KWS Manufacturing

KWS Solves Chemical Transfer Needs for Waste Management

General Description

Waste Management is a provider of comprehensive environmental services headquartered in Houston Texas. The company’s network includes 346 transfer stations, 293 active landfills, 146 recycling plants, 111 beneficial landfill gas projects and six independent power production plants. Waste Management also specializes in the safe disposal of hazardous industrial waste. Their extensive network of facilities and state of the art technologies help to meet or exceed local, state, and federal regulations.

At one of the many Waste Management facilities, petroleum tank bottom sludge is chemically and thermally processed to create an inert product that can be landfilled. The sludge was loaded into an existing hopper with screw feeder that fed a thermal processor. The current system had continual problems with insufficient hopper volume and screw feeder plugging. When an urgent need for a very complex conveyor project arose, Waste Management quickly teamed with Motion Industries and KWS.

Individual Drive Units Provide System Redundancy

Individual Drive Units Provide System Redundancy

Design Parameters

  1. Product Type: Petroleum Sludge Mixed with Lime
  2. Material Density: 60 Lbs. per Cubic Foot
  3. Capacity: 167 Cubic Feet per Hour
  4. Duty: 12 Hours per Day, 7 Days per Week

KWS Advantages

Highly technical KWS field engineers surveyed the current application and gathered customer input to optimize system design. Having personnel in the field to discuss and determine specifications allowed for clear communication and guaranteed that the replacement unit fit and performed without issue. Detailed dimensions were recorded for a large custom hopper. The original hopper was supported on six small pedestals that matched integrated hopper legs, making the dimensions of the replacement hopper critical. Using laser and string-line procedures, exact measurements and support locations were obtained. These details were documented and the KWS team of degreed engineers created a 3D parametric model of the design along with approval drawings.

Petroleum Tank Bottom Sludge is Loaded in Hopper by Front End Loader

Petroleum Tank Bottom Sludge is Loaded in Hopper by Front End Loader

KWS Special Features

KWS provided a new loading hopper with twin-screw feeder to transfer petroleum tank bottom sludge from storage to thermal processing. KWS designed the hopper to accept a larger volume than the front-end loader could deliver, improving efficiency. The twin-screw feeder design with special ribbon flights eliminated the plugging problems of the previous design.

The hopper and twin-screw feeder weighed over 9,000 pounds and required structural supports that integrated with load cells to remotely monitor the amount of material in the hopper. KWS used heavy duty I-beam construction to fully support the hopper and integrate accurately with the load cells.

KWS also planned for the unexpected. Heavy-duty grizzly bars were placed at the opening of the hopper to prevent large debris from entering and damaging downstream equipment. Recognizing the importance of proper shaft sealing on the twin-screw feeder, interior excluder rings were added to compliment the exterior seals. The excluder rings provide a secondary shaft seal to prevent any leaking related to the heavy load of material in the hopper. Each screw was driven separately by high-torque drive units. Individual drives allow for system redundancy. Feed rate was controlled by variable speed controllers for maximum variability.


"The new KWS twin screw feeder and hopper is working just as designed. Getting it right from the start makes this a success. We are looking forward to the next project."

David Michaelis, Sr. District Manager – Waste Management

Structural Supports Integrate with Load Cells for Accurate Loading

Structural Supports Integrate with Load Cells for Accurate Loading

Twin Ribbon Screws Eliminated Plugging Problems

Twin Ribbon Screws Eliminated Plugging Problems

Petroleum Sludge

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