Foodservice Equipment Reports

SPECIAL REPORT: Watching Your Waste Line

These days, more municipalities are on a stricter diet where it comes to foodservice waste, and they’re imposing those diets on your operations, too. Areas where landfill space is at a premium may encourage you to send as much food waste as possible down the drain. On the other hand, areas of the country where water is precious or sewer lines are old have banned the use of disposers, forcing you to get rid of waste in other ways. And a lot of “green” cities are asking (or telling) you to separate your trash into recyclables, compostable materials and garbage.

On top of all that, garbage haulers are charging higher fees for pickups and often are raising rates per ton, too. So a lot of money is riding on what you do. Taking the time to spec and install the right waste handling equipment may save you a ton of money as well as a ton of garbage.

Ultimately, the goal of any waste management program is twofold: Minimize the amount of waste you’re producing in the first place, and then properly handle that waste.

You have several ways to reduce your waste. First, take a look at the waste stream your stores generate to get a better sense of the types and quantities of refuse you’re dealing with. Your waste obviously depends on your operation, customer volume, location and other factors. Full-service restaurants, for example, are likely to have more food waste; QSRs are likely to have more solid refuse like disposables.

Trash Or Treasure?

Once you get a handle on all that, you can begin thinking about what to do with it. While you might be thinking, “Where can I get rid of this?” a better notion is the old saying that one man’s trash is another man’s treasure.

Which means maybe some of your waste isn’t necessarily waste. Make sure you’re recycling everything that can be recycled in your area. Granted, some cities are more enlightened than others when it comes to environmentally friendly practices. If your garbage hauler or municipality doesn’t provide recycling service, check around to see if there’s a recycler that would be willing to pick up at your location. In any case, separate out whatever you can recycle—glass, aluminum, tin/metals, paper or plastic—and you’re already on your way to reducing your trash volume.

Food waste is another issue. Like recyclables, food waste can be reused or “repurposed” in many cases. Several areas of the country, like San Francisco, now have composting programs, and some will take food waste off your hands for free (or at least as part of their regular haulage fee). If that’s not the case, again, check in your area for companies that may want your food waste for a composting or energy co-generation operation.

Waste handling equipment, of course, helps you reduce the volume of your trash by grinding it to a pulp or compressing it. And in recent years, as waste has become a hotter topic, new equipment has found its way onto the market.

How Much, How Often?

First things—and maybe obvious things—first. You can easily lower your garbage hauling expenses by reducing the number of pick-ups your hauler makes each week, especially if your dumpster is only half full each time the truck shows up.

Encourage your store managers to keep a log of when and how much trash goes out the door into the dumpster. Then figure out what size dumpster you need and how often your hauler should tip it. One cubic yard of dumpster space holds about 202 gals. of trash. An 8-cu.-yd. dumpster holds about 1,616 gals. of trash. If you use 30-gal. trash bags, roughly 50 bags will fill the dumpster. Conversely, if you use 50-gal. bags, about 30 bags equals a full load.

Figure out how many bags are actually going into the dumpster between each pick-up, and you may be able to reduce the number of pick-ups, the size of your dumpster, or both. Sometimes simply rescheduling a pick-up can help you eliminate one on some other day of the week.

Now, if you squish (yes, a technical term) the trash heading to the dumpster, you can reduce its volume by 50% or more, and suddenly you’ve created space in your dumpster for twice as much trash. That means half as many pick-ups to remove the same amount of trash.

Trash compactors reduce trash volume by a ratio of up to 25 to 1, depending on the type of trash you generate. If you have a high volume of food waste, compaction rates will be lower than if you’re compacting trash that consists of a lot of air—cups and disposables in the front of a QSR, for example.

Compactors, Wheels & Winches

There are two general types of compactors. One uses a compaction plate to flatten trash inside a container. Smaller units may use an electrically operated screw to drive the compaction plate. Larger units typically use a hydraulic piston. The other type doesn’t use a plate. Instead, an auger compresses trash as it’s forced through a tube into a collection area.

Another question is indoor vs. outdoor. You can stick indoor compactors either in the front of the house or in the kitchen. Some small indoor units are designed much like typical waste receptacles in fast food stores. They’re unobtrusive enough to sit in the dining area. Some models sense when a customer gets near, and automatically open the trash chute door.

Automatic compaction cycles are as short as five seconds so customers don’t have to wait, and the reduced volume means that staff members don’t have to empty trash bins as often, potentially saving labor.

