Investigating the Efficiency of Phosphate Removal from Wastewater from Sugar Cultivation Industry Using Baffled Subsurface-Flow Constructed Wetland

Phosphorus is recognized as a nutrient in aquatic environments, but increasing its concentration in water resources causes the occurrence of eutrophication in water and, as a result, causes the death of aquatic organisms. Therefore, removal of phosphate from water is very important. In this research, in order to remove phosphate from water resources, the baffled subsurface-flow constructed wetland was used. In order to increase the efficiency of the wetland system, experiments were designed in 3 different phases. In the first phase, in the form of batch experiments, the composite performance of cheap materials such as zeolite, bentonite and pumice aggregates (The stabilization of nanoparticles of zeolite\bentonite on the surface of Pumice aggregates) to absorb phosphate and select the preferred candidate for placement in the wetland was investigated. In the second phase, in the form of pot experimentation, the performance of native plants of khuzestan province such as salicornia, Typha, and Juncus, In order to uptake phosphate and select the best candidate for cultivation in the bed of the wetland was investigated. Finally, in the third phase, with the placement of the selected bedding and plant (selected from previous experiments) in the wetland system, experiments were carried out to study the effect of parameters such as the percentage of optimum mix of Selected bed with gravel, hydraulic residence time and temperature changes on the phosphate removal efficiency. The results showed that among absorbent materials and candidate plants for placement and cultivation in the wetland, the maximum capacity to absorb and accumulate phosphate by Pumice aggregate coated by zeolite nanoparticles (1.08 mg/g) and salicornia (9.68 mg/g of plant dry weight) was observed. In this experiment, The use of a combination of 10% of the selected bed with 90% of the gravel was obtained as the best and most economical option for removal of phosphate. Also, the efficiency of removal of phosphate in the 1-day hydraulic residence time was achieved at the highest intensity (99.60%) and was selected as the optimum time to remove phosphate. Finally, the results of the effect of temperature changes on the efficiency of the wetland system showed that the removal efficiency from March 2018 (20 °C) to July 2018 (40 °C) increased to about 1 percent, which indicates the effect of temperature changes on the performance of the wetland system. According to the results, in the case of adequate land availability, the use of subsurface-flow constructed wetland systems to wastewater treatment of agricultural and industrial units is very convenient and cost-effective

Experimental Investigation of using the Piano Key Weirs in the Outlet of the Clarifier Structure

Sustainable development and survival depends on environmental protection, especially water. Water treatment aims to produce safe and healthy water, which is possible in water treatment plants. Therefore the importance of water is understandable, and the importance of building and equipping a water treatment plant is paramount. Many principles have been proven. Moreover, ideas for upgrading treatment plants worldwide have increased treatment plants' capacity and improved water quality.. The proposed methods can not only be applied to optimize existing water treatment plants but can also be used to design New refineries will also be used. One of the critical parts that are considered in clarifiers is the weir part. Increasing the weir width to increase the discharge capacity of the design due to the width limit is one of the problems that designers face. This has led engineers to design weirs with nonlinear geometry. Congress weir and piano keys are two essential types of nonlinear overflows in which the length of the weir crest is increased by the crinkle of this structure in the plan. The use of nonlinear overflows is increasing worldwide, which has led researchers to estimate the discharge coefficient for weir efficiency. Tullis et al. (2020) conducted a study to investigate the effect of engineering specifications on the hydraulic performance of congressional weirs. The results of this study showed the effect of the number of weir cycles on hydraulic performance. As the number of congressional weir cycles increases, the hydraulic performance of the overflow decreases. Kumar et al(2019)., in their research, examined the effect of the ratio of crest length to width (L/W) and overflow height (P) of the piano key. Using soft calculations, the discharge coefficient was considered a function of geometric variables without the dimension of piano key overflow. Therefore, in this research, an attempt was made to evaluate the hydraulic flow in the overflow of refinery clarifier structures with the shape of a piano key at its outlet using a physical model

