Wastewater facility reassessed to accommodate growing West Oahu

AIEA—The recent and continued growth of the population of West Oahu, along with the related boom of business development, has caused water recycling needs to significantly increase. This means more reassessments and changes are being made to the sewer system served by the Honouliuli Wastewater Treatment Plant (WWTP). The City and County of Honolulu recently contracted AECOM Pacific, Inc. to provide engineering planning for a study of the sanitary sewer system operated by WWTP.

Current equipment and technology at the Honouliuli WWTP is no longer suitable for the rapid growth in water and sewage. It is AECOM Pacific’s job study the changes and predict future problems.

AECOM Pacific is one of the world’s largest engineering and architectural design firms specializing in transportation, environmental, and energy facilities.

A study of the sewer system will include areas from Kapolei to Halawa. The purpose of the project is to determine the improvements necessary to provide sufficient transportation and treatment systems to decrease sanitary sewer overflows. More importantly, the system must follow the terms between the City and County and the Environmental Protection Agency (EPA) to fulfill future sanitary sewer needs.

Many of the alternative options that are being discussed between AECOM and the City and County include increased capacity and additional gravity sewers as well as larger storage tanks at the Halawa, Waimalu and Pearl City pump stations. Other options being considered are a modification or an upgrade of the Honouliuli WWTP and/or the relocation of the Pearl City or Waipahu pump station. 

The summary of work performed with findings and recommendations will be provided in the form of a Preliminary Engineering Report (PER) that will be the basis for future Capital Improvement Program work, according to Linda Rosehill of Rosehill and Associates. There are many other assessments and reports that AECOM will perform and prepare to be submitted to the City and County to ensure that a full study is made to better the sewer system.

The study phase of the complete project has been estimated to take two years and completed by the end of 2011. After the study phase is completed further steps can be taken to start the process of taking action to better the system.