pH-dependent leaching behaviour and other performance properties of cement-treated mixed contaminated soil

作     者：Reginald B. Kogbara Abir Al-Tabbaa Yaolin Yi Julia A. Stegemann 

作者机构：Geotechnical and Environmental Group Cambridge University Engineering Department Trumpington Street Cambridge CB2 1PZ UK. Center of ExceUence in Environmental Studies King Abdulaziz University Jeddah 21589 Saudi Arabia Institute of Geotechnical Engineering Southeast University 2# Sipailou Nanjing 210096 China Department of Civil Environmental and Geomatic Engineering Chadwick Building University College London WCIE 6BT UK 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2012年第24卷第9期

页      面：1630-1638页

核心收录：

学科分类：12[管理学] 1204[管理学-公共管理] 082803[工学-农业生物环境与能源工程] 08[工学] 0828[工学-农业工程] 120405[管理学-土地资源管理] 

基　　金：support the ProCeSS project which was conducted by a consortium of five universities led by University College London and 17 industrial partners under the UK DIUS Technology Strategy Board (TP/3/WMM/6/I/15611) 

主　　题：diesel heavy metals hydraulic conductivity porosity Portland cement stabilisation/solidification 

摘      要：Portland cement has been widely used for stabilisation/solidification （S/S） treatment of contaminated soils. However, there is a dearth of literature on pH-dependent leaching of contaminants from cement-treated soils. This study investigates the leachability of Cu, Pb, Ni, Zn and total petroleum hydrocarbons （TPH） from a mixed contaminated soil. A sandy soil was spiked with 3000 mg/kg each of Cd, Cu, Pb, Ni and Zn, and 10,000 mg/kg of diesel, and treated with ordinary Portland cement （CEM I）. Four different binder dosages, 5%, 10%, 15% and 20% （m/m） and different water contents ranging from 13%-19% dry weight were used in order to find a safe operating envelope for the treatment process. The pH-dependent leaching behaviour of the treated soil was monitored over an 84-day period using a 3-point acid neutralisation capacity （ANC） test. The monolithic leaching test was also conducted. Geotechnical properties such as unconfined compressive strength （UCS）, hydraulic conductivity and porosity were assessed over time. The treated soils recorded lower leachate concentrations of Ni and Zn compared to the untreated soil at the same pH depending on binder dosage. The binder had problems with Pb stabilisation and TPH leachability was independent of pH and binder dosage. The hydraulic conductivity of the mixes was generally of the order, 10-8 m/sec, while the porosity ranged from 26%--44%. The results of selected performance properties are compared with regulatory limits and the range of operating variables that lead to acceptable performance described.