**4.2 Selective waste collection**

We developed a project in June 2018 for domiciliary selective waste collection for the city of Bom Jesus dos Perdões – SP. The city's population is estimated to be 24 mil inhabitants [32], and it is a small and winter/summer town. The project was specific to generating sectors and routes, and their schedule was for periods of one week, for a contractor [33] of the local selective collection association. The contractor implemented a new recycling plant for the association, with the support of the best Brazilian knowledge in recycling tools and operational management. Here we detail how we developed this project.

The geographical data set came from OSM (Open Street Map), Google Maps™, and Bing™, and it were adjusted with QGIS 2.18 to be completely legible and useable for sector-arc routing. The data from population density and distribution along the municipality were obtained from the "Setores Censitários, IBGE" [34].

The work consisted of creating sectors and collection circuits from the collection area, **Figure 8**, and studying a better place to install the recycling plant (Distrito Industrial or in the Transfer Station), respecting the data provided by the contractor. The sectors and routes were divided into three geographic levels of grouping areas (regional, zones, sectors, and circuits) and thus named (Regional: 01; Zones: 01..05; Sectors: 01..04; Circuits: 01.. 04). This method allows the total route of the vehicle to carry out the selective collection to reach the shortest/fastest possible length while at the same time allowing the most adequate execution and inspection on the field.

A sector in the domiciliary selective collection has the same definition as in the household refuse collection, and the trips represent the circuits. The basic difference is that the trips are composed of lighter loads, and the vehicles used are not compactors. The garbage is measured in volume, and it is disposed of in a way to be separated manually faster. The garage and the recycling plant were running in different places; the garage were in the Distrito Industrial but for the project evaluation it could also be considered in the same location of the recycling plant, as can be seen in **Figure 8**.

The plans considered operational speeds, as exposed in **Table 6**, where these values were obtained from other experiences in a city with same features. Basically, it is the defined speed while vehicles are empty, in the collection, deadheading (traversing between two collection points without service), and in full charge or going to the recycling plant.

The effort of the drivers was considered, as proposed by McBridge [35] and Bodin et al. [36], to reduce "U" turns in arc-routing route calculations (**Table 7**); we used the

#### **Figure 8.**

*Maps of the selective collection situation in the city of Bom Jesus dos Perdões on Google maps™ and SisRot LIX®.*

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


#### **Table 7.**

*Measures of steering effort in route movements.*

approximative line-graph methods proposed by Negreiros & Palhano [37] to reduce the effort on maneuvers.

The workload was set to be 8:00 with an interruption of 1 h for lunch, as per the regular Brazilian labor laws. On tough days, like Mondays, when the garbage is of higher load than the rest of the week, there is a necessity of extra labor time; the association regulates this once all the people are in cooperation. The discharge time was defined to be 20 min because, in this case, there was a necessity for other people to come and help discharge manually the incoming vehicles.

The parameters related to the production of recycling were: 1 kg/inhab, where 30% were recycled with 55% of it recovered, totalizing 0.165 kg/day-inhab of recycled available (1 kg 0.3 0.55). The collection would be performed by one vehicle with 28 m<sup>3</sup> of maximal occupation and 95% (26.6 m<sup>3</sup> ) – a surcharge of 20% is admissible. The admitted ratio between production and volume was 36 kg/m<sup>3</sup> . The load collected by the vehicle per trip was 28m<sup>3</sup> or 957.6 kg (28 m3 36 kg 0.95) or at most 1200 kg or little more (5%) in cases of possible seasonality.

• The city has four condominiums: Alpes D'Ouro, Vale do Sol, Vista Alegre, Santa Fé and Marf II, where the waste is more frequent on weekends and holidays. For them, it is admissible that the vehicle can carry kg.

The sectors were created to be covered one day a week from Monday to Friday. As can be seen in **Figure 8**, the polygon returns:



The street network was identified, as in **Table 8**:

**Table 8.**

*Numerical data of the network and waste production estimates.*

#### *4.2.1 Census sectors', occupation, and production of the streets*

Census sectors are defined by georeferenced polygons, where a census taker performs his survey task in the demographic census every ten years. The publicly available information informs a digital cartography of the number of households and residents in the inner region of the polygon that represents it. Using geoprocessing, the production of waste in each census sector is found by multiplying the number of people by the estimated production of selective waste per person per day of collection (0.165 kg/day of collection). By doing so, the perimeter of the street network considers only the places where the truck must pass (required street network) and receive the garbage distribution for each street segment, thus transforming the garbage in kg/ m in the required graph. In the example in **Figure 9**, the required graph is weighted with 0.165 kg/person 603 people = 102.79 kg, and given that this required graph perimeter is 1821 m, then we find 0.056 kg/m to distribute among the 1821 m of required connections of the set.

#### *4.2.2 Collection zones*

**Table 9** presents the numerical data referring to the collection zones built with SisRot® Lix. **Figure 10** shows a geographical representation of the division of selective collection zones for better visualization. It is understood that this final configuration is the most appropriate, as it allows for better contiguity and adequate compaction, given the presence of the D Pedro I road, or Marginal Bom Jesus, separating the municipality into two large regions. It can be seen in **Figure 9** that to the north, the Vista Alegre condominium exceeds the city limits, causing an unfavorable impact on the calculation of routes in this zone.

