Carting Away Food Waste

Food waste has long been something mixed in with the regular trash being put out on the street each week. But things are starting to change on a wider basis, away from that model. In Canada, a much larger segment of the population than in the US has been more amenable to separating food waste and having pickups on a bit different schedule than the regular trash.

Cities like Portland, OR, and San Francisco, CA, have been on board with separate food waste collection for some time. Manufacturers mentioned here are ready for the changes whenever and wherever they may pop up.

City On Board With Food Waste As Separate Entity
Portland has over 1,000 businesses participating in food waste collection-something that’s been going on a while now. A lack of space for composting has been the biggest factor hampering development of that program, says Arianne Sperry, coordinator of “Portland Recycles!” However, the city’s food scrap program for residents rolled out in fall of 2011.

“I think we’re starting to get to a point where we are sustainable for our operation,” explains Sperry. “We had weekly garbage collection [and] weekly recycling of comingled paper, plastic, and metal containers-in Portland, we keep glass on the side.”

The city also has had a roll cart program for yard waste. In the fall of 2011, garbage collection moved to every other week. Yard waste collection moved to every week, with the food waste added to that collection mix and taken to designated composting area. The city swapped the collection schedule of the garbage with that of the compost. This was really just a trading of containers, according to Sperry.

“The new food scrap program itself was very controversial at first,” she says. “A lot of residents were used to having their garbage collected every week-that was just how things were always done. So, when we switched to every other week, there were concerns, because they’d never experienced that before. Folks are generally nervous about change, and in this case, it was something in your daily habits in your kitchen.”

The city did pilot studies before program implementation. Most residents had concerns before it started. They had to try it for 6 months, says Sperry, and, once they tried it, they saw that the new program was no big deal. Those involved in the pilot survey found that they liked it.

“That was very interesting to us, and one of the things especially noteworthy for us was that Portland actually saw the amount of garbage that they collected drop by 37% during the first year of the program-as well as that we went to every other week garbage pickup,” she explains. “Some of this was simply the drop in the weight of the food going from the garbage into the yard debris. They amount of yard debris collected almost tripled. But, in the end, people found having yard debris pickup every week to be a real benefit.

“While our program is voluntary, people have a strong incentive to participate, because if they want their food scraps collected every week, they need to remember to put those out with the yard waste now collected weekly,” she continues. “We’ve seen other programs similar to ours going on much longer, but not [being] as successful as ours. People don’t have as strong of an incentive to make that change in their habits; it’s hard to make changes because people don’t like that.”

There are no issues with food odors, as food scraps are still collected with the same frequency-now the food scraps are in with the yard debris, and they are collected weekly. “The businesses that are composting are leaders that want to be as green as possible,” adds Sperry. “They’ve voluntarily negotiated with their haulers to have that service. Also, not all composting facilities are able to deal with food scraps
-they have to receive a permit from our state with certain requirements involved, which they must meet. The haulers working for Portland purchase the carts involved in the program with specs from the city of Portland, which must be met by the particular manufacturer involved.”

Beginning January 1, no food and compostable paper-including food-contaminated cardboard, paper napkins, and paper towels-is now allowed in the garbage, however Seattle Public Utilities will not begin full enforcement until July 1 of this year.

On a Resort Island With Highly Seasonal Population
Nantucket Island, MA, composts food waste in a digester, which is part of the Bedminster BioEnergy Technology. The system can be configured to produce either a bioenergy or compost material. In each case, the initial part of the process uses the patented Bedminster Digester to separate waste into biodegradable and non-biodegradable fractions.

Waste is received onto a tipping floor where any oversized items are removed before being transferred, unshredded, to the Bedminster Digester. The Digester can be sized to suit the material to be processed, but typically a digester drum with a capacity of 50,000 tons per annum would be 70 meters (230 feet) in length, 4.6 meters (15 feet) in diameter.

In two days, the Digester breaks down the biodegradable material by a combination of microbial and mechanical activity, to form a consistent biomass material less than 12 millimeters or 25 millimeters (1 inch) in size separated from the non-biodegradable fraction, which remains fundamentally whole. This is achieved by passing the output from the Digester over a trommel screen; in this case, the biodegradable fraction drops through the trommel and the unshredded material such as plastic bags, bottles, cans, and similar items pass over the screen.

The Overs are passed through magnetic and eddy current separators so that metals can be recovered for recycling, while the balance synthetic material, chiefly comprising plastic and non-biodegradable textiles, is baled and transported for further processing/recycling. The system’s composting process takes advantage of separation achieved in the Digester drum where 95% of the biomass in the delivered waste is separated to achieve a homogenous product with low levels of contamination.

The now homogenized organic rich Unders are formed into windrows in an enclosed Maturation Hall. Material spends 21 days being aerated and consistently turned. Monitoring ensures that the material is turned at least three times at no less than two-day intervals attaining a minimum temperature of 140°F between turnings to ensure that the final compost is fully sanitized.