Electrocoagulation Process Efficiency for Removing Effluent Pollution Caused by Drilling of Oil Rigs

Background: Electrocoagulation (EC) is a safe method for removing environmental pollutants without the need for additional chemical materials. This study investigates the performance of EC in removing chemical oxygen demand (COD), total organic carbon (TOC), total suspended solids (TSS), and turbidity from drilling waste generated by oil rigs.Methods: An experimental study was performed on a pilot scale in an EC reactor provided from a cylindrical glass cell (height: 30 cm and inner diameter: 5 cm), a pair of aluminum and iron electrodes, a power supply, an aeration system. wastewater Samples were collected from one of the drilling rigs in Khuzestan. The effect of current density, operation time and pH parameters on removal of COD, TOC, TSS and turbidity were determined and the optimal values of the parameters were determined.Results: It was found that system voltage, operation time and pH values on the removal efficiency of pollutants were statistically significant at the 0.01 level. The optimum values of pH, current density and operation time were obtained 7, 20 mA/cm2 and 60 minutes, respectively and the removal efficiencies of COD, TOC, TSS and turbidity under the optimum conditions were 72%, 79%, 67% and 63%, respectively. Also, the consumption of energy was estimated to be 8.4 kWh/m3.Conclusion: The results indicated that the EC process is a cost-effective method in removing pollutants caused by drilling of oil rigs and its efficiency can be improved by applying optimal conditions such as current density and pH

Simulation of Ogee Spillway by FLOW3D Software (Case Study: Shahid Abbaspour Dam)

Dam's weir is one of the most important dam structures that play a significant role in flood routing in the dam reservoir. Since the dam's level significantly affects the storage, changing the level and increasing its height can increase storage volume and flood control in some situations. Shahid Abbaspour Dam (Karoon 1), due to the reduction of the dam volume, affected by the accumulation of sediments and the construction of upstream reservoir dams, it is necessary to increase the dam's weir height. This research used a numerical simulation of the weir with Flow3D software. Moreover finally, after the model verification, its height was increased. All model outputs were compared with the physical model results and the dam's data, and the simulation fit well with both systems. According to the model results, in exchange for changing the level of the dam from 510 to 513.5 and the fully opening of the Gates, no negative pressure is created on the weir surface, and the cavitation index is within the allowable range

Investigating the Effects of the Block Geometries and Sidewall Divergences on the Local Scour Downstream of Baffled Chute Spillways

Due to the lack of any specific study about the sidewalls and other blocks’ changes in the case of hydraulic and scour downstream, the present study was conducted to investigate this issue. For this purpose, drainage projects and spillway chutes, as well as many baffle block chutes, were designed and constructed with the parallel sidewalls and trapezoidal shape using the U.S. Bureau of Reclamation (USBR) instructions. Three divergence ratios of b1/b2=1.45,1.75, and 2.45, a parallel sidewall of b1/b2=1, and also three geometry blocks including trapezoidal USBR, trihedral, and semicircle blocks were applied and tested in the hydraulic laboratory using a baffle chute with the slope of (2 : 1), (H : V). The material used in this study was sediment sand with a uniform grain size of d50 = 1.2 mm, 15 cm of thickness, and 2 m of length. The experiment was conducted with seven different discharges in lasting condition, and the flow characteristic and scour hole dimensions were measured. The results revealed that in comparison with the USBR blocks, changes in the baffle sidewall and block shape made an approximate 50% reduction in the maximum depth of the scour hole. Thus, increasing the divergence ratio from 1 to 2.45 had a significant effect on reducing the maximum depth and the topographic shape of the scour hole. According to the range mentioned in the literature for the Weber number, the scale effect was negligible for the chute with baffle blocks. Generally, it can be concluded that the sidewall changes also can make a reduction in the number of overbaffle blocks, causing a reduction in the construction cost