Recycling waste cooking oil into soap: Knowledge transfer through community service learning

Abstract

Waste cooking oil (WCO) is oil that has been used more than once in the food frying process. Consumption of more than twice-used cooking oil as a source of fried food has carcinogenic effects on human health due to the changes in the molecular structure of the oil caused by high temperatures during the frying process. Furthermore, the disposal of used cooking oil into sewage systems drains, rivers and land results in environmental pollution. This community project provides awareness, exposure and training to 30 participants within the communities under the jurisdiction of the Shah Alam City Council to recycle the used cooking oil into soap production at their homes or business premises. The approach includes identifying communities and training locations, developing training modules with target groups, preparing teaching and demonstration workshops, interactive training, monitoring and impact studies. Soap optimizations were carried out in the lab and were simplified to suit the community’s knowledge background and at-home facilities. The quality of soap production was optimized by using a different formulation and analysing its moisture content, fragrance, pH value and physical properties of the soap. WCO was treated with corn flour powder, followed by the addition of an alkaline solution until the solution became slightly viscous. Statistical analysis results showed that 98.8% of the participant benefited from the knowledge transfer program, increased their awareness and received positive impacts that were measured through focus group discussions using pre- and post-questionnaires. This community service has not only raised awareness of the importance of recycling used cooking oil, but also the potential to generate new income through the business of making soap from used cooking oil, thereby improving the economy of the Selangor state community.