Dumpster truck optimization: what environmental gains

Two-compartment roll-off trucks and mechanical sorting, hybrid vehicles … All types of alternative collection services for communities. If they represent an additional cost compared to conventional skips, they generate concrete environmental gains.

The optimization of waste collection depends on the type of vehicles used and better management of the tours. In a study dated May 2013 of more than 150 pages, an association of elected officials and Ademe gathered the feedback from communities that tested different ways of innovation in transport, with cleaner waste and brakes to lift for deployment.

The objectives was to reduce the financial and environmental impacts, while improving the quality of service to the residents and the comfort of the collection agents.

Compartmented garbage containers (BOM), hybrid vehicles (electric, natural gas for vehicles (NGV), diesel, biomethane) are all solutions tested by municipalities. The study quantified the gains generated in terms of collection costs, reduced kilometers traveled and therefore fuel savings and CO2 emissions, but also a reduction in noise pollution compared with conventional garbage trucks.

The compartmentalised skips allow the simultaneous collection of several waste streams: residual household waste (OMR) and bio-waste, recyclable packaging and glass, OMR and cartons … The undeniable advantage of this type of vehicle is to allow the optimization of the routes with a collection of at least 2 waste streams in a single pass which is accompanied by a decrease in the routes served and associated service operating costs (fuel and collection personnel).

Mechanized separate collection

Among the initiatives to be able to develop better some municipalities are experimenting with a bi-compartmentalized 4×4 waste collection vehicle (Renault Trucks de total permissible gross weight (GVWR) of 14 tonnes) to collect the bins installed on the sand. This vehicle, in service since 2006, is suitable for driving on sand and allows to mechanically collect the waste containers of the two streams simultaneously (residual household waste and recyclable household packaging + mixed papers). In high season (May to the end of September), the dump collects this waste 7 days out of 7.

This type of separate collection vehicle generates a lower fuel consumption. Thus the old solution used to collect waste on the beach (tractor + trailer with bagged flow) consumed 84 L / 100 km of diesel in manual gripping. With the new BOM 4×4, this consumption has increased to 68 L / 100 km in mechanized collection. If the community did not specify the amount of the vehicle, it indicates an additional cost compared to a conventional BOM of + 25% in investment and + 20% in maintenance. The brakes remain the specific driving on sand generating risks of stagnation, but also the scarcity of the vehicle.

The intercommunal water union also had in 2006 its first bi-compartmented bucket then in 2009 and in 2012 of two others to optimize the costs on the distant sectors where the bucket ran more than 100 kilometers a day. The total investment cost of the three skips (2 RVI chassis and a 26-tonne Volvo truck chassis) was high. The union stresses a reduction in the environmental impacts related to the circulation of collection vehicles without, however, quantifying them.

On two-compartment bins, the capacity of the small compartment for the selective has necessitated a reorganization of the routes and the garbage dumps sometimes come to 2/3 of filling in household garbage: the compartment of the recyclables is too small and its speed of filling can penalize the optimization of the tours. It is therefore recommended before any implementation, a global preliminary feasibility study as well as to opt for “a 50-50 distribution for household and recyclable waste compartments.

New generation hybrid vehicles

Ambitious technical choices made by some communities, especially in terms of motorization of collection vehicles confirm the desire to move towards a cleaner transport of waste. These technical guidelines are however, to be studied closely in terms of financial stakes, fuel supply conditions (which may come from the transformation of waste itself), from the adequacy to the typology of the habitat crossed with the performance and autonomy of vehicles.

Some local authorities test diesel / electric hybrid garbage trucks. Since February 2012, M2A has been experimenting with a prototype developed by Renault Trucks (Distribution Hybrys Tech of 26 tons PTAC) which circulates in sixteen municipalities of the agglomeration. The manufacturer had already tested it in some streets in 2009. With approximately 500 hours of operation, this vehicle had traveled more than 5,000 kilometers and collected 550 tons of waste.

The hybrid BOM delivered to M2A is the first of its kind to be operated on a pay-as-you-go basis, and the hybrid technology is particularly suited to the distribution or collection of waste in urban or peri-urban areas. The fuel consumption gain, estimated by the manufacturer can go up to -25%. That is an average consumption of 52 L / 100 km representing a drop of 16 liters compared to a conventional diesel bucket of the same size. This reduction in fuel consumption suggests a gain of $5,000 per year on the fuel item by BOM table agglomeration.

The estimated gain in carbon footprint is estimated at 8 tonnes of CO2 per year. The vehicle’s electric motor has a power output of 120 kW (kilowatt) peak and 70 kW continuously. The agglomeration concludes to a reliable technology with successful operation. Traction batteries do not need to be recharged.

From about 20 km / h, the diesel engine takes over. It is then used only in the phases where it consumes the least, that is to say outside the startup phase. The vehicle is renting full service over 5 years as part of the test. It costs almost double the equivalent of a diesel vehicle. The agglomeration does not provide for extension of the test to other sectors or purchase of hybrid BOMs at the moment. Due to the presence of automatic electric containers (high hopper), the collection of bags is made difficult for the collection agents.The containerization of the agglomeration has been effective for many years in half of the communes, it is In the near future, this constraint will no longer be one.

In 2012, the mixed garbage syndicate park was composed of twenty-six hybrid natural gas CNG (natural gas for vehicles) and electric waste vehicles of PTAC of 26T. The investments of the collection provider are $238,000 per hybrid dump versus $140,000 for a conventional diesel vehicle. The mixed union has installed 26 electrical terminals for a cost of $132,000 for recharging vehicles. Since 2003, it has a GNV delivery station and 10 supply terminals (investment of $747,000).

The choice of NGV reduces nitrogen oxide emissions by 2 to 5 times compared to diesel at 20 km / h and emits almost no particles. A hybrid CNG / electric dump also allows for an additional 20% reduction in NGV consumption. The optimization of the collection circuits thanks to the versatile modular hopper system reduces the fleet of 10 trucks. The new hybrid vehicles also guarantee a lower noise level compared to a diesel vehicle equipped with a non-electric compaction grab.

That is a 40% decrease in noise pollution (from 107 to 72 decibels). Its brakes? Technical points are however, to be settled upstream of the service set up: the hybrid skips represent a door overhang 50 cm higher than the old skips, which requires a redesign of some circuits. For narrow or sloping streets and for cul-de-sacs, mini-dumps ensure the collection of residual household waste, recyclable household packaging / mixed paper and green waste.

For its part, the urban community has chosen to develop biomethane-fuel produced from organic waste to feed its garbage dumpsters, in partnership with a collection provider and a supplier of CNG trucks Mercedes. They have a fleet of 10 BOMs running on the CNG / biomethane mixture: 9 19T PTAC and one 26T BOM, acquired between 2005 and 2008. The metropole raises up to 95% reduction of particulate emissions and 85% reduction of nitrogen oxides compared to diesel-powered dumpsters!

It also sees a 23% reduction of CO2 emissions compared to gasoline and up to 5% compared to diesel. Up to 50% reduction in noise pollution compared to a diesel vehicle is found. The BOMs feed on CNG / biomethane on the bus depot managed by Transpole. They consume between 80 and 100 normal cubic meters (NM3) per 100 km.