Valorization of petroleum refinery oil sludges via anaerobic co-digestion with food waste and swine manure. (1st April 2022)

• Record Type: Journal Article
• Authors: Lee, Changmin; Kim, Seunghwan; Park, Man Ho; Lee, Young Su; Lee, Changweon; Lee, Sungho; Yang, Junmo; Kim, Jae Young
• Is Part Of: Journal of environmental management. Volume 307(2022)
• Publication Date: 2022-04-01
• Subjects: Anaerobic digestion -- Co-digestion -- Oil sludge -- Organic wastes -- Petroleum waste; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.114562
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Valorization of oil sludge has been gaining attention to improve the sustainability of the petroleum industry. This study aimed to assess the possibility of anaerobic co-digestion of oil scum and secondary sludge with food waste (or swine manure). Oil scum and secondary sludge were obtained from a wastewater treatment plant (WWTP) of a petrochemical plant. Physicochemical properties, hazardous materials, and microbial community were characterized and biochemical methane potential was performed by a simplex-lattice mixture design. More than 87% (wet wt.) of the oil scum consisted of total petroleum hydrocarbons (TPHs) (21, 762 mg/L) that are difficult to be degraded by anaerobes. The secondary sludge showed low TPHs (5 mg/L) and a bacterial community similar to that of municipal WWTPs. The heavy metal (Cu, As, Cr, Ni, Mn, Zn, and V) concentrations in the oil scum and secondary sludge were similar (20–600 mg/L). The maximum methane potentials of the oil sludge and secondary sludges were 20 ± 2 and 56 ± 3 mL CH4 /g-volatile solid, respectively. The co-digestion with food waste or swine manure led to a synergy effect on methane production of the co-digestion substrate (10–40% increase compared to the calculated value; v/v) by balancing the C/N ratio. Due to the high TPH contents, oil scum is not appropriate for co-digestion. The co-digestion of secondary sludge with food waste and/or swine manure is recommended. It is necessary to consider whether the concentration of heavy metals is at a level that inhibits the anaerobic co-digestion depending on the operating conditions such as mixing ratios and solid contents. Highlights: Oil sludges from petrochemical wastewater treatment plant were characterized. Oil scum and secondary sludge were co-digested with food waste and swine manure. Heavy metals in oil sludge were in inhibition level for anaerobic digestion. The organic waste can cause synergy effect on methane potential by balancing C/N.