Immobilization of leachateʹʹs heavy metals using soil-zeolite column

Introduction: Soil hazardous heavy metal pollution is increasingly a decisive problem all over the world. One of the problems associated with organic fertilizer factories is the discharge of leachate containing solid wastes. The leachate percolates through the soil and where there is no proper leachate filtration, this discharge could be potentially a primary pollution source of soil and water resources. Iran has limited water resources and oppositely large number of unused lands. Therefore, properly managed land treatment may be a suitable solution for the filtration of leachate before it enters the environment or is reused as irrigation water. To investigate the potentiality of soil-zeolite in the immobilization of heavy metals and prevention of groundwater contamination, a lysimeter study was performed with two types of soil texture (clay loamy and loamy sand) and two levels of zeolite and a blank (0, 5, and 10%). Results: The results showed that soil with a clay loamy texture can adsorb heavy metals such as Cr3+, Pb2+, Ni2+, and Cd2+ from influent leachate stronger than soil with loamy sand texture. Application of zeolite had a significant effect (p < 0.05) on Pb2+, Ni2+, and Cr3+ concentration in the effluent. Increasing applied zeolite, reduced the concentrations of these heavy metals in the effluent. Furthermore, application of zeolite and irrigation with leachate decreased the bulk density, hydraulic conductivity, and infiltration of the soil in all treatments. Conclusion Briefly, this research indicated that land treatment is a good way to reduce leachate electrical conductivity (EC) and elimination of leachate heavy metals.