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

Statistical Optimization of Lipid Extraction from Wastewater Scum Sludge and Saponifiable Lipids Composition Analysis

“…The maximum amount of lipid extracted was 29.4% of dried scum sludge which is lower than the results obtained by Wang et al (2016) who claimed the extraction of 33.3% lipids to dry scum sludge using similar extraction conditions. The lower amount of lipid extracted in the current study compared with Wang et al [32] findings can be referred to the variations in scum sludge composition based on the type of wastewater collected.…”

“…The Design of Experiment (DoE) approach allows investigating the influence of different factors on a given process, through conducting a minimal number of experiments [35]. DoE as a statistical method has been widely used and successfully implemented for different bioprocess optimization purposes [22,29,[35][36][37][38][39].…”

“…DoE as a statistical method has been widely used and successfully implemented for different bioprocess optimization purposes [22,29,[35][36][37][38][39]. Process optimization used in the present study was conducted in four main steps: 1) independent variables selection and their variation ranges and defining dependent (response) variable(s); 2) data screening for determining the main effect independent variables on response variable; 3) conducting the path of steepest ascent to direct the experimental outputs towards the optimum; 4) carrying out the statistically designed experiments in a randomized order and estimating the coefficients and the mathematical model.…”

“…Several authors investigated lipid extraction for biodiesel production from primary sludge [16,21,24,27,28,[28][29][30][31], secondary sludge [15,18,24,27,32]. Only a few studies gave attention to scum sludge as a source of lipids for biodiesel production [33][34][35]. Scum sludge is a floatable material usually skimmed from the surface of primary and secondary settling tanks in wastewater treatment plants.…”

A solvent-free approach to extract the lipid fraction from sewer grease for biodiesel production

“…H 2 SO 4 ) may be a concern. In-situ conversion may be an effective method to convert the lipids in the sewer grease directly into biodiesel, however, the downside is the significantly extended reaction time (up to 24 h) and substantial use of MeOH (Mondala et al, 2009;Choi et al, 2014;Sangaletti-Gerhard et al, 2015;Wang et al, 2016). In addition, the quantity of trap grease remains unknown for most municipalities, which hinders its reuse in commercial scale.…”