Strength in numbers

New York City proper covers nearly 800 square kilometres, and has a population of 8.5 million people – people who all generate waste every single day of their lives.

For the people who collect that waste, New York may be the most challenging place on Earth – the volume of garbage and recycling that is generated is vast and varied, and requires a massive fleet of vehicles to keep streets and sidewalks clean.

The City of New York Department of Sanitation (DSNY) moves a whopping 10,500 tons of residential and institutional waste each day along with nearly 1,800 tons of recyclables. That much material requires a fleet just as large, and a fleet of that size demands a lot of maintenance and support.

For DSNY, their fleet is made up almost entirely of heavy-duty trucks supplied by Mack. The department in charge of managing that fleet – referred to as “New York’s Strongest” – boasts some of the finest maintenance and repair facilities in North America. Considering their trucks, nearly 2,500 in the fleet, never stop – even in the dead of winter – reliable trucks and the means to keep them moving are key to maintaining a clean city.

Challenging city to keep tidy

Anyone who has been to New York will understand the challenges faced by the DSNY. Traffic congestion, narrow streets, sprawling boroughs – it could be a “nightmare” for any sanitation crew to tackle.

“We do every street in the city, basically every single day – and during snow operations, we’re going to do 19,000 miles, hopefully twice every shift if not more, until we’re through that snow event,” said Kathryn Garcia, DSNY commissioner. “We are putting a lot of miles on these vehicles.”

New York City’s tight confines in many places makes it difficult to take steps similar to other cities, where collection may be easier to manage.

“In most large cities in America, there are things that make life easier for collections – there are alleys, there’s no parking on every single street,” Garcia said. “They can do container runs… but in many cases, that’s not how these buildings are designed, so it’s all bag stops.”

New York’s quest for clean streets started in the 1880s, with the founding of the Department of Street Cleaning. In the 1890s its mandate moved forward with a drive towards reduced garbage disposal and greater recycling efforts. Over the years methods of trash disposal have moved ahead – a zero-waste effort is underway and the city no longer has any active landfills or incinerators, with all non-recyclable refuse shipped out-of-state by rail.

Along the way, DSNY has established a strong relationship with Mack for supply of its collection fleet.

“Our roots go back to the 1920s, and we will find Mack trucks here since the ’20s,” said Rocco DiRico, DSNY deputy commissioner. “Our heavy-duty trucks are primarily Mack… they’ve been able to produce trucks that meet the stringent needs we have at a competitive price.”

In fact, most of the DSNY’s nearly 2,500 collection trucks – and many of their support and specialized vehicles – are supplied by Mack. The current fleet is made up extensively of the Mack LR series cab-forward truck, equipped with either a single- or double-bin body, depending on whether the truck is focused on refuse or also used for recycling.

DSNY says their sanitation crews appreciate the LR for a range of features; it offers a low step and large handholds for getting in and out multiple times on a route, along with a roomy cab and air conditioning to help handle humid summer days.

In crowded city streets, the LR provides a safer drive, with large, wraparound windows offering the necessary visibility, especially considering the vast number of pedestrians making their way around New York.

“Safety is one of our high priorities here all the time. [Refuse trucks] are inherently more dangerous than any other vehicle because even empty, they’re heavy. We are installing side guards on our vehicles in order to protect pedestrians from themselves,” Garcia said.

According to Garcia, their safety technology is continuously being evaluated to protect pedestrians. Blind spot indicators are being considered to help drivers detect people and bicycles along the side of the truck, and other types of technology are under review. Unfortunately, she says, there’s little to be done with other vehicles, driven by the public, whose drivers aren’t paying adequate attention or being careful enough.

“Some drivers think their cars are narrower than they are – they should never [try to squeeze past a collection vehicle] because the car will lose,” she said. “The big white truck will always win.”

