Air Flow Control Valve for Shippensburg WWTP
Success Story About IRIS Control ValveShippensburg Wastewater Treatment Facilities
Borough of Shippensburg, Pennsylvania
Shippensburg WWTP is a 5.0 MGD facility servicing the Borough of Shippensburg and is the first plant of its kind (in Pennsylvania) to respond to tighter government regulations regarding the discharge levels of ammonia, phosphorous and nitrogen.
The process required precise control of the level of nitrates in the effluent stream based on influent flow and current levels of dissolved oxygen in the system. Furthermore, nitrate re-circulation based on flow needed to be tightly controlled, while also monitoring the dissolved oxygen levels in each tank based on flow and existing DO levels.
In 2017, Egger was 1st contacted by GHD Engineers to help meet these new discharge regulations using Egger’s Iris valve to provide tighter regulation, linear & repeatable air flow control, while reducing energy consumed by the blower system.
The project included eight valves to control the process air feeding the droplegs and diffusers. This project required Qty. four – 6 inch & four 8 inch valves rated to 1,682 and 2,225 scfm at 8.2 psig each. The Iris valve has a turn down ratio of 11 to 1, this allows the air to be accurately controlled from 200 to 2,225 scfm.
Many thanks to GHD Engineers for their thoughtful consideration to supplying the “Best in Class” valve for precise (linear, accurate, & repeatable) air flow control. A secondary benefit, is the reduced pressure drop from a typical 1.0 psig with a Butterfly valve to a 0.15 psig using the Iris control valve. This greatly helps reduce the blower’s energy consumption by approximately 10 percent.
