Wastewater spills declined for the second year in a row, according to the City and County of Honolulu’s Department of Environmental Services (ENV), according to The Hawaii Reporter .
Wastewater spills in calendar year 2008 declined 20.8 percent compared to 2007. Last year, ENV recorded 117 total wastewater spills from gravity mains, lower laterals, pump stations and force mains, compared to 144 in 2007.
“Repairing our collection system infrastructure has been a top priority of my administration,” Mayor Mufi Hannemann said. “There’s no doubt our city’s sewer system is in better shape today than it was four years ago, and we’ll continue to do the work necessary to make more improvements to ensure we leave this place better than we found it.”
For the year, roots, grease, broken pipes, debris and wet weather caused the majority of spills.
ENV conducts a preventive maintenance program implementing various facets to address both roots and grease in the City’s sewer lines.
ENV’s Collection System Maintenance addresses roots by mechanical and chemical approaches, inserting rods with sharp cutters into the ends of affected pipes to cut away intruding roots. After this process is completed, crews shoot a foam poison through the pipes to deter roots from growing for the next six to 12 months. For grease, crews utilize high-pressure Vactor trucks to flush it from sewer lines.
Smoke testing blows non-toxic smoke into sewer lines and records where it appears through broken pipes, illegal connections, open cleanouts and other paths on private properties. These areas allow rainwater inflow and infiltration to enter and overwhelm the sewer system causing spills.
Additionally, ENV’s Regulatory Control Branch of the Environmental Quality Division addresses commercial and residential grease through its FOG (fats, oil, grease) program, which includes inspections, investigation of problem areas, follow-up warnings and enforcement actions, along with outreach and educational programs.
“We are at the halfway point of our 20-year rehabilitation program for our collection system,” ENV Director Tim Steinberger said, “and the results are very encouraging.” Mayor Hannemann encumbered more than $1.1 billion to refurbish the city’s wastewater infrastructure since January 2005 and estimates appropriating another $1.5 billion in the next six years