Geo-Environmental Assessment for Naturally and Artificially Contaminated Cohesive Soil Remediated with Granular Carbon

The present study is focused on the ability of granular activated carbon (GC) for reduction of contaminants in polluted soils and its effect on physical and chemical properties of these soils. The effect of thermal power plant effluent on soil characteristics was also evaluated by conducting physical and chemical laboratory experiments. The contaminant was industrial effluent obtained from Al-Musayyib thermal power plant located in Iraq which is disposed as side product. With percolation of effluent from drainage into the soil, many processes like physico-chemical decomposition process, ion exchange reactions, chemical alterations, oxidation, hydrolysis etc. lead to the changes in natural soil properties. For these reasons, two types of soils have been proposed, first is naturally contaminated soil obtained from the site nearby of drainage channel which is located in Al -Musayyib power plant discharging industrial effluent for nearly 20 years. The second soil is artificially contaminated soil obtained from Aligarh (India), at depth “3 m”; the soil was contaminated by mixing with the 15% of the effluent collected from Al-Musayyib thermal power plant and contaminated for seven days.

Granular carbon was added to the naturally and artificially contaminated soil in proportions of 5 and 10%, by dry weight of the soil and thoroughly mixed to ensure homogeneity. For physical properties of each percentage performed by specific gravity, compaction, natural water content, filled and dry density and chemical properties for two percentages performed by pH, EC, TDS, ORG, Cl, SO₄, NO₃ and heavy metals. The soil samples were air dried and crushed and then sieved by 4 mm sieve, then the contaminated soil was mixed with GC which passed through sieve (1.17 mm). The results in this research showed slight changes in soil properties when mixed with effluent whereas in naturally contaminated soil, the results showed more changes in geo-environmental properties.