Enhancing biogas production from palm oil mill effluent through the synergistic application of surfactants and iron supplements

• Published in: Heliyon 2024-04, Vol.10 (8), p.e29617-e29617, Article e29617
• Main Authors: Mekwichai, Pannawee, Chutivisut, Pokchat, Tuntiwiwattanapun, Nattapong
• Format: Article
• Language: English
• Subjects: adsorption; anaerobic digestion; anionic surfactants; biogas; cationic surfactants; cetyltrimethylammonium bromide; chemical oxygen demand; gas production (biological); methane; micelles; microbial communities; nonionic surfactants; oil mill effluents; oils; particulates; polysorbates; sodium dodecyl sulfate; synergism; water solubility
• ISSN: 2405-8440; 2405-8440
• DOI: 10.1016/j.heliyon.2024.e29617

In this study, the effects of various surfactants on the soluble chemical oxygen demand (COD) fraction and biogas production from palm oil mill effluent (POME) were investigated. A cationic surfactant (cetyltrimethylammonium bromide, CTAB) and a nonionic surfactant (Tween 80; TW80) were found to adsorb onto the particulate matter from POME, markedly reducing the soluble COD, unlike an anionic surfactant (sodium dodecyl sulfate, SDS). The mechanism underlying this phenomenon might be the adsolubilization of oil on particulate matter induced by the adsorbed surfactants. In terms of biogas production, 0.1 % w/v SDS and CTAB dramatically reduced the biogas yield, while 0.1 % w/v TW80 did not have this negative effect. A synergistic effect was observed when TW80 (0.1 % w/v) was combined with FeSO4 (400 mg/L), resulting in a 17 % greater biogas yield than that achieved with treatments using TW80 or FeSO4 alone. Moreover, the combination of TW80 and FeSO4 increased the biogas production rate. Surprisingly, the water-soluble iron fraction remained consistent across all treatments, suggesting that the adsorption of TW80 on particulate matter may limit micelle formation. Importantly, the proportion of methane in the generated biogas remained stable in all the treatments. Microbial community analysis revealed that the introduction of TW80 and FeSO4 had no discernible impact on the microbial community of the system. Pretreatment with TW80 and an iron supplement significantly enhanced biogas production and reduced the retention time of the anaerobic digestion (AD) system while maintaining the biogas quality and microbial community stability. •The effectiveness of surfactants in AD systems depends on their concentration and interactions with particulate matter.•The combination of TW80 and FeSO4 increased the biogas yield by 17 %.•The combination of TW80 and FeSO4 decreased the retention time of the AD system.•The combination of TW80 and FeSO4 did not alter the microbial community or biogas quality.