KWS Manufacturing

Shaftless Conveyors for Organic Waste Processing

General Description

Americans generate over 300 million tons of Municipal Solid Waste (MSW) every year, averaging 5 pounds per person per day. Of the MSW generated, approximately 69 million tons are recycled, and 25 million tons are composted each year. Recycling is the recovery of useful materials, such as paper, glass, plastic, and metals, from the trash to use to make new products, reducing the amount of virgin raw materials needed. Composting involves collecting organic waste, such as food scraps and yard trimmings, and processing it into compost to be used as natural fertilizers. Together, almost 94 million tons of MSW are recycled and composted annually, equivalent to 32-percent of the total generated.

CR&R, located in southern California is a waste collection and recycling company, serving more than 3 million people and over 25,000 businesses throughout Orange, Los Angeles, San Bernardino, Imperial, and Riverside counties. Using the latest technologies, CR&R recycles over 500,000 tons of materials each year, creating cleaner communities, reducing air and water pollution, conserving landfill space, and extending our natural resources.

Shaftless screw conveyors are used to convey organic waste and compost to various areas of the process at the CR&R facility. Operating the largest anaerobic digestor in North America, CR&R converts organic waste such as food waste, grass clippings, and other compostable materials into renewable gas and organic fertilizer. The renewable gas is used to power CR&R vehicles, reducing their carbon footprint.

OEM Spirals from Germany Provided No Improvement in Performance

OEM Spirals from Germany Provided No Improvement in Performance

Design Parameters

  1. Product Type: Organic Waste
  2. Material Density: 60 Pounds per Cubic Foot
  3. Capacity: 500 Cubic Feet per Hour
  4. Duty: 24 Hours a Day, 7 Days per Week

KWS Advantages

CR&R uses shaftless screw conveyors to convey organic waste and compost, which can be both abrasive and corrosive. Uptime is very important since the anaerobic digestion process cannot be interrupted. Several of the current shaftless screw conveyors were failing and causing downtime. KWS met with the CR&R maintenance group to better understand their process and as well as pain points. Through this on-site visit, KWS was able to learn more about the process and the shaftless screw failures. CR&R had been buying stainless steel shaftless screws from the OEM in Germany and then welding chromium carbide teeth to the outer edge of flights. The process was extremely time consuming and expensive with no improvement in performance. KWS provided a better solution.

KWS Special Features

KWS-350 shaftless spirals are the hardest, and toughest in the industry. No other manufacturer offers a shaftless spiral with a minimum hardness of 350-BHN except KWS. The KWS-350 shaftless spiral also eliminated the need to weld on chromium carbide teeth. KWS provides a long-lasting, cost-effective solution for the application. Now, CR&R is in the process of retrofitting all shaftless screw conveyors at the facility to KWS-350 shaftless spirals.


"Thanks for solving my shaftless screw conveyor problems. The KWS-350 spiral works very well in our process. We will be buying more from KWS in the future. The payback is less than 6 months!"

Nate Woods, General Manager of Bio Energy – CR&R, Inc.

KWS-350 Shaftless Spirals are Cost-Effective and Long-Lasting

KWS-350 Shaftless Spirals are Cost-Effective and Long-Lasting

Organic Waste

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