Wet Waste Issues: Commercial and Light Industrial Applications
By Chuck Cini
Summary: Business and industry face an ongoing challenge in dealing with wet waste solids in a cost effective, time efficient and environmentally friendly way. The good news is that there are various options available, depending on what application is being considered.
Drainage is a broad term for a spectrum of issues for various industries, commercial operations and residences. There’s the complex system of waste processing at a major industrial plant. There are drain pipes as part of a large municipal plumbing system from a restaurant or hospitality business site to a processing plant. Even the gutters on a home that catch rain and debris qualify. The challenge for commercial and industrial applications is how to handle waste in the easiest, safest and most economical way. Water treatment equipment dealers may face these issues with customers they already serve.
Wet waste solids are a part of doing business for restaurants, hotels, resorts, office and school cafeterias, food industry plants and businesses that deal with animal waste, such as farms and companies whose primary product is from animals. No food or animal is so perfect that there isn’t some type of residual solid matter leftover after raising/slaughtering the animal, processing the food or product in a plant, or serving the food in a restaurant. Wet waste solids come in many forms, and government regulations vary state to state, so it’s important to look at what a business generates and what the laws are for that city or region. There are ways to meet the legal standards and minimize the nuisance of dealing with the necessary by-product—wet waste solids.
Options for wet waste solids
A garbage grinder or waste disposer breaks food into small particles by protruding bars attached to the revolving disposer rotor. The waste continues to break down until it’s small enough to be washed through a sizing ring, which is a fixed ring around the perimeter of the disposer cavity. During this process, water is being mixed with the solid particles to promote an easy flow into the pipes and sewage system. Beware that not all grinders are created equal, and that functionality is more critical than price in business and industry applications. Manufacturers produce a variety of units for different locations within a restaurant, for example, and with horsepower ratings from usually about one to five.1 Some cities or island resorts ban such units because of the scarcity of water in the area or lack of an adequate municipal treatment plant.
A pulper is a step beyond the grinder process. It functions to separate the wet waste solids from the water and uses a water press to accomplish this task. Some water-soluble matter is flushed down the drain, but the waste product that results from the water press is a damp, grayish, pulverized material that can be removed from the building. Waste odor is reduced significantly, since many odor-causing proteins are washed away in this procedure.1
Grinders are ideal for areas of a business facility that primarily produces wet waste solids related to food matter. Pulpers can be used in these same areas, but also handle disposable paper and plastic. Another advantage to pulpers—they’re more water conversion-friendly because most of the extracted water can be recirculated for reuse, unlike grinders.
Another type of separation device involves use of centrifugal force. This is ideal when solids are more formed, such as wet waste from a hatchery. The liquid is refrigerated and transported by tanker truck to a pet food manufacturing plant; the solids (chicks, membranes, eggshell) are landfilled.2
When the former methods aren’t appropriate, or not permitted with regard to legal codes, collectors are another option. Think of this as a trash collector that functions like a sieve so that water can flow through it to rinse off some matter, yet strain the larger particles for removal to another trash receptacle. A unique example of this method was discussed in an article in WC&P’s October 2001 issue.3 Briefly, this unit functions like a porous trash bag—allowing water to flow through the pipes but automatically removing wet waste solids in a convenient, disposable “trash bag.” It’s available for home and commercial use.
Benefits of this system include:
- Significantly reduces operating costs by reducing the frequency and associated costs of grease trap maintenance,
- Prevents clogging and reduces maintenance of drainage systems and grease traps,
- Reduces the cost to municipalities for treating sewage at treatment plants,
- Meets wastewater discharge regulatory compliance standards,
- Reduces odors created by grease traps,
- Minimizes the need for costly enzymes and bacteria treatments; and
- Reduces the amount of airborne bacteria released when cleaning a grease trap.
What to do
There are a number of options for handling wet waste solids already captured in the system established at a place of business or industrial site. Compaction, liquid extraction, burning, recycling, etc., are among them.
Liquid extraction can be done in a variety of ways, such as with the water press described above or by using a more complex dewatering precrusher/compactor. This machine reduces the weight and creates a by-product that’s typically suited for landfills, and can even mean reclassification from hazardous waste to non-hazardous in some cases.4 There are liquid extraction systems made by companies like Marathon Equipment Company, of Vernon, Ala., for uses specifically in industries such as pulp mills, dairies and food processors, beverage and liquid packaging facilities, food service, and more.
Incineration is ideal for waste materials in which solids content is high. Floor sweepings from commercial and industrial sources, cardboard, rags, wood pieces and paper products typically contain less than 25 percent moisture. Refuse is comprised of waste mixed with wet vegetable or meat waste, such as that found in food processing centers and may consist of up to 50 percent moisture. Garbage from small eateries, hotels, markets, campsites and larger restaurants can contain as much as 70 percent moisture from waste mattter.5 Howden 3Ts International Ltd., of Monmouthshire, Wales, in the United Kingdom, makes such a product for factories, pharmaceutical labs, hospitals, schools, zoological gardens, parks and resorts called a BP Range incinerator, and a variety of other specialty incinerators.
Disposal through trash and landfill is an obvious way to get rid of unwanted by-products from a home, business or industrial facility. Restaurants, hotels, industrial plants and similar business facilities face the challenge of meeting legal guidelines, employing a system that’s “user-friendly” and convenient for personnel, and tailoring how they process and dispose of waste in a way that’s specific to the nature of the by-products that might be encountered. What comes out of a fishery, farm or hatchery is quite different than waste from a hotel, bakery, butcher shop, restaurant or, on a larger scale, a vegetable canning plant or other food-related industrial facility. The key is how to process that waste and eventually remove it from the building.
As an example of a state recommendation, the Washington State Department of Ecology stated, “Current data and regulations suggest that street waste solids from sites that are not obviously contaminated classify as solid waste and can be used, recycled, or disposed of in ways that do not pose a threat to human health or the environment.”6 Catch basin solids, street sweepings, ditch spoils, settling basin sediment and other stormwater facility waste must be analyzed, tested and determined to be safe for recycling or otherwise be treated as hazardous waste.
Business and industry are challenged with maintaining a balance between savvy and efficient operations and attention to harmony with the community and environment. They provide a product, and produce waste in the process of creating, serving or managing it. Knowing what’s available and tailored to the specific industry/commercial application, and what laws govern waste handling for that region, promote wise decisions that benefit a business, its individual personnel, and the community where it resides.
- Bendell, Dan, “Disposers & Pulpers,” Food Management, June 2000.
- Cawthon, Don, “In-Vessel Composting of Un-Separated Hatchery Waste,” Department of Agricultural Sciences, Texas A&M University-Commerce, Texas, 1998.
- Wiertzema, Mark, “The Plumbing Industry and Environmental Issues,” Rhino Ecosystems Inc., WC&P, October 2001.
- “Precrusher Dewatering/Liquid Extraction Systems,” SP Industries Inc., www.sp-industries.com/Dewater.htm
- BP Range—Industrial Waste Incinerators, Howden 3Ts International, Ltd., www.howden3ts.co.ae/products/range_bp.htm
- “Washington State Department of Ecology BMPs for Mgmt and Disposal of Street Wastes,” www.americansweeper.com, 1995.
About the author
Chuck Cini is the new president of Rhino Ecosystems. His company’s product, available through both national and international dealerships, is the Wet Waste Interceptor®. These units provide an inexpensive solution for restaurants, hotels and food related industries to dispose of wet waste solids with considerable benefits from a health and conservation perspective. He can be reached at (877) 746-6224 or website: www.rhinoeco.com