Management of biodiesel wastewater by the combined processes of chemical recovery and electrochemical treatment

• Published in: Energy conversion and management Vol. 51; no. 3; pp. 531 - 537
• Main Authors: Jaruwat, Pattaraluk, Kongjao, Sangkorn, Hunsom, Mali
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.03.2010; Elsevier
• Subjects: Applied sciences; Biodiesel; Biodiesel wastewater; Crack opening displacement; Electro-oxidation; Electrodes; Exact sciences and technology; Greases; Industrial wastewaters; Management; Oil-rich phase; Phase separation; Pollution; Raw; Recovered; Ti/RuO 2; Waste water; Wastewaters; Water treatment and pollution; Recovered; Ti/RuO 2; Management; Biodiesel wastewater; Electro-oxidation; Oil-rich phase; Alternative fuel; Industrial production; Grease; Combined process; Ti/RuO; Biofuel; Oils and fats; Biodiesel; Alternative motor fuel; Industrial waste water; Protonation; Physicochemical purification; Oxidation; Waste water purification; Electrochemical reaction
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2009.10.018

A two stage management of raw biodiesel wastewater was carried out at a laboratory scale and ambient temperature. In the first step, biodiesel was chemically recovered from the wastewater using sulphuric acid as a proton donor with subsequent natural phase separation. Biodiesel was recovered from the raw biodiesel wastewater, in this case at 6–7% (w/w). In the second stage, the aqueous phase discharged from the first stage was supplemented with sodium chloride to 0.061 M and subject to electro-oxidation using a Ti/RuO 2 electrode. The combined treatment completely removed COD and oil and grease, and reduced BOD levels by more than 95%. The rate of removal of all three pollutants fitted a pseudo-first-order rate kinetics with oil and grease removal being approximately 8–16- and 2–7-fold faster than BOD and COD removal, respectively.