NDWWTP Effluent Outfall Diffuser

Location: Tanguisson Beach, Guam

Owner: Guam Waterworks Authority

Completion Date: June 30, 2021

Healy Tibbitts Builders, Inc. completed the NDWWTP Effluent Outfall Diffuser Project in June of 2021. The project consisted of adding 400 ft of HDPE diffuser pipe to an existing sewer outfall in 140 ft water depth. The purpose of the diffuser is to spread out the sewer effluent so it will more efficiently mix with the saltwater, preventing potential damage to the sensitive coral habitat in the area. The scope of the project included installing an HDPE elbow, 4 each 100 ft long HDPE pipe segments with diffuser ports, 36 each articulated concrete block mats, and installing a landside sewer bypass. The work was performed utilizing a Dynamically Positioned vessel as a work platform. HTBI subcontracted the diving and ROV support to Global Diving.

The project was honored with the 2022 AGC Build America Awards Merit Award in the Best Environmental Enhancement Project category.