#### **Figure 9.**

*Census sector, reproduced from the digital base of the IBGE census sector mesh (IBGE, 2016) of the city of BJ dos Perdões/SP by SisRot® LIX. The required road network (in darker yellow) that is within the sector receives the production of the corrected population of the sector.*

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


#### **Table 9.**

*Numerical construction details of the zones, with information on the required street segments.*

**Figure 10.** *Map containing the division of the clusters of selective collection zones for the city of BJ dos Perdões.*

#### *4.2.3 Collection sectors*

**Table 10** presents numerical data referring to the collection sectors built with SisRot® Lix. **Figure 11** shows a geographical representation of the division of selective collection sectors for better visualization. This final configuration is the most suitable for the context of the local knowledge that has been made available. The dispersion of contiguous areas is noted in **Figure 11**, but all represent the same collection context, mainly in the condominiums to the northeast of the city (Vista Alegre, Marf II, and Vale do Sul).

#### *4.2.4 Collection circuits*

We finally arrive at the division of collection circuits. At this stage, it is necessary to guarantee the maximum contiguity between the circuits to compose the collection sectors and hence allow the creation of routes with the best operational results. **Figure 12** shows a geographical representation of the division of selective collection circuits for better visualization. This final configuration is best suited to the context of


#### **Table 10.**

*Numerical data of the selective collection sectors projected for BJ dos Perdões.*

**Figure 11.** *Map with the division of sectors in the city of BJ dos Perdões.*

the local knowledge that has been made available. Note in **Figure 12** the dispersion of contiguous areas further to the northeast (in condominiums).

**Table 11** presents the numerical data referring to the collection circuits built with SisRot® Lix. Note that the nominal values allowed for each circuit were exceeded considering the maximum volume of the vehicle trunk of 26 m<sup>3</sup> . At first, it should be considered that the updated IBGE data indicate 20% more in the population that was passed to this study; in addition, the seasonality of the places in overload brought the need to maintain the structure in this way. It is recommended that these areas be observed during the implementation phase of the routes, as there are no reliable data for this sizing.

The solutions presented in **Table 11** consider the following nomenclature: Circuit: is the identifying label of the circuit (Reginal, Zone, Sector, Circuit); *Optimized Planning and Management of Domiciliary and Selective Solid Waste... DOI: http://dx.doi.org/10.5772/intechopen.111432*

#### **Figure 12.** *Visualization of the distribution of the collection circuits designed for BJ dos Perdões.*

SSeg: Number of street segments in the sector; Perimeter: is the total length of the required street segments of a circuit; Prod: is the estimated production (in kg) of the circuit; CDist: is the distance that the vehicle would travel per trip; CTime: is the time spent on the trip; Bal: is the rate between trips in the sector – Bal = ( P*nv i*¼1 *Prodi nv* <sup>∗</sup> max f g *<sup>i</sup>*¼1, *::*, *nv*:*Prodi* ); Load: is the estimated total load collected in the sector;

Time: is the estimated total travel time in the sector (hh:mm:ss);

Km: is the total distance traveled in the sector (in km);

Vehicle: is the maximum capacity—in kg (�20%)—of the reference vehicle.

### *4.2.5 Routes of collection circuits*

All the circuits clustered were calculated for both final destinations in evaluation (Distrito Industrial and Transfer Station); these two places already have the basic infrastructure to install the recycling plant, and it was necessary to define the best solution obtained with routes and time between both. The result presented in **Table 11** refers to the installation of the plant in Distrito Industrial; the variable cost gained with this installation was 16.5% better than if it was installed in the Transfer Station.

An example of the multigraph of the routes directly extracted from SisRot®Lix can be seen in **Figure 13**. The use of the generalized sector-arc-routing solver that joins node and arc routing in the same context of decision-making is shown.

#### *4.2.6 Sectors' schedule*

Only one vehicle and one crew (driver and three collectors) will be needed to carry out the work of the entire city. The scale of the vehicle and crew, as shown in **Table 11**, indicates that the sector that covers the Alpes D'Ouro condominium (Sector: 010401) should be visited on Wednesday afternoon, since it is not possible to serve all the condominiums on the same day as required by RECICLEIROS. The Santa Fé


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


#### **Table 11.**

*Collection circuits and sector results, showing the final numbers with routes and schedule of one vehicle during the week.*

#### **Figure 13.**

*Routes for sector 10,102 - (a) route for circuit 1,010,201, (b) route for circuit 1,010,202, and (c) route for circuit 1,010,203.*

condominium (Sector: 010201), while the Vista Alegre, Marf II, and Vila do Sol condominiums (Sector: 010202) must be covered on Tuesdays as required by the association. In this way, operations are as close to Tuesday as possible. Friday had zone 0105 with the highest service load; however, it can be changed by moving the service of zone 0105 to Thursday or zone 0101 to Monday.

Alternative scales can be made, as a discharge time of 20 minutes was considered, and this can be reduced over time.
