In the present study, electrocoagulation-flocculation method was used to treat the wastewater from Shazand Oil Refinery in Arak, Iran. The wastewater contained 170,000 mg/L COD and 5.3 mg/L lead (Pb). In each step of the experiment, 2 L of the refinery wastewater was poured into a pilot made up of Plexiglas, and bipolar electrode arrangement was used. Optimum values of time, pH, and voltage parameters were determined for the aluminum electrodes. Results showed that time duration of 90 m, pH of 6, and voltage of 30 V was suitable for the removal of lead and COD. It should be noted that 48% of COD was removed and lead concentration decreased from 5.3 mg/L to lower than 0.05 mg/L. In addition, the COD removal efficiencies were 56 and 64% for eight and ten aluminum electrodes, respectively. The effect of iron electrodes on the removal of COD and lead was investigated under the same optimum conditions. Comparison between iron and aluminum electrodes indicated that iron electrodes demonstrate a better efficiency by removing 66.94% of COD from wastewater. It was also found that pH played a significant role in pollutants removal due to the formation of aluminum hydroxide gelatinous polymer.

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Purpose Green infrastructures have been considered as a sustainable solution to deal with the problems in dense urban spaces. This acceptance has led to the use of various materials and methods in designing and producing green infrastructures. The purpose of this study is to emphasize the components and materials used in the green walls system. By determining the environmental impact of each element, it can be replaced with another component with the same function. This approach ultimately leads to the sustainable design of systems. Methods Accordingly, two green wall systems were selected for the environmental assessment using the life cycle assessment method. Data related to all processes and components involved in each system are reviewed for a 10-year lifespan. For each system, eight different scenarios of component composition are considered. The functional unit is 1 square meter and the ILCD method is used to evaluate the impact of the life cycle. OpenLCA software and Ecoinvent® v3.7 database are used to model and analyze all 16 scenarios. Results The results clearly show that the components and materials used in the production and construction of the green wall system have a very high impact on the environmental performance of these systems. A better design can be achieved by doing an environmental assessment, identifying the undesirable components in the system, and replacing them. Different scenarios' results show the potential to improve the environmental performance of systems in all impact categories. This highlights the great importance of the green wall system's design, material selection and maintenance methods. Conclusions Considering the ability of the LCA method to identify the weak and strong points of the systems, the lack of using this method in the design phase is strongly sensed. With this method's help, it is possible to produce more sustainable systems. On the other hand, the studies conducted in the field of green walls are limited compared to other green infrastructures. At the same time, the design of the green wall system can be changed based on geographical location, weather conditions, access to raw materials and consumer needs. As the number of studies on these systems increases in different places and weather conditions, it can help the stability of these systems.