Assessment of composting potential of screened and decanter-separated pig slurry solids based on oxygen uptake rate
Year: 2025
Type: article
Abstract: This study was conducted to identify appropriate composting conditions for solids separated during the pretreatment processes of pig slurry treatment system, specifically focusing on primary solid-liquid separation using a screen and secondary solid-liquid separation using a decanter, through the evaluation of oxygen uptake rate (OUR).Seven treatment groups were used to compare primary screened solids (T1), secondary decanter-separated solids (T2), mixtures of primary and secondary solids without bulking agents (T3 and T5), and additional treatments incorporating sawdust as a bulking agent with different mixing ratios (T4, T6, and T7).OUR was evaluated to assess the biodegradability of different solid fractions.Oxygen uptake rates ranged from 7.1 to 14.2 mg O 2 /g VS•d.The highest value observed in T2 (secondary decanterseparated solids).Lower oxygen uptake rates were observed in sawdust-amended treatments, indicating reduced microbial activity.This suggests that secondary decanter-separated solids contain more readily biodegradable organic matter and provide a favorable environment for composting.The reduced oxygen uptake rate in sawdust-amended treatments was likely attributable to excessive C/N ratios and the presence of lignin-rich recalcitrant material.Additionally, the increased porosity in sawdust mixtures may have contributed to a substrate dilution effect.Treatments combining both screened and secondary decanter-separated without bulking agents (T3) and (T5) exhibited intermediate OUR 10.3 and 11.5 mg O 2 /g VS•d, respectively.Overall, these findings demonstrate that secondary decanter-separated solids (T2) represents the most suitable fraction for composting, whereas sawdust addition requires careful optimization to avoid nitrogen limitation.
Authors: Yongwoo Song, Abera Jabessa Fufa, Heekwon Ahn
Institution: Chungnam National University
Language: English
Subfield: Soil Science
Domain: Life Sciences
Open Access status: diamond
OpenAlex ID: W7119510555