KWS Manufacturing

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution

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End User or Owner

Maryland Board of Public Works
Anapolis, MD

Contractor

The Belt Group of Companies
Cumberland, MD

Consulting Engineer

Hatch Mott MacDonald
Hunt Valley, MD

Plant Name and Location

Maryland Correctional Institution - Hagerstown WWTP
Hagerstown, MD

General Description of the Application

The Maryland Correctional Institution-Hagerstown has a waste water treatment plant that treats 1.6 million gallons of wastewater per day. The plant had recently undergone a state-mandated plant rehabilitation to improve nitrogen removal from its outgoing treated water. The improvement project included installing denitrification filters, an ultraviolet disinfection system, a plant effluent supply line to the press building, a carbon source for further denitrification, a lime silo, an automated control system, a new belt filter press, rehabilitating the headworks, and upgrading two clarifiers with launder covers.

A new bar screen was installed as part of the headworks rehabilitation for removing objects such as rocks, cans, plastic bags, sticks, rags and leaves. These residuals are taken out of the influent stream and conveyed to a grinder to reduce volume. The ground waste was then directly discharged to dumpsters which had to be manually emptied several times a day. The original design of discharging from the grinder to dumpsters was not successful because the grinder did not have the power to push the waste through the piping. KWS Environmental solved the problem by adding a shafted inclined screw conveyor that receives residuals from the grinder and discharges to the dumpsters located outside the building.

Design Parameters of Application

  1. Product Type: Screenings
  2. Material Density: 50 to 80 Lbs. per Cubic Foot
  3. Capacity: 170 Cubic Feet per Hour
  4. Duty: 7 Days a Week, 24 Hours per Day

Advantages Provided by KWS

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution - KWS Manufacturing

Explosion-Proof Sensor Monitors Conveyor Speed

The consulting engineer contacted KWS Environmental to solve the problem. KWS provided several different solutions and it was agreed that a shafted screw conveyor was the best choice. Shafted screw conveyors have minimal maintenance items and are completely enclosed to eliminate mess or odor. Using 3D CAD modeling, The KWS engineering team provided a simple solution that integrated with the existing equipment. The on-site training and start-up services were performed by two degreed mechanical engineers from KWS. KWS even helped with control panel upgrades after start-up to improve the system operation including adding a timer delay so the new screw conveyor ran for a few minutes after the grinder shut down and a second timer delay, so the conveyor did not fault out due to loss of voltage when the plant switches power sources.

Special Features of KWS Design

For corrosion resistance, KWS Environmental supplied a shafted screw conveyor constructed from 316 stainless steel. The new KWS screw conveyor was very cost-effective and required minimal maintenance. KWS designed the screw conveyor for upset conditions to ensure it would start even when completely loaded with material. KWS included adjustable support legs so the precise height of the conveyor could be set in the field. An explosion-proof sensor monitors conveyor speed. KWS also provided a control panel to run the screw conveyor with features including an emergency stop switch, an under-voltage fault light, a hand/off/auto switch, a conveyor running light, a conveyor fault light, and a conveyor reset button.

Testimonial

"The conveyor is really well built and works great! Thanks for helping solve our conveying problem."

Jared Burkett – Vice President, The Belt Group of Companies

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution - KWS Manufacturing

Discharge of Grinder was Modified to Feed to New KWS Inclined Screw Conveyor

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution - KWS Manufacturing

New KWS Inclined Screw Conveyor Discharges to Dumpsters

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution - KWS Manufacturing

KWS Control Panel Has Many Features for Operating Screw Conveyor

Screenings Loadout Screw Conveyor for Sewage Treatment Plant at the Maryland Correctional Institution - KWS Manufacturing

Screenings are Ground Up by Grinder and Discharged to Dumpsters

Screenings

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