Environmental remediation of synthetic leachate produced from sanitary landfills using low-cost composite sorbent

The possibility of preparing a composite sorbent consisted of an activated carbon (AC) and waste foundry sand (WFS) for the treatment of synthetic leachate is of greater importance in this work; particularly the use of byproduct waste as a substitute for commercial material. A composite sorbent of 25% activated carbon mixed with 75% waste sand was able to remove the dissolved organic constituents (DOC), ammonia nitrogen (NH3-N) and the divalent dissolved zinc ions (Zn(II)) from simulated leachate in the acetogenic and methanogenic phases with removal efficiencies not less than 75%. For column tests, two beds were prepared from mixing of composite sorbent and reference sand (which consisted of 40% fine sand and 60% coarse sand) with weight proportions of 10:90 and 20:80 to obtain acceptable hydraulic conductivity and reactivity. For leachate with two phases under consideration, the increase of composite sorbent from 10 to 20% will increase the capturing of contaminants and longevity of the barrier for same location along the packed bed; however, this was associated with slight decrease of hydraulic conductivity. Empirical models such as those depicted by Thomas, Belter and Yan have yielded satisfactorily agreement for the uptake of DOC, NH3-N and Zn(II) multicomponent of the simulated leachate through the mentioned beds with determination coefficient >= 0.959, Nash-Sutcliffe efficiency >= 0.98, and sum of squared errors <= 0.78. (C) 2020 Published by Elsevier B.V.