KWS Manufacturing

Dewatered Biosolids Conveyor System Cedar Creek WPCP, Nassau Co., NY

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Nassau County Department of Public Works
Nassau, NY

Consulting Engineer

CDM Smith
Woodbury, NY


R.J. Industries, Inc.
Plainview, NY

Plant Name and Location

Cedar Creek WPCP
Wantagh, NY

General Description

The county of Nassau, NY coordinates municipal services for many of the suburbs on Long Island. The county decided to upgrade existing facilities to be more energy efficient. The Cedar Creek Water Pollution Control Plant (WPCP) is one of the three plants in Nassau County managed by Suez, a multinational utility service company. The plant is rated for 72 MGD and needed service and upgrades do to age and increased demand. Events like super storm Sandy punished municipal plants along the east coast as well.

Upgrades to the Cedar Creek Water Pollution Control Plant included the demolition of three belt filter presses and installation of two new centrifuges and screw conveyors. The centrifuges dewater primary and secondary sludge which has undergone digestion. During dewatering the sludge is treated with cationic emulsion polymer, which reacts with the sludge causing the sludge particles to coagulate. Each of two screw conveyors convey dewatered biosolids cake directly from the centrifuges and discharge to an existing distribution conveyor which takes the sludge to a loadout system.

Design Parameters

  1. Product Type: Dewatered Biosolids
  2. Material Density: 50 to 60 Lbs. per Cubic Foot
  3. Capacity: 380 Cubic Feet
  4. Duty: 5 Days a Week, 8 Hours per Day
Dewatered Biosolids Conveyor System for Cedar Creek WPCP, Nassau Co., NY - KWS

Special Inlet Chutes and Centrate Drains with Flushing Ports

KWS Advantages

KWS Environmental was chosen for the project because Nassau County wanted a high-quality partner with engineering capabilities to work out a few unknowns in the initial design. The centrifuge discharge height was needed to be as low as possible. The KWS design team provided a cost-effective and simple layout with the screw conveyors designed for current and future capacity requirements. A licensed professional engineer from KWS Environmental visited the site to finalize the design and confirm measurements. The Engineer and Contractor were so impressed with the capabilities of KWS that additional work was added to the scope of supply.

KWS is the only ISO-9001 2015 certified screw conveyor manufacturer in North America and produces the highest quality products. After the new screw conveyors were delivered to the site, a licensed professional engineer from KWS Environmental conducted equipment start-up and training. While on site, the engineer was able to quickly troubleshoot incorrect wiring in the control system. The site services were a success, requiring only a few minor punch-list items to resolve.

Special Features

KWS Environmental designed, manufactured and delivered two shaftless screw conveyors to meet the needs of the process. The two conveyors are identical in design, which eases maintenance due to commonality of parts. Both shaftless screw conveyors utilize KWS single-piece drive shafts. The drive shafts are machined from solid bar stock, which KWS guarantees for the lifespan of the equipment due to its incredibly high torsional strength. KWS designed the custom supporting structure to be bolt-together and required no welding or field modification.

To better protect our Customers from rotating machinery, each shaftless screw conveyor has under-speed sensors, emergency pull cord safety stop systems and fixed covers secured with safety bolts requiring a special tool to remove. The conveyor inlets and discharges were designed with flexibility of installation in mind to fit the existing equipment without the need to modify or field-fabricate a transition. The motors are energy efficient and integral to the gear reducers. KWS also provided control panels for both conveyors for local control.


"I am really impressed by not only the quality of the conveyors, but the quality of the service KWS provided."

Tony Etersque – Site Superintendent, R.J. Industries

Dewatered Biosolids Conveyor System for Cedar Creek WPCP, Nassau Co., NY - KWS

New Andritz Centrifuges Discharge Dewatered Sludge to the New KWS Shaftless Screw Conveyors

Dewatered Biosolids Conveyor System for Cedar Creek WPCP, Nassau Co., NY - KWS

New KWS Inclined Shaftless Screw Conveyor Discharges to Existing Screw Conveyor

Dewatered Biosolids Conveyor System for Cedar Creek WPCP, Nassau Co., NY - KWS

Under-Speed Sensors and Emergency Pull Cord Safety Stop Systems Provide Protection for the Operators

Dewatered Biosolids Conveyor System for Cedar Creek WPCP, Nassau Co., NY - KWS

New KWS Screw Conveyors can be Controlled by Local Control Panel

Biosolids / Sludge

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