These smaller indoor units can handle about 50 lbs. of waste, reducing volume of most front-of-the-house waste by up to 90%. Trash is compacted into heavy-duty plastic liners, preventing leaks of any liquids like soda or water. The liners are petroleum-based, not compostable like some can liners, so they’re not as eco-friendly. They’re also more expensive than typical trashcan liners, but you’ll use fewer of them.

With a 50% reduction in trash volume, and a corresponding reduction in the size of your dumpster and frequency of pickups, typical payback for these units is about 14 to 18 months.

Indoor units for the back of the house are larger, with capacities generally ranging from 300 gals. up to 1,000 gals. They also use plastic liners to prevent leaks, but most models have a drip pan that holds a modest amount of liquid just in case.

Depending on the model, some units compact trash into wheeled bins for easy transport out to a dumpster. Others come with a winch-lift dolly as standard or optional equipment that lets employees walk bins of compacted trash outside and raise it up to the height of the dumpster for easy disposal.

Depending on climate and other variables, maybe you’d rather do the compacting outdoors. If so, you’ll find outdoor models come in a multitude of sizes, with smaller units holding about 4 cu. yds. of trash. Larger units often are self-contained, meaning they compact trash directly into a dumpster unit that your hauler empties on a regular schedule.

Typically these large compactors feature a compaction cycle that positions the plate inside the dumpster chute after compacting a load. The plate seals the dumpster to prevent bug or vermin infestations. It also helps hold down odors.

Or Maybe A Pulper

To handle large volumes of trash, especially when a big percentage of it is food waste, you may want to consider a pulper. A pulper is a two-stage machine that grinds all kinds of waste except metal and glass in a chamber with water to form slurry. An auger forces the slurry through a perforated tube, squeezing the water out.

On self-contained models, the (mostly) dry, ground pulp feeds through a chute directly into a trashcan. Several manufacturers offer the option of remote units that pump the slurry to a remote dewatering machine, often outdoors at a loading dock or garbage bay. The option gives you the flexibility of hooking up several pulping machines to a single dewatering machine in a large property with multiple kitchens, or making disposal easier from awkward locations such as a dishroom on an upper or below-ground floor, saving employees from carting waste out by hand.

One manufacturer makes a system that moves waste through a facility to different pieces of treatment equipment with a vacuum.

The smallest of pulping machines have a capacity of about 500 lbs. of waste per hour, but most pulpers chew up about 900 lbs. to 1,250 lbs. per hour. Larger units are available for really high-volume feeders.

Most manufacturers only make a few models, and most models on the market tend to be fairly similar in general operation. However, there are some details to consider.

Power is one. Pulpers typically start with a 5-hp motor for the grinder, and horsepower goes up on bigger machines. So keep an eye on power specs, and if you have unusual needs, discuss them with the supplier.

The type and composition of cutting blades in the grinder vary, too, from manufacturer to manufacturer. Some have more stationary than moving blades; others have more blades on their impellers or cutting discs than they do stationary blades. Blades are typically made of hardened steel or a carbide-tipped alloy like tungsten.

Access & Replacement Cutters

Whether grinding discs, impeller blades or stationary blades, all the cutting surfaces should be replaceable when they wear out. In many cases, makers design blades to be reversible to double their life. And often, some blades are adjustable to maximize performance as they wear. Ask suppliers why they espouse one type of mechanism and material over another.

Pulping machines can handle just about anything up to and including steak bones, but some machines will have difficulty chewing up a few types of material. Some models have trouble with plastic straws, though most other plastic is okay. And a few models have trouble with expanded polystyrene foam because it floats. Older designs put the grinding mechanism at the bottom of the slurry tank; newer designs with the grinding mechanism on the side of the tank seem to handle materials like polystyrene foam that float a little better.

As mentioned earlier, the machines don’t have much of a taste for glass and metal. So, most units come with either a standard or optional flatware catcher, usually magnetic, that prevents metal tableware from getting into the machine.

Saving Water, Saving Space

While most pulping machines can be loaded manually, typically they’re hooked up at the end of a scrapping trough in the dishroom. The flow of water in the trough automatically feeds the pulper and is used in the slurry tank to help grind the waste.

While you might think that’s a lot of water going to waste, pulpers typically use far less water than disposers—usually about 2 gals./min. vs. 7 to 10 for disposers. The reason is that the water used in a pulper to make slurry gets pressed out and recycled to the slurry tank or the scrapping trough where it’s mixed with additional fresh water.

Dewatering is accomplished by pushing the ground up trash through a cylindrical stainless screen with an auger. The water is forced through the screen and the auger pushes the pulp out a chute at the end of the cylinder. Auger motors are typically rated around 2 hp and up, depending on the size of the machine. Again, both vertically-mounted and horizontally-mounted models are available, giving you some flexibility when it comes to space.

