Cleanit – efficient removal of soil contamination
Zero valent iron (ZVI) for soil remediation
Many soils have been contaminated by either natural or anthropogenic activities, and the number of contaminated sites is increasing.
For in-situ soil/groundwater remediation, iron based media including zero valent iron (ZVI) have been used for decades. Major target contaminants are heavy metals such as hexavalent chromium and arsenic, and chlorinated volatile organic carbon (C-VOC, e.g. perchloroethylene (PCE), trichloroethylene (TCE) and polychlorinated biphenyls (PCBs).The heavy metals in contaminated soil can be removed by ZVI media through the reduction and adsorption mechanism. For removal of the C-VOC, specifically PCE/TCE, microbial dehalogenation pathway is widely used. The PCE/TCE can be broken down by certain microorganisms living in the soil – called dehalogenation bacteria.
However, these microbes are not very active under a normal soil environment. Thus, a typical in-situ soil remediation technology focuses on enhancing the growth of the dehalogenation bacteria by providing proper a carbon source and ZVI media as an electron/hydrogen donor. Use of ZVI can also enhance a direct reduction of PCE/TCE through an abiotic pathway. Occasionally, a combination of ZVI media and oxidants is applied for generating.
Cleanit outperforms other ZVI media
According to laboratory assessment, Cleanit media showed 8 times higher gas production rate compared to other ZVI media. In addition, the total yield of gas production is 47 times greater than that of other ZVI media for an identical test period. The superior hydrogen gas production of the Cleanit media is a strong indicator of high reactivity and longevity of the media. In addition, other ZVI media tend to increase ambient pH in the soil, but Cleanit media maintains the pH at circum-neutral range, which is an optimum condition for microorganism and reduces chemical usage for pH control.