Document Type : Research Paper
Department of water and wastewater engineering, Faculty of Civil, Water and Environmental Engineering, Shahid Beheshti University, Tehran, Iran
The issue of optimal disposal of sludge in water treatment plants is among the important issues in line with the principles and goals of sustainable development. In this study, the possibility of applying activated carbon and water treatment sludge with the purpose of reducing the consumption of cationic polyelectrolytes in the thickening stage of wastewater treatment sludge on a laboratory pilot scale was investigated. For this purpose, the effect of these additives on SVI, TTF, DS, pH, and the dosage of polyelectrolytes used was evaluated. SVI and TTF of conditioned sludge at a dose of 300 mg/g along with 1 mg/l of cationic polyelectrolyte decreased to less than 100 ml/g and 100 s-1, respectively, and also increased the amount of sewage sludge solids to at least 5%. Large flocs formation, particles size distribution change, and increasing the porosity of the sludge have become as a result of adding the conditioning materials, and facilitating the thickening and releasing of free water. In addition to improving the efficiency of sewage sludge thickening, these industrial wastes reduce polyelectrolyte consumption by 50%, protecting the environment from the negative impacts of their disposal.