JOURNAL OF ENVIRONMENT AND WATER ENGINEERING
Year:2018 | Volume:4 | Issue:2 |Papers Count:8

Modeling the dam break phenomenon is more important in order to calculate the approximate discharge flow due to break to perform the measures to control it or to prevent the resulting hazards. In this research, Gambit software was used to generate the form and dimensions of the geometry of the laboratory model. Then, the generated geometry file was transferred to the Fluent hydraulic model. In Fluent environment, all effective parameters were determined. The VOF method was used for modeling. The case study in this research was the rocky sedimentary located near the Nowshan basin, which is located around Urmia city, and the dam break modeling was done for it in a three-dimensional characteristic. The results obtained from the laboratory conditions were compared with the results of the Fluent model, which is related to modeling the dam break phenomenon in two-dimensional form. Various wave characteristics were studied, including wave propagation, wave velocity, and water depth variation at the bottom of the dam in dry and wet bed conditions. Comparison of the results shows that the Fluent model has high accuracy in modeling the flow due to dam break. To construct the geometry of a part of the stream that includes the reservoir and the reservoir, a topographic map of the stream was used in AutoCAD environment.

One of the main reasons of bridge destruction is the bridge piers scour. A more accurate computation of scour depth would lead to a more solid design of bridge piers. Empirical equations can be applied to compute the scour depth. In this study, the coefficients of 17 empirical equations were optimized using genetic algorithm and fieldwork values. 80% of the field data were used to optimize the equations and the rest were used to verify them. The RMSE, MAE, E and R2 criteria were applied to evaluate the optimization method where the results showed the ability of genetic algorithm in empirical equations optimization. The Froehlich (1988) equation had the highest degree of precision among the empirical equations, so the genetic algorithm has had the least effect on the optimization of this equation. The optimized Neill (1964), Melville (1975), Laursen and Toch (1956), Blench II (1962) and Hancu (1971) equations with respectively, 75, 72, 71, 71 and 71 percent showed the highest reduction in RMSE error criteria. The optimized Blench II (1962) equation with RMSE, MAE, E and R2 criteria equal to 0. 57 m,-0. 085 m, 62 and 0. 65 percent respectively, presented the highest correlation coefficient and lowest error. In the end, more equations were proposed to predict the bridge piers scour depth.

Nowadays, rapid development of the chemical industry has brought about environmental pollution, a serious threat, as a result of the entry of organic and inorganic chemicals, as well as heavy metals. Surface absorption by the use of biological polymers is a novel environmentally friendly technology for reducing and removing heavy metals from industrial wastewater. The objective of this study was to investigate the performance of lignocellulose nanofiber (LCNFs) adsorbents in the removal of Cu(II) from aqueous media. The test conditions are considered for two completely identical adsorbents. In the batch system, parameters of pH (4-8), adsorbent dosage (0. 1-0. 5 g/l), contact time (15-120 min), Cu(II) initial concentration (5-50 mg/l), and temperature (15-40 ° C) were studied. The results were analyzed by one-way ANOVA and Duncan's tests for significant evaluation of changes in parameters. Results showed that the highest percentage of removal of Cu(II) (99. 8%. ) for LCNFs at pH 7, Cu(II) concentration of 10 mg/l, adsorbent dosage of 0. 3 g/l, contact time of 60 min at temperature of 25 ° C was obtained. This study showed that LCNFs adsorbents are considered as an optimal adsorbent for removal Cu(II) by removing more than 98% of Cu(II) from aqueous solutions.

The use of plant residues as fertilizer in sustainable agricultural systems is important in order to maintain soil fertility and achieve sustainable production. The purpose of this study was to evaluate the effect of plant residues of wheat, corn, and green sugarcane on some soil chemical properties. For this purpose, a pot experiment was conducted in a completely randomized block design with three replications in the greenhouse of the Faculty of Agriculture, Shiraz University. To test the straw and wheat straw, corn, and sugarcane residues, three types of soils with silty loam texture, loam, and sand were added under incubation conditions in two periods of 30 and 120 days. Changes in organic carbon, nitrogen, phosphorus, potassium, acidity, and soil salinity were investigated under different treatments of plant residues. The results showed that the amount of organic carbon, nitrogen, phosphorus, potassium and soil acidity increased significantly with application of plant residues. Soil salinity was not affected by plant residues. Residues of sugarcane on the amount of organic carbon and acidity, wheat residues on potassium and nitrogen and corn residues on phosphorus and nitrogen had the most effect. In our research, it was found that maintaining 50% of plant residues, especially straw and wheat straw, not only improved the physicochemical conditions of the soil, but also the need for nutrient consumption decreased significantly.

Underground dams are structures blocking the natural flow of groundwater and provide groundwater resources. In arid regions with limited water resources, it can be managed by constructing these structures. The purpose of this study was to select suitable site for the construction of underground dams in ShahreKurd and Marghmalek watersheds based on site selection criteria. As several different criteria should be considered, it is essential to use methods that are capable of fulfilling the desired criteria. For this purpose, GIS and Analytical hierarchy process (AHP) were used in this research. To prioritize the areas, different criteria and sub-criteria such as water (quantity, quality), reservoir (reservoir depth, reservoir slope, permeability and reservoir area), axis (axis length, axis depth and lithology of the supports) and socio-economic factors (distance from rural areas, distance from road, drinking, agricultural and industrial water supplies, and impact on water resources) were considered. The water quantity with a weight of 0. 83 had the highest rank. Finally, 15 regions were introduced for prioritization out of 60 suitable sites in the study area using Boolean logic. The results showed that the best axes for underground dam construction were located in alluvial beds of low slope, high-flow rivers, with large reservoir volume, high runoff, and high permeability.

Zinc is one of the essential micronutrients for plant growth and its deficit is often reported in calcareous soils. The total amount of soil Zn does not necessarily indicate Zn availability for plant. Therefore, finding an appropriate extractant, in order to estimate plant available Zn in soil is important. Considering that little information in Iran is available regarding available Zn, in heavy metals contaminated calcareous soils, therefore, assessment of status of available Zn for plants by chemical extractants is very important and necessary. The aim of this research was to assess extraction methods Mehlich 3, AB-DTPA and DTPA-TEA to estimate the sunflower available Zn in 9 contaminated soils. Sunflower plant parameters including dry matter, concentration, and Zn uptake were determined in a pot experiment. The results showed that in contaminated soils, the highest concentration of Zn by use of AB-DTPA and the lowest concentration of Zn by use of DTPA-TEA were extracted. Moreover, in contaminated soils significant correlation wasfound between extracted Zn by DTPA-TEA with concentration and Zn uptake (r=0. 78). There were significant correlations between extracted Zn by Mehlich 3 with concentration (r=0. 68) and Zn uptake by plant (r=0. 80). Thus, it can be concluded that DTPA-TEA and Mehlich 3 methodes can be used to estimate the ability of sunflower-available Zn in contaminated soils.

Due to the environmental hazards, nitrogenous wastewater treatment is essential and important. In recent decades, novel biological processes such as Annamox and SHARON have developed which are cheaper and more effective compared to conventional processes. In the present study, several significant biological parameters such as temperature, pH, dissolved oxygen, organic carbon, salt concentration, nitrite concentration and sludge retention time (SRT) were investigated. The results showed that SHARON process lowered the need for carbon source while Annamox process without carbon source requirement, was implemented in anaerobic condition. The optimum pH for Annamox process was reported 6. 7-8. 3. Nitrite and salt concentrations were important control parameters to prevent Annamox bacterial activity. Desired temperature for the bacterial growth was 30-40 ℃ for Annamox and higher than 25 ℃ for SHARON, and process efficiencies were not directly related to SRT. Overall, the new biological processes of nitrogen removal were described promising due to the decrease in need for aeration and carbon source and are suitable alternatives for conventional processes.

Rivers are important as one of the main sources of water supply for uses including agriculture, industry, and human consumption. This study evaluated the water quality of the Beheshtabad River (Shalamzar Spring-Jointing to Koohrang River) located in Chaharmahal and Bakhtiari Province, using the National Sanitation Foundation Water Quality Index (NSFWQI). Using standard methods, this study determined nine water quality parameters: nitrate (NO3), temperature (T), phosphate (PO4), turbidity, dissolved oxygen (DO), biochemical oxygen demand (BOD), electrical conductivity (EC), total solids (TS) and pH, at five selected stations along the river for three months, July to September 2015. Results showed that water quality fluctuated between medium and good quality during the investigation. In addition, according to the mean values of WQI, water quality was classified as medium quality for the three months. Water pollution increased from upstream to downstream in the end of summer because of agricultural fertilizers and wastewater discharge from upstream fish farms and recreation service centers.