چكيده به لاتين
Wastewater, a byproduct of wastewater treatment plant, owing to containing heavy metals and pathogens brings about several adverse impacts in terms of environment and human health. Given that the annual production of wastewater in our country, Iran, has reached more than 3.9 billion cubic meters and only about 9% of it is treated, Iran is planning to construct more treatment plants. With the increase in the number of treatment plants, Iran, like other countries in the world, will be encountered with the problem of sludge management. One of the proper approaches which has recently been utilized by European and Asian countries for sludge burial is sludge incineration, which not only does reduce the volume of sludge by 90%, but also leads to the elimination of toxic substances, heavy metals, odour decimation and subsequently generates a harmless and pathogen-free mineral gray. In recent years, sewage sludge ash has been used as a substitution for cement and fine-grained concrete. By doing so, in addition to the reduction of economic costs, diminishing carbon dioxide and greenhouse gases emission, decreasing energy consumption in construction projects (due to lower consumption of cement per cubic meter of concreting) will bring about a reduction in the costs of stabilization and disposal of this material. In this study, fine-grained soil stabilization has been performed using sewage sludge ash. Compressive strength tests, TCLP, FESEM, EDS and Mapping were used to study the mechanical and microstructural performance of the samples. The results indicate that although the compressive strength decreased by increasing the percentage of sewage sludge ash, which is due to the effect of interference between the phases of sewage sludge ash and volcanic ash, the amount of heavy metal leakage from the samples was very low, Moreover anorthite and N-A-S-H gels were observed in microstructure analysis.
