Product Knowledge Guide: Pulpers

With municipal and contract hauling costs increasing by as much as 5 percent to 7 percent nationwide, and even as much as 11 percent in some cities, larger foodservice operations continue to look for ways to lower waste disposal costs. This has been good news for the pulper segment, since this equipment can reduce foodservice-related waste by between 80 percent and 95 percent on average and offers a relatively quick return on investment.

iStock 000016306779XXXLargeConsidered more of a spec product now than ever before, pulpers remain particularly popular in foodservice facilities pursuing LEED certification from the U.S. Green Building Council. Although these systems primarily consolidate waste, pulpers also can save labor by potentially reducing the number of trips staff make to the dumpster.

Pulpers work by grinding up waste and removing water to decrease the volume of the waste stream. Specifically, big commercial pulpers utilize large cutting disks, a water press, a recirculating trough system and a 7 to 10 hp motor to consolidate and remove wet waste from disposables. This process reduces the amount of garbage in receptacles and, subsequently, the number of waste pickups a foodservice operation requires. Not only can operators save on waste hauling costs, but this also helps minimize the health hazards associated with storing excess garbage.

Foodservice operators can choose from two types of pulper systems. Close coupled are stand-alone units that are less expensive and don’t require a custom build. With this type of pulper, the pulping and water extraction occur at the same place. These easier-to-install systems require less cleaning because they have no remote lines that require maintenance.

Remote pulpers are better suited for larger operations with higher waste volume. This type utilizes a macerating chamber to grind food waste or can be fitted with several macerators hooking into one water press. The system pumps the waste to a water press, typically located away from the input area in such spaces as a rear dock or separate pulp collection room. An operation may have several grinding stations leading to one discharge station with remote pulpers. Foodservice operators can opt to place the discharge unit by the dumpster to save labor. Also, operators may elect to include additional grinding tanks if they have more than one dish room.

When utilizing remote pulpers, use sweeping 90s piping, as opposed to hard 90s, to help reduce the incidence of clogs around tight corners. The piping should feature hard copper construction, with rigid soldering to withstand pipe vibrations during use. With remote units, operators should ensure that enough cleanout access points are available throughout the piping to facilitate easier unclogging of waste.

Some pulping units can accommodate between 300 and 1,000 pounds of waste per hour. This includes processing materials like Styrofoam and plastics, although stretchy plastic wrap is not recommended for disposing in these systems, since it can stick to the components.

While the pulper housing typically features heavy- gauge stainless steel construction, most manufacturers tend to use a durable tungsten steel that can hold an edge when making their cutter blades. Systems are available in three-phase, 208, 230 or 460 volts.

One environmentally friendly aspect of pulpers is that they extract gray water and recirculate it to help grind and dispose of organic waste. While a standard cold water garbage disposer utilizes 14 gallons of water a
minute and a recirculating system uses 7 gallons of water per minute, a pulper uses only 2 gallons of water a minute. Also, water usage is further reduced, since these units remove most of the solids out of the water strain. There also is a new vacuum technology for these systems that utilizes no water.

Despite the fact that these systems reduce landfill garbage, a number of municipalities prohibit the use of these units. This is because some believe pulpers put undue stress on sewage systems, while others don’t want to contend with gray water. For this reason, operators should check with local municipalities and conduct a cost benefit analysis to confirm that this waste management option is feasible for their operation.

For operations that cannot utilize traditional pulpers, organic waste disposal systems represent a new, self-
contained alternative. These waste processors decompose food waste into liquid by applying heat, water and motion to organic waste that is held in a central drum. The liquid can either be disposed through existing sewage treatment facilities or used as a supplement to irrigation and plant-watering systems.

When choosing a pulper, assess the type of food and how the operation will serve it.

Q&A with Marc Sherman, senior foreman, General Parts & Service, Bloomington, Minn.

FE&S: What is the typical service life of a pulper?

MS: Pulpers can last indefinitely, since all parts are replaceable and affordable. Tanks are made of durable stainless. Broken parts can be rewelded, and brushes and screens can be easily replaced.

FE&S: What are the cleaning requirements for pulpers?

MS: Most units have a system that pumps in chemicals to keep them clean. Operators can purchase these solutions from cleaning supply companies. Pulpers also have a shutdown mode that runs water through the unit. This flushes out the system, helping to control odors and bacteria growth. Some manufacturers recommend filling the pulper with strips of cardboard to clean it out daily.

FE&S: What are the biggest maintenance requirements with these units?

MS: Maintenance on most pulpers is blade related and involves either repairing, resharpening or changing the blades. It’s also important to keep the proper gap between the shredding head or sizing rings and blade. If clearance gets too big, then bigger debris will get through the system without being properly ground up. This can be a big issue that leads to major clogging of the drain lines.

FE&S: What steps can operators take to help prolong the life of the pulper?

MS: Some types need occasional greasing, and that’s relatively minor. Pulpers with water presses may have brushes that need to be checked and replaced at different intervals, depending on the unit’s usage and brand. This may be as often as monthly in high-volume operations.

FE&S: What can cause jams with these units?

MS: If blades are dull, the bigger refuse goes through and that will jam up pumps. Also, the water press will start clogging and/or breaking down.

Pulper Specifying Considerations

Pulpers can save both money and labor when utilized in the proper environment. Here, John Marenic, principal at Charlotte, N.C.-based Marenic Food Service Consultants, provides his insight on this type of foodservice equipment.

  • Pulpers are basically oversized garbage disposals that can accommodate higher volumes of waste. Operators use these units in conjunction with a big trough.
  • The trough is just as important as the pulper, because this is what takes garbage from point A and brings it to the pulping area.
  • This equipment is really designed for high-volume use in institutional operations such as hospitals and universities.
  • Some big cities and many beach side communities don’t allow pulpers due to sewage system issues. Before considering this equipment, operators should confirm that codes don’t prohibit use.
  • Operators can choose from different sized pulpers and, like garbage disposals, various horse powers. Prior to purchasing, determine how long and wide the unit’s trough should be. This is generally based upon the number of employees working the unit and the number of plates that will be cleared at one time. For example, for a hospital cafeteria operation that includes 3 people at the trough area clearing 33 trays at a time, there needs to be enough clearance for everyone. I generally allow between 24 and 30 inches of space for each person working the pulper. This allows room for moving hands, pivoting and accessing the unit.
  • The trough requires cleaning. Many models include an automatic sensor that turns on when the unit is full and off when it’s emptied. Floor switches also are available that can turn on different sprayers at various times as necessary. For example, with an individual switch, I can turn sprayers on only in the clogged section, which saves water.
  • Pulpers will need water, electrical and the correct drainage hookups. Operators need to check with their city about drain requirements for these units. Each city is different, even those within the same state.
  • Operators should look for a pulper model with an auto stop feature for added safety, which most units have.
  • I recommend adding a magnetic catchall, one in each zone. This is an added expense up front, but saves money in the long run, since it prevents silverware from getting chewed up in the pulper as well as the use of extra water needed to push metal down the drain.


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