Effects of Inorganic Passivators on Gas Production and Heavy Metal Passivation Performance during Anaerobic Digestion of Pig Manure and Corn Straw

Xiaoliang Luo, Bincheng Zhao, Mingguo Peng, Rongyan Shen, Linqiang Mao () and Wenyi Zhang ()
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Xiaoliang Luo: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China
Bincheng Zhao: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China
Mingguo Peng: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China
Rongyan Shen: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China
Linqiang Mao: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China
Wenyi Zhang: School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, China

IJERPH, 2022, vol. 19, issue 21, 1-15

Abstract: The treatment of livestock manure caused by the expansion of the breeding industry in China has attracted wide attention. Heavy metals in pig manure can pollute soil and water and even transfer to crops, posing harm to humans through the food chain. In this study, corn straw was selected as the additive and introduced into the anaerobic digestion. Sepiolite (SE), ferric oxide (Fe 2 O 3 ), attapulgite (AT) and ferric sulfate (FeSO 4 ) were used as passivators to compare the effects of these inorganic passivators on gas production and passivation of heavy metals during the process of the anaerobic digestion. When the dry mass ratio of pig manure to straw is 8:2, the gas production efficiency is optimal. SE, AT and ferric sulfate have a much stronger ability to improve gas production performance than Fe 2 O 3 . The total gas production increased by 10.34%, 6.62% and 4.56%, and the average methane production concentration increased by 0.7%, 0.3% and 0.4%, respectively. The influence of SE, AT and ferric sulfate on the passivation of heavy metals is much better than Fe 2 O 3 , and the fractions in biological effective forms of Cu and Zn reduced by 41.87 and 19.32%, respectively. The anaerobic digestion of mixed materials is conducive to the gas production and the passivation of heavy metals. Therefore, SE, AT and ferric sulfate are selected as composite passivators, and the optimal ratio of inorganic composite passivators i: AT 7.5 g/L, ferric sulfate 5 g/L and SE 7.5 g/L, according to the results of orthogonal experiments. This study can provide a theoretical basis for the safe application of biogas fertilizers.

Keywords: pig manure; anaerobic digestion; gas production; inorganic passivator; heavy metals (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2022
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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