Underground Injection Control Program-Revision to the Federal Underground Injection Control Requirements for Class I Municipal Disposal Wells in Florida, 70513-70532 [05-23088]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 70, Number 224 (Tuesday, November 22, 2005)]
[Rules and Regulations]
[Pages 70513-70532]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 05-23088]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 146

[FRL-7999-7]


Underground Injection Control Program--Revision to the Federal 
Underground Injection Control Requirements for Class I Municipal 
Disposal Wells in Florida

AGENCY: Environmental Protection Agency.

ACTION: Final rule.

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SUMMARY: Today's rule amends the current Federal Underground Injection 
Control (UIC) requirements by providing a regulatory alternative to 
owners and operators of Class I municipal disposal wells in specific 
areas of Florida that have caused or may cause movement of fluid into 
an Underground Source of Drinking Water (USDW). Because operation of 
Class I wells with fluid movement into a USDW is prohibited by Federal 
UIC regulations, this new rule offers owners and operators of municipal 
disposal wells in certain counties in Florida the ability to continue 
to operate their wells provided they meet additional wastewater 
treatment requirements. These new treatment requirements, which apply 
only to injection operations in certain counties of Florida, are 
designed to provide an equivalent level of protection to USDWs that is 
afforded by the no-fluid-movement standard.

DATES: This regulation is effective December 22, 2005. For purposes of 
judicial review, this final rule is promulgated as of 1 p.m., Eastern 
time on December 6, 2005, as provided in 40 CFR 23.7.

ADDRESSES: The official public docket for this rule is located at the 
U.S. Environmental Protection Agency (EPA), Region 4 Library (9th 
Floor), Sam Nunn Atlanta Federal Center, 61 Forsyth Street, SW., 
Atlanta, GA 30303-8960. The docket is available for inspection from 8 
a.m. to 3:30 p.m., Eastern time, Monday through Friday, excluding legal 
holidays. For information on how to access Docket materials, please 
call (404) 562-8190 and refer to the Florida UIC docket.

FOR FURTHER INFORMATION CONTACT: For technical inquiries, contact Nancy 
H. Marsh, Ground Water & UIC Section, U.S. EPA Region 4, 61 Forsyth 
Street, SW., Atlanta, GA 30303-8960 (phone: 404-562-9450; E-mail: 
marsh.nancy@epa.gov) or Lee Whitehurst, Office of Ground Water and 
Drinking Water, U.S. EPA, EPA East, 1200 Pennsylvania Avenue, 
NW.,Washington, DC 20460 (phone: 202-564-3896; E-mail: 
whitehurst.lee@epa.gov). For general information, contact the Safe 
Drinking Water Hotline, at 800-426-4791. The Safe Drinking Water 
Hotline is open Monday through Friday, excluding legal holidays, from 9 
a.m. to 5 p.m., Eastern time.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. General Information
    A. Who Are Regulated Entities?
    B. Abbreviations and Acronyms Used in the Preamble and Final 
Rule
II. Background
    A. Why Is EPA Taking This Regulatory Action?
    B. Statutory and Regulatory Framework
    C. Requirements To Prevent Fluid Movement
    D. Domestic Wastewater Disposal in Florida Through Class I Wells
    E. July 7, 2000 Proposed Rule
    1. Option 1: Advanced Wastewater Treatment (AWT) with a Non-
endangerment Demonstration.
    2. Option 2: In-depth Hydrogeologic Demonstration and Advanced 
Treatment, as Necessary

[[Page 70514]]

    F. 2003 Relative Risk Assessment
    1. Relative Risk Assessment Question 1: What Level of Treatment 
and Disinfection Is Provided for the Management Options of Treated 
Wastewater in South Florida?
    2. Relative Risk Assessment Question 2: What Stressors Remain 
(After Treatment) That May Be a Concern for the Management Options 
of Treated Wastewater in South Florida?
    3. Relative Risk Assessment Question 3: What Exposure Pathways 
Are (or May Be) of Significance for the Management Options of 
Treated Wastewater in South Florida?
    4. Relative Risk Assessment Question 4: What Is the Overall 
Estimate of Risk for the Management Options of Treated Wastewater in 
South Florida?
    5. Relative Risk Assessment Question 5: What Are the Important 
Data or Knowledge Gaps for Deep Well Injection?
    G. May 5, 2003, Notice of Availability and Notice of Data 
Availability
    1. NODA Question 1: What Is the Appropriate Level of Wastewater 
Treatment Prior to Injection?
    2. NODA Question 2: Is it Feasible To Predict Movement of Fluids 
Through Hydrogeologic Demonstrations?
    3. NODA Question 3: Have Some Deep Wells Been Misclassified as 
Class I, When They Are Actually Class V?
III. Summary of Public Comments
    A. Comments on the July 7, 2000, Proposed Rule
    1. Selection of Option 1, Option 2, or a Combination of Both
    2. Appropriate Level of Wastewater Treatment
    3. Need for Pretreatment
    4. Feasibility of Hydrogeologic Demonstrations to Predict 
Movement of Fluids
    5. Monitoring Requirements
    6. Rule Applicability
    7. Suitability of Florida Geology for Domