نشریه مهندسی آب
سال چهارم شماره 1 (بهار و تابستان 1395)

Due to the importance of stilling basin blocks and the significant effect of their shape and dimension on energy dissipation, and since various studies have been carried out on hydraulic jump properties and properties of stilling basins while fewer studies have addressed the effect of integrated sinusoidal blocks on hydraulic jump properties, the present research was designed to analyze the effect of sinusoidal blocks height using the Flow 3D model, which is a powerful software product for simulating flow turbulence in two or three dimensions. Froude numbers in this research ranged from 4.6 to 12.2, which indicated that as flow’s Froude number increases from 4.2 to 11, the length of roller and hydraulic jump escalate. Moreover, relative roller length changes for about 30% to 40% by changing the height of blocks. Consequently, jump submerges in the beginning of outflow of flow from below the vent and output flow dissipates quickly. Jump length also decreases with an increase in blocks height. Finally, roller length decreases by 40 to 50 cm with outflow of flow from below the vent for the following two values: (The wave steepness) t/s=0.25 and 0.75.

There are more sewage pollution by organic substances Nhast.ayn by oxygenation and oxidation of the material can be converted into nitrites, nitrates, phosphates, etc. and then settle down, separated from the waste water.Generally, wastewater treatment methods can be divided into three main categories: physical, chemical and biological division is now widely Nmvd.astfadh biological methods for wastewater treatment is common.Biological methods are able to lower costs, a wide range of pollutants to be refined to remove biodegradable organic material and nutrients (nitrogen and phosphorus) are used.Activated sludge process and biological trickling filter is the most common treatment methods.The aim of this study was to evaluate the use of batch process alternating aerobic and Anoxic and anaerobic removal of nitrogen and phosphorus from a wastewater treatment plant in laboratory scale (pilot) is to determine the effect of rescheduling the anaerobic, Anoxic, aerobic performance system for the removal of nitrogen and P, change the sequence of steps and timeliness effect on the removal efficiency of nitrogen and phosphorus deals.

One of the important environmental problems is finding a place suitable for municipal solid waste disposal (Landfill). Choose the wrong place causing damage to the environment, human health and pollution of surface and groundwater. Several factors affect landfill site selection and there are different ways to this issue. In this paper, GIS and analytic hierarchy process (AHP) have been used to identify suitable locations for landfill in the city of Susa. For this purpose, four main factors selected that have a substantial impact on the landfill site selection consisting of technical and operational criteria, ecological and biological, socioeconomic and physical. According to these criteria, 15 information layers prepared. The final score of the parameters were calculated by using the paired comparison. After combining 15 data layer using fuzzy analysis and AHP method and helping ARC GIS software, the final map was prepared for Solid Waste. Based on the results, western parts of the city of Susa were proposed for landfill. Because of the great distance from the city of Susa and lack of proper access road, this section has been ignored as the best place appropriate waste disposal. A closer look at the result, 3 regions, with the suitable level of value, range and access road, were determined.

More rainfall in arid and semi-arid just evaporate into the atmosphere and so estimates the amount of water vapor in the water cycle will be important. Evaporation is dependent on various parameters and to its estimate needs for a different climate variables and the interaction of these variables is very complex, so it must be accurate methods to be used in the evaporation study. In this study, artificial neural networks were used to estimate the pan evaporation of Dez regulating dam station. As ANN hyperbolic tangent function and the learning momentum was used. Multilayer Perceptron structure which used a network of six input neurons, three hidden layer and an output neuron was formed. Input layers include maximum temperature, minimum temperature, sunshine hours, average wind speed, relative humidity and an average rate of evaporation from water surface to the output layer. The relationship between climatic factors showed that the average temperature on the surface evaporation caused more than sunshine and wind speed. High coefficient of determination (92/0) between the actual data with simulated data with artificial neural network plus a small error (RMSE = 1.41) showed that the estimate accuracy is very high. Verification by t-test revealed no significant (P> 0.01) differences were between actual and estimated values.