Solid Waste & Recycling Magazine

Feature

Automated Solid Waste Collection

The collection aspect of North American waste management system planning tends to be very “truck” focused. However, in Europe and elsewhere, alternative systems exist that are beginning to garner local attention. Just as deep...


The collection aspect of North American waste management system planning tends to be very “truck” focused. However, in Europe and elsewhere, alternative systems exist that are beginning to garner local attention. Just as deep underground collection containers like the Finland-based Molok now offer an alternative to wheeled collection bins for recyclables, organics and residual material, Finland has also originated “pneumatic” or vacuum waste collection systems that are finding favour in hundreds of communities worldwide.

Vacuum or “automated” waste collection is a simple concept that might nevertheless seem startling to people in Canada and the United States, habituated to large waste collection trucks noisily picking up waste materials from curbsides, set out in bags or carts, or from big bins in laneways or behind commercial buildings.

With automated collection, material is placed in ground-level containers from where it falls into special auger-type equipment that forms and sizes it for transport via underground pipes under vacuum pressure to a central plant. The systems allow dry recyclables, wet organics and residual waste to be segregated at the source — much as in cart- or bag-based systems. Roadside vehicles only become involved when it’s time to transport the segregated materials from the central plant (which functions much like a transfer station) to markets or final disposal sites.

The problem with automated collection has been that the systems can be costly and difficult to install, triggering a high initial investment and large operating expense. Systems with large pipes consume a lot of energy, and can therefore be expensive.

A new solution

MariMatic Oy of Vantaa, Finland (marimatic.com) — part of Göran Sundholm’s MariCap group — has researched and developed an improved pneumatic system that overcomes these challenges. The company has the largest research facility in the world for pneumatic waste collection technology, which has yielded two product lines: the TaifunT, launched in the 1980s for use in the food industry, and the MetroTaifun®, launched in 2010, which is specifically designed for subterranean conveyance of urban waste.

The number of systems supplied has already topped 700, distributed throughout more than 40 countries.

After the loose or bagged waste material is deposited in the street-level container, it falls into a “waste formator” which rapidly forms the material to fit in small 200 mm pipes. This size of pipe is highly beneficial; installation costs are lower — by more than 25 per cent — and space is saved from the smaller pipe size (200 mm compared to 500 mm). Fewer pipe corners cuts installation time in half.

Most importantly, less energy is consumed creating the necessary vacuum inside the pipes to pull the waste from the various deposition nodes to the place of storage in the central building. (Pipelines can extend up to four kilometres from the waste collection facility.)

The composite pipe is easily fused together and is flexible, which creates more varied installation possibilities. Composite pipe is less prone to corrosion allowing for a longer life (e.g., 50 years).

Advanced technology

MariMatic Oy realized its customers wouldn’t settle for having all the waste streams commingled, so its engineers designed a system with different vacuum machines at the central plant that can selectively retrieve the different waste and recycling streams from the various input points. In other words, the waste is segregated and transported underground, much as different trucks, or trucks with different compartments, might collect and transport material aboveground, on lanes and roadways.

Radio frequency identification (RFID) can be used with the system to support a user-pay type of set up. This technology also adds an element of security and control of the actual users. (Users are issued individual swipe cards that open the ground-level bins.)

The large “final” waste containers are out of sight in buildings that do double duty as transfer stations.

In terms of energy, the MetroTaifun typical power requirement is around 150 kW, compared to around 600 kW for other systems. Operational energy consumption compares favourably as well. Where truck and bin systems consume the equivalent of 100 kWh per tonne of waste, and other automated vacuum systems may consume more than 150 kWh/t, the MetroTaifun system requires less than 50 kWh/t.

In case anyone is worried about the works getting gummed up, the company provides a unique blockage removal system, a flushing and drying system, as well as a pipe cleaning system.

Think of it as being like a pipe and sewer system for garbage and recyclables, but it’s based on vacuum suction rather than hydraulics.

Importantly, the waste formation equipment beneath the ground-level bins is fully accessible for maintenance and repair underground.

New markets

In 2012 the company turned over approximately 15 million Euros and order book of 60 million Euros. Installations range from housing complexes and industrial complexes to whole municipal areas.

“We’re actively exploring the environmental and operational benefits of pneumatic collection systems for new high density developments in Markham,” says Claudia Marsales, Senior Manager Waste & Environmental Management for the City of Markham, Ontario.

“We’re excited by the potential of these systems to both increase participation and diversion in developments where recycling has been a challenge,” she says. Discussions are underway with developers and municipal officials in other jurisdictions across the country.

“Examples of suitable sites for automated collection include parks, shopping centres, airports and multi-function sports arenas and entertainment facilities,” says Kerry LeBreton of Renewaste of Lively, Ontario (MariMatic Oy’s partner in Canada and the United States).

“Other examples include large hospitals and health care complexes,” Le Breton adds.

To date, the largest installation worldwide has been in Mecca, where millions of people pay homage during Ramadan, presenting unique waste management challenges. This system, which has a 900 t/day capacity, demanded extensive design work. The installation is mainly inside buildings, in tunnels and culverts; thus co-ordination with other infrastructure and services was vital.

Even whole municipalities can be served by automated collection. A new suburban development, being built in the City of Tampere, Finland, will be home to 13,000 inhabitants, creating approximately 5,000 jobs along the way. The suburb of Vuores will have a total of 124 collection points and 368 waste inlets, plus 13,000 m of pipeline. The system’s daily collection capacity for dry waste, bio waste, paper and recyclable cardboard comes to a combined total of 13,000 kilos. Annually, the system will deal with 1.9 kg of residential waste, and 650,000 kg of office waste, sorted into four different fractions.

The system was scheduled to start collecting waste in 2012.

Guy Crittenden is editor of this magazine. Contact Guy at gcrittenden@solidwastemag.com



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