Class I Deep Injection Wells	August 22, 2007
Posted by Derik Howard at August 22, 2007 09:22 PM

Forward:  I'm hoping the readers of this blog can help.

Too many water treatment facilities simply pipe their liquid waste to a municipal treatment facility or zero liquid discharge installation at great expense.

I'm trying to show the owners of facilities that generate wastewater, which includes brine, RO concentrate, reuse residuals, industrial sewerage, that they consider using deep injection wells to dispose of wastewater. Their wastewater disposal costs could be reduced by an order of magnitude and save them millions of dollars.

The following white paper is an introduction to deep injection wells (DIW's).  If you know of any plants in California that might profit by considering this alternative means of wastewater disposal, please send this article to them. -- Derik Howard

Class I Deep Injection Wells
A proven, cost-effective wastewater disposal technology

Introduction

The increasing cost and regulatory complications associated with wastewater disposal is a concern for many industrial facilities in the Central Valley of California.

Large volumes of wastewater, high in total dissolved solids (TDS) and inorganic chemicals can be injected into deep injection wells (DIW) at a fraction of the cost of alternative waste disposal methods, including municipal sewer, evaporation ponds and zero liquid discharge (ZLD) systems. Deep injection well technology has the added benefit of removing potential pollutants from the accessible biosphere and can reduce regulatory compliance burdens.

Many industrial facilities are installing DIWs as a safe, long-term, low cost means of disposing of liquid wastes. With a DIW system, wastewater streams with a wide range of TDS, pH and flow rates can often be economically managed in porous formations at depths of between 2,000 and 10,000 feet below ground.

DIW systems have been implemented at facilities located within the Central Valley that produce less than 100 gallons per minute (SMS Briners, Stockton), to those with a waste stream of more than 2 million gallons a day (Hilmar Cheese). Around the country, rates of 20 to more than 2,000 gpm have been economically managed with DIW systems. The average cost of operating a DIW system, capable of handling a half million to a million gallons of wastewater a day in the Central Valley, is typically projected to be $10,000 to $20,000 a month.

The advantages of DIW systems

The treatment and disposal options available to most industrial facilities that generate wastewater in California appear to be limited to either zero liquid discharge (ZLD) installations or municipal treatment facilities. In the construction of many facilities, DIW technology has been either rejected or ignored as a suitable disposal option by design and project managers because they are not core technologies offered by many wastewater treatment firms.

Although DIW systems must be properly screened for site-specific applicability, proponents of alternative wastewater disposal systems have sometimes erroneously dismissed the application of DIWs as a disposal option based on invalid perceptions. In fact, the following have been proven:

1. The permitting process is readily facilitated by the EPA;
2. Properly sited and designed wells are not particularly vulnerable to seismic events;
3. Significant injection rates are often practical;
4. For proper waste streams, injection zone plugging can be economically avoided;
5. Easy to design and maintain;
6. Little or no treatment infrastructure;
7. High water disposal rates;
8. Knowledge and technology transfer from oil & gas production;
9. Relatively inexpensive construction and operating costs;
11. Indefinite life; and
12 Minimal restriction on the quality of the injectate.

The safety and cost effectiveness of properly sited and designed DIW systems are well understood by the relatively small community of consultants, engineers, DIW owners and regulatory agencies that monitor the installation and operation of DIW systems throughout the USA. Few DIWs have failed, and these have been due to inappropriate application of the technology. The fact that 500 Class I industrial DIWs and more than 100,000 Class II oilfield wells are operating successfully in the USA is testament to the widespread applicability of the technology.

Technical Feasibility

Californian oil and gas companies have demonstrated the technical feasibility of brine injection and have relied on deep injection wells (Class II wells) throughout the Central Valley for decades.

The proper siting of a DIW requires that sufficient sedimentary layers beneath a target property are present, and that they consist of thick permeable formations with a relatively impervious cap-rock. The porous layers should be capable of receiving a sufficient volume of wastewater at a sustained rate for at least 30 years. Based on thousands of oil well logs, many areas within Central California meet this criterion and are geologically suitable for the installation of DIWs.

