Continuous High Rate Anaerobic Treatment of Oleic Acid Based Wastewater is Possible after a Step Feeding Start-Up

• Published in: Environmental science & technology Vol. 43; no. 8; pp. 2931 - 2936
• Main Authors: Cavaleiro, Ana J, Salvador, Andreia F, Alves, Joana I, Alves, Madalena
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.04.2009
• Subjects: Anaerobiosis; Applied sciences; Chromatography, Gas; Chromatography, High Pressure Liquid; Exact sciences and technology; Methane; Methane - metabolism; Mineralization; Minerals; Oleic Acid - metabolism; Pollution; Reactors; Remediation and Control Technologies; Sludge; Water Pollutants - metabolism; Water treatment; Methane; Batchwise; Anaerobe; Organic loading; Mineralization; Reactor; Fatty acids; Waste water
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es8031264

Mineralization of a synthetic effluent containing 50% COD as oleic acid was achieved in a continuous anaerobic reactor at organic loading rates up to 21 kg COD m−3 day−1, HRT of 9 h, attaining 99% of COD removal efficiency and a methane yield higher than 70%. A maximum specific methane production rate of 1170 ± 170 mg COD-CH4 g VS−1 day−1 was measured during the reactor’s operation. A start-up strategy combining feeding phases and batch degradation phases was applied to promote the development of an anaerobic community efficient for long chain fatty acids (LCFA) mineralization. Through the start-up period, the methane yield increased gradually from 67% to 91%, and LCFA accumulated onto the sludge only during the first 60 days of operation. For the first time, it is demonstrated that a step feeding start-up is required to produce a specialized and efficient anaerobic community for continuous high rate anaerobic treatment of LCFA-rich wastewater.