Wow. Since Americans discard 250 million tires a year this plant seemed like an ideal solution for a growing problem. A good example of resource conservation, the facility also utilized its by-products. Gypsum, for example, was sold to make wallboard, while the zinc and iron from the ash were used for pigments, animal feed, and concrete. Specialized filters removed the pollutants like sulfur dioxide and dust particles from the plant's emissions.
Unfortunately, it turns out that this project is no longer operational. Since 1988, a power plant had converted the tires into energy. Specially designed boilers burned 6 million tires a year (saving about 30 million cubic feet of landfill space annually). The tires - incinerated at 2500°F to ensure a clean burn - ultimately fueled a steam turbine/generator, which provided enough electricity for 18,000 homes.
The owner, United American Energy, had acquired the plant from its previous owner in 1993 when it declared bankruptcy. By reducing costs and finding markets for the by-products, Modesto Energy Limited Partnership (a subsidiary of UAE) was able to successfully operate the site while meeting California's strict environmental standards.
So why has it shut down? A neighboring - and unpermitted - tire dump caught fire, and forced the closure of the MELP site. Despite that fact, MELP assisted in the clean-up efforts, burning tires from the neighboring site as well as collecting, testing, and treating the water used to extinguish the fire. There is also one other environmentally-friendly action the company has taken: MELP helped initiate California state legislation to crack down on illegal tire dumps.
Although the tire-to-energy project is now defunct, the parent company UAE currently manages several other waste-to energy assets (in addition to hydroelectric, cogeneration, and coal operation). One such project is the Wadham Biomass Facility just north of Sacramento, CA, where the company incinerates rice hulls. The rice chaff, which decomposes too slowly to be returned to the rice fields, was formerly burned in the fields, causing alarming air pollution. The biomass plant now incinerates 200,000 tons of chaff per year, generating enough electricity to cleanly power 34,000 homes. The main by-product, silica, is also used. According to UAE, "Wadham sells its silica to the steel industry as an insulating material and to environmental remediation companies as an ingredient in a patented environmental process for treating metals-tainted soil and similar waste streams. Ground rice hull silica, when mixed with Portland cement, aids in the production of special high-strength, low-permeability concrete. Unsold silica is donated to farmers to help break up heavy clay soils."
Go To Page: 1 2
| Here's the follow-up discussion on this article: | View all related messages |
For a complete listing of article comments, questions, and other discussions related to Erica Myers-Russo's Conservation topic, please visit the Discussions page.