Submerged Grit Screws and Ceramic-Lined Shaftless Screw Conveyor Pawling, NY WWTP

General Description

The town of Pawling is in Dutchess County, NY with the wastewater treatment plant permitted for 320,000 gallons per day (GPD). On a project over ten years in the making, the town required a new Sequencing Batch Reactor (SBR) wastewater treatment system, a new headworks building and equipment, and many more new facilities and processes. Headworks are located at the beginning of the process to remove large inorganics from influent flow to prevent damage to pumps and other equipment downstream.

The new headworks building required a new grit removal system with two aerated grit chambers and a screenings loadout screw conveyor. At the bottom of aerated grit chambers, heavier grit in the wastewater flow settles to the bottom and is conveyed to a grit pump via a shafted screw conveyor. KWS Environmental provided the aerated grit screws and the screenings loadout screw conveyor.

Design Parameters

1. Product Type: Grit and Screenings
2. Material Density: 100 to 120 Lbs. per Cubic Foot
3. Capacity: 50 Cubic Feet per Hour
4. Duty: 7 days a week, 24 Hours per Day

KWS Advantages

KWS supported the consulting engineer years before equipment was installed at the site. A professionally licensed KWS engineer specified many of the maintenance-friendly features of the screw conveyor design. KWS aided the consulting engineer in preparing the bid documents and drawings, saving the end user time and money. As a result of upfront efforts and competitive pricing, KWS was an easy choice for the winning contractor. The KWS design was submitted and approved with little modification. A KWS engineer traveled to site to conduct installation verification and startup of the conveyor system, and even helped with issues with an upstream control panel that KWS didn’t even provide. KWS is dedicated to full customer service.

Special Features

The new KWS grit screws operate in a submerged environment in grit tanks approximately 5-feet deep. The drive units are located above ground level with chain drives, simplifying maintenance and access. The chain drive is adjustable vertically for proper tension. The shafted grit screws utilize abrasion-resistant steel flights to provide a lasting solution against the coarse grit material.

The KWS shaftless screenings conveyor troughs and covers were constructed from 304 stainless steel for corrosion resistance. The shaftless spiral was KWS-350 micro-alloy and is the strongest and most long-lasting spiral available on the market. The troughs were lined with ½-inch thick ceramic tiles, ensuring an extremely long maintenance life while handling the abrasive screenings. The electrical components were designed to be explosion-proof, typical of a headworks area.