Individual APP Applications Individual APP Applications Best - - PowerPoint PPT Presentation

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Best Available Demonstrated Control Best Available Demonstrated Control Technology (BADCT) Technology (BADCT) for Facilities for Facilities other than

• ther than

Wastewater Treatment Plants Wastewater Treatment Plants

Individual APP Applications Individual APP Applications

Vimal Chauhan Vimal Chauhan October 21, 2010 October 21, 2010

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ARIZONA MINING GUIDANCE MANUAL BADCT (Publication # TB 04-01)

• Process of selecting BADCT in accordance

with A.R.S. 49-243.B.1.

• All permitted facilities shall utilize BADCT in the

design, construction and operation.

• A.A.C. R18-9-A202(A)(5) requires that an APP

application include a description of the BADCT for the proposed facility.

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BADCT Selection Process Overview

• To demonstrate BADCT, a facility must be

evaluated in terms of:

• Use demonstrated discharge control elements
• 1. Discharge characterization
• 2. Siting
• 3. Design, construction, and operation
• 4. Closure and post-closure

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• Key concepts of the manual are:
• BADCT must be determined on a site specific basis.
• No single technology or group of technologies can be

mandated as appropriate for all discharge control systems.

• NOTE: The Demonstrated Control Technologies (DCTs)

presented in the BADCT manual are simply alternatives.

• Monitoring is generally not regarded as part of the BADCT

design.

Determination of BADCT

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• BADCT determination process involves deciding

whether to use:

• “Prescriptive” approach

Or

• A site specific “Individual” approach
• Both approaches have the same goal of

preventing, or minimizing to the maximum extent practicable, the loading of pollutants to an aquifer.

The BADCT Process

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• Objective: To simplify and expedite the

permitting of conventional facilities by:

• Minimizing required information gathering
• Adopting an approved design
• Limited information review
• Limited negotiations

Prescriptive BADCT Criteria

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• The Prescriptive BADCT Criteria provides the following:
• Use of a predetermined DCT as the BADCT design.
• Simplified method to propose acceptable BADCT.
• Generally conservative, hence minimizes the level of site

investigation and engineering evaluations.

• Based on the premise of minimizing any discharge beyond the

engineered containment. Therefore, natural attenuation is not a consideration.

Prescriptive BADCT Criteria – cont.

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Individual BADCT Criteria

• The Individual BADCT Criteria provides the

following:

• Allows evaluation of alternative discharge control (ADC)

systems which combine site characteristics with DCTs.

• Provides a method to utilize a site specific BADCT

design.

• Allows BADCT design to be optimized compared to the

generally conservative Prescriptive BADCT criteria.

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Prescriptive BADCT (Section 1.1.1)

• Designed to be generally conservative for most site

conditions.

• Includes specific design criteria for many of the BADCT
• elements. However, engineering equivalents may be

acceptable (see Table 2-1 of the BADCT manual).

• NOTE: Engineering equivalents cannot rely on seepage

attenuation or other geologic properties of the vadose zone as part of minimizing aquifer loading.

• ADEQ may require specific supporting evaluations for

the proposed element.

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Prescriptive BADCT – cont.

• Facilities eligible to utilize the Prescriptive

approach:

• Non-Storm Water Ponds (seepage or contact

stormwater from a tailing impoundment, waste dump, process area, etc.)

• Process Solution Ponds
• Heap Leach Pads
• Tailing Impoundments

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Prescriptive BADCT – cont.

• Conditions affecting the use of Prescriptive

BADCT approach:

• Facilities located in areas of shallow groundwater.
• Facilities located in areas prone to excessive

subsidence.

• Facilities located in the vicinity of active faults.
• Facilities located in landslide prone terrain.
• Facilities located in other locations of known geologic

instability.

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Individual BADCT Review Process for New Facilities (Section 1.1.3)

• Definition: "New facility" means a previously closed

facility that resumes operation or a facility on which construction was begun after August 13, 1986 on a site at which no other facility is located or to totally replace the process or production equipment that causes the discharge from an existing facility.

• Only general guidance is provided for the development
• f an Individual BADCT design process, since it follows

the general principles of engineering design.

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Individual BADCT Review Process for New Facilities – cont.

• The application shall include a statement of

the technology which shall describe the following:

• ADC measures considered
• Advantages and disadvantages of each

alternative

• Justification for selection or rejection of each

alternative

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Individual BADCT Review Process for New Facilities – cont.

• The applicant shall evaluate:
• Each alternative DCT relative to the amount of

discharge reduction achievable.

• Site specific hydrologic and geologic characteristics.

Provide demonstration through modeling or data collected during the application process.

• Other environmental impacts.
• Water conservation or augmentation considerations.

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Individual BADCT Review Process for New Facilities – cont.

• Important aspects of developing an Individual

BADCT design are:

• DCTs constitute a discharge control system

incorporating engineering features, operational measures and site characteristics to achieve BADCT.

• Alternative designs must be considered to arrive at a

BADCT design.

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Individual BADCT Review Process for New Facilities – cont.