To create a clean, energy-rich biogas, the biomass is indirectly heated in the Pyrolyser in an oxygen-depleted atmosphere. This prevents the formation of harmful compounds such as dioxins and furans associated with conventional combustion. The biogas is passed through a gas cleaning stage prior to being stored in gas storage tanks.

The biogas is fed to gas turbines or gas engines that power the electrical generators to produce renewable electrical energy. It is subjected to such high temperatures within the turbines/engines that any traces of dioxins and furans are completely destroyed. Exhaust heat produced by the turbines/engines is reused in a heat recovery steam turbine to increase the overall electrical conversion efficiency. This results in an available net electrical output power of approximately 1.0-2.0 MW per 40,000 tons per annum of MSW input (dependent on waste input).

Helping Things Take Off With Food Waste Handling
Orbis originally involved themselves with the blue curbside recycling bins; that is where they got their start in this particular segment of their business. Now as a whole, they do a lot in returnable, reusable packaging-primarily plastic packaging-such as those found in industrial applications, those used at an automobile assembly plant. They will use the company’s products, like a big bulk bin, to bring components into an assembly plant. Once those parts are placed in a car for assembly, the packaging is shipped back and used over and over again. This cuts down on corrugated waste, optimizes the amount that can fit on a trailer. So freight costs are minimized as well.

“A lot of what we do in our business is all about trying to save money, cut down on costs, reduce carbon footprints, and any other benefits,” says John Sebranek, environmental marketing manager for Orbis. “The segment of the business I’m responsible for involves environmental products. We started with the blue bins for recycling products.”

From there, they went into organic waste collection in Toronto, Ontario, some 12 years ago, developing the first major program in North America for food scrap collection. They developed a cart specifically designed for food waste, as well as a kitchen container. This was a complete program allowing residents to easily collect scraps in the kitchen.

Once such food refuse is collected easily in the kitchen and can be taken to the garage before being wheeled out in the curbside container. Orbis products are specifically designed for organics and handling such waste, such as latches to keep pests out. Rather than having a container that might have an extension bar that actually bisects the lid, theirs will fully enclose all of the waste as food waste and its leakage, as that tends to be more liquid in nature.

“Our products tend to have a bit thicker walls because of the density of food scraps,” adds Sebranek. “They also must be more durable because of all the extra weight they are handling. All of this is done to have a container specifically designed for this purpose, as opposed to one that’s simply built to handle general municipal solid waste. Over the past 12 years, this product and concept has really expanded in Canada. Forty-five percent of residents in Canada now have access to curbside food scrap handling-that’s really where our key market is located. In the United States, the cities where this has caught on include Seattle, San Francisco, and Portland.”

The firm is seeing more growth in food waste handling in the Northeast. A lot of that has to do with space limits, spurring some demand for the product. Massachusetts, Vermont, and Connecticut are putting in food scrap bins for large commercial food scrap generators so that restaurants and hotels, as well as hospitals, can handle this waste and convert it into compost.

“Food scraps are placed in piles or “˜windrows,’ and what ends up happening is that compost is turned over on a regular basis in order to process it,” says Sebranek. “The other way to deal with the scraps is by using an anaerobic digester. Both are better options than simply taking the waste to a landfill since communities-or at least their directors and recycling coordinators-share so much information among themselves as far as best practices. So, as a result, this trend of dealing with food waste is really starting to catch on.

“Here in Canada, the fact is that much of the population of the country is centered right here in Ontario, and not spread out like in the US; it caught on in Toronto and in the other municipalities right around there, making a big difference in why it’s taking off,” he continues.

More and more regulations are occurring, however, to keep food out of the landfill. The other trend really making a difference, according to Sebranek, is the concept of zero waste, an issue many of the cities are now undertaking. Even if an area has a pretty aggressive waste diversion initiative, you can’t really do that without adding food scraps to the mix, because between the yard and food waste, it’s anywhere from 25-30% of overall waste.

“That’s going to be the next area when municipalities max out their ability to divert aluminum, paper, plastic, and other items,” he says. “Food scraps are the last area that is left. One way municipalities in Canada deal with this new change is by allowing residents to use compostable bags; that makes a big difference as there are compostable bags designed to fit our kitchen container. I think this development increases the participation rate by residents as trash and food waste removal doesn’t seem quite so nasty.”

They’re using their green bin (curbside container) and kitchen collector (container the residents use for food scraps). “We’re working on making it as easy as possible for residents to participate in the program, and to make it easy for them to scrape their food waste into the container and minimize the odor emanating from a food waste container,” adds Sebranek. “How can we make it as easy as possible for them to use that wastebasket, making it as simple as possible so that you are not even thinking about it on a daily basis? Smooth, easy-to-clean surfaces are important.

