Several hundred Mililani residents have signed a petition in opposition to the city's proposed modifications to the Mililani Wastewater Preliminary Treatment Facility, said state Rep. Ryan Yamane, D-37th (Mililani, Waipi'o).

About 25 residents attended a meeting Wednesday of the Mililani/Waipi'o/Melemanu Neighborhood Board. Residents expressed concerns about possible odor, increased noise and sewage overflows.

The city has hired Hawaii Pacific Engineers as a consultant for the proposed headworks modifications and flow equalization basin project at the Mililani sewage treatment plant.

The proposed basin would be 260 feet by 160 feet and 12 feet deep, and would allow for the temporary storage of 1.7 million gallons per day of wastewater that cannot now be accommodated by downstream facilities during times of peak flow.

The neighborhood board, which in June 2005 approved a resolution supporting the project, reconsidered its position in January when it learned residents of Makapipipi Street were not notified about the project.

Reach Rod Ohira at rohira@honoluluadvertiser.com.