Proper diffusion is enabled by Proco ProFlex Style 710 duckbill check valves. from uwnmspqr5's blog

The Water Authority of Istanbul serves a population of around 15 million people with a biological wastewater treatment plant. To meet strict environmental regulations, the Water Authority hired Marine Consultants Group (MCG) in April 2017 to help find a suitable product for their marine wastewater outfall.

Duckbill diffusers designed by MCG and Proco convey effluent from the treatment plant via an 87-inch-diameter steel pipe. The pipe is 1.35 miles (2230 meters) long and ends 154 feet below sea level.

Proco had several concerns about this project. Passing maritime vessels could damage diffusers and duckbill check valves. Proco had to calculate the optimal diffuser length, which in this case was 741.5 feet at the far end of the 1.5-mile runout fall pipe.

To make ports functional at lower flow rates while keeping them open for future maximum flow rates, engineers and contractors used tothem. The maximum flow rate was set to meet the 20-year outfall rate criteria. Because the current flow rate is below capacity, Proco and MCG had to build large check valves to mitigate the risk.

MCG recommended Proco ProFlex Style 710 duckbill check valves for this project, and each port discharge had two 10-inch (250 mm) duckbill check valves.

Duckbill valves prevent backflow in deep marine outfall/diffuser operations. Initially, the Proco ProFlex 710 duckbill check valves saved multiple ports from blind capping. Using Proco ProFlex 710 duckbill check valves eliminates the need to Blind Flange ports, reducing future maintenance and diver time.

Duckbill check valves were used to prevent saltwater intrusion into the line when no inlet pressure was present. When the head pressure between saltwater and discharge water is low or there is no intake flow, seawater enters the line. Ports may get blocked or plugged if the reverse flow is not prevented. Derivative dilution ratios are not reached. Conversely, duckbill check valves have a higher dilution value than typical flap gates even at moderate flow rates.

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

It was then dragged to a designated area and allowed to sink to the seabed. This enabled the Proco 710 valves to be opened and the necessary outfall diffusion to occur. The system has been fully operational throughout the region, and Proco continues to assist with comparable systems globally.