Affiliation:
1. Zhejiang Environmental Science and Design Institute
2. Zhejiang University of Technology
3. Hangzhou Huanjie Environmental Engineering Co. Ltd
Abstract
Lead pollution, commonly found in lead-acid battery plants or electroplating manufactures, has drawn more and more attention due to its intrinsic toxicity to human health and potential disturbances to local ecological system. Soluble phosphates showed great advantages over other inorganic stabilizers and could provide a rapid, cost-effective approach for lead contaminated sites, despite of complex contaminants presence and heterogeneity distribution of contamination. Chemical stabilization using soluble phosphates was demonstrated by immobilize both lab samples and on-site samples from a local lead contaminated site in this study. The soil samples were mixed with soluble phosphates and stabilized for selected intervals, while adding supplements for the purpose of pH control and solidification. Experiments for treatment duration and immobilization rate in comparison with other stabilizers were also investigated to provide guidance for following demonstration project. Soil samples were analyzed before and after the treatments to compare lead immobilization rates under different circumstances. The results suggested that 90% of lead in lab soil samples was stabilized after one day treatment with phosphates, while on-site soil samples took another 30 to 50 days due to their complexity. Phosphates treatment showed great consistence over all the soil samples after 50 days in contrast with the performance of lime treatment and ferrous sulfate stabilization. It is recommended that the stabilization duration for the specific site should be longer than 30 days, at an average cost of stabilization per ton of soil around 300 RMB. This study demonstrated the use of soluble phosphates in pilot-scale lead pollution remediation, as well as the possibility of extending the remediation concept for other heavy metal contamination scenarios. In addition, chemical stabilization could also be combined with other remediation technology in future due to its simplicity and convenience.
Publisher
Trans Tech Publications, Ltd.
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