ORGANIC AND INORGANIC MATERIALS AS PERMEABLE REACTIVE BARRIERS FOR GROUNDWATER REMEDIATION FROM TOXIC METALS AND BTEX - CONTINUOUS FLOW STUDY

摘要

The main goal of this study is the evaluation of an organic material (compost) in comparison to an inorganic one (zeolite) as potential reactive barriers in order to deal with mutli pollutant groundwater contamination. The reactive barriers technology achieves groundwater remediation utilizing the physical flow.The present study focuses on the comparison of compost from municipal solid waste and natural zeolites for the simultaneous removal of petroleum hydrocarbons (benzene, toluene, ethylbenzene, and xylenes - BTEX) and toxic metals (Cd, Zn) from groundwater. Experiments in small scale tanks were conducted simulating the real field conditions. Basic hydraulic parameters such as hydraulic conductivity and porosity of each material were determined. The effect of the initial concentration of the pollutants were also studied. Finally, the contaminants flow was simulated through the use of simulation software.The results indicate that the mature compost achieve 80% removal of heavy metals and 90% removal of BTEX when the zeolite had 75% and 80% respectively. The real groundwater was not polluted in the same level as the experimentally prepared dilutes so under the same conditions the removal was almost 98% and the exhaustion time of the barrier was expanded. The selectivity of zeolites follows the order Cd > Zn & toluene > m- & p-xylene > ethylbenzene > o-xylene > benzene, while the selectivity of com post follows the order Cd > Zn & toluene > ethylbenzene > m- & p-xylene > o-xylene > benzene.The utilisation of the Princeton Transport Code (PTC), which is a simulation program for groundwater flow, enables the accurate and efficient design of the reactive barriers technology eliminating the need of time consuming and expensive laboratory tests. In conclusion, compost has many advantages, when applied as a reactive material, and achieves high removal percentages both for organic and inorganic pollutants.