Studio Plastic Beach visited three sites, each contracted by the City and County of Honolulu to manage an aspect of the waste cycle on Oahu.
Hawaiian Earth Products, located in Wahiawa, manages the green waste component of the waste triad. The operation receives yard waste from residences, pallets and green waste from commercial entities, and other green waste from people not serviced by the green waste bin collection. HEP transforms the green waste into compost by grinding and aerating (wind rows) the waste. The end products vary in color (think decorative), consistency (fine to course), and application (decoration, nutritive soil, mulch, etc.). There is some plastic (and other contaminant) content in the product; some of this is due to consumer error (placing the wrong material in the green waste bin), some is due to land-based litter entering the wind rows, some is due to material incorporated in the waste by design (e.g. nails in the pallets). My overall impression is that the facility is clean, quiet, and odor-free. The product is useful, and the operations provides a positive reuse/recycling of yard waste as a beneficial service to both government and residents/commerce. The company benefits from revenue from sale of products.
H-Power, located in Kapolei, manages the waste to energy (W2E) effort. From and energy perspective, this is one source of distributed energy (about 7%) within the Hawaiian Electric Company (HECO) portfolio, which also includes coal, oil, biodiesel, wind, and solar electricity generation. The City and County of Honolulu employs Covanta to manage the W2E plant, which consists of three boilers (two 1990 vintage, one 2012 vintage). H-Power processes about 90% of Oahu’s volume of waste (about 75% by weight). When recycling isn’t economical (e.g. plastic recycling categories 3-7), waste is combusted. The newer system is better able to accept a broad mixture of waste; it employs a mixing system rather than a sorting system to maintain a consistent energy output based on the materials combusted. The metal waste is sorted both before and after combustion to ensure that the material is recycled rather than trapped in a land fill. The operation benefits from revenue from tipping fees (waste collection/disposal; $50M/year), energy sales (electricity to HECO; $70M/year), and metal recycling ($0-5M/year). The energy costs HECO about $.17/kW whereas the coal-burning plant next door provides energy for $.04/kW. The renewable energy (wind, solar) is weather dependent; HECO uses a power purchase agreement to optimize electricity supply/return. The W2E plant can also burn sludge from the water treatment process. Sludge has a low energy content, but requires additional absorptive material when it is placed in a landfill; this is an effort to balance waste management/storage. There are byproducts: fly ash and bottom ash. Fly ash results from the removal and ph. neutralization of particulate matter from the exhaust stacks. Bottom ash is solid material removed from the combustion chamber. 400 tons of ash is removed and stored in the landfill daily. While this figure is high, it should be contrasted with the amount of waste that enters the plant, which would otherwise enter the landfill (84% reduction of waste entering the landfill by weight). W2E is considered ‘renewable energy;’ although the concept of a never-ending supply of waste (at this level of consumerism) doesn’t sit well with me!
Waimanalo Gulch Sanitary Landfill, located mauka Ko’Olina, manages solid waste, both garbage and ash from the W2E effort, using sanitary landfill measures. Waste Management runs the operation in Waimanalo Gulch, a roughly 200-acre facility in a draw within the Waianae Range. A double layer plastic liner (60mm x2) and a Bento Liner (clay) prevent waste from leaching into the soil, and the older portions of the facility have been capped. Water is collected below the waste above the liners and sent to a water treatment plant. The waste that enters the landfill is covered by a 6” layer of soil daily. The operation includes extensive monitoring of ground water and gas byproducts, and there is a system to divert stormwater from the gulch so leachate doesn’t enter the ocean or ground water (contrary to other stormwater management principles, the goal is to move the water off site quickly to prevent infiltration). The facility has two active fills: one for ash and one for garbage. The ash is separated from the garbage to provide monitoring opportunities to prevent unknown contamination. The garbage site will accommodate seven additional years’ material (at current rates); the ash site will accommodate 30 additional years’ material. The landfill on Kauai is managed by the local government, and it is not as efficient or as sanitary. One of the metrics is waste per airspace – density of waste while maintaining sanitary requirements. There are only 10 employees at Waimanalo Gulch, who are augmented by day laborers if there is blowing debris due to high winds or significant garbage quantity.
Overall Impression. I was surprised by how clean and efficient the operations are! I don’t think many residents know what is going on at these locations, and I think they would be surprised to know that their waste is being managed right under their noses. The companies operating the facilities seem very professional and very concerned that they achieve the primary goal of preventing waste from ending up in a landfill! In Hawai’i where stewardship of the land and sea is so rooted in the native culture, it was interesting to see that the primary driving factor for waste management is revenue generation. More surprising to me was the seriousness and professionalism of the companies who are contracted by the local government to complete the task – they seem driven by Capitalism, but in the sense of doing a job well to stay in business, and the individuals we spoke to seem to honestly believe in what they are doing in a professional, environmental, maybe even altruistic sense – they uphold a standard!
Jay moorman 