These aren’t small machines, so if space is a problem, a remote system is one option. Manufacturers also let you specify where to locate the pulp chute, which may help resolve some space issues. Most let you situate the chute on the front, end or back of the machine, but a few models give you even more flexibility. On these, the chute can be situated at any 45° angle instead of 90°.

Hybrid Solutions

If you really don’t have room, or you can’t quite justify the capacity and cost of a pulper, a couple of manufacturers now make smaller alternatives to pulpers. These consist of a heavy-duty disposer linked to a dewatering unit that can be installed under a sink. Designed primarily for food waste, the disposers are capable of chewing up most of the same waste a pulper can, up to about 50% nonfood to food.

Capacities of these units run about 500 lbs. to 700 lbs. per hour, and their smaller size make them a nice compromise when you want to reduce your trash volume and can’t send food waste down the drain, but don’t need a large pulper.

A benefit, of course, is that the dewatering units linked to these disposers recirculate water to the disposers’ grind chambers, saving a lot of water over traditional disposers.

Eco-Alternatives & Bio Approaches

Pulping machines can do more than reduce trash volume. If you purchase compostable disposables, and train employees properly, you can send all the pulp from the machine to a composter, making your machine even more environmentally friendly.

In the last few years, a few other eco-friendly alternatives have shown up on the market. The first is a shredder that chews up food waste, disposables and other materials like a pulper does. Unlike a pulper, the unit doesn’t use any water to grind waste. It’s ideal for self-bussing operations, such as cafeterias, that use all disposable products.

The unit does need a fresh water hook-up for its self-cleaning function (which uses a nominal amount of water). And it needs to be situated near a floor drain for liquids removed by the dewatering auger and water from the cleaning cycle. It uses about 40% less energy than a pulper, but has the capacity to shred 1,200 lbs./hr.

Another new device on the market dehydrates compostable waste by “cooking” it at low temperatures (about 180º F.) The heat evaporates all the moisture in the waste and is high enough to kill odor-causing and potentially dangerous bacteria and pathogens. Paddles macerate the waste during the dehydration cycle. The result is an even greater reduction in volume than pulping alone and sterile material that can go straight to a composting facility. The unit’s capacity is 660 lbs., and a cycle takes about 18 hours.

Yet another alternative for food waste is a mechanical stomach. Digesters, which have been used on a larger scale in industrial applications, now are available in a smaller model designed for foodservice use. The unit uses microorganisms (not enzymes) to break down food waste. You can feed the unit continuously, though the maker recommends adding a batch of waste every four hours. The units doesn’t digest waste like bones, pineapple tops, large fruit pits (e.g., avocado) or grease, fats and oils. Occasionally, staff will have to clean indigestible items out of the unit.

After digestion, the solid waste is turned into a liquid, which you simply discharge down the drain. The unit is about 80% to 90% efficient over 16 to 18 hours, meaning a 1,200-lb.-capacity unit will discharge about 400 gals. to 500 gals. of liquid waste per day. The units come in 400-, 800- and 1,200-lb. capacity sizes.

The microorganisms that aid digestion must be “recharged” every three months. Also, you should check with your water/sewer utility to make sure it permits the use of digesters. While the microorganisms are environmentally friendly, some sanitary sewer districts may have rules regarding the effluent. The units also require the addition of wood chips, which provide an ideal habitat for the microorganisms. The units need to be lubricated and cleaned quarterly, which staff can do, and serviced every six months.

Cleaning Counsel

Since any garbage that comes in contact with food waste can get funky after a short amount of time, you have to keep waste handling equipment clean.

On compactors, the plastic liners prevent most problems, and they’re usually changed often enough that odors don’t have a chance to build up. But occasional leaks and garbage that lingers too long can cause smells. Make sure staff cleans them regularly.

Pulping machines should be cleaned daily. Though not required, most manufacturers recommend running cardboard or paper stock through the machine to clean cutting surfaces and absorb grease and odors.

A few models have water-flushing nozzles and an automatic cleaning cycle to rinse the perforated screens around the dewatering auger. Some also give you the option of a hot water inlet for these cycles. Several models also give you the option of a deodorizing unit that dispenses chemical deodorants to dramatically reduce the “pee-yew” factor.

Many manufacturers recommend an optional rinse hose that attaches to their machines. Since pulpers are built to withstand a dishroom environment, a lot of operators find it easier to simply hose down the machine at the end of the day. Best advice is to follow the manufacturer’s cleaning instructions to keep your equipment performing well and eliminate odors.

No matter how you grind it, pulp it, shred it, compact it or digest it, there’s a way to reduce your waste and save you money.

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