DISTRIBUTION ROUTE OPTIMIZATION FOR WASTE COOKING OIL COLLECTION WITHIN A CLOSED-LOOP SUPPLY CHAIN IN SURABAYA USING THE VRPSPD MODEL

Abstract

Improper disposal of waste cooking oil (WCO) poses significant environmental risks, particularly to water ecosystems and public health in Indonesia. Despite the increasing volume of WCO generated from restaurants and food service industries, systematic collection and recycling systems remain limited. This study proposes a Closed-Loop Supply Chain (CLSC) system integrated with a Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD) approach to optimize simultaneous WCO collection and empty-container distribution activities. The study employs a simulated case study involving 15 restaurants in Surabaya, Indonesia, with routing calculations solved using the Nearest Neighbor algorithm. Within the proposed CLSC framework, motorcycles simultaneously distribute empty jerry cans to restaurants and collect filled containers containing WCO for recycling purposes such as biodiesel production. The results demonstrate that the WCO collection system can be effectively modeled using the VRPSPD approach. The proposed routing system generated three vehicle routes with a total travel distance of 131.9 km, a total operational cost of IDR 1,793,916.46, and a total travel time of 4 hours and 21 minutes. Furthermore, the integration of forward and reverse logistics activities within a single transportation network improves transportation efficiency, reduces unnecessary trips, and supports sustainable waste management practices aligned with circular economy principles.

Keywords: Closed-Loop Supply Chain; Nearest Neighbor Algorithm; VRPSPD; Waste Cooking Oil (WCO).