Spec Check: Pulpers

Pulpers consolidate waste and these units can reduce the mass of garbage foodservice operators contend with by 80 percent to 95 percent. It is important to note that these units reduce the volume or mass of the waste, not the actual poundage.

The waste consolidation a pulper performs is comparable to the process of mulching leaves, which can reduce 10 bags to just 2. Pulpers accomplish this by grinding the waste and removing the water. Shrinking the size of the garbage creates more room in trash receptacles, which results in fewer garbage collection pickups. Consequently, foodservice operators that use pulpers may be able to reduce their hauling charges. These units can also enhance the cleanliness of a foodservice operation since staff have to transport and store less garbage.

An environmentally friendly alternative to garbage disposers, pulpers were the first waste handling systems that tackled the water reduction issue. By extracting gray water and recirculating it, then grinding and disposing organic waste, these systems can reduce energy consumption and result in less garbage sent to landfills.

The Pulping Process

The process of pulping involves taking waste to a scrapping station that includes a recirculating trough system. Staff feed garbage into the pulper unit, which operates via a 7 to 10 hp motor with large cutting disks. The pulper cuts all waste prior to the system adding and recirculating the water. The system processes the waste into 95 percent liquid and 5 percent solids. The system removes the extracted water and recirculates it through the pulper for the next batch of garbage. Meanwhile, the system disposes the greatly reduced waste in a trash container. Pulpers can run as long as 8 to 10 hours at a time in high-volume operations.

Foodservice operators can choose from two basic types of pulpers: close-coupled and remote systems.

Close-coupled pulpers are free standing systems that consist of a grinding unit and water press, which process waste at one location. This setup helps decrease waste volume in operations that do not allow centralized food waste collection.

Remote pulpers are an engineered system that requires piping to and from the press and transfer pumps between the press and macerator, which recycle the water being used. Foodservice operators can choose to locate this equipment anywhere from a few feet to several yards away. Remote pulpers include a separate macerating chamber that grinds the food waste before pumping it to a water press situated in a remote location, such as a back dock, pulp collection room or somewhere away from the input area. Operators can fit these units with several macerators hooked into one press.

When specifying a pulper, operators need to determine if there is room on-site to accommodate a close-coupled unit. When space becomes a key specifying consideration, operators can choose a remote system. Both systems have their own advantages, so operators need to decide which option best addresses their waste handling needs.

A close-coupled pulper can be a less expensive option because it doesn't require a custom build. These units also feature less complicated installations and require less overall cleaning due to the lack of separate plumbing lines that require maintenance.

The benefits of a remote system include the ability for operators to add multiple grinding tanks, which can handle one or more dish rooms or discharge stations. Also, operators can opt to place discharge units by dumpsters, which saves labor due to the short transport of waste. Operators that use remote pulpers will need to decide how and where to run the pipes, which will depend on the bin locations. If the pipes' path to the bins include excessive turns and lengths, the system may require extra transfer pumps. Also, with remote units, operators should ensure that enough cleanout access points are available throughout the piping for easier unclogging of waste.

One common mistake operators make when specifying remote pulpers is not utilizing the right type of piping. Typically, operators should use sweeping 90s, not hard 90s, to help reduce the incidence of clogs around tight corners. Piping should feature hard copper construction and have rigid soldering to withstand vibrations, which occur during use.

Organic waste disposal systems represent a newer, completely self-contained pulper type. These systems hold organic food waste in a central drum and decompose it into liquid by applying heat, water and motion. These systems dispose liquid through existing sewage treatment facilities or they can serve as a supplement to irrigation and plant-watering systems.

Prior to purchasing a pulper, operators need to decide if the business warrants it. Operations serving between 1,000 and 3,000 meals at a time are most likely to benefit from pulpers. These typically include such high-volume operations as hospitals, colleges and universities as well as large business and industry feeders. Also, a growing number of mid-sized foodservice operators now use these units.

When specifying a pulper, foodservice operators need to take into consideration the type of food and service style. Operations using compartmentalized trays or china with linen napkins won't use these systems as much as a facility that utilizes paper plates for serving and has excessive amounts of milk cartons or juice boxes, along with large amounts of paper goods. The ability to put disposable servingware in these units is why cafeteria-style operations are more likely to utilize pulpers than high-end hotels.

Operators need to consider their current waste-handling practices, looking at how the business processes garbage and the collection method. For those with a batch system, a pulper can help process between 300 and 1,000 pounds of food and fiber waste per hour.

When choosing a pulper, operators also need to consider the layout of the dishroom and how staff will scrape the dishes. If the operation uses runners to bring waste in on banquet trays that need sorting or large carts with insulated trays sorted by one or two people, there may not be space for a pulper in that area. These systems work best for operations constantly sorting for warewashing, but not for those sorting through large batches of dishes and waste at one time.

The position of the operator in terms of processing organic and inorganic waste also represents another consideration when determining if a pulper is the right fit for a business. Some users of these systems turn pulpers into profit centers by sorting out inorganics.

When choosing the type of pulper, operators need to consider not just the number of covers a day, but the average waste per cover, which will help determine the waste load. This also will help in figuring out what size pulper is needed and the energy or water consumption necessary for processing. Pulpers are available in three-phase, 208, 230 or 460 volts.

One common misconception with pulpers is that the systems can handle all types of waste. Although these units can process Styrofoam and some plastics, pulpers are not designed to handle stretchy wrap plastics and inorganics.

By design, pulpers use much less makeup water than other waste disposal systems. Whereas a standard cold water disposer uses 14 gallons a minute and a recirculating system uses 7 gallons a minute, a pulper uses as little as 2 gallons of makeup water per minute. The process reduces waster use by removing most of the solids out of the water by straining, and recirculating the water back into the unit.

Newer water conservation pulpers utilize a vacuum technology. Instead of the garbage trough recirculating water, garbage is dropped in a hopper and a vacuum sucks the food waste into a central macerator, where it's ground up, water pressed and digested. This one-way system is pricier than traditional pulpers, but can save on water usage.

Hauling bills and waste handling costs are another consideration for those deciding to incorporate a pulper into a facility. Operations that have had a sudden increase in garbage and are dealing with frequent waste pickups may be well-suited for these systems.

Operators should be aware that, although pulpers can reduce waste volume and the associated handling costs, these systems do not completely eliminate the need for labor.

Using these systems is not feasible for all operations. Before purchasing a pulper, operators should refer to state and city laws to ensure these units are not prohibited in commercial establishments. While some areas, such as New York City, do not allow pulping systems in commercial foodservice operations, other locations, like Washington, D.C., encourage their use as a green alternative to garbage disposals.

Because larger pulpers need to connect to a trough system, verify sizing. Incorrect measurements will require new connectors, which could delay the installation of the system.

Operations utilizing silverware should make sure to specify a pulper with an external silverware catcher. These big magnets will stop forks, knives and spoons from getting caught in the trough, where they will either get stuck or ground up in the system.

For tighter floor plans, some pulpers can be customized with corner designs upon request. Pulpers can vibrate substantially during use, so rubber feet will help isolate the shaking and the noise.

Specify additional push/stop buttons for other areas of the kitchen, even as far as 20 feet away from the pulper. This not only saves energy by turning the pulper off when it's not in use, but also can stop operation in case of an emergency.

Because pulper prices can vary drastically, operators are advised to get multiple quotes from various vendors. Both cost and maintenance should be considered, as these are major pieces of equipment.

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