Influence of zeolite on heavy metal immobilization in municipal solid waste compost contaminated soil

Abstract

The application of Municipal solid waste as compost (MSWC) in agricultural fields has become one of the most common practices. Besides its benefits, it poses some harmful effects on soil, as it increases the heavy metal content in MSWC of the soil. It is necessary to find a way to reduce the bioavailability of heavy metals in MSWC before its application into the soil. This study aimed at exploring the efficiency of zeolite as an immobilizer to dwindle heavy metal bioavailability. An incubation experiment was conducted wherein the soil samples were artificially spiked with different rates of MSWC (0, 5, and 10 t ha-1). The zeolite was added to the spiked soil at 5 different levels, namely 0, 5, 10, 15, and 20 %, and their effect on bioavailable heavy metal status was observed during different incubation intervals (0, 15. 30, 60, 90, and 120 days). Results unveiled that applying 10% zeolite significantly (P<0.05) reduced the bioavailability of lead (Pb) and nickel (Ni) to Below the detectable limit (Bdl) in all soil samples. Furthermore, the organic carbon status of soil was also enriched by MSWC and 10% zeolite application. The soil pH slightly increased (7.39) with applying 10% zeolite resulting in the immobilization of heavy metals. Hence, 10% zeolite application was one of the most effective immobilizers in eliminating the bioavailability of heavy metals. Therefore, it can be concluded that mixing zeolite with MSWC before applying it to crop fields can reduce the heavy metal overload in soil. Hence, this study highlights the potential of zeolite as an effective choice in dwindling the soil's bioavailability of heavy metal content.

Variability of the components of oil drilling waste according to the treatment temperature

“…This phenomenon is associated with the textural properties of the solid, which can change depending on the conditions to which they are exposed. For example, some barium oxides usually retain Cr (Czop & Łaźniewska-Piekarczyk, 2020;Naveenkumar et al, 2022).This has also been reported for calcium carbonates, and some clay (montmorillonite and zeolite) which retain metals such as Cd, Pb, Ni, and Zn (Manjaiah et al, 2019;Moghal et al, 2020). This phenomenon can explain why after removing some of the hydrocarbons, the retention of metals on the solid was increased.…”