Study On Identification Theory And Method For Extraction Toxicity Of Hazardous Waste

Environmental management and pollution control of hazardous waste are important for solid waste management, and identification of hazardous waste is the technical foundation and key process. However, there was no integrated identification system for hazardous waste established in China. Therefore, research on identification technique for hazardous waste should be greatly strengthened, so as to perfect Chinese hazardous waste management system.At first, comparing research on identification system for ET of hazardous waste in some countries was carried on, especial for appraisement method and criteria of ET. Then, in the ground of current management situation and practice of hazardous waste, existing problem of ET for hazardous waste in China was introduced.After investigating and analyzing hazardous waste generation, management and pollution, groundwater was deemed as the Environmental protection target for ET. Then, appraisement method was established: Simulating pollution scene was that industrial solid wastes were irrelevantly landfilling disposed and stored, which soaked by acid rain simultaneously, and then extracted harmful substances were transferred into underground water. So, underground water was to as protected target. According to simulating pollution scene, major parameters of extraction method (or extraction procedure for extracted solution) were reckoned, which were validated and optimized through pertinent experiment: liquid to solid ratio (L/S ratio) is 10 to 1; extraction solvent is a blend of thick H₂SO₄ and HNO₃, and its weight ratio is 2 to 1; acidity of extraction solvent is 3.20±0.05 (pH).At last, based on environmental protection target and appraisement method, and appraisement criteria for ET was researched: Toxic substances of TC were derived from the substances controlled in priority in national drinking water standard. Meanwhile, toxicological data of those substances should be considered, as well as other factors, such as category characteristic of hazardous wastes, experimental extraction characteristic, criteria methods for extracted liquid analyzed; limited value of identification criteria was determined both by acceptable dosage for human being in drinking water, and dilution and attenuation factors.