Disposers in commercial foodservice operations can help reduce trash-hauling costs by decreasing waste, eliminating food waste odors and decreasing labor by minimizing trips to the dumpster.

Disposers often come with a control, sink or sink mount for existing sinks, stopper, water inlet hardware, back flow preventer, solenoid valve and flow control.

This equipment is typically installed in dish tables and pot/pan sinks as well as in vegetable prep, salad prep and meat prep areas. While a commercial disposer is more durable than the residential type and is capable of grinding more items, manufacturers still recommend using these units only for edible food waste. This is because some waste, such as corn husks and seafood shells, can clog drains.

All disposers handle the same type of waste, but configuration and horsepower determine the operational capacity and volume. Most commercial disposers range from ½ to 10 HP and operate essentially the same as
residential disposers.

Controls range from simple manual start/stop operation to more sophisticated electronics that reduce water and energy use. Some disposers automatically reverse the cutting teeth to maximize the unit’s service life. Energy-saving models can determine when water becomes necessary and can turn the system off when the operator is not present.

Disposer construction materials vary, depending on the manufacturer, but most have a corrosion-resistant finish. Disposer housing construction options include aluminum, stainless steel and cast iron, which can be either coated or plated. Also, these units use different types of cutting mechanisms, such as rust-resistant nickel, stainless steel or austempered heavy ductile iron.

Foodservice operations use disposers with rotor-fixed cutting teeth, units with swivel cutting teeth or units with a hammer mill grinder. All three types include a cutter operating at high speed inside a stationary shredder ring.

Voltage options include 115, 208, 230 and 460, with either a single or triple phase. In terms of operation, operators can choose from standard electrical wall switches or electronic controls.

Water-saving and water quality control features can help save money over time. Systems on some units help regulate the amount of water going into the disposer according to the disposer’s current draw. A sensor automatically turns off the high-water flow when the unit completes the grinding application.

Scrapping systems are typically used in conjunction with disposers. While some systems include a disposer and use water for scrapping, others are installed in a trough application for multiple scrapping stations. Scrapping units may also use a basket instead of a disposer to collect insoluble food while allowing solubles to wash down the drain. One system, installed in a trough application, uses a scrap basket instead of a disposer.

Some models have specific features for different applications. For example, disposers designed for the correctional market offer optional offset shoots, which sit several inches from the sink drain to prevent tampering. Units also can be equipped with tamper-proof screws and guards that prevent arms from reaching into operating units.

It’s important to note that the disposal of any effluent into municipal wastewater (sewer) systems is typically governed under municipal by-laws/ordinances and enforced at the local level or through a regional municipal authority, in accordance with state and federal environmental legislation. These ordinances detail permissible limits of various materials and chemicals that can be present in effluent that is being disposed of into the municipal waste water system, and that ultimately need to be processed and treated at the wastewater treatment plant.

Purchasing Considerations

Some municipalities prohibit disposer use or have regulations regarding the utilization of these systems. Foodservice operators should check with local zoning or municipal boards to ensure these units can be used and if there are any requirements, such as the use of interceptors or grease traps.

Not following manufacturers’ recommendations when selecting a disposer can result in an inadequate system that will not meet the operation’s waste needs.

Because most operations become more dependent on these systems than expected, it is better to go bigger in terms of horsepower to ensure the waste amount can be accommodated.

Operators should weigh a variety of factors when selecting the correct disposer. Start with size. The more food waste the operation will grind, the larger the unit.

The density of the food waste plays a role in sizing the disposer. Under sizing can become problematic and cause jamming and slow throughput. For most commercial foodservice operations, anywhere from ¾ to 5 HP will meet most operational requirements.

Consider the drain line size to ensure efficient operation and help circumvent sink backups. Some manufacturers provide free site surveys to verify the disposer’s drain line can handle the foodservice operation’s waste.

The disposer’s location and mounting also are key. Manufacturers typically provide two different mounting types, a prefabricated bowl welded into a stainless-steel countertop or a sink collar adapter to install into a sink drain. Sink collar adapters are used more often when a sink is going to be used in conjunction with the disposer for more than just food disposal, such as with food preparation, rinsing out coffee equipment or just general-purpose use. The bowl accessory is used more often in the pot/dish area when a multipurpose sink is not required.

Another scenario includes the use of a scrap sink for breaking down dishes and silverware at a dishwasher. In this instance, the disposer works in a sink application with a rack guide for scrapping/loading of dish racks into the dishmachine.

There are various other options to consider as well. Auto-reversing motors help prevent jamming. Perforated silver savers prevent metal silverware from getting into the grinding chamber. Throat guards and offset chutes also can be used to prevent access to the cutting chamber inside of the disposer.

Cleaning and Maintenance

Operators should consider a variety of factors when it comes to the use and maintenance of disposers. First, do not use these systems to dispose fat, oil and grease. Also, batch feeding food waste into disposers blocks water, resulting in drain line clogs. For clogs, fill a 5-gallon bucket with cold water and run it through the disposer to push waste through.

After feeding product through the disposer, operators should allow cold water to run for 10 to 20 seconds to ensure small particles push to the main sewer line. Do not use hot water as doing so can melt fat and allow it to solidify and block the drain line.

Keep plastics, silverware, straws and other non-food items away from the disposer to minimize jams.

Only use disposers with the appropriate food waste. Some food scraps, like potato skins, can build a layer inside the unit and dull the blades quicker. This also turns into a paste that drags motors down. Also, the higher the horsepower, the more volume the disposer can handle. It also helps to start and stop the unit as much as possible since the blades go in different directions when power is interrupted.

Many people think disposers have blades that spin, but this isn’t the case. These units use two weighted pieces on a spinning disk that throws food onto blades at the sides of the machine. Putting inappropriate food waste down disposers can clog the drain and grease trap, which is difficult to empty out.

All disposers are sealed, so there is no way to physically oil the unit. Operators should make sure the contactors on the control box are tight so there’s good contact. Also, making sure high volumes of food waste aren’t thrown in all at once and plenty of water is used for flushing the system during operation will help extend the unit’s service life.

If the grinding becomes really loud, this could signify the bearings are bad. Also, leaking out of the disposer’s bottom means the shaft seal is compromised. Typically, this will take out the motor, but not always.

The life expectancy of a disposer depends on the type of food it grinds, the food’s composition and how long the unit is in operation. Life cycles range from 3 years up to 20 years, with an average service life of 5 years for disposers that are cleaned and properly maintained.

Signs that indicate a disposer needs replacing include increased grind time, which can be caused by blades wearing out, motor failure or smoke, cracks, unusual or excess noise, and frequent repairs.

Commercial disposers that are 5 HP and up can be rebuilt, but with smaller units, too many things can go wrong, and it’s not worth the cost. Also, disposers with leaks in seals or shafts should be replaced.