The TIRE Project involves the partnership of various agencies and organizations to demonstrate the innovative technology of converting biosolids into clean energy through deep-well injection and geothermal biodegradation. The City of Los Angeles contracted the development and construction to GeoEnvironment Technologies and also collaborated with the US Environmental Protection Agency for permits and design approval. The US Department of Energy and the National Science Foundation have also supported the TIRE Project.
The TIRE Project injects slurry mixtures of treated, non-hazardous, municipal sludge and water into a high-permeability, unconsolidated sandstone formation below the Terminal Island Water Reclamation Plant. Multiple injection and monitoring wells extend to depths of about 5,300 ft beneath the surface. Using technology optimized for solid waste slurry injection, biosolids are injected into these formation sands. At this depth, the material undergoes a natural process of high temperature anaerobic biodegradation, similar to the process of digestion that naturally deposited organic layers undergo over time. Retention in the high temperature (114°-159°F, or 45°-70°C) saline environment of the deep geologic formation will treat and convert the biosolids into methane, carbon dioxide, and non-volatile residual solids.
The carbon dioxide will be preferentially dissolved and sequestered in the formation brine, while the goal is for relatively high purity methane to migrate and become trapped, in sufficient quantities, in the reservoir to be recovered for beneficial use at the surface, or stored for subsequent use.
Since the TIRE injection operations began in 2008, geological formation response has been consistent and there has been no impact on public health or the environment. Based on the response both from the public and scientific community, the City continued the TIRE project under a new five-year permit.To date there have been no odor or noise complaints and no unexplained seismic events associated with the operations of TIRE. The TIRE project continues to be recognized as one of the most innovative demonstration projects utilizing this method of biosolids beneficial reuse in the country.
The overall outcomes from the TIRE project have encouraged the City's decision to continue the project. There are now two injection wells and two monitoring wells. The City and GeoEnvironment Technologies are hoping an alternating injection well strategy can be used to maximize the daily injection period and the useful life of the injection wells. Under a new approved EPA UIC permit, the City hopes that by expanding the scope of the current operations, environmental benefits will be maximized and the City will be able to take full advantage or injecting up to 400 tons of biosolids per day.
The City will continue to provide weekly and quarterly reports on the project to the EPA and conduct outreach events to update the interested parties and the public. The City will continue with the TIRE project as an opportunity to demonstrate the environmentally sound and safe placement of biosolids in deep subsurface as a beneficial management option for biosolids that can be replicated world-wide.
At the start of the TIRE Project in 2006, a set of environmental and economic benefits were projected (left column) as a consequence of the project. After 5 years of injection, the benefits (right column) thus far recorded are compared to what was expected.