Spatial Variation of Haloacetic Acids in Indoor and Outdoor Desalinated Household Drinking Water in Kuwait

The present study reveals spatial variability of haloacetic acids and the basic physiochemical properties of drinking water samples through visualization based on the Kriging algorithm and hierarchical cluster analysis. Both projection and statistical method contributed to the logical classification of the indoor and outdoor water samples collected from various governorates covering more than 95% of the residential areas in Kuwait. Clustering of the variables led to the formation of several significant clusters corresponding to the effect of chlorine concentration and its residence time on the formation potential of chlorinated acetic acid derivatives in desalinated drinking water as well as to the total ionic composition of water samples and to the effect of the formation of brominated acetic acid derivatives. Clustering of samples, both indoor and outdoor, indicated that all of governorates located in the northern part of Kuwait are supplied with water containing high concentrations of chlorinated acetic acid derivatives, whereas significantly lower amounts of chlorinated or monobrominated acetic acids were found in water samples in the central and southern parts of the country.     

Metal Retention Experiments for the Design of Soil‐Mix Technology Permeable Reactive Barriers

Soil‐mix technology is effective for the construction of permeable reactive barriers (PRBs) for in situ groundwater treatment. The objective of this study was to perform initial experiments for the design of soil‐mix technology PRBs according to (i) sorption isotherm, (ii) reaction kinetics and (iii) mass balance of the contaminants. The four tested reactive systems were: (i) a granular zeolite (clinoptilolite–GZ), (ii) a granular organoclay (GO), (iii) a 1:1‐mixture GZ and model sandy clayey soil and (iv) a 1:1:1‐mixture of GZ, GO and model soil. The laboratory experiments consisted of batch tests (volume 900 mL and sorbent mass 18 g) with a multimetal solution of Pb, Cu, Zn, Cd and Ni. For the adsorption experiment, the initial concentrations ranged from 0.01 to 0.5 mM (2.5 to 30 mg/L). The maximum metal retention was measured in a batch test (300 mg/L for each metal, volume 900 mL, sorbent mass 90–4.5 g). The reactive material efficiency order was found to be GZ > GZ‐soil mix > GZ‐soil‐GO mix > GO. Langmuir isotherms modelled the adsorption, even in presence of a mixed cations solution. Adsorption was energetically favourable and spontaneous in all cases. Metals were removed according to the second order reaction kinetics; GZ and the 1:1‐mix were very similar. The maximum retention capacity was 0.1–0.2 mmol/g for Pb in the presence of clinoptilolite; for Cu, Zn, Cd and Ni, it was below 0.05 mmol/g for the four reactive systems. Mixing granular zeolite, organoclay and model soil increased the chemisorption. Providing that GZ is reactive enough for the specific conditions, GZ can be mixed to obtain the required sorption. Granular clinoptilolite addition to soil is recommended for PRBs for metal contaminated groundwater.     

Dye Removal from Colored Textile Wastewater by Poly(propylene imine) Dendrimer: Operational Parameters and Isotherm Studies

This paper deals with the removal of textile dyes from aqueous solutions by poly(propylene imine) dendrimer (PPI). Direct red 80 (DR80), Acid Green 25 (AG25), Acid Blue 7 (AB7), and Direct Red 23 (DR23) were used as model dyes. The effects of operational parameters on dye removal such as dendrimer concentration, dye concentration, salt (inorganic anions), and pH have been studied at 25°C. The Langmuir and Freundlich isotherm models were investigated. In addition, dye desorption of dendrimer was studied. The results indicated that acidic pH supported the adsorption of dyes by dendrimer. Furthermore studies of dye concentration and salt effects exhibited that dye removal percentage by dendrimer was decreased. It was found that the isotherm data of DR80, AG25, and DR23 followed Langmuir isotherm and isotherm data of AB7 followed Freundlich isotherm models. Desorption tests showed that maximum dye releasing of 76.5% for DR80, 84.5% for AG25, 87% for AB7, and 93% for DR23 were achieved in aqueous solution at pH 12. Based on the data of present study, one could conclude that the dendrimer being an environmentally friendly adsorbent with relatively large adsorption capacity might be a suitable alternative for elimination of dyes from colored textile wastewater.     

Dye Removal,Energy Consumption and Operating Cost of Electrocoagulation of Textile Wastewater as a Clean Process

In this research, the efficiency of electrocoagulation treatment process using aluminum electrodes to treat synthetic wastewater containing Reactive Red198 (RR198) was studied. The effects of parameters such as voltage, time of reaction, electrode connection mode, initial dye concentration, electrolyte concentration, and inter electrode distance on dye removal efficiency were investigated. In addition, electrical energy consumption, electrode consumption, and operating cost at optimum condition have been investigated. The results showed that dye and chemical oxygen demand removals were 98.6 and 84%, respectively. Electrode consumption, energy consumption and operating cost were 0.052 kg/m³, 1.303 kWh/m³ and 0.256 US$/m³, respectively. Dye removal kinetic followed first order kinetics. It can be concluded that electrocoagulation process by aluminum electrode is very efficient and clean process for reactive dye removal from colored wastewater.     

