Isolation and analysis of wax esters from activated sludge

Neutral lipid from activated sludge (AS) as a potential source for biodiesel production has recently received considerable attentions. The utilization of useful compounds in AS may help reducing the cost of biodiesel production from AS. One of these compounds is the valuable wax esters (WEs) found in AS from a food processing company in Taiwan. About 4.13% (based on dry sludge weight) bleached wax was obtained after pretreatment and bleaching of crude sludge wax obtained from the dewaxing of crude sludge oil. The major WEs detected in the bleached wax were C46–C60 with small amounts of C37–C43 and C62 WEs. The fatty acids (FAs) and fatty alcohols (FALs) profiles of WEs were also investigated. Activated sludge WEs are mainly mixture of C14–C28 FAs and C24–C37 FALs, in which the predominant FAs are C16 and C18 while the predominant FALs are C32 and C34.