With a growing population and increasingly stringent effluent limits, the City of Worthing faced the need for additional wastewater treatment capacity. Due to land constraints, the solution was the addition of a Submerged Attached Growth Reactor (SAGR) system.
The SAGR system consists of two below-grade treatment cells, each measuring 60 feet by 125 feet with a depth of 8.5 feet. The cells were constructed using sacrificial wood formwork, lined with HDPE, filled with well-graded clean rock, and topped with wood mulch. Wastewater enters the SAGR through four influent chambers and exits via a single longitudinal effluent chamber. A network of aeration piping is installed at the bottom of each cell to support the treatment process.
To feed the SAGR system, a new lift station and control building were constructed. The lift station includes two submersible pumps that draw wastewater from the existing lagoon. The adjacent control building houses the electrical controls and two automatic wastewater samplers, which collect both pre- and post-treatment samples.
Aeration for the SAGR is provided by a precast blower building, which contains two 30-horsepower blowers. These blowers are controlled through a dedicated panel located within the building.
After treatment in the SAGR, the effluent flows through a UV disinfection channel. This premanufactured UV system is housed in a below-grade concrete structure and operates seasonally, running for five months out of the year and bypassed during the winter.
Stockwell was responsible for identifying space within the existing wastewater treatment facility for the new SAGR system, control building, and blower building. To accommodate the necessary footprint, a portion of an existing lagoon cell was regraded. The full scope of the project included design and construction management for grading, SAGR system installation, precast and wood-frame buildings, below-grade concrete structures, the lift station, and associated underground piping.
