Los Angeles Breaks New Ground with Deep-Well Biosolids Injection Project

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Water Environment & Tec hnology Terralog Technologies

Los Angeles breaks new ground with One Mile deep-well biosolids injection project Ben Attai, Omar Moghaddam, Mike Bruno, and Jean Young Undereeking an alternative to land application, the City of Los Angeles is evaluating the viability of injecting biosolids deep into the ground, the first project of its kind in the United States. Surmounting regulatory and environmental issues, public skepticism, and doubts from Ssome of the city’s own management, the city secured permits for a 5-year demonstration project at the Terminal Island Treatment Plant. Construction began in June 2007, and operation is expected to commence in May. If this project proves successful, other wastewater agencies will have an alternative way to manage their biosolids. Layout Confirmation Only Workers drill a well at the Terminal Island Plant.

© 2008 Water Environment & Technology All rights reserved Layout Confirmation Only Project Drivers the high temperature and pressure that naturally Each year, Southern California wastewater exist beneath Earth’s surface, developed and pat- treatment plants generate more than 907,000 Mg ented by Terralog Technologies USA Inc. (Arcadia, (1 million ton) of municipal biosolids from waste- Calif.). In 1999 Terralog proposed deep-well injec- water treatment, one-third of which comes from tion to the Bureau of Sanitation. The Los Angeles the City of Los Angeles’ Hyperion and Terminal Board of Public Works approved the proposal, Island treatment plants. The volume of biosolids and the city started negotiating with Terralog for a and the costs of land application are steadily contract to drill wells and inject biosolids slurry at increasing. At the same time, regulations are one of its wastewater treatment plants in the San becoming more restrictive. Pedro area. The city currently manages four wastewater treatment and reclamation plants, which pro- How It Works duce about 608 wet Mg (670 wet ton) of biosolids While underground injection of biosolids is per day. About 90% of this residual material is a relatively new concept, underground place- trucked to Kern County in central California, ment of petroleum waste has been practiced where the city’s Bureau of Sanitation owns and in the United States for more than 20 years. For operates a land application farm. At this farm, instance, the Wilmington Oil Field in Los Angeles biosolids from two plants are mixed with the County (adjacent to the proposed biosolids injec- soil, and crops are grown for feedstock. Because tion site) has injected more than 350 million bar- of local opposition to this practice and desire for rels of petroleum waste to date. The mechanics more diversification, the city has been looking in- and operating conditions for biosolids injection to alternative biosolids management solutions. are very similar to those of petroleum waste Significant environmental and economic ad- injection, and indeed, we benefit from the petro- vantages can be achieved through subsurface leum industry’s vast experience. biodegradation of biosolids, an innovative way of The Los Angeles demonstration project calls converting biosolids to renewable energy by using for three injection wells and extensive monitor-

Figure 1. Aerial View of Terminal Island Renewable Energy Site (TIRE)

march 2008 3 Layout Confirmation Only Figure 2. Biosolids Processing Summary

ing and parallel laboratory research to better combination of biosolids, digested solids, waste quantify biodegradation rates, long-term carbon activated sludge, brine from the reverse osmosis sequestration, and optimum injection parameters plant, or tertiary effluent. The process therefore for enhanced methane generation. The demon- can utilize a variety of injectates, eliminating the stration project will be located at the Terminal need for disposal of the effluent and brine at sea. Island Treatment Plant, on the flank of the vast At the beginning of each day, clean water will Wilmington Oil Field (see Figure 1, p. 46). be pumped into the sand formation. Pressure will With appropriate geological formation selection, increase until the soft sand parts and deforms. Solid well design, and monitoring, biosolids slurry can be material then will be blended into the flowing liquid injected at parting pressure into soft, porous, sand stream and travel down the well into the formation. formations at depths far below the surface. For The slurry material travels down the steel casing of the Los Angeles project, geological properties are the well that runs through several layers of shale excellent for injection. There are multiple sand and and brine-filled sand and exits through perforations shale layers beneath the Terminal Island Treatment in the target interval. At the end of the day, the solid Plant site, as predicted from the nearby geology material stream will be cut back, and only clean of the Wilmington Oil Field. Injection will start in water will continue to flow to flush the wellbore of the bottom layer of sand (see Figure 2, above) and solids. Then pumping will stop, the high-porosity move up as the sand formation becomes full. The formation will close in on the solids, and fluid pres- first layer of sand is 17 m (56 ft) thick. Above the sure will bleed off and return to natural conditions sand is a 26-m-thick (85-ft-thick) shale bed, which (see Figure 3, p. 48). The next day, the process will will act as a cap rock for the underlying injection be repeated. interval. Multiple capping shale beds, including At the target interval depth, the injected bio- one 34 m (110 ft) thick, are found above the first solids undergo high-temperature anaerobic bio- injection level. degradation, similar to the process of diagenesis When the project is complete, up to 363 Mg that naturally deposited organic layers undergo (400 ton) of biosolids slurry will be injected over a over time after deposition and burial. Retention in 10- to 12-hour period each day about 1.6 km (1 mi) the high-temperature (50oC) saline environment of underground. The slurry will be created with any the deep geologic formation will treat and convert

(a) Fracture during fluid injection (b) Fracture during fluid and slurry injection (c) Fracture closure after fluid leak-off

the biosolids into methane, carbon dioxide, and • reduction or elimination of saltwater brine nonvolatile residual solids. The carbon dioxide disposal from the plant into harbor waters; will be preferentially dissolved and sequestered • local treatment and management of bio- in the formation brine, while relatively high-purity solids, which avoids political opposition methane will migrate and become trapped in the from other communities that might receive updip reservoir to be recovered for beneficial use biosolids; and at the surface or stored for subsequent use. • reduced traffic, vehicle emissions, and odor Monitoring and sampling of fluids will occur by elimination of long-distance trucking. at the injection well and at two offset monitoring wells. Samples will be analyzed to evaluate bio- Project Oversight degradation, gas generation, and carbon dioxide This project has undergone extensive technical solubility and sequestration. reviews and oversight by the U.S. Environmental Protection Agency (EPA). After extensive study Environmental Benefits of the area geology and consideration of environ- Groundwater resources will not be affected in mental safeguards, EPA Region 9 issued the permit any way by this project, as the slurried biosolids in late 2006. EPA required two monitoring wells are placed at a depth greater than 1524 m (5000 beside the injection well. Prior to the injection ft), which is more than 762 m (2500 ft) below operation, core samples and baseline fluid samples any usable source of groundwater. The slurry is will be taken. During the operation phase, the isolated by many impermeable layers of clay and monitoring program requires monthly collection shale above the injection level. The steel tubing of fluid samples and analysis for gas constituents. of the well is located within another large-diam- A continuous temperature and pressure monitor- eter steel casing, which is cemented along its ing system will be in place to identify any poten- entire length into a drilled wellbore. In general, tial problems that can then be corrected before safe operation of the project is ensured by the injection resumes. Additionally, microseismic and heavy-duty well casing design and installation, tiltmeter tools will be installed to characterize ideal geologic conditions, and a supersensitive, fracture dimensions and orientation. state-of-the-art monitoring program. The project also has been presented to the Environmental benefits of the project are sum- California Division of Oil, Gas, and Geothermal marized in Figure 4 (p. 49). They include Resources; the State Land Commission; the • enhanced thermal treatment and pasteuriza- Society of Petroleum Engineers (Richardson, tion of biosolids in a natural environment; Texas); the U.S. Department of Energy; Argonne • cost-effective conversion of biosolids to National Laboratory (Argonne, Ill.); petroleum clean, renewable energy; and slurry injection specialists THUMS (Long • use of generated methane to produce green Beach, Calif.); and the U.S. Geological Survey. power; During the concept and approval phases, both • reduced greenhouse gas emissions by per- environmental groups and local stakeholders have manent sequestration of carbon dioxide in scrutinized many aspects of the project. The city’s the formation brine; Community Oversight Committee has routinely

