Dewatered Biosolids Load Out System for Fall River WWTF

General Description

Fall River Wastewater Treatment Facility (WWTF) located in Fall River, Massachusetts is an oxygen activated sludge (biosolids) secondary treatment plant with an average monthly permitted capacity of 30.9 millions of gallons per day (mgd). Recent improvements include process upgrades to the thickening, dewatering, biosolids storage and odor control systems of the solids processing facilities.

Two new belt filter presses feed a new KWS load out system, which is designed to feed tractor trailers in three loading bays. The load out system consists of five shafted screw conveyors, three slide gates, structural supports, speed sensors, emergency stop controls and flexible chutes.

Design Parameters

1. Product Type: Dewatered Sludge (Biosolids) Cake
2. Material Density: 65 to 70 Lbs. per Cubic Foot
3. Max Capacity: 200 Cubic Feet per Hour
4. Duty: 24 hours a day, 7 days a week

KWS Advantages

KWS was selected as the screw conveyor supplier based on engineering capabilities, prior project successes and overall equipment quality. The new load out system fit in the limited space allowed by the dewatering building. Working with the Engineer and Contractor, KWS modified the design of the conveyor layout and structural supports until the system met the needs of all parties involved. KWS also quickly assisted the Contractor during the installation phase to make minor adjustments to the structural supports. With any challenge that arose, KWS communicated and coordinated with all parties to ensure that the project was a total success.

KWS Special Features

KWS engineered custom inlet chutes from the two belt filter presses to the receiving screw conveyor to prevent biosolids spillage. Biosolids are then conveyed to a transfer screw conveyor to feed one of three distribution screw conveyors. The system was designed to fill one truck at a time. After a truck is full, the biosolids could be rerouted by simply closing a slide gate and diverting the material to the second or third truck. The distribution screw conveyors also act as a leveling conveyors with no trough bottom along the loading section. The leveling design ensures even loading of biosolids for maximum volume. Screw conveyors are the perfect solution for transferring bulk materials to multiple discharge points.

As part of the project specifications, zero-speed and emergency stop switches were included. Zero-speed switches detect the loss of rotation due to a failure or upset condition. Emergency stop switches stop a conveyor in the event that an unfavorable operating situation is detected. Zero-speed and emergency stop switches both contribute to the safety of plant workers and to protect the conveyor and upstream and downstream equipment from damage.