Effects of oxygen supply rate on organic matter decomposition and microbial communities during composting in a controlled lab-scale composting system. (November 2022)

• Record Type: Journal Article
• Authors: Nguyen, Thien-Phuc; Koyama, Mitsuhiko; Nakasaki, Kiyohiko
• Is Part Of: Waste management. Volume 153(2022)
• Page Start: 275
• Page End: 282
• Publication Date: 2022-11
• Subjects: Oxygen supply -- Composting -- Microbial community -- Enzymatic activities; OSR oxygen supply rate -- XC conversion of carbon; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2022.09.004
• Languages: English
• ISSNs: 0956-053X

Abstract

Highlight: Critical oxygen supply rate controls composting degradation rate. Below critical oxygen supply rate, enzymatic activities were inhibited. Geobacillus was dominant with above critical oxygen supply rate. Caldibacillus and Ureibacillus proliferated with below critical oxygen supply rate. Effect of oxygen supply rate was evaluated independently from other factors. Abstract: The study aimed to elucidate the effect of oxygen supply rate (OSR) on the composting of model organic waste independently from other factors by using a controlled laboratory-scale reactor system. Four OSRs, 96.2, 24.2, 13.7, and 3.45 mL-O2 /min/kg-WS (wet solid), were tested. The delay of organic matter degradation was observed temporarily in the early stage of composting with 13.7 mL-O2 /min/kg-WS and severe oxygen deficiency was observed in lower OSR, indicating that the critical OSR existed around this value. Composting with 3.45 mL-O2 /min/kg-WS resulted in constantly low CO2 evolution rate and remarkably low degree of organic matter degradation. Under deficient oxygen, all enzymes measured, such as phosphatases, esterases, lipases, proteases, and sugar degrading enzymes, showed lower activities. High-throughput sequencing revealed Caldibacillus and Ureibacillus became dominant in the later stages of the oxygen deficiency composting, while Geobacillus was the most dominant microorganism throughout composting with OSR higher than 13.7 mL-O2 /min/kg-WS.