(2024) Bioresource Technology_Biodiesel production, calcium recovery, and adsorbent synthesis using dairy sludge

Abeysinghe S.; Jeong W.-G.; Kwon E.E.; Baek K.

(Elsevier Ltd) Bioresource Technology ISSN: 9608524 Vol.413 Issue. Article No.131494 DOI: 10.1016/j.biortech.2024.131494

Dairy sludge (DS) consists of organic compounds such as lipids and valuable inorganic elements. Biodiesel recovery from dairy sludge extract (DSE), using conventional acid (trans)esterification yielded only 16.5 wt%. In contrast, non-catalytic (trans)esterification generated a substantially higher biodiesel yield of approximately 74.0 wt% due to the method's tolerance for impurities. Defatted dairy sludge (DDS) contained a higher Ca concentration than DS. DDS-produced biochar (DDSB) increased its Ca concentration predominantly in the form of CaO. 91.1% of the Ca was recovered from the DDSB containing Ca. The Ca remaining in the biochar residue (DDSBR) after Ca recovery was in the form of CaCO₃. The porous structure developed as the Ca dissolved, implying that DDSBR could be an effective pollutant adsorbent. In this study, a method is proposed to maximize the utilization of DS by producing biodiesel, recovering Ca content, and using it as a pollutant adsorbent. © 2024 Elsevier Ltd

This work was supported by the Rural Development Administration \u201CCooperative Research Program for Agriculture Science and Technology Development (No. PJ01699104)\u201D, part of the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. RS-2023-00265179, RS-2024-00339551), part of National University Development Project at Jeonbuk National University in 2023, part of the Ministry of Environment and \u2018BK21 Four\u2019 program (Jeonbuk National University \u2013 Department of Environment and Energy - Environmental Education and Research Center for Glocal Resources Circulation), and part of Korea Ministry of Environment (MOE) as Waste to Energy-Recycling Human Resource Development Project (YL-WE-23-001).