M a r ch 2 0 0 8 5 Layout Confirmation Only Figure 4. Environmental Benefits of Deep-Well Injection

tracked the project. The committee consists of rep- water treatment agencies aggressively study and resentatives from the Office of the Mayor, Council evaluate alternative biosolids management options. District 15, four neighborhood councils, Port Both regulatory and wastewater agencies can learn Citizens’ Advisory Committee, Heal the Bay, and from the merits of this project in the areas of opera- the Santa Monica Bay Restoration Commission. tional viability, geomechanical technology, econom- Technical advisors to the project and the com- ics, and production of renewable energy. mittee consist of eight agencies, including the Los Since deep-well injection has a long track re- Angeles Harbor Department and two universities. cord in water desalinization projects and in the oil and gas industries, we believe that this project Progress to Date has promise. The City of Los Angeles can further The first two wells were drilled successfully in evaluate the applicability of this technology to June and July 2007, and monitoring instrumenta- biosolids and provide a field demonstration of tion has been placed. At press time, the third well its feasibility. was scheduled to be drilled in July 2008. The next phase of the project will be the startup Ben Attai is project manager, and Omar of biosolids injection. For the first 2 to 3 months, Moghaddam is division manager with the City of slurry injectivity and formation evaluation will Los Angeles Bureau of Sanitation. Mike Bruno is be performed. Short-term injection tests and president, and Jean Young is project manager at multiple episodic slurry injection tests at low to Terralog Technologies USA Inc. (Arcadia, Calif.). high concentrations will be performed. A step rate The authors would like to thank the following indi- test will be conducted to evaluate in situ stress. viduals who provided their valuable assistance in this Temperature and tracer surveys will be run to project: David Albright, Chris Lister, George Robin, evaluate containment and match with historical and Matt Small at the U.S. Environmental Protection field data. After proper evaluation of the formation Agency; Anneliese Anderle of the California Division and injectivity, the facility will commence full-scale of Oil, Gas and Geothermal Resources; John Apps operation, with 363 Mg (400 ton) of biosolids and Dmitriy Silin of Lawrence Berkeley National slurry-injected into the target injection zone. Laboratory (Berkeley, Calif.); Michael Land, Daniel The city’s portion of the construction cost Ponti, and Eric G. Reichard of the U.S. Geological will be about $7.9 million. However, the deep-well Survey; John Veil of Argonne National Laboratory injection of biosolids is expected to create sav- (Argonne, Ill.); Roland Gritto of Multimax Inc. ings in operations and maintenance costs of the (Herndon, Va.); Norm Warpinski of Pinnacle wastewater treatment plant. Technologies (Houston); Christian Klose of Columbia Because of the constrained regulatory climate University (New York); and Yung Chun Tang of the for biosolids in California, it is critical that waste- California Institute of Technology (Pasadena).

Terralog Technologies

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Terralog has led the industry for more than 10 years in design and management of large volume injection operations. Our expertise and focus are on the down-hole mechanics of slurry and liquid injection for waste disposal, with special emphasis on design, equipment selection, and operating specifications to maintain containment in the target interval, to reduce operating costs, and to optimize formation storage capacity and injection well life. With offices in Calgary, Los Angeles, Vienna, and Jakarta, and with a strong staff of earth scientists and engineers, Terralog provides clients with a unique combination of geomechanics expertise, regulatory experience, and extensive waste injection design, facility construction, and operating experience.

Reprinted with permission from WE&T, March 2008. By The Reprint Dept., 800-259-0470 (11025-0508) Layout Confirmation Only Layout Confirmation Only