“Raccoons are a big problem, too. Toronto has the largest population of raccoons in North America, and now they’ve become urbanized. They’re smart, and they teach their offspring.”

What Goes Around Comes Back Around for Food Scraps/Compost
In San Antonio, one westside neighborhood has become part of a sanitation experiment to go organic. At a resident’s home, today’s breakfast is tomorrow’s plant fertilizer. “This is carne guisada,” she says, collecting the remaining food to be disposed in a special bin. She is one of 30,000 residents taking part in the city’s organic recycling program-already recycling aluminum, plastics, and paper, and, for a year now, there’s a third bin she places weekly on her curbside: for leftovers. “I’ve enjoyed it, and it’s good for us,” she says.

David McCary, director of San Antonio’s Solid Waste Management, says, “You can now recycle your pizza boxes that may be soiled, as well as look at coffee grinds, fruits, vegetables, mixed fruits-all of those types of materials can now by recycled.”

Food scraps and yard trimmings make up over 1/3 what San Antonians throw away. That trash puts an added strain on the landfill. So, the city is piloting a program to collect organic waste and convert it to compost material. “It’s cheaper to process it than throw it away at the landfill,” adds McCary.

The city expects to recycle 60% of its garbage by 2020. This circle of recycling waste has motivated some to be more aware of the food waste recycling process. The resident mentioned above indirectly composts her scraps as they actually make it back into her yard and garden through San Antonio’s returning of the compost to neighbors, free of charge.

If successful, the program will be unloaded citywide. It is projected to cost households another $3 per month in garbage collection.

Recycling has also reached a milestone in San Francisco, with food scraps collected through an urban compost program reaching 1 million tons, according to the city’s collection service, Recology. It took 15 years to get to the 1-million-ton mark, measuring the food scraps taken to one of two compost facilities.

“We started the program in 1996, and the tonnage that we’ve been separating for compost has been increasingly pretty regularly each year,” says Recology CEO Mike Sangiacomo.

San Francisco recently composted its millionth ton of food.

Officials with Recology and the Department of the Environment made the announcement, appropriately, at a restaurant in the popular Fisherman’s Wharf-Scoma’s-which was held as a model for recycling. “The employees have really kind of rallied around this; they want to do it,” says chef and buyer Kelly Bennett. “However, even with the colored bins-green for compost, blue for mixed recycling, and small black for landfill-people make mistakes. I do end up walking around and watching the trash cans once in a while.”

“I’m predicting we’ll hit our second million in five years,” adds Sangiacomo.

Alexa Kielty, Residential Zero Waste and Special Projects Assistant for San Francisco’s Environment Department, believes composting is one of the best things we can do for the environment. “We’re able to increase the soil fertility, also [reduce] methane production, and really create healthy food systems.”

Cleaning Up the Carts…Instantaneously
AaquaTools Inc. is one of few companies involved with cart cleaning of organics, and Eco-Feed Inc., Honolulu, HI, was among the first firms they dealt with. Eco-Feed works with wet food waste; organics have become very popular with their systems.

AaquaTools’s Tip Too and CartBlaster-the company’s original device-pressure wash the carts. “Our focus is on container cleaning,” says Steve Buchan, company president. “We have more cart sanitation systems than anyone else in the country. What used to be only a stepchild is now a very important part of our business. We have several thousand of our units out across the country now.”

The CartBlaster II has a relatively small 2-power nozzle, which can be configured to 4 on a large-pressure washer. The system has oversized casing gears resulting in smoother motion and the ability to withstand greater pressure. Innovative self-lubricating plastic construction on the gears is more durable than brass. The spray nozzle works on a variety of containers as the spray pattern, while the equipment completely covers the inside of the container. A widescreen particle filter keeps debris from entering during cleaning operations with help from a bleedoff valve. Water at temperatures up to 190°F can be used at 4-10 gallons of water per minute. Forces of 1,500-2,000 psi are involved in the operations. The cart cleaning typically takes just 1 minute.

In the Tip-Too model, loading bars keep in position all types of carts. Cleaning happens in some 30 seconds. Errant spray also is kept to a minimum. The devices used for the process are quite complex, according to Buchan; they need regular maintenance. “You can sell the product, but then it also needs to be kept up and cared for,” he says.

“Container cleaning in Europe and Canada is far ahead of the US. I work with companies here in this country every day that are trying to develop trucks, trying to go mobile. When I first got into this business, things were simply about cleaning carts. Now everything is about developing this or that product or system.

“In my opinion, no one in the US has developed a truck that is reliable or efficient,” he continues. “I’ve met people wanting to import trucks into the States; it’s very complex. The standards are very different than they are in Europe as far as potential for wastewater issues. It’s not so much with the technology, as in infrastructure. But in the end, any cart size used by any city or municipality will work with our system.”