Estimation of dump and landfill waste volumes using unmanned aerial systems.

The paper discusses how the choice of software and hardware components used in unmanned aerial systems (UAS) affects the accuracy of estimating volume on landfills and dumpsites, and the amount of ground work needed to create a high-altitude justification of reference geodetic network. A non-specialized low-cost unmanned aerial vehicle (UAV) and a specialized UAV of a geodetic class were compared in scenarios with different numbers of ground control points. In addition, the use of desktop and cloud software for photogrammetric data-processing was assessed. Both specialized geodetic and non-specialized low-cost UAVs made it possible to obtain fairly accurate estimates of waste volume. The differences in the UAV results compared to data obtained by ground surveys were about 1.0%, even with a minimum number of ground control points (GCP). With complete abandonment of GCP and processing aerial data in cloud services, these differences increased to 5.0%. Low-cost UAV and cloud services can be used for operational monitoring of waste volume changes at landfills and dumpsites. A geodesic-class UAV allows researchers to build a more accurate digital terrain model of the landfill surface, but it does not give any advantages in waste volume estimation.

Determination of the composition and properties of PET bottles: Evidence of the empirical approach from Perm, Russia.

Efficient collection systems and information about the characteristics and quality of collected secondary plastic waste flows are of fundamental importance for the development of circular economies. In order to assess the effectiveness of the implementation of separate collection systems for plastic packaging, especially polyethylene terephthalate (PET) bottles, characteristic of the collected PET bottles in street mesh containers were studied in the city of Perm, Russia. The share of extraneous fractions was assessed and differentiation was carried out by volume, type of product, label presence, shape, content of solid and liquid impurities and colour. These results indicate that PET composition in different seasons is very similar, despite the assumption that the consumption of PET bottles in the spring and autumn seasons varies. In the mesh containers, up to 34% of the items were foreign objects, considering that only PET bottles should be collected. In each dimensional flow of PET bottles, the proportion of transparent bottles prevailed; it ranged from 31% to 70%. Based on the results of the experiment, almost all PET bottle categories had a standard shape, except packaging for food products and household chemicals, in which 26-27% of PET bottles had a non-standard shape. The results about charactersitic of source-separated PET bottles are fundamental for goal-oriented design and implementation of collection, recycling technologies, secondary separation facilities, the economics of recycling intitatives and reverse vending machines for collecting materials.