Influence of industrial wastewater on the geotechnical and physicochemical properties of fine-grained soil

Fine-grained soil contamination is a daily occurrence due to industrial development and pipeline or reservoir leaks. The modification of the geotechnical properties of the polluted soil is a worry in addition to environmental issues like groundwater pollution. Recent studies have carefully examined the characteristics of contaminated fine-grained soils because it has been demonstrated that contamination modifies the geotechnical properties of soil. However, a thorough evaluation of the impact of industrial wastewater from paper (PW) and leather (LW) wastewater on the geotechnical characteristics of fine-grained soils is still lacking. As a result, thorough experimental studies have been carried out on both uncontaminated and contaminated fine-grained soils that include various concentrations of PW and LW. The soil samples were extracted from the lands in Benha City, Cairo, Egypt, which were exposed to PW and LW at 2, 4, 6, 8, 12, and 16 months. The findings showed that as soil ages, there is a decrease in the maximum dry density and Atterberg limits of the soil containing PW, as well as a increase in the optimum moisture content (OMC) and cohesive. On the other hand, the findings also showed that there is a decline in maximum dry density and Atterberg limits as well as a rise in OMC and cohesive. Additionally, ageing caused a further decrease in cohesion and increased the free swelling values in the case of the soil coated with PW, while decreasing the leather wastewater exposure. Finally, the microscopic investigations and mineralogical analysis confirmed the trend of the experimental results on the mechanical properties of the contaminated soils.