**1. Introduction**

Solid waste management deals with planning resources that are largely neglected by major Brazilian municipalities. The number of services related to the waste management in municipalities goes is more than 16. To mention some of these services, we have: domiciliary and selective waste collection (door-to-door), mechanical and human street sweeping, commercial and health waste collection, fair waste removal, cleaning and sweeping, container waste collection, painting gutters, and so on. All these services need plans and detailed establishment of the operation. Major work is done using unspecialized software tools, such as GIS-based software, but there is

decision-making technology available, not well known by environmental engineers and managers, which can be suitable and adequate for better planning and optimizing resources [1].

For the domiciliary (door-to-door) waste collection, we define a sector as a defined region where staff (driver and collectors) do the domiciliary collection in a workday with the same weekly frequency. A circuit (shift, route, or collection trip) is the subregion where the vehicle used by the staff travels until it reaches its waste storage capacity. A trip is a route between the garage, collection sector, and destination (typically a transfer station or landfill). Reinforcing the definition, a sector is composed of one or more collection circuits or routes that can be performed during a workday [2].

Most of the domiciliary and selective waste collection managers in Brazil plan their sectors and routes by using paper and drawing plans. The more effective and advanced ways of planning use AutoCad™, other tools incorporated by geoprocessors like Caliper™ [3], and apis from ESRI™, Here Maps, Open Street Map, Google Maps™ and others.

This work shows how we have solved these optimization and planning problems by using spatial decision support system (SDSS) technology composed of a software framework that allows users to design and manage mechanical collection and other service plans. To prepare the plans, we used SisRot® LIX, from Graphvs Ltda. [4], which calculates the collection sectors and street-by-street routes. The motion to use this system in counterpart to the others mentioned is that the SisRot®LIX is specialized in sector-routing problem, and it generality gives us back the opportunity to show the appropriateness of sector-routing for waste collection in different areas of waste collection management like domiciliary waste collection and domiciliary selective waste collection.

We present an application where we have re-sectored and rerouted the Petrópolis/ RJ municipality, including the fleet, man hours, and overtime reductions. Finally, improvements are also presented for the new sectorization and optimization of selective waste collection sectors and routes in the city of Bom Jesus dos Perdões/SP, where the best placement of a recycle plant in the city was also studied.

We have organized this work into six sections. In Section 2, we illustrate the differences between capacitated arc-routing problems (CARPs) and SARPs. The third section presents the OPILM architecture with the SDSS SisRot® LIX features. Section 4 presents the results of the technology application. Section 5 studies the effect of savings in the waste collection system, taking as example the work done in downtown Petrópolis/RJ, here evaluated, and Section 6 summarizes the conclusions.
