Investigating the leaching properties of MBT wastes and composts from aerobic/anaerobic processes

Abstract

This work assessed and compared the leaching properties of two types of compost and stabilized waste from a mechanical-biological treatment (MBT) plant. The first type of compost and the MBT waste were produced by aerobic treatments, while the second type of compost was generated from a combination of anaerobic and aerobic biodegradation processes. Both static-batch leaching tests, carried out applying a single liquid to solid (L/S) ratio equal to 10 L kg-1, and dynamic column percolation tests, investigating constituents release as a function of different L/S ratios, were performed. The three materials were also characterized in order to investigate their biological stability degree, organic matter content, and metals total content. As expected, due to the differences in feed input waste or treatment conditions, the three types of samples showed different characteristics and leaching concentrations. However, the leaching behavior of the three types of treated materials presented similar trends of dissolved organic carbon (DOC) and metals (Cu, Ni, Pb, Zn) leaching as a function of the L/S ratio. A screening model proposed and developed for MBT waste in a previous study, which allows the description DOC release as a function of the L/S ratio, was applied and discussed. The comparison of model predictions with the experimental leaching data highlighted that for all three samples the screening model describes quite well the release trends of metals.

Release of pollutants in MBT landfills: Laboratory versus field

“…This result reinforces those obtained in other works (Lombardi et al, 2018;Pantini et al, 2015a), in which metals such as Mg, Ni or Zn showed a linear correspondence with the concentration of organic matter (represented by the COD in those cases) for different samples of the same MBT material. In this study it is also observed how this correspondence persists even when the sizes or fractions of the studied waste are different.…”

“…In recent years, works have been published that use the CEN/TS 14405 test to characterize the washing of contaminants in MBT waste (Lombardi et al, 2018;Pantini et al, 2015a) or to evaluate the possibility of washing these materials prior to landfilling (Cossu and Lai, 2012). However, some authors have observed limitations of laboratory tests on biodegradable waste (Di Maria et al, 2013;Fellner et al, 2009), and they suggest that the best option to estimate the washing of contaminants in the landfill is in situ sampling.…”

Effect of Particle Size on the Hydraulic Characteristics of Mechanically and Biologically Treated Waste

“…Kuehle-Weidemeier [9] found the uniformity coefficients of MBT waste (from Germany) with particle size ranges of 0-60, 0-40, and 0-20 mm to be 50, 123, and 192, respectively. In another study, Tungtakanpoung [10] determined different contents of the components of MBT waste (from ailand) with three particle size ranges (<10, 10-40, and >40 mm); the results were quite different from the results of MBT waste in Italy [11].…”