The Proco ProFlex Style 710 duckbill check valves ensure proper diffusion for the Istanbul maritime wastewater outfall.

The Water Authority of Istanbul serves a population of 15 million people in Istanbul, Turkey. The Water Authority engaged Marine Consultants Group (MCG) in the spring of 2017 to identify a suitable product for their marine wastewater outfall.

MCG collaborated with Proco to design and engineer duckbill diffusers for the treatment plant's outfall sewage line. The pipe runs for 1.35 miles (2230 meters) and drains at 154 feet below sea level.

Proco has various obstacles to consider for this project. Diffusers and duckbill check valves were feared harmed by passing marine boats. Proco required to establish the appropriate diffuser length, which in this case was 741.5 ft at the 1.5-mile runout fall pipe's far end.

To allow for future maximum flow rates, engineers and contractors used to blind flange some ports. Maximum flow was calculated for a 20-year outfall rate. Proco and MCG needed to develop adequately sized check valves to relieve this worry due to the current flow rate not functioning at maximum output.

MCG recommended Proco ProFlex Style 710 duckbill check valves for this project, and each port discharge had two 10-in.

They prevent backflow in deep marine outfall/diffuser projects. During the initial years of operation, Proco ProFlex 710 duckbill check valves saved some ports from blind capping. Using Proco ProFlex 710 duckbill check valves eliminates the need to blind flange ports since the lines can work efficiently from the start, reducing maintenance and diver time to add more valves.

Using duckbill check valves prevented saltwater entry into the line when no inlet pressure was present. Seawater enters the line when the head pressure is low or when there is no inlet flow. If the ports are not blocked, marine life may enter the lines. Derivative dilution ratios will not be obtained. Even at low flow rates, duckbill check valves improve jet velocity and produce a different dilution value than flap gates.

The Proco ProFlex Style 710 duckbill check valves are also 100% barnacle and algae resistant, which is vital for a salt water project. Proco's engineering team also helped with the head loss calculations.

Inflated with air to ensure buoyancy, the completed assembly was hauled into position and permitted to sink to the seabed. This enabled the Proco 710 valves to operate, allowing proper outfall diffusion through all 46 valves. The system has been completely operational for the region, and Proco continues to provide global help and engineering experience on similar systems.