Mineral Content of Bottled and Desalinated Household Drinking Water in Kuwait

Three hundred and twenty‐two samples of desalinated household water were collected from 99 sampling locations that covered 95% of Kuwaiti's residential areas. Seventy‐one brands of bottled water were collected from Kuwaiti markets. The water quality parameters that were studied included pH, electrical conductivity (EC), total dissolved solids (TDS), F^?, Cl^?, Br^?, , , , , , , , and the major macronutrients Na⁺, K⁺, Ca²⁺, and Mg²⁺. The analysis yielded a large range of results for most of these parameters, with differences in some cases exceeding 10‐fold. With a few exceptions, the results were found to comply with US‐EPA and WHO standards. Only the water in two brands of bottled water was acidic (pH < 6.5). The TDS was found to be higher than the US‐EPA regulated value in 4 and 3% of the household samples and bottled water brands, respectively. The fluoride levels were generally higher in bottled water than in household water. However, the household water that was produced by the Doha desalination plant and some of the European brands of bottled water were the best samples studied in terms of their quantity of Ca²⁺, Mg²⁺, and Na⁺ compared with the DRI values for those substances. EC and TDS were positively correlated with , , Na⁺, K⁺, Ca²⁺, and Mg²⁺ for household water but only with Ca²⁺ and Mg²⁺ for bottled water.     

Modelling the initial shear stiffness of unsaturated soils as a function of the coupled effects of the void ratio and the degree of saturation

Existing models for predicting the small strain behaviour of unsaturated soil are not capable of predicting the initial shear stiffness during suction reduction under normally consolidated conditions. This problem has been addressed in the present study by combining an existing elastoplastic model and recent experimental data to provide a new model for the initial shear stiffness. The model, which is similar to that typically adopted for saturated soils, uses the average skeleton stress and an additional function of the degree of saturation. This new model not only captures the behaviour of the new experimental results, but it also describes a unique relationship between saturated and unsaturated soils.     

Temporal and spatial distribution of dissolved Cu, Ni and Zn in the coastal waters of Jeddah, eastern Red Sea

Dissolved Cu, Ni, and Zn were measured in the surface coastal waters of Jeddah, eastern Red Sea during October 2004 and April 2005. High values of trace metals, particularly Zn, were recorded in the Southern Corniche area close to a sewage effluent indicating a significant contribution from the wastewater. Concentrations of trace metals decreased northward and southward under the effect of dilution. Another hot spot was also observed in the vicinity of Jeddah Desalination Plant (JDP) during April 2005 indicating a possible contribution from the JDP to trace metal contents in the study area. Trace metals were correlated to salinity, nutrients and particulate organic carbon (POC). The good association between Zn and reactive silicate and Ni and ammonium is attributed to simultaneous biological utilization and regeneration. The behavior of copper suggested adsorption of Cu onto the POC during October 2004 whereas in April 2005 the most important process seems to be desorption of Cu from the particulate materials.     

Identification of hazardous waste landfill site: a case study from Zanjan province, Iran

The study of landfill sites is one of the most important studies in landfill engineering, and the landfill site selection involves combination of engineering, science, and politics. This paper describes a comprehensive hazardous waste landfill site selection methodology with the combined utilization of geographic information system and multiple criteria analysis methods, as applied to the Zanjan province in Iran. The six main data categories that were used are geological/engineering geological, geomorphological, hydrological/hydrogeological, climatological, pedological, and social/economical criteria, which included 31 input layers in total. A suitability map for hazardous waste landfilling was prepared for study area with five classes from most suitable to completely unsuitable. Finally, out of the three sites, one site was selected which was chosen by the local authorities. Our work offers a comprehensive methodology and provides essential support for decision-makers in the assessment of hazardous waste management problems in Zanjan province in I.R. Iran and other developing cities in other countries.     

Variations of the Earth’s magnetic field in the Phanerozoic

The global VDM database, which was later supplemented by new determinations published in the world literature (a total of 3194 determinations), is used as the basis for addressing the VDM behavior in the Phanerozoic (0–542 Ma) and up to 580 Ma. The results revealed a positive linear trend to higher VDM values from 3.5 × l0²² Am² to 5.7 × l0²² Am². Against this background, fluctuations of the mean VDMs occur with a periodicity of about 40 Myr. In the Phanerozoic, prominent minima of the intensity are found in the time intervals of 510–520, 420–460, 340–370, 290–300, 240–270, 190–210, 165–140 Ma (chrons M17–M43), 130–120 Ma (chrons M2–M10), 100–110 Ma (chron C34), 75–85 Ma (chrons C33 and the beginning of chron C34), 70–60 Ma (chrons C31–C27), and 40–15 Ma (chrons C18–C5AD). The distribution of the VDMs appears to reflect the paleomagnetic field behavior and may be taken into account in a magnetization model for the reversely magnetized oceanic crust.     

Evaluating the efficacy of SVMs,BNs, ANNs and ANFIS in wave height prediction

Wave Height (WH) is one of the most important factors in design and operation of maritime projects. Different methods such as semi-empirical, numerical and soft computing-based approaches have been developed for WH forecasting. The soft computing-based methods have the ability to approximate nonlinear wind–wave and wave–wave interactions without a prior knowledge about them. In the present study, several soft computing-based models, namely Support Vector Machines (SVMs), Bayesian Networks (BNs), Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS) are used for mapping wind data to wave height. The data set used for training and testing the simulation models comprises the WH and wind data gathered by National Data Buoy Center (NDBC) in Lake Superior, USA. Several statistical indices are used to evaluate the efficacy of the aforementioned methods. The results show that the ANN, ANFIS and SVM can provide acceptable predictions for wave heights, while the BNs results are unreliable.