Chemical Removal of Cu and Zn from Swine Feces before Soil Application

Moo-Joon Shim and Seung-Mok Lee
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Moo-Joon Shim: Department of Biosystems and Convergence Engineering, Catholic Kwandong Univeristy, Gangneung 25601, Korea
Seung-Mok Lee: Department of Biosystems and Convergence Engineering, Catholic Kwandong Univeristy, Gangneung 25601, Korea

Agriculture, 2021, vol. 11, issue 5, 1-14

Abstract: Cu and Zn are known to be abundant in swine feces; hence, concentrations of these metals need to be lowered before swine feces are applied to land in order to prevent potential environmental problems. The main objective of this study was to develop an appropriate chemical process to remove Cu and Zn from swine feces using acid extractions. The removal efficiencies of Cu and Zn decreased in the order of H 2 SO 4 > HNO 3 > organic acids (citric and oxalic acids). Owing to the highest removal efficiencies of Cu and Zn by using H 2 SO 4 , it was selected for further elimination of Cu and Zn from swine feces. By using H 2 SO 4 , the optimal concentration, solid-to-liquid ratio, and reaction time were 2%, 1:50, and 8 h, respectively. At the optimum conditions, Cu concentration was decreased from 198 mg/kg to 40.1 mg/kg and Zn concentration from 474 mg/kg to 80.0 mg/kg, with removal rates of 79.7% and 83.1%, respectively. The low Cu removal efficiency, resulting from the strong complexation between Cu and organic matter of swine feces, was improved by the increase in the reaction time and H 2 SO 4 solution concentrations. However, about half of the total nitrogen (TN) was also removed by using H 2 SO 4 , indicating that the swine feces treated with H 2 SO 4 may have poor value as fertilizer. Additional studies are required to find an optimal method to maintain TN concentrations while simultaneously removing Cu and Zn.

Keywords: swine feces; metals; fertilizer; removal; sludge (search for similar items in EconPapers)
JEL-codes: Q1 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 (search for similar items in EconPapers)
Date: 2021
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