جستجوی مقالات مرتبط با کلیدواژه "آلودگی زیست محیطی" در نشریات گروه "فنی و مهندسی"

In the present century, the use of various petroleum products and fossil fuels has been an integral part of industry and human progress. Nowadays the major concern, in addition to the use of petroleum products, is their uncontrolled diffusion in various parts such as extraction, processing, transfer and use. The other problem with the utilization of these products has arisen in the field of geotechnical engineering includes environmental pollution and the creation of problematic contaminated soils. Many solutions to these problems have been investigated and presented separately. In the present study, the microbiologically induced calcium carbonate precipitation (MICP) method, as a solution to purify contaminated soils and to improve its reduced bearing capacity with two petroleum products, diesel and engine oil, has been proposed. The bacterium used in this process was Sporsarcina pasteuri, which was added to the contaminated soil as a flocculate bacterium. In two stages; purification evaluation (using chromatographic results) and geotechnical improvement (using direct shear and permeability test results) were performed. With the aid of FTIR (Fourier-transform infrared spectroscopy) analysis and chromatographic diagrams, a reduction of peaks of the identified components in the treated sample in comparison to the standard sample (prepared from diesel or engine oil) was observed. On the other hand, improving the geotechnical properties of contaminated soils was one of the most important effects observed in the treated samples.

Coastal areas of Caspian Sea have been affected by pollution in recent years. These areas are exposed to environmental problems due to the presence of hydrocarbon resources in the Caspian Sea basin as well as human factors. Investigating the concentration of normal alkanes in the studied stations shows that the amount of hydrocarbons contaminated in the studied area, compared with previous year’s studies, shows a significant increase in concentration. The concentration of n-alkanes are among the 24.3 µg/g (the minimum concentration) in Nashtarood Station to 690.7 µg/g (the maximum concentration) in Noshahr Station and most of the stations have moderate concentration of n-alkanes. The increase of pollution in recent years as a result of increased oil activities related to the exploration, production and exploitation of oil resources and human factors. Also, the presence of Hyrcanian forests on the southern shores of the Caspian Sea and increasing seizure of forests in recent years have also led to increased contamination in the region due to pollution transmission to the Caspian Sea. In order to determine the origin of normal alkanes in the region, the indexes of CPI, LMW / HMW, Pristane / Phytane, n-C17 / Pristane and n-C18 / Phytane were used. The results show petrogenetic and biogenic inputs at sampling stations that petrogenetic contamination is prevalent in the region.