**5. The effect of savings in domiciliary waste collection**

Using as parameter the spreadsheets of costs publicly available in Brazilian municipality bids, there are mainly two centers of costs considered: staff and vehicle (or equipment). In the staff spreadsheets, the costs consider labor hour, unsanitary, extra time (day or night), working hours on holidays (day or night), vacation, food and transportation, termination, and social security according to the category's municipal syndicate rates. For the vehicle or the equipment spreadsheets, the costs consider maintenance and fixed costs, tires and tubes, lubrication and washing, average costs of vehicle consumption per km or per hour in operation while stopped, depreciation, annual license, insurance, and, finally, the percentage of the invested capital to have the vehicle if it is included. All these are composed in a final cost, which is approximately 60% consumed by the staff and 40% by the vehicle and/or equipment used. Depending on the value of the fossil fuel (diesel) used and distance traveled by the fleet, this difference can be lower, but it also suffers from syndicate annual intervention on the labor costs of collection.

**Figure 14** presents the behavior of waste collection in downtown Petrópolis/RJ, where (a) presents the loading per day and (b) presents the distance traveled collecting in the sectors that are covered from Monday–Saturday at night with an 8.2-ton compactor and three garis per vehicle.

In sector routing, the major impact on savings is in the reduction of the number of sectors, meaning fewer vehicles used, and in the total distance traveled. In our evaluations in the field, we also found an expressive reduction in the staff for domiciliary waste collection. Although it was indicated in Plan A that it is better to use four men

*Optimized Planning and Management of Domiciliary and Selective Solid Waste... DOI: http://dx.doi.org/10.5772/intechopen.111432*

**Figure 14.** *Domiciliary waste collection in downtown Petrópolis/RJ. (a) Load per day – Downtown Petropolis/RJ. (b) Distance travelled per day – Downtown Petrópolis/RJ.*

instead of three on daily-night collection in downtown Petrópolis/RJ, the global savings can be confirmed with our work of 7.52%. But, if the concessionaire wanted to use three men on Tue-Sat instead of four, it could bring a result in global costs savings of 14.04% (**Table 12**).

**Table 12** presents an approximation of the global expenses with the vehicles and staff for the actual execution in comparison with Plan A and Plan B. These expenses depend on the costs according to the labor laws and the costs of maintenance of the vehicles, including expenses with fuel, tires, and so on. We did not include the costs of a vehicle, because the remained vehicle will be operated on Mondays in any case.

Considering the global costs (fixed and variable) of absorbing the sector-routing technology, as in **Table 12**, the results we obtained can be considered in the graphics exposed in **Figures 15** and **16**. The figures present three parts of bars corresponding to the costs of investing in the technology presented in this manuscript - project to revise sectors and routes of the city; for the amortization cost, the interest rate was set to


**Table 12.**

*Global savings including all the real costs with staff and vehicles spences.*

#### **Figure 15.**

*Recovering investment when considering the team of collectors of plan a, returns start 15 months after project's end (may/2024).*

#### **Figure 16.**

*Recovering investment when considering the team of collectors of plan B, returns start in Oct/2023, 9 months after project's end.*

0.5% per month, and a 12% overprice in collection expenses from December to February, because of the rainy season and tourism overflow in downtown. For last the savings obtained with the results of the application.

The project returns the savings as the sectors and routes are implemented by the concessionary in the city; it starts returning as it starts to run. The breakeven point with the investment occurs in the 15th month from the beginning of the project for 7.52% of savings over spends in operational costs if Plan A is adopted (**Figure 15**). The breakeven point between savings and investment is reduced to the 9th month if the savings are of 14.04% (**Figure 16**).

*Optimized Planning and Management of Domiciliary and Selective Solid Waste... DOI: http://dx.doi.org/10.5772/intechopen.111432*
