Reappraisal of permeable reactive barrier as a sustainable groundwater remediation technology

More than two-third of the world population depends on groundwater for drinking purpose. Several countries are on the verge of water crisis due to the overexploitation of groundwater for irrigational and industrial purposes. The available sources of water are currently affected by a large number of geogenic (As, F, NO3, etc.) and anthropogenic contaminants (Pb, Cd, Hg, etc.). These contaminants cause severe health effects both carcinogenic and mutagenic. There are several remediation technologies employed for the groundwater as well as soil remediation including pump and treat, air sparging, natural attenuation and containment. For the second and third world countries, permeable reactive barrier (PRB) can prove to be a major replacement for the already existing methods like the pump and treat. The topics which are discussed in the chapters following PRBs are its design, mechanisms, softwares, reactive materials, case studies in developed countries and its economic viability. The important aspects of using PRBs are easily available adsorbent material like compost, limestone, etc.; the time scale for which it can be used is decades, and the operational and maintenance cost are low. The chapter also includes favorable hydrogeological conditions for the installation of PRBs. It also brings the different set of adsorbents (reactive materials) that can be used for a different type of contaminants organic and inorganic. We have also looked out for the mechanism of degradation being a reduction, sorption, etc. This chapter also includes the possibility and problems which we can face during the installation of PRB in pilot-scale before implementing it at a larger scale. At last, we have compared different case studies, the filler material used, the type of construction used, the date of operational setup and cost analysis of PRBs. The chapter has been concluded in a good note depicting all the pros and cons of PRBs.