A dynamic Milk Run in WEEE Reverse Logistics

The management of waste electrical and electronic equipment (WEEE) is an important and critical aspect in the field of Reverse Logistics. The strategic importance of good treatment of waste is fundamental for reaching the objectives of environmental protection (as energy, natural resources, waste reduction) and economics goals (the lower cost of secondary raw materials for example). The following study is focused on the problem of management of waste electrical and electronic equipment. The objective is to build a new different system of waste based on a pull – logic. It starts with the analysis of present system and identifying its key features so it builds a new different management system of WEEE based on a pull – logic. Then it assumes a new system and following the basic concepts of Lean Production it separates the waste stream into two flows resulting one from the classic warehouse and the other from the new points of storage called collection center based on a pull logic. The Treatment Center is the system pacemaker process; it requires the amount of waste to Supermarket and it obtains its needs by a Milk Run system. We introduce the main features of new system with the use of a causal loop diagram (CLD) that shows the links (feedback or loops) between the variables of the system, then following the system dynamics approach it builds the stock and flow diagram (S&FD’s) of the system. S&FD’s it is necessary in order to use the simulation software (Powersim). In fact it analyzes the behavior of the model in simulation; by simulation it shows a positive trends in the level of WIP and a particular behavior of the treatment center. Then at the beginning are shown the concepts and tools that we use, that is Reverse Logistics and Lean Production System, Milk Run, vehicle routing problems, System Dynamics approach, and finally the design of new system and this new model simulation with the results analysis.