• The BADCT design is developed through the following

approach:

• Develop a range of ADC systems
• Screen the ADC systems based on the relative degree of

discharge control

• Select the best ADC systems for further analysis
• Refine designs for the selected ADC systems
• Estimate discharge control for the selected ADC systems
• Selection of BADCT design

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Individual BADCT Review Process for New Facilities – cont.

Site Selection

• The design documents submitted for APP permitting must describe

the site selection process.

• Site selection can be performed in a formal or informal process.
• Formal Process: The preferred site will be selected through a

process of:

• Fatal flaw screening
• Site evaluation and ranking
• Limited site investigations and final ranking (in some cases)
• Informal Process: This process is often necessary because of

limited availability of suitable sites in the vicinity of the ore body (proximity to the plant area/processes).

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Individual BADCT Review Process for New Facilities – cont.

Development of Reference Design

• The following must be considered:
• 1. Industry-wide DCTs taking into account differences in industry

sectors

• 2. The type and size of the operation
• 3. The reasonableness of applying controls considering the site

climatic conditions

• 4. Other site specific conditions
• A systems approach should be used which considers all phases of

the project including:

• 1. Site characterization
• 2. Design, construction and operations
• 3. Closure and post-closure

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Individual BADCT Review Process for New Facilities – cont.

Development of Reference Design – Cont.

• For example, in developing a Reference Design, site specific

DCTs should be included such as:

• Selection of a site with low permeability geologic formations
• Specific design elements such as:

– Use of single synthetic liners – Specific operational technologies such as maintaining the low hydraulic head on a leach pad – Specific operational monitoring proposals such as regular inspections by the facility operator – Specific closure and post-closure technologies such as bacterial rinsing for a gold heap leach pad

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Estimation of Aquifer Loading

• An evaluation must be performed to estimate the potential loading of

pollutants to the aquifer. At a minimum, the following steps shall be followed in performing this evaluation:

• Estimate the potential release from the facility.
• Estimate the travel time of a pollutant to the water table
• Estimate attenuation of pollutants in the foundation or vadose zone
• Estimate aquifer loading of constituents including but not limited to those

that have established water quality standards

• However, keep in mind that it is not intended that this evaluation

should turn into a research project.

Individual BADCT Review Process for New Facilities – cont.

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Alternative Design(s) Selection

• This can include the evaluation of alternative control

technologies or design elements for each applicable type of facility, or, as may be appropriate, the evaluation of alternative sites.

Individual BADCT Review Process for New Facilities – cont.

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Selection of BADCT Design

• Finally, make a selection from the Reference Design and the

alternative design(s) based on aquifer loading. Selection should be based on minimum pollutant loading to the aquifer.

• If the evaluated designs results in similar aquifer loading, the design

with lowest cost may be selected (as long as the discharges do not contain materials listed in A.R.S. 49-243.I).

• If the discharge contains materials listed in A.R.S. 49-243.I, the

applicant must limit discharges to the maximum extent practicable regardless of cost.

Individual BADCT Review Process for New Facilities – cont.

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A.R.S. 49-243.I

• With respect to the following pollutants, the permit applicant for a new facility

must meet the criteria of subsection B, paragraph 1 of this section to limit discharges to the maximum extent practicable regardless of cost:

• 1. Any organic substance listed by the secretary of the department of health and

human services pursuant to 42 United States Code section 241(b)(4), as known to be carcinogens or reasonably anticipated to be carcinogens.

• 2. Any organic substance listed in 40 Code of Federal Regulations section

261.33(e), regardless of whether the substance is a waste subject to regulation under the resource conservation recovery act (P.L. 94-580; 90 Stat. 2795).

• 3. Any organic toxic pollutant that the director lists by rule after determining that

minute amounts of that pollutant in drinking water will present a substantial short- term or long-term human health threat.

Individual BADCT Review Process for New Facilities – cont.

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Individual BADCT Review Process for Existing Facilities (Section 1.1.4)

• Definition: A facility that is neither a new or

closed facility and at which “construction began before August 13, 1986” (A.R.S. 49-201.14).

• A closed facility that is reopened is regarded as

a new facility (A.R.S. 49-201.18).

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Individual BADCT Review Process for Existing Facilities – cont.

• The distinction between existing and new facilities is

important in determining BADCT for the following two basic reasons:

• 1. At an existing facility, it requires ADEQ and the applicant to

consider potential upgrades to the facility design.

• 2. Additional factors for existing facilities apply as listed in

A.R.S. 49-243.B.1(a) through (h), such as:

• a. Cost vs. discharge reduction
• b. Equipment age
• c. Engineering aspects relating to various types of industrial

and control processes

• d. NOTE: The requirement of A.R.S. 49-243.I relating to limiting

discharges to the maximum extent practicable regardless of cost does not apply to existing facilities

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Individual BADCT Review Process for Existing Facilities – cont.

• Two major differences in determining BADCT for an

existing facility, compared to that for a new facility.