Busy maintenance and repair facilities

When their ‘big white trucks’ do need repair or maintenance, DSNY is ready for any eventuality through a combination of strong support from Mack dealers and its own collection of maintenance and repair shops. Local dealerships have also adapted based on the needs of the DSNY. According to DiRico, originally, there was a single dealer that had responsibility for servicing the DSNY fleet where necessary, but two more have come onboard since.

“Their expansion has taken place parallel with our partnership,” DiRico said. “When we’re open, they’re open – and when I say they’re open, they’re open with road service, dealer support, R&D support… it makes for a better operation.”

During the winter months, the DSNY trucks pull double-duty: when snow starts to fall, they pull into one of the many local garages, a plow is attached to the truck, and they head back on to their routes. Sanitation drivers are trained to handle both refuse collection and snow clearing, and the LR trucks are equipped for a fast changeover. They operate 24/7 through snow events, and the Mack dealerships are open to help out, DiRico noted.

Along with support from Mack, DSNY also does much of its own maintenance. Its Central Repair Shop in Queens is a vast, multi-storey facility that houses a wide variety of workshops, each of which contributes to keeping the fleet on the road.

A full machine shop is capable of making any number of parts, right down to the engine and transmission and includes hydraulic shops where staff can repair or rebuild nearly everything the DSNY fleet uses on refuse trucks. There’s even an upholstery shop on site for repair and refurbishment of everything from truck seats to office chairs.

Targeting a cleaner fleet

On the first floor, DSNY’s Central Repair Shop also features a facility that helps the department in its efforts to reduce the environmental impact from its trucks. A fully computerized emissions laboratory is built around a dynamometer system on which the garbage trucks can be run at various speeds, simulating travel conditions the vehicles would face on a typical collection route. The system allows the department to make educated decisions about how to manage emissions reduction within the fleet. That has proven successful thus far, Garcia said.

“From 2005 to today, we’ve reduced particulate material out of tailpipes by 90 percent, and reduced everything… partly by changing fuel types, partly by retrofitting, and partly by buying new vehicles,” she said. “We’re running a very clean fleet at this point in time.”

Alternative fuels are a part of the program, with new types of fuel being evaluated regularly. Currently the fleet runs on biodiesel – in fact, DiRico noted that they worked with Mack to confirm that they could run B20 biodiesel without any detriment to the engine or need to change warranty terms. But beyond that, other options are always being considered.

Compressed natural gas is popular in refuse fleets, but not practical in New York due to a lack of space for fuelling facilities.

“The footprint for natural gas fuelling is larger, and there are not a lot of locations where we have a lot of space,” Garcia noted. “We’ve actually challenged the industry on multiple occasions to rethink those fuelling stations – to go from a horizontal setup to vertical, and shorten the footprint. In that case, we could possibly squeeze something in, but to get to the pressures and volumes we need, we haven’t been able to overcome that.”

Renewable diesel – made from similar feedstock as biodiesel but hydro-treated to create a similar fuel in a more efficient manner – is being looked at as a potential for future fuelling options. In the nearer term, DSNY is looking at dimethyl ether (DME) as a possible alternative to natural gas. DME is a gas that can be generated from waste, biomass, agricultural products and fossil fuels. It burns very clean and does not require the same levels of emissions treatment on vehicles as other fuels.

Mack and the DSNY have collaborated on developing a test vehicle that will be used for more intensive investigation into DME’s benefits for the city in the near future.

“Because it’s very clean burning and behaves like diesel, I can fuel the trucks in the same way, and it makes the engine less complicated,” Garcia explained. “You don’t have the same after-treatment parts – it’s almost like you take the engine back to a more simple design.”

If DME proves successful, it’s entirely possible that DSNY may be able to start making its own fuel from waste.

“There are a number of companies that have the technology to convert organics to DME or natural gas – that would be a match made in heaven,” DiRico said.

“That fits in well with the concept that trash has value and can be converted into energy or things like compost, particularly on the food side,” Garcia added. “Creating that closed loop is a very different way of thinking about waste than anyone has in the recent past.” RPN

This article originally appeared in Recycling Product News, Volume 24, Number 7.