Current Environmental Management (Formerly: Current Environmental Engineering) - Current Issue

Background: It has been seen that 90% of municipal solid waste is disposed off in open dumps and landfill sites, causing problems for the environment, and public health in developing countries. Many technological options can convert waste into various forms of energy. Heat and electricity can be generated and utilized for specific thermodynamic conversion processes and different types of biofuel can also be extracted from the organic municipal solid waste. Objective: This study evaluates the different treatment options available to convert waste into energy, and also concludes its environmental aspect with suggestions, which may be beneficial for encouraging the researchers to work for further improvement in this aspect. Methods: For each technological area, results from the literature review and the different expert opinions were considered to provide an analysis of the treatment technology, identify the internal and external environmental threats and important gaps in treatment technologies for MSW in India. Results: It has been observed from various studies that the pyrolysis/gasification is the suitable option for the treatment of different compositions of solid waste with high energy recovery in India, while bio-methanation is suitable for a decentralized system with a high energy value, and a minimum level of pollution & health hazards. Conclusion: The study and observations show that there are multiple technological options for the treatment of municipal solid waste. Research and development in the MSW sector is not a priority in India, therefore, it has been recognized that expert research advice is required while selecting technology as well as for deciding the tools and techniques to handle this issue.

Taking Iran as the 7^th Greenhouse Gas (GHG) emission source of the world, the country contains a high potential for the emission management plans and studies. As the economy is a significant factor in the greenhouse gas emission, studying the economy and GHG emission integrated relations must be taken into account of every climate change and environmental management plan. This paper investigates the relationships among the economic, demographic, foreign policies, and many other domestic and foreign parameters, which are illustrated by sixth Iranian document over development and GHG emission in three progress scenarios made for this plan. In this paper, all the significant GHG emissions such as CO2, SO2, NOx, hydrocarbons, and CO in the period of 2014-2020 are being studied. As the results show, the number of emissions is directly related to domestic and foreign parameters, which means a better economic status in Iran causes an increase in the number of emissions. The foreign policies are more effective in the Iranian economy and emissions than the domestic policies and parameters. The scenarios and the results show that the Iranian economy and energy systems have a significant potential for efficiency development plans. However, one thing is clear that Iranian emissions will be increased to 800 million tons by the end of the plan period (by 2021). This significant increase in the amount indicates the importance of optimization and efficiency development plans in Iran, which is predicted to control and fix this increment around 3-4% .

Background: Purification and remediation of water remain to be a mammoth challenge for environmental engineers, continuously mounting pressure on providing safe water for consumers. Nevertheless, care has to be taken to avoid chemicals in treatment, which could prove to be toxic. One of the most prominent stages in treating water for human consumption is clarification through coagulation and flocculation to remove colloidal particles including silt, clay, precipitated iron or manganese oxides along with bacteria and algae. Objective: In order to achieve sustainability, the only possible way is to use innate materials in combination with inherent technologies. Considering this, the present review will appraise the efficiency of natural coagulants in treating surface water. Several researchers have tested numerous natural coagulants for clarification of water. Nevertheless, information on various natural coagulants and their efficiency has not yet been presented. Methods: Hence, an attempt is made to bring about a comprehensive account of various natural coagulants and also to understand their properties and efficiencies in treating water. Results: Cumulative information regarding natural coagulants presented in this review will add to the database of natural coagulants and can be adopted at various temporal and spatial levels according to the availability of these coagulants to treat water. Nevertheless, precise research on coagulation parameters and shelf life of treated water will enhance the opportunities for point of use water treatment technologies. Conclusion: The current review presents natural coagulants having the potential to treat surface water as sustainable alternatives to point of use treatment.

Background: Heavy metals are the most common form of environmental pollution and the evaluation of heavy metal contaminated soils is necessary for reducing the associated risks, making the land resource available for agricultural production, and enhancing food security. There are 2,000 contaminated sites in Greece, according to a previous survey report issued by the Greek Ministry of Environment, out of which 300 required immediate restoration. Objective: This study investigated the effects of Cd, Pb, and Zn on Triticale (Triticosecale wittm.) growth in an above-referenced multi-metal contaminated site. Methods: In order to evaluate Triticale growth in metal contaminated soil, Triticale plants were cultivated in pots filled with unpolluted and metal-polluted soils in the absence/ presence of Zeolite as an agent empowering the restoration of pollution and immobilizing heavy metals. Results: The results showed that the Triticale plant in polluted soils with high metal concentrations, namely 4.34, 295 and 1,467 mg/kg for Cd, Pb, and Zn, respectively, can act as a “moderate” accumulator of Zn and as a “weak” accumulator of Pb and Cd; while the presence of 1% Zeolite in multi-metal-polluted soils can significantly contribute to plant growth by limiting the uptake of Cd, Pb, and Zn. Conclusion: This study demonstrated that the addition of 1% Zeolite to multi-metal contaminated soils could minimize metal (Pb, Cd, and Zn) pollution in the environment and positively contribute to the growth of Triticale biomass for use as an animal feed within the context of sustainable development.

Objective: The objective of this study was to assess the outcome of fine grid modeling on top of a courser grid to predict the NO2 concentration more accurately in an airshed and at sensitive receptors. Methods: This study assessed the cumulative NO2 impact of all major emission sources in an airshed using USEPA regulatory model AERMOD. A 50 km by 50 km airshed is considered in the study. Micro-environmental pollution was modeled using a refined grid analysis. An area (4 km x 4 km) close to GTPS, with receptors at every 150 m apart and a further fine grid (500 m x 500 m) with receptors at every 50 m apart, was modeled. Results: Coarse grid modeling showed annual average NO2 concentration levels within applicable standards. However, when fine grid modeling was conducted, the predicted annual average NO2 concentration levels were found to exceed World Bank Guidelines and Bangladesh Standards. A source contribution analysis showed that a quick rental power plant (natural gas generators) without proper stacks contributed a significant portion of the maximum 1-hr and annual average NO2 concentration (76% and 86%, respectively). Conclusion: The findings of fine grid modeling can be used at the policy level of the government to enforce environmental regulations on the minimum height requirements of stacks and city planning, avoiding downwind directions and the close proximity of powerplants to safeguard human health.