• 1. Existing design and site conditions offer constraints on

what can be achieved with the final BADCT configuration

• 2. Analysis of cost vs. discharge reduction applies in

determining BADCT

NOTE: Remedial or mitigative efforts do not constitute part of BADCT for the facility (Section 1.1.4, page 1-20).

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Individual BADCT Review Process for Existing Facilities – cont.

• There are five basic steps in the existing facility process.
• 1. Identify current DCTs and site factors
• 2. Estimate performance (determine aquifer loading)
• 3. Prepare a candidate list of technically feasible alternative

DCTs.

• 4. Use the candidate list to arrive at one or more alternative

systems.

• 5. Weigh cost vs. discharge reduction for each alternative system

to arrive at BADCT.

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Individual BADCT Review Process for Existing Facilities – cont.

Development and Evaluation of the Reference Design

• Steps 1 & 2: Identifying Current Discharge Controls and Assessing

Their Performance - The Reference Design

• Step 3: Identifying Technically Feasible DCTs for Improvement
• Step 4: Use Candidate List to Arrive at One or More Alternative

Discharge Control Systems

• Step 5: Weigh Cost vs. Discharge Reduction by Calculating Aquifer

Loading for Alternative System(s) and Calculating Cost for New DCTs

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Individual BADCT Review Process for Existing Facilities – cont.

Steps 1 & 2: Identifying Current Discharge Controls and Assessing Their Performance - The Reference Design

• BADCT determination depends on an adequate characterization of the

discharge quantity and quality.

• Inventory the discharge controls used in the facility’s current design to

establish the Reference Design.

• DCTs to consider include process solution controls in conjunction with a

number of factors.

• Evaluate the overall discharge control performance of the facility.

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Individual BADCT Review Process for Existing Facilities – cont.

Step 3: Identifying Technically Feasible DCTs for Improvement

• Develop a list of technically feasible alternative DCTs.
• Ideas for candidate DCTs are presented in Part 3 of the BADCT Manual.
• Following DCTs may offer considerable improvement in facility

performance to control discharge, and are often easily implemented:

• 1. Operational controls - physical and chemical
• 2. Run-on and other storm water management controls
• 3. Closure elements - removal of free liquids, grading, covering, etc.
• 4. Containment systems for process solution and other pollutant sources
• 5. Stability improvements - berming, benching or regrading

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Individual BADCT Review Process for Existing Facilities – cont.

Step 4: Use Candidate List to Arrive at One or More Alternative Discharge Control Systems

• Select alternative design(s) based on a systems approach

considering technologies, as well as site conditions.

• Use the alternative DCTs list to identify components that may be

incorporated in the existing reference design to arrive at the alternative design(s).

• Use professional judgment and provide justification for the

selected DCTs

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Individual BADCT Review Process for Existing Facilities – cont.

Step 5: Weigh Cost vs. Discharge Reduction by Calculating Aquifer Loading for Alternative System(s) and Calculating Cost for New DCTs

• Prepare additional aquifer loading calculation(s) using the same

considerations as for the Reference Design.

• Contribution to discharge reduction of additional DCTs (if used),

should be factored into the aquifer loading calculation(s).

• The estimated performance of a new DCT (if substituted for an

existing one) should be used in the calculation.

• The aquifer loading(s) of the alternative system(s) need to be

compared to the Reference Design.

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USING SITE CHARACTERISTICS AS A PART OF THE BADCT DESIGN

• This section includes discussions on:
• 1. Waste types and process solution characteristics
• 2. Water resource values
• 3. Climatic conditions
• 4. Site factors
• Geology/stability
• Topography
• Soil properties
• Surface hydrology
• Hydrogeology
• Barriers
• 5. Passive containment (A.R.S. 49-243-G)

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Common Requirements for APP Applications

• The following items are common requirements for APP

Applications that are sometimes deficient:

1. Provide closure strategy. 2. Cost estimates should have sufficient details including unit costs and breakdown of all tasks, material, equipment, labor, quantities and subcontractors involved. NOTE: Lump sum costs are not acceptable. 3. Provide all pertinent calculations; e.g. liner leakage alert level, water balance, wave run-up, wind-uplift, surface water hydrology, etc. Include references used in the calculations and provide details of the calculations as opposed to a Table of results.

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Common Requirements for APP Applications – cont.

4. Provide sealed construction and as-built drawings (as appropriate). 5. All the above documents should be certified by an Arizona registered Professional Engineer. 6. Characterize the site and include information related to hydraulic conductivity (seepage and infiltration rates), discharge characteristics 7. When submitting an amendment and if there are any changes to any listed discharging facilitiy, submit all pertinent design documents

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Additional References

ADEQ Webpage www.azdeq.gov APP Webpage (includes BADCT Manual) http://www.azdeq.gov/function/forms/appswater.html#app AZ State Legislature – Title 49 – The Environment http://www.azleg.state.az.us/ArizonaRevisedStatutes.asp?Tit le=49 AZ Administrative Code – Title 18 – Environmental Quality http://www.azsos.gov/public_services/Title_18/18_table.htm