Abstract: Water quality index (WQI) is valuable and unique rating to depict the overall water quality status in a single term that is helpful for the selection of appropriate treatment technique to meet the concerned issues. However, WQI depicts the composite influence of different water quality parameters and communicates water quality information to the public and legislative decision makers. In spite of absence of a globally accepted composite index of water quality, some countries have used and are using aggregated water quality data in the development of water quality indices. Attempts have been made to review the WQI criteria for the appropriateness of drinking water sources. Besides, the present article also highlights and draws attention towards the development of a new and globally accepted “Water Quality Index” in a simplified format, which may be used at large and could represent the reliable picture of water quality.

Abstract: This survey was carried out during wet and dry seasons in three stations represent the upper, middle and lower reaches of Huweza Marsh, Southern Iraq. Physical and chemical parameters including the natural water quality parameters such as temperature, pH, salinity, turbidity, electrical conductivity, dissolved oxygen, bicarbonates and total hardness along with nutrients levels were monitored for the period from July 2007 to April 2008. Results showed that water quality parameters of Huweza marsh are all within the standard criteria for freshwater habitats with pronounced seasonal variation between dry and wet seasons. Significant differences were also recorded between upper and lower stations in the marsh which can be attributed to local conditions. In general all parameters are within the tolerance limits of fresh water plants and animals except water salinity which needs to be monitored seasonally and spatially, as variations are noticed between various parts of the marsh and at different seasons. Some recorded levels exceed the normal favorable levels for freshwater fauna and flora. The marsh water is rich in nutrient especially nitrate and phosphate, reflecting high productivity in similar manner to other Iraqi marshes. Results were compared with other studies in the area. The present survey can act as a basis for future monitoring and recovery of the marshland ecosystem.

Abstract: The impact of landcover/landuse type on the groundwater scenarios has not been investigated extensively in Zimbabwe due to lack of groundwater observation data. The research was aimed at using remote sensing to unravel the groundwater scenarios under different landcover/landuse types in the middle Save catchment of Zimbabwe. The research used the gravity recovery and climate experiment (GRACE) satellite to measure regional groundwater fluctuations from 2004-2010. Landsat satellite images were also used to classify the study area into three landcover/landuse types: grasslands, forests and shrublands. The results showed that grasslands occupy 59% of the land area, forests occupy 22% of the place and shrublands cover19% of the study area. On seasonal groundwater scenarios, areas under forests had the highest magnitude of groundwater recharge (up to 20cm) and also the highest levels of groundwater lose (up to -20cm). Shrublands had recharge levels of up 13cm and loses of about -14cm. Grasslands had the least recharge of about 6cm at peak and the lowest magnitude of groundwater loses of about -7cm. The research also showed that from 2004- 2010 groundwater levels have been in a state of decline in the study area. The research concluded that landcover/landuse affects only seasonal not year on groundwater fluctuations. Geographical information systems and remote sensing were shown to be capable of producing groundwater scenarios of the study area in the absence of systematic ground based groundwater observations.

Abstract: This study aimed at exploring whether product quality, membrane fouling and salt reverse flow would be challenges in forward osmosis (FO) of seawater using NH₄₃ as an osmotic agent. Experiments were conducted with a lab scale FO system containing effective membrane area of 95 cm². Synthetic seawater (SSW) with 3.5-7.0 mg/L boron and a real seawater (RSW) were used as feeds and 1.5-2.5 M NH₄₃ as draw solutions. The experimental operation could be stablized within 0.5 h. For the SSW, boron rejection ranged of 47-85% and increased with increasing water flux while boron in the permeate was greater than 0.8mg/L. Water flux with RSW was 3 times lower than that with SSW, indicating that there might be serious membrane fouling with RSW. It was surprisingly observed that non volatile organic in the FO permeate was 8-10 mg/L, which was from the draw solution although NH₄₃ used was analytical grade. Additional water cost would be $0.4/m³ because of NH₄₃ loss. It was concluded that product quality in terms of high TOC contaminant in NH₄₃ and low boron removal, serious fouling with RSW and salt reverse flow could be challenges for the FO process using NH₄₃ as osmotic agent for seawater desalination.

Abstract: Surface water is an important water resource for drinking and irrigation purposes in the central part of Ekiti-State. The water bodies are used with little attention to their quality status in addition to increased threat of anthropogenic contamination in view of rapid growth in population. The objectives of this study were to determine the physico-chemical characteristics of surface water, its hydrochemical controls and suitability for drinking and irrigation. Forty surface water samples were investigated. Field measurements of physical parameters were preceded by chemical analyses of the samples for major ions concentrations and bacteriological content. The surface water has pH ranging from 8.3 – 9.6 implying that the water was barely alkaline. Electrical conductivity [<205 µS/cm] and total dissolved solids [<154 mg/l] were low suggesting low-mineralised freshwater. The relative abundance of major ions [mg/L] was Na⁺>Ca²⁺>Mg²⁺>K⁺ for cations and Cl^- >SO₄^2-> HCO₃^->NO₃^- for anions. Major ion concentrations were low and within the WHO guidelines for drinking water indicating chemical suitability of surface water. The water samples tested positive to total bacterial count and E – coli with median values of 31.50 and 8.00 (cfu/100ml) respectively. Main water types and proportions were [70 %] mixed Ca²⁺-Mg²⁺-Cl^-, [20%] Na⁺-Cl^- and [10%] Ca²⁺-Cl^-. Predominant processes influencing water chemistry were incongruent dissolution/weathering of silicate minerals and cation-exchange of Na⁺ in rocks for Ca²⁺ in water. The low major ion concentrations indicated low water-rock interactions and short residence time. Irrigation quality indices [Sodium absorption ratio, salinity hazard, Kelly ratio and permeability index] revealed that the analysed water was suitable for irrigation.