The production of biodiesel from the lipid of wastewater sludge was studied using SBA-15 impregnated with the heteropolyacid H3PO4.12WO3.xH2O (PW12) as a mesoporous heterogeneous catalyst. X-ray diffraction, Brunauer-Emmett-Teller surface area, thermalgravimetric analysis, and scanning electron microscopy were applied to characterize the prepared catalysts. Catalytic performances were evaluated in a microreactor setup under different experimental conditions. The biodiesel yield for a sample impregnated with 15?% PW12 was 30.14?wt-% at a temperature of 135?degrees C and a pressure of 135?psi for 3?h reaction time.