Applied Water Science (v.2, #2)

Decision support system for economic value of irrigation water by Inas El-Gafy; Akram El-Ganzori (63-76).
The mismatch between the supply and demand, inequitable distribution and the over irrigation of water consuming crops are the main constraints that are faced in the implementation of the integrated water resources management in Egypt. With water scarcity, the problem under consideration is that the current cropping pattern is not economically efficient in the utilization of the available water resource. Moreover, in consequence of the importance of the agricultural sector to the national economies, it is necessary to be aware of the economic performance of water use in the crops production. The scope of this study is to develop economic value of irrigation water maps of Egypt. The objective of the study is carried out by acquiring a Decision Support System for economic value of irrigation water of Egypt. This Decision Support System is applied for developing economic value maps for the irrigation water that is used for cultivating 45 crops under cereal, fiber, legumes, and vegetables, herbalist, and forages categories at each governorate of Egypt in year 2008 and 2009. The crops that achieve the highest and lowest economic value of irrigation water at each governorate of Egypt were identified. The reasons of the variations in the economic value of irrigation water at the governorates of Egypt were determined. The developed Decision Support System could be used yearly as a tool for demonstrating a picture about the economic value of irrigation water for the decision makers in the areas of water resources and agriculture. The developed economic value of irrigation water maps can be used in proposing a cropping pattern that maximizes the economic value of irrigation water in each governorate of Egypt.
Keywords: Economic value of irrigation water; Decision Support System; Cropping pattern; Maps; Integrated water resources

Adsorption of phenol on natural clay by M. Djebbar; F. Djafri; M. Bouchekara; A. Djafri (77-86).
Natural clay being locally abundant and cheap material in Algeria can be easily activated to become a promising adsorbent for phenol removal from aqueous solution. The natural clay before and after activation was characterized using XRD and IR techniques. The effects of various experimental parameters, such as initial phenol concentration, temperature, pH, contact time, and adsorbent dose on the adsorption extent were investigated. Langmuir adsorption model was used for the mathematical description of the adsorption equilibrium and the equilibrium data fixed very well with this model. The activated natural clay had the monolayer adsorption capacity equal to 15 mg/g at pH value of 5.0 and 23°C; adsorption measurements show that the process is very fast and physical in nature. The extent of the phenol removal increased with decrease in the initial concentration of the phenol and contact time of solution. The results showed that as the amount of the adsorbent was increased, the percentage of phenol removal increased accordingly. Thermodynamic parameters showed that the adsorption of phenol on activated natural clay was exothermic.
Keywords: Phenol; Activated clay; Adsorption isotherm; Thermodynamic parameters; Montmorillonites; Adsorbent; X-ray diffraction

The effect of algal biomass on the removal of faecal coliform from domestic wastewater by E. D. O. Ansa; H. J. Lubberding; H. J. Gijzen (87-94).
The effect of algal density on faecal coliform (FC) decay under conditions of light and darkness were monitored in low and medium strength wastewater and in a ‘mixture of treated and raw wastewater’ depicting conditions of a variety of dissolved organic compounds. Rates of decay of FC varied in darkness with varying chlorophyll-a concentrations, supporting the hypothesis that algae may produce substances that are toxic to FC. The first empirical evidence that an optimum chlorophyll-a concentration (10 ± 2 mg L−1) for maximum FC destruction in wastewater exist is reported. Rate of decay was higher in medium strength wastewater compared with low strength wastewater at higher algal densities of ≥13.9 mg L−1 chlorophyll-a both in light and in darkness, while addition of fresh wastewater to an ongoing wastewater treatment process may lower the rate of FC decay for a wide range of algal densities (0.6–19.6 mg L−1), under light conditions.
Keywords: Algae; Decay; Organic matter; Wastewater

Ministry of water resources and irrigation in Egypt is currently implementing projects that expand new cultivated area, and accordingly the supplies of Nile River to the Nile Delta will be negatively affected. So, Enormous interest toward water resources management has been taken in the Egyptian water sector. Conveyance infrastructure and irrigation technology has been gradually improved to ensure efficient distribution and utilization of scarce water resources. The present study is focused on the optimum utilization of water resources in Sharkia governorate, Egypt. Operational and planning distribution model is implemented on the selected case study (Sharkia governorate) to develop appropriate water plan. The gross revenue of all crops is correlated to surface water discharge, ground water discharge, surface water salinity, and ground water salinity. In addition, the effect of varying both surface and groundwater quantities and qualities on the gross revenue has been investigated. Moreover, the effect of limiting rice production on the gross revenue is allocated.
Keywords: Water resources management; Sharkia governorate; OPDM; Crop pattern; Surface water; Groundwater

