مجله پژوهش و فناوری محیط زیست
پیاپی 4 (بهار و تابستان 1397)

In recent decades, with the rapid growth of urbanization and population growth in cities, the use of public transport and personal vehicles has been on the rise, which has many consequences such as greater dependence on the car, long travels, increased transportation costs and most importantly, environmental hazards and air pollution. The Irregular use of cars leads to the loss of irreversible energy, the effects of greenhouse gas, and the dissatisfaction of townspeople of the high levels of noise and air pollution, resulting in a reduction in economic efficiency. In this regard, governments have set various rules and standards for reducing car pollution and the car makers are required to comply with them. These requirements have prompted carmakers to find ways to reduce the environmental pollution of their products and to create new technologies in this industry. Therefore, attention to environmental studies in the automotive industry is one of the most important factors. In this research, we investigate the types of pollution caused by automobile industry and practical ways to reduce these contaminations.

Colors are one of the most important pollutants of water, and only one entry into the water can significantly reduce the quality of water. In addition, due to the synthetic origin and the presence of complex molecules in the structure of colors, the purification process is sometimes accompanied by some problems. Colloidal nanoparticles play an important role in technology, especially in the manufacture of glass and ceramics, and are used as a suitable method for cleaning pollutants in water and wastewater. In this study, a chemical regeneration method was used to synthesize colloidal silver nanoparticles. Then, to evaluate the efficiency of synthetic silver nanoparticles, several solutions of dye and pigments such as sulfur, azo, reactive, cationic and anionic dyes were prepared and synthetic material was used for degradation of different colors. Finally, the effect of this colloidal nanoparticle on each of them was studied and compared. The results showed that silver colloidal nanoparticles have the ability to degradation and removal of methyl orange and methyl red dyes from aqueous samples, and these nanoparticles can be used for treatment the water and wastewater containing these dyes.

Natural gas and crude distillates such as naphtha from petroleum refining are used as feedstocks to manufacture a wide range of petrochemicals that are in turn used in the manufacture of consumer goods. Petrochemical plants are typically large and complex, and the combination and sequence of products manufactured are often unique to the plant. Petrochemical plants generate significant amounts of solid wastes and sludges, some of which are hazardous because of the presence of toxic organics and heavy metals. A good practice target for a petrochemical complex is to reduce total organic emissions (including VOCs) from the process units to 0.6% of the throughput. In this paper a variety of control of air emissions techniques is has been studied. Petrochemical waste waters often require a combination of treatment methods to remove oil and other contaminants before discharge. For solid and hazardous wastes, combustion (preceded in some cases by solvent extraction) of toxic organics is considered an effective treatment technology for petrochemical organic wastes. Steam stripping and oxidation are also used for treating organic waste streams. The generation of sludges should be minimized. Wastes containing toxic metals should be stabilized before disposal.

Applying a proper management on water resources by identifying vulnerable areas as the first solution can be useful. The purpose of this study was to assess the vulnerability in the central plain of Guilan with drastic model. To identify the vulnerable areas of the central plain of the Guilan plain to pollution, drastic model was used and an aquifer vulnerability map was developed. The principles of the drastic model are based on the combination of seven components, depth to static level, net nutrition, aquifer environment, soil environment, topography, unsaturated environment, and hydraulic conductivity, which after ranking and applying weight impact on each component and algebraic composition of seven components, the final result will indicate the aquifer vulnerability. For this purpose, first, the information of the seven components in the central aquifer of Guilan was collected, and after entering in the GIS software, the layers needed for the model were finally prepared. Then, by using overlapping techniques after applying the required weight coefficients for each layer, a final vulnerability map was prepared. The profile of the drastic model varied from 82 to 182 for the vulnerability of the central aquifer of Guilan. The final drastic model map showed that 48.64% of the area had a high vulnerability and 50.55% had moderate vulnerability and only a small area of the plain (0.81%) had a low vulnerability. Based on the sensitivity method of map removal and single component and using the Monte Carlo technique, the depth distance to the station level was identified as the most effective component and saturation zone as the second most effective component in the central plain of Guilan.

Coagulation is a process that increases the tendency of small particles in an aqueous suspension to attach to one another and to surfaces such as the media in a filter bed and is applied through mixing coagulants such as aluminum sulfate (alum), ferric chloride and polyaluminum chloride with raw water. Sludge containing coagulant is formed after coagulation and through sedimentation of natural turbidity. Presence of high amounts of coagulant in waterworks sludge, increases environmental risks and disposal costs. Coagulants in sludge have high economic value. Therefore, if these coagulants recover, not only sludge disposal risks but also expenses related to supply of fresh coagulant in water or wastewater treatment plant may decrease. In this paper, researches conducted by acid digestion method for coagulant recovery from waterworks sludge are investigated. Amounts of coagulant recovery, advantages and disadvantages and economic aspects of this method are studied. Results of the investigation showed that using sulfuric acid is the best option for conducting acid digestion process because it is cheap and available. Moreover, if the purpose of recovering process is to achieve a recovered coagulant with a similar quality to the commercial ones, acid digestion method will not satisfy related standards.

Landscape ecology metrics are used to describe composition and configuration of landscapes. The aim of this study was examination of habitat loss and fragmentation in Lisar Protected area in Guilan province during time period of 1990-2015.In this study , using Landsat images(1990-2015), after radiometric and atmospheric correction, three density classes of forest cover(10-40%,40-70% and above 70%) were produced. Reference maps and field study were applied for interpretation of images and maximum likelihood method was used for classification. Using ArcGis and Patch Analyst software, with derived metrics, trend of habitat loss and fragmentation was examined.

Today, steel production and consumption is applied as an important criterion for measuring the degree of countries industrial development. Needing to investment in construction and economic infrastructure in developing countries, their steel production policy is in the direction of producing the various types of structural steel. In this regard, the main object of the studied steel plant construction is creating jobs in the region, reducing imports and contributing to the country's economic development through carbon ingot production with electric arc furnace technology. After assigning the direct study area of the project, the major contaminants arising from the project implementation were investigated in construction and implementation phases and the corrective actions considered to reduce the contaminants effects. In this research, Rapid Assessment method was used for environmental impact assesment that according to the results, among 96 detected impacts, 55.1 percent of the impacts are negative and 44.9 percent are positive that in case of observing the corrective actions before and after the project implementation, its negative impacts will be minimized. Also, it is recommended that after the plant costruction, apply a periodic monitoring of the outlet contaminants every three months.