Wastewater Outfall Pipeline Installation Requires Pumps And Secondary Containment In Environmentally Sensitive Puget Sound

A large paper products manufacturing company located in Everett, Washington was having a new 63" HDPE wastewater outfall pipeline installed on the floor of the Puget Sound, which required some unique installation techniques and solutions.

A national construction/diving company contacted Rain for Rent to help with a critical portion of the install. A 2800-foot section of the pipeline was to be anchored to the Sound floor. The pipeline would be set on an underwater trestle and had to be lowered slowly into position to ensure accuracy. The 2800 feet of pipe was built in 700 foot sections at a nearby lumber processing yard. The sections were then floated in a canal next to the yard and then towed by tug boat to the installation area.

Rain for Rent, Arlington office worked with the diving company to design a pump station that would supply water at a metered rate to slowly sink the pipeline to the mounting position where it would be attached to the underwater trestle by the diving company. An air release system would be used to modulate the descending rate.

The Rain for Rent team positioned the pumping station on a barge which would be towed to the offshore location where the pipeline was to be installed. The pump station consisted of two 6" DV-150 and one 8" DV-200 Power Prime™ pumps and a Spillguard to keep any possible contaminants from reaching the environmentally-sensitive Sound waters. Rain for Rent hose bridges were also used to secure the containment walls.

Each pump’s 40 foot of suction was lowered to 4 feet below the water line. A Micrometer flow meter was used to measure the rate and flow of water being pumped to the line.

The pumping station performed as expected and provided a timely solution to a unique pipeline installation