Wastewater Ocean Outfall

The City of Rehoboth Beach was required, under the terms of a consent order from the Dept. of Natural Resources, to eliminate the discharge of treated effluent from the Rehoboth Beach Wastewater Treatment Plant into the Lewes-Rehoboth Canal. The city, after detailed studies and the evaluation of all options, constructed an ocean outfall to comply with that order.

This project consists of a new pump station and a 24-inch force main/pipe which are required to convey the treated effluent to the ocean outfall and to provide the head required to pump the effluent through diffusers located 6,000 feet offshore in water approximately 40 feet deep. Vertical turbine effluent pumps will be installed in the existing post-aeration tank. The force main will be aligned along the plant access road and end at the public access parking area at the beach near Henlopen Avenue.

The pipeline from the Rehoboth Beach Wastewater Treatment Plant to the ocean outfall was sized to handle the summer peak flow. As part of the overall project analysis, a detailed alignment study was completed to determine the best routing of the force main considering such issues as cost, environmental issues, permitting, potential interferences, traffic control, and public concerns. The preferred alignment was selected based on the recommendations of the Rehoboth Beach Wastewater Treatment Plant Effluent Force Main Alignment Study.

Project Update

Drone video of the ocean outfall HDD Pipe towed from Lewes to Rehoboth.

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On August 14, 2017, the Rehoboth Beach Commissioners unanimously approved awarding four bid packages to various contractors to begin construction on the ocean outfall project. The project consists of a new pump station and 24-inch force main, which are required to convey the treated effluent to the ocean outfall and to provide the head required to pump the effluent through diffusers located 6,000 feet offshore in water approximately 40 feet deep. The bids totaled $37,381,407. The ocean outfall bid was awarded to Manson Construction of Seattle, Washington, for $27,655,850. Allan Myers Construction of Worcester, Pennsylvania, was awarded the effluent pumping station bid for $1,768,555, and the wastewater treatment plant upgrades for $2,256,555. A-Del Construction of Newark, Delaware, won the force main bid for $5,700,447. Contractors were pre-qualified by GHD, the engineering company for the project. Steps taken to pre-qualify were assessing each contractor's project completion record, reviewing their performance on similar projects, safety record, insurance coverage and other factors. Mobilization of equipment will tentatively begin October 1, 2017, and work is to be completed by April 30, 2018.

On August 7, 2017, the Rehoboth Beach Commissioners unanimously approved a renewed and expanded Agreement for Wastewater & Biosolids Services with Sussex County. Sussex County Council unanimously approved the

Agreement for Wastewater & Biosolids Services.pdf

at their meeting on August 8, 2017. Under the new agreement, the county will continue to pay the city to treat wastewater from surrounding areas of the county's sewer system. The county will be responsible for hauling via truck the city's biosolids to a new treatment plant at the county's Inland Bays facility. Fees will be determined once the new facility is operational, and the city will not have to contribute to operating costs until that time. Sussex County's contribution toward the $52.5 million outfall project will be based on utilization of services.

Announcement of Rehoboth Beach issuance of outfall permitting

On May 25, 2017, Delaware Department of Natural Resources and Environmental Control (DNREC) Secretary Shawn M. Garvin approved and signed the Secretary’s Order for the Rehoboth Beach ocean outfall which includes all required DNREC permits to move forward with construction. The U.S. Army Corps of Engineers will be issuing a permit along with a Sediment and Stormwater Permit from the Sussex Conservation District, and DelDOT permits for work on state road right-of-ways.

The approved pipeline alignment begins at the existing Rehoboth Beach Wastewater Treatment Plant, follows the Lewes and Rehoboth Canal north to Grove Park. The pipeline will then turn northeast to Henlopen Avenue and continue along Henlopen Avenue to the Deauville Beach parking area and terminate in the Atlantic Ocean, approximately 6,000 feet from the parking area. The 24-inch high-density polyethylene (HDPE) pipeline will be installed via horizontal direction drill approximately 3,000 feet and marine open-cut trench approximately 3,000 feet. Once the pipe is anchored in place with concrete collars, the open-cut trench will be backfilled. The terminus of the outfall pipe will consist of a 120 linear foot diffuser comprised of eight risers, 1.5 feet above the ocean floor, with four discharge ports per riser. The diffuser will be installed on pilings to ensure stability. Mobilization of equipment will tentatively begin October 1, 2017, and work is to be completed by April 30, 2018.

The Secretary's Order can be viewed at http://www.dnrec.delaware.gov/Info/Pages/SecOrders_Permits.aspx