Evaluation and selection of a rational test method for heavy metal leaching in terms of environmental and economic factors

Abstract

The paper presents a specific model used to assess and select the method of heavy metal leaching from waste materials. A recommendation for the rational selection of the leaching method was made, taking into account the crucial parameters affecting the leaching process derived from the authors' research experience. The assessment models were supplemented with characteristics relating to the cost and time required to perform the tests. An approach was developed that links the weights of the assessment criteria with the degree of environmental risk from a particular heavy metal and waste type. Using multiple-criteria decision analysis, four models were developed for the assessment and selection of a test method for the leaching of heavy metals from waste. The difference is in the way the weights of the assessment criteria depend on the potential threat of the waste to the environment. A key element of the proposed approach is assigning the weights of the criterion to the toxicity of the heavy metal, the type of waste, and their management method. The results obtained prove that the current practice of only employing the batch leaching test is inappropriate. The choice of method should be justified in terms of environmental safety as well as time- and cost-effectiveness. The results of the paper show that the proposed model can be used in practice and be a recommendation for choosing the method of leaching heavy metals from waste and their further treatment, following the principles of sustainable waste management.