Shaftless Screw Conveyor for Miners Ranch Water Treatment Plant Oroville, CA

General Description

Miners Ranch Water Treatment Plant is in Butte County, California near the Miners Ranch Dam that separates Miners Ranch Reservoir from Lake Oroville. Serving approximately 6,700 households, the plant needed to be upgraded to increase capacity and meet stringent drinking water regulations. This was a Progressive Design-Build Project to upgrade and expand the plant. The project improvements expanded treatment capacity from 14 to 21 MGD and included expansion of the solids handling facilities with a new mechanical dewatering process. KWS provided a shaftless screw conveyor to transfer dewatered sludge cake from the centrifuge in the dewatering building to a truck unloading point outside. It is anticipated that the 21 MGD design capacity will satisfy projected water demands for the next 30 years.

Design Parameters

1. Product Type: – Dewatered Sludge
2. Material Density – 55 to 65 Lbs. per Cubic Foot
3. Capacity – 19 Cubic Feet per Hour
4. Duty – 4 Days a Week, 4 Hours per Day

KWS Advantages

Sludge from a water treatment plant typically has a much lower concentration of organics (broken down plant or animal or human waste) than in a wastewater plant but a much higher concentration of abrasives such as river silt, clay, and sediment. KWS Environmental, with our decades of experience in the environmental industry, understands this and helped the engineer design a long lasting system for the project. KWS was involved with the design-build engineer early on with providing valuable CAD drawings for the plant layout and recommendations for the design features.

When there were questions early on about the right set of features for the conveyor controls, KWS provided input to ensure the customer got a simple to operate system. KWS designed the system in 3D Autodesk Inventor, which made it easy for the contractor and engineer to evaluate the PE-stamped seismic support design that KWS provided. A KWS engineer performed the startup and operation/maintenance training for the conveyor. The startup was completed without a hitch, and during that process KWS ensured all electrical connections and process piping went to the right locations when it was unclear on the contract drawings.

Special Features

KWS Environmental designed a shaftless screw conveyor with the KWS 350 spiral made for handling the abrasive, sticky product. The KWS 350 spiral is the hardest and toughest material offered in the industry. The drive for the conveyor was located near the ground at the inlet portion of the system to ensure easy access for maintenance and replacement. The conveyor troughs and covers were made from 316 stainless steel to ensure long life in the face of corrosion.

The design included a drain at the low end of the conveyor to capture the low percentage biosolids produced while the centrifuge is ramping up so it can be put back into the process instead of being conveyed to the truck. KWS provided a small local control panel with emergency stop switch and run switch for forward or reverse operation.