Oahu recycling rates are above the national average and Honolulu ranks among the top cities in the country in landfill diversion. By employing both recycling and waste-to-energy, most of Oahu's Municipal Solid Waste (MSW) is being diverted from Waimanalo Gulch Sanitary Landfill (WGSL). Increases in recycling and waste-to-energy will further reduce what goes to landfill in the coming years.
In 2015, more than 78% of Oahu's MSW was diverted from the WGSL. Of the roughly 22% of material being landfilled at WGSL, 17% is ash/residue from H-POWER and only about 5% is unprocessed MSW.
By 2017, the City anticipates that little more than ash residue will be disposed in the Waimanalo Gulch Sanitary Landfill. Of the 20% going to landfill, only about 4% will represent MSW that could neither be recycled nor processed through waste-to-energy. Recycling rates are expected to rebound with an improved recyclable commodities market along with greater levels of awareness and public participation, and the amount of waste processed through H-POWER is expected to continue its steady rise.
Looking further ahead -- The biggest gains in reducing the amount of waste going to landfill are expected to occur through expansions in technology and capacity at the City's H-POWER waste-to-energy operations. Expansions to H-POWER in 2012 increased the plant’s capacity by an additional 300,000 tons per year. A new sewage sludge receiving station went into operation in May, 2015 that diverted an additional 20,000 tons of sewage sludge and 20,000 tons of bulky waste that had been used to "bulk" the sewage sludge in the landfill. from the landfill. All medical waste, except for sharps, is now processed through H-POWER. The City is working to redirect additional wastes from landfill to H-POWER, including Auto Shredder Residue (ASR) (25,000 tons) and special wastes such as bar screenings from the sewage treatment plants and sludges from rendering plants. Within five years, the City hopes to have plans for reutilizing the ash as well. (H-POWER video and Powerpoint).
How we manage our island’s waste will affect generations to come. The ultimate goal is to minimize the use of landfills to the absolute smallest practical level. Currently on Oahu, both recycling and waste-to-energy divert a majority of the waste from the landfills. Recycling remanufactures waste products into new products. On Oahu, our waste-to-energy facility (H-POWER) enables us to convert garbage into energy, which contributes to our island's energy sustainability. In order to further increase landfill diversion, we must consider how best to utilize our garbage as a resource - to remanufacture new products or generate additional power.
Each Hawaii county is required to submit an integrated solid waste management plan to the State Department of Health every 10 years, and to provide an interim status update report on the implementation of that plan five years after it is submitted. The City and County of Honolulu’s most recent plan was submitted in December 2008, and the interim report on implementation was submitted in December 2013. The next revised plan will be submitted in 2018. The City's 2008 solid waste management plan, the 2013 interim report and the technical studies that contributed to the development of the plan, are posted online in the Resource Library, along with previous master plan documents and studies and annual recycling rate data for 1988 to present.