This study was carried out at a greenhouse of Sabahia Horticulture Research Station, Alexandria, Egypt, to study the effect of sewage effluent on the growth and chemical composition of Tipuana speciosa (Benth.) Kuntze seedlings as well as on soil properties for three stages. The irrigation treatments were primary-treated wastewater and secondary-treated wastewater, in addition to tap water as control. Therefore, the treated wastewater was taken from oxidation ponds of New Borg El-Arab City. Results of these study revealed that the primary effluent treatment explored the highest significant values for vegetative growth and biomass, compared to the other treatments. In addition, the higher significant concentration and uptake of chemical composition in different plant parts were obtained from the primary effluent treatment during the three stages of irrigation. It was found that the concentration of heavy metals in either plant or soil was below as compared to the world-recommended levels. These findings suggested that the use of sewage effluent in irrigating T. speciosa seedlings grown in calcareous soil was beneficial for the improvement of soil properties and production of timber trees, and also important for the safe manner of disposal of wastewater.
Keywords: Irrigation; Sewage effluent; Vegetative growth; Chemical composition; Soil properties; Heavy metalsTipuana speciosa (Benth.) Kuntze

Shallow aquifer systems overlain by rivers constitute normally one hydrogeological entity, because of the interconnection between aquifers and surface water. On the one hand, groundwater abstraction in such aquifer systems may deplete streams. On the other hand, overexploitation of surface water may result in a drop in groundwater level and adverse effects on the environment. It is important, therefore, to understand the relation between rivers and aquifers and to quantify the loss–gain relationship between them. This will help establishing a better water resources management and to reduce or prevent impacts on the environment. In this study, historical rivers flow data in the Ruataniwha Basin in New Zealand has been used to simulate groundwater–surface water, using the finite difference-based MODFLOW model. The model results were checked against six runs of recent concurrent gauging covering the whole basin. The numerical model results show that rivers and aquifers relation varies spatially from one location to another. Quantitatively, rivers gain from the aquifer system much more than what they lose. These results are consistent with the concurrent gauging data.
Keywords: Groundwater–surface water interaction; Numerical modelling; Ruataniwha Basin; Concurrent gauging; Stream routing

Evaluating the accuracy of soil water sensors for irrigation scheduling to conserve freshwater by Girisha K. Ganjegunte; Zhuping Sheng; John A. Clark (119-125).
In the Trans-Pecos area, pecan [Carya illinoinensis (Wangenh) C. Koch] is a major irrigated cash crop. Pecan trees require large amounts of water for their growth and flood (border) irrigation is the most common method of irrigation. Pecan crop is often over irrigated using traditional method of irrigation scheduling by counting number of calendar days since the previous irrigation. Studies in other pecan growing areas have shown that the water use efficiency can be improved significantly and precious freshwater can be saved by scheduling irrigation based on soil moisture conditions. This study evaluated the accuracy of three recent low cost soil water sensors (ECH2O-5TE, Watermark 200SS and Tensiometer model R) to monitor volumetric soil water content (θv) to develop improved irrigation scheduling in a mature pecan orchard in El Paso, Texas. Results indicated that while all three sensors were successful in following the general trends of soil moisture conditions during the growing season, actual measurements differed significantly. Statistical analyses of results indicated that Tensiometer provided relatively accurate soil moisture data than ECH2O-5TE and Watermark without site-specific calibration. While ECH2O-5TE overestimated the soil water content, Watermark and Tensiometer underestimated. Results of this study suggested poor accuracy of all three sensors if factory calibration and reported soil water retention curve for study site soil texture were used. This indicated that sensors needed site-specific calibration to improve their accuracy in estimating soil water content data.
Keywords: Arid regions; Freshwater conservation; Irrigated pecans; Irrigation scheduling; Real time soil moisture data; Soil moisture sensors; Water scarcity

The groundwater sources in the El Elma plain have been evaluated for their chemical composition and suitability for irrigation uses. Cluster analysis in Q-mode resulted in three major water types (HCO3–Ca-2+dominated, Cl–HCO3–Ca2+-dominated and Cl–Ca2+–Na+-dominated) for the groundwater. The US salinity diagram illustrates that most of the groundwater samples fall in C3S1 quality with high salinity hazard and low sodium hazard. Based on RSC values, all the samples of the three groups had values less than 1.25 and were good for irrigation.
Keywords: Hydrochemical; Q-mode cluster analysis; Irrigation; El Eulma area; Algeria

Biosorption performance of pineapple leaf powder (PLP) for removal of crystal violet (CV) from its aqueous solutions was investigated. To this end, the influence of operational parameters such as pH, biosorbent dose, initial dye concentration and temperature were studied employing a batch experimental setup. The biosorption process followed the Langmuir isotherm model with high correlation coefficients (R2 > 0.99) at different temperatures. The maximum monolayer biosorption capacity was found to be 78.22 mg g−1 at 293 K. The kinetic data conformed to the pseudo-second-order kinetic model. The activation energy of the system was calculated as 58.96 kJ mol−1, indicating chemisorption nature of the ongoing biosorption process. A thermodynamic study showed spontaneous and exothermic nature of the biosorption process. Owing to its low cost and high dye uptake capacity, PLP has potential for application as biosorbent for removal of CV from aqueous solutions.
Keywords: Biosorption; Pineapple leaf powder; Crystal violet; Equilibrium; Kinetics; Thermodynamics