EPA Permit for DIW's

It requires no more effort to permit a DIW system than most other wastewater treatment systems, including ZLD systems. Class I wells are relatively straightforward to permit for the injection of nonhazardous wastes into zones separated from the lower most underground source of drinking water (USDW), defined by a TDS concentration of <10,000 milligrams per liter.

The United States Environmental Protection Agency (U.S. EPA), Underground Injection Control (UIC) program grants permits for the installation of Class I DIWs. Regulations for this program are found in the Federal Code of Regulations, Title 40, Chapter 1, Parts 144 and 147 (40 CFR 144-147).

Wastewater Specifications

The non-hazardous liquid waste injected at most industrial and municipal facilities using DIW technology have elevated levels of TDS, nitrates, phosphates, pathogens and/or inorganic chemicals.  For the effective operation of a DIW, the wastewater should have relatively low suspended solids concentrations.

Installing a DIW system

The installation of a DIW can be viewed as a six-step process as follows.

1. Feasibility study to evaluate both site geology and waste stream
2. U.S. EPA permit application
3. Injection system design
4. Construction
5. Testing
6. Operation and Maintenance

Monitoring and Reporting

The DIW operator is typically required to submit a sample of the injectate to a state certified laboratory for regular periodic characterization of the operation. Quarterly summary reports of injection volume and pressure are also required. The DIW operation and monitoring can be automated, thereby minimizing labor costs.

Estimated Cost

The average cost of a DIW system consisting of two DIWs, surface treatment and monitoring equipment, is often on the order of two million dollars. Depending on a number of variables including the pre-injection treatment requirements, if any, the operating cost is typically between $10,000 to $20,000 a month.

The above-noted $10,000 to $20,000 per month operation and maintenance cost is consistent with published values as follows. Green, et al. (1999) determined that operation and maintenance costs for a DIW system are about 8 percent of the capital costs, including electric power and treatment chemicals for corrosion and biological growth control.

A study by the University of Texas at El Paso in 2002 indicated that operation and maintenance costs including pumping and maintenance are approximately 4 percent of capital costs. Using these published values, and assuming a capital well cost of $2,000,000, the operation and maintenance costs would be between $ 80,000 and $160,000 per year (i.e., median cost of $10,000 per month). These literature values are also consistent with costs experienced by the team for the operation of disposal wells under similar conditions.

Schedule

Generally, a DIW system can be permitted and installed within two to three years.

-Site-Specific Feasibility Study - 2 to 4 months
-Preparation of the U.S. EPA permit application - 6 to 9 months
-Review of permit application by the U.S. EPA - 9 to 12 months
-DIW construction and testing - 4 to 6 months
-U.S. EPA’s review and issuance of a permit to operate - 3 to 5 months
  Total time required - 24 to 36 months

Conclusion

The capital cost of a DIW system for many facilities can be recovered within two to three years. This is primarily due to the low monthly operating costs, which are a fraction of ZLD system operating costs or the costs of disposal to a municipal wastewater treatment facility.

Attractive benefits of the technology include corporate control of dedicated waste management capacity along with reducing plant sensitivity to future regulatory changes that are likely to result in increased disposal costs over time. Additional advantages of DIWs are the low maintenance, longevity, minimal staff oversight requirements, and recognized safety of the technology.

by Derik Howard
DIW Services, LLC
Redlands, CA
Telephone:  (909) 307-0270
Email:  derik.howard@gmail.com

References

Green, T. S. (1999) Design and costs for a system to reduce chloride levels in the Red River by shallow well collection and deep-well disposal. Environmental Geology, vol. 38, issue 2, p. 141-147.

University of Texas at El Paso (UTEP) (2002) Zero Discharge Brine Management for Desalination Plants. Desalination Research and Development Program Report No.89. US Department of the Interior, Bureau of Reclamation.

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Comments

Posted by: Joe Taylor at September 1, 2007 11:34 AM

Posted by: Martin Zhekov at September 11, 2007 07:53 AM

Posted by: Rachel Jang at September 19, 2007 07:19 AM

Posted by: Ken Cooper at September 23, 2007 12:34 AM

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