Role of electron acceptors in soil resource circulation for organic waste composting

Authors

• Zahra Mohebi ¹
• Noppawan Semvimol * ²
• Onanong Phewnil ^{3, 2}
• Thanit Pattamapitoon ^{3, 2}
• Kasem Chunkao ^{3, 2}
• Chulabut Chanthasoon ^{3, 2}
• Watcharapong Wararam ^{3, 2}

1. Department of Natural Resources, Faculty of Agricultural Sciences & Natural Resources, Razi University, Kermanshah, Iran.
2. The King’s Royally Initiated Laem Phak Bia Environmental Research and Development Project, Chaipattana Foundation, Phetchaburi, Thailand
3. Department of Environmental Science, Faculty of Environment, Kasetsart University, Bangkok, Thailand

Abstract

Purpose Soil is an important accelerator for biodegradable processes. Soil resource circulation concept by using the compost from the previous crop as cover materials for the recent composting mass was evaluated as it contained soil and amorphous Fe as an energy source. Therefore, this research was focused on the possibility and the changes in the electron acceptors in the organic waste composting process.
Method The 2 experiments using different covering materials: paddy soil as a control (T1) and compost (T2) in a completely randomized design. An amount (670 g) of organic wastes was altered with 210 g of materials covered in 3 layers with 60 mL of water added every 7 days during a period of 30 days. The physico-chemical parameters, redox potential (Eh), and electrical conductivity (EC) were studied beside the basic soil parameters including electron acceptors such as NO^–₃, MnO₂, Fe₂O₃, and SO₄^-2.
Results The changes in physical and chemical properties during the degradation process were not different. The Eh reacted intensely and continuously in the same direction. The T2 compost product contained the highest SO₄^-2 level compared to T1 but there were no significant differences in the organic carbon and C/N ratio, though the quality of T1 was better.
Conclusion Covering the organic waste with compost improved the nutrient content in the compost products. Therefore, compost can be used as a cover material instead of soil in the composting process. However, to increase the number of electron acceptors, cover materials should be mixture of soil with compost for greater efficiency.

Highlights

• Quantity of nutrients in compost product related to the humic formation process and exchangeable cation functions.
• The biochemical reaction of the composting process was stable after the third week until compost maturity.
• Surfaces area affects the adhesion of microbes by produced linking-agent and promotes the biochemical reaction.
• The nutrient in compost was positively correlated with the proportion of clay particles, oxide compounds, and porosity properties.
• High moisture during composting process affects the oxidation-reduction reaction of organic and inorganic compounds resulting in pH and EC changes.

Keywords

• Compost
• Electron acceptors
• Organic waste
• Redox potential (Eh)