Dewatered Biosolids Load Out for North Regional Wastewater Treatment Plant in Broward County, FL

General Description

Broward County Water and Wastewater Services plans, designs, and constructs facilities to ensure adequate capacity for potable water, sewer, and storm water, and provides retail water and sewer services for more than 50,000 customers. Water and Wastewater Services is also responsible for pumping, treating, and distributing water, as well as providing for the collection, treatment, reuse, and disposal of wastewater for more than 600,000 residents.

The North Regional Wastewater Treatment Plant (NRWWTP) was established in 1974 and is now a 95 million gallon per day facility that provides a regional wastewater treatment and disposal solution for Broward County’s retail water customers and large users, including the Cities of Coconut Creek, Coral Springs, Deerfield Beach, Lauderhill, North Lauderdale, Oakland Park, Pompano Beach, and Tamarac; North Springs Improvement District, Parkland Utilities, and North Springs Improvement District and Royal Utilities. The NRWWTP effluent ocean outfall nutrient reduction goals continue to exceed those established by the State of Florida in response to the ocean outfall legislation. Legislation passed by the State of Florida, known as the “Ocean Outfall Rule”, eliminates the use of ocean outfalls for effluent disposal after 2025. The legislation also requires a wastewater reclamation program with a capacity of 60 percent of the treatment facility’s baseline flow. In order to meet these demands, it was imperative that the plant undergo facility improvements.

Improvements to the plant included a new biosolids load-out facility. The new system dewaters biosolids via a centrifuge that directly feeds a KWS Environmental load-out system consisting of two shafted screw conveyors, supports, flexible chutes, monitoring instrumentation, and control panels. During the wastewater treatment process, organic solids, called biosolids, are separated out. These biosolids are treated using a special process and transported for disposal.

Design Parameters

1. Product Type: Dewatered Biosolids (Sludge)
2. Material Density: 40 Lbs. per Cubic Foot
3. Capacity: 680 Cubic Feet per Hour
4. Duty: 7 days a week, 24 Hours per Day

KWS Advantages

KWS Environmental was selected to provide a load-out system that required minimal operator involvement. Working very closely with the consulting engineer, contractor, and local operators, KWS designed a system that met the requirements of the process and fit in the very confined space at the plant. The load-out system design went through several iterations before the final design was approved by the contractor and consulting engineer. KWS provided valuable input to the design and accommodated changes to the building layout and mating equipment. Structural supports for the new load-out system were analyzed, approved, and stamped by an engineer certified by the state of Florida. KWS Environmental assisted the contractor during the installation, commissioning, and start-up phases to ensure the system was installed in accordance with the consulting engineer’s design.

KWS Special Features

The new KWS load-out system included two identical shafted ribbon flight screw conveyors, conveyor supports, and control panels for operating the conveyors locally. KWS also incorporated flexible chutes to keep the sludge contained as is loaded into dumpsters. The conveyor and supports were manufactured from 304 stainless steel to prevent corrosion. Custom structural supports were designed to bolt together and required minimal field welding during installation.

To prevent catastrophic damage to the screws, shafts, and other components during an unlikely occurrence of a backup or plug at the discharge chute of the conveyor, the conveyors were fitted with hinged and weighted overflow doors. These doors mounted directly above the discharge chute and were fitted with limit switches to shut down the conveyors and alert operators of a potential problem. To better protect the equipment and operators, the screw conveyors were also fitted with a speed sensor and emergency pull cord safety stop systems.