We found that behaviors of SWCCs would be different when the matric suction was greater than a certain value. The two SWCC equations have approximately the same performance in describing the SWCC. The rates of desorption decrease and residual water content increases with increasing the initial dry density, while the initial dry density has little, if any, influence on the air-entry value (AEV). The specimen compacted under higher initial water content would exhibit a higher AEV value and residual water content but lower rate of desorption as compared with the lower initial water content. The magnitude of suction stress had an approximately linear relationship with matric suction before the AEV value, the SSCC shapes will be markedly varied with the initial dry density and water content.     

Ponded infiltration and spatial–temporal prediction of the water content of silty mudstone

Bulletin of Engineering Geology and the Environment - Ponded infiltration is very common in silty mudstone and has a great influence on the stability of related slopes, road cuttings, and tunnels....     

Urban and semi‐urban planning in developing countries from a water and waste water treatment point of view

Several appropriate technology alternatives are suggested for water and wastewatei treatment in less developed countries. Large‐scale water supply systems employing conventional water treatment methods should be replaced by several small‐scale water treatment units utilizing appropriate water treatment methods.

Conventional sewerage systems should be replaced by low cost on‐site sanitation systems and several other low‐cost wastewater treatment methods such as oxidation ponds, aerated lagoons and anaerobic lagoons. Wastewater renovation and re‐use should be actively encouraged in view of dwindling water resources in these countries.     

Rethinking water reform policies as a ‘wicked problem’ the case of urban water supply in Ghana

Based on the theory of ‘wicked problem’ this paper investigates the causes of unsuccessful reform of urban water utilities in Accra, Ghana. The authors of this paper argue that reforms based only on managerial perspectives are not enough. Taking into account institutional and social issues is a key for the success of such reforms. Donors and international agencies lack such outlook and therefore fail to develop effective water policy reforms in developing countries generally. The paper discusses inter-twined and multi-dimensional institutional constraints that hinder the development of an appropriate approach to water utility reform in Accra.     

The role of partnerships in water‐related research in Palestine

This study analyses the good effect of science and engineering inputs from partnerships and applied research in promoting sustainable management of water and environmental resources in Palestine. The capacity building achieved during the past 10 years at the Institute of Environmental and Water Studies (IEWS) is reviewed. Palestine faces major constraints, and these affect everyone and everything. A problem‐solving approach can be beneficial.     

Role of microorganisms in water purification of compounds of iron and manganese in a dense layer of sorbent–catalyst

The article contains assessment and contains experimental substantiation of the involvement of iron- and manganese-oxidizing microorganisms in the removal of manganese compounds from model solutions. Defined and identified are cultures of such microorganisms. The article has shown the efficiency of removing manganese compounds by the layer of a sorbent–catalyst under conditions of changing the temperature conditions for a long time.     

Effect of water–silt composite blasting on the stability of rocks surrounding a tunnel

This paper describes a new method using water–silt composite blasting for tunneling and the field tests conducted in the Tieshanping tunnel, Chongqing City, China. In this method, water–silt composite is substituted for the traditional pure silt stemming of the blast holes. Because of the incompressibility of water, the attenuation of the blasting wave is postponed and the effect of the blast air extended. The water–silt blasting method resulted in a larger crack zone, improved the breakage of rock, reduced the rock heap, lowered the dust and saved explosive. The stability of the surrounding rock was studied using theoretical analysis, in situ measurements and numerical modeling. The measured displacement at the tunnel crown was in good agreement with the theoretical and numerical results.     

Chemistry of tap water in Sri Lanka‐implications on health

A preliminary survey on the chemical quality of tap water in Sri Lanka has been carried out and has been grouped into three categories depending on the source of the water. It was revealed that in certain parts of Sri Lanka, the tap water does contain excess quantities of lead. The Piper trilinear diagram shows that much of the tap water of Sri Lanka belongs to the Ca#shMg‐HCO₃ type. Low pH values have also been observed in certain areas and could bring out excess dissolved ions into the tap water. In view of the fact, that only a small percentage of the population of Sri Lanka have access to piped water, no serious health hazards due to the poor quality of the tap water have been encountered.     

Aquifer characteristics and water quality of Miocene–Pleistocene sediments, Kuwait

Al-Atraf is one of the water well fields of Kuwait supplying Kuwait City with the brackish groundwater obtained from the Kuwait Group aquifer of Miocene–Pleistocene age. The study determined the hydrogeological and hydrochemical characteristics of the groundwater in order to identify the major chemical processes that influence the groundwater quality of the study area. The results of the aquifer test analyses indicate that the Kuwait Group is a confined to semi-confined aquifer, with a transmissivity ranging between 62 and 321 m²/day. The flow net analysis implied that the groundwater moves from southwest to northeast. The estimated transmissivity values agree well with those calculated from the aquifer test. The results of the chemical analyses data of the Al-Atraf field show that the groundwater is mainly brackish, of NaCl and Na₂SO₄ water types. The groundwater is undersaturated with respect to halite, gypsum and anhydrite and supersaturated with respect to quartz, dolomite and calcite in the direction of groundwater flow. The average Pco₂ of the groundwater is higher than the Pco₂ of the earths atmosphere indicating that the groundwater is supplied with CO₂ during the infiltration processes and dissolves the carbonate minerals under closed-system conditions.     

Impact of household plumbing fixtures on drinking water quality — a review

This paper reviews the pertinent literature published since 1970 on the impact of household plumbing systems on drinking water quality through the leaching of metals such as cadmium, copper, iron, lead, tin and zinc into potable water. Copper is found to be more easily and extensively leached than lead. Copper is leached almost exclusively from copper tubing. Lead can be leached from lead pipes, lead‐tin solders and faucets in residences. Zinc and tin require to be monitored as well.     

Does public ownership of utilities matter for local government water policies?

What differentiates local governments that implement water policies on equity and the environment? Analyzing a 2015 national survey of 1,897 U.S. municipalities, we find municipalities that own their water utilities are more likely to report policies to protect low-income residents from disconnection and implement water resource management. Respondents from 8% of municipalities report protecting residents from disconnection. State economic regulation of municipally owned utilities and Democrat-majority municipal governments are positively associated with local policies to protect low-income households from shutoffs but bear no association with resource management. Both municipal ownership of utilities and state economic regulation may play a role in meeting certain local water policy goals.     

Palygorskite–TiO2 nanocatalysts for photocatalytic degradation of tebuconazole in water

Palygorskite–TiO₂ nanoparticles are frequently used as nanocatalysts. In the present study, two different nanocatalysts were developed based on the use of different palygorskite–TiO₂ ratios: 40–60 and 10–90. The nanocomposites were investigated for the photocatalytic degradation of the common fungicide tebuconazole (TEB), under aquatic conditions. The samples were extensively characterized by X-ray powder diffraction, attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy and N₂ specific surface area (SSA) by Brunauer–Emmett–Teller (BET) analytical techniques. The TiO₂ nanoparticles were successfully dispersed on the mineral's surfaces and the photocatalytic activity reached 88.4% for the palygorskite–TiO₂ ratio of 40:60, where the dispersion was better as proved by the total pore volume and BET parameters (0.49 cm³/g and 258 m²/g compared to 0.33 cm³/g and 220 m²/g of the 10:90 ratio). The photocatalytic efficiency of the proposed materials was significantly higher than Degussa P25 (33.2%), and that makes the palygorskite–TiO₂ nanocomposites very promising for advanced application in fungicides' degradation in aquatic environments.     

Does the reuse of PET bottles during solar water disinfection pose a health risk due to the migration of plasticisers and other chemicals into the water?

Solar water disinfection (SODIS) is a simple, effective and inexpensive water treatment procedure suitable for application in developing countries. Microbially contaminated water is filled into transparent polyethylene terephthalate (PET) plastic bottles and exposed to full sunlight for at least 6 h. Solar radiation and elevated temperature destroy pathogenic germs efficiently. Recently, concerns have been raised insinuating a health risk by chemicals released from the bottle material polyethylene terephthalate (PET). Whereas the safety of PET for food packaging has been assessed in detail, similar investigations for PET bottles used under conditions of the SODIS treatment were lacking until now. In the present study, the transfer of organic substances from PET to water was investigated under SODIS conditions using used colourless transparent beverage bottles of different origin. The bottles were exposed to sunlight for 17 h at a geographical latitude of 47° N. In a general screening of SODIS treated water, only food flavour constituents of previous bottle contents could be identified above a detection limit of 1 μg/L. Quantitative determination of plasticisers di(2-ethylhexyl)adipate (DEHA) and di(2-ethylhexyl)phthalate (DEHP) revealed maximum concentrations of 0.046 and 0.71 μg/L, respectively, being in the same range as levels of these plasticisers reported in studies on commercial bottled water. Generally, only minor differences in plasticiser concentrations could be observed in different experimental setups. The most decisive factor was the country of origin of bottles, while the impact of storage conditions (sunlight exposure and temperature) was less distinct. Toxicological risk assessment of maximum concentrations revealed a minimum safety factor of 8.5 and a negligible carcinogenic risk of 2.8 × 10⁻⁷ for the more critical DEHP. This data demonstrate that the SODIS procedure is safe with respect to human exposure to DEHA and DEHP.     

Effects of water content and interface roughness on the shear strength of silt–cement mortar interface

Although the shear behaviors of silt–structure interfaces are critical in engineering practice, they have not been extensively investigated systematically. In this study, the influence of the silt water content and interface roughness on the shear behaviors of silt–cement mortar interfaces is investigated. Forty–eight silt–cement mortar structure interface tests and 18 silt direct shear tests were carried out. The results indicated that as the water content of the silt gradually increased to saturation, the interface shear stress–displacement curves changed from strain softening to strain hardening, and the interface shear strength decreased significantly. The shear strength of the rough interface was found to be significantly greater than of the silt, and the shear strength of the smooth interface was found to be lower than that of the silt. The interface shear strength gradually increased with the surface roughness, but the increase tended to be gentle. A large shear deformation was observed, and this increased with the decrease in soil water content and the increase (up to a point) in interface roughness. A model of the interface shear strength between unsaturated soil and structures considering the influence of water content and interface roughness was established and verified.     

Estimation of environmental impacts on the water quality of Incesu-Dokuzpınar Springs in Kayseri,Turkey

Industrial and agricultural activities have directly or indirectly affected the concentrations of a large number of inorganic chemicals in groundwater, for example NO₃, N₂, Cl, SO₄, H⁺, K, Mg, Ca, Fe, Cu, B, Pb and Zn, as well as a wide variety of pesticides and other organic compounds. For reactive contaminants like NO₃, it is recommended that a combination of hydrochemical and environmental-tracer analytical approaches might be required to resolve changing inputs from subsequent alterations as causes of concentration gradients in groundwater. The water type of ncesu-Dokuzpnar Springs is mainly Na–Mg–Ca–Cl–HCO₃. Note that the water types of the Springs were directly related to the hydrogeochemical properties of outcrops at the study area. Thus, the high concentration of Ca⁺² and HCO₃ is mainly related to the high CO₂ contents in the marbles, whereas the high Na concentration arises from the existing syenite, volcanic ash, basalt and clay units, although the ncesu-Dokuzpnar Springs cover most of the drinking and irrigation water demands at the study area. Therefore, relevant hydrogeochemical and statistical studies were carried out for estimating the mentioned environmental impacts on the water quality of ncesu-Dokuzpnar Springs.