Extraction and analysis of neutral lipids from activated sludge with and without sub-critical water pre-treatment

Scum sludge as a potential feedstock for biodiesel production from wastewater treatment plants

“…This result indicated that the neutral lipid was dominant in scum sludge but not in secondary sludge. Huynh et al (2010) extracted lipids from secondary sludge using hexane and claimed that the neutral lipid content of secondary sludge was only 2.1%. Furthermore, approximately two-thirds of the lipid can be converted into biodiesel after dewaxing and degumming.…”

In situ biodiesel production from wet Chlorella vulgaris under subcritical condition

“…Typically, 5 g of wet C. vulgaris biomass (moisture content adjusted to 80% by adding 4 mL deionized water to 1 g dry biomass) and a pre-determined amount of methanol were put into the reactor. Temperature in the reactor was raised to 175°C, with a corresponding vapor pressure of about 22 bar, based on results from our previous works [27,28]. After a pre-determined time, reaction was stopped by releasing vapor in the reactor to reduce the pressure to about 2 bar.…”

“…In a previous work, it was reported that SCW pretreatment of the biomass of the oleaginous yeast Yarrowia lipolytica Po1 g can increase its extractable neutral lipids two folds [27]. SCW can also act as an effective catalyst for hydrolysis or biodegradation reactions and to increase the extractable neutral lipids from activated sludge [28,29]. Base catalyzed methanolysis of soybean oil under a subcritical condition of 160°C was reported by Yin et al [30].…”

Value-Added Products Derived from Waste Activated Sludge: A Biorefinery Perspective

“…Based on data acquired, they claim that outfitting 50% of municipal wastewater treatment plants for lipid extraction from sludge and transesterification could contributed to replacement of 0.5% of the national petroleum diesel demand in US (0.7 × 10 6 m 3 year −1 ) by biodiesel produced. Huynh et al (2010) profiled the amount of neutral lipids and fatty acid in neutral lipids extracted from activated sludge pretreated with or without sub-critical water (SCW) treatment [45]. Results indicated that the amount of neutral lipid extracted from SCW-treated activated sludge was nearly four times more than the process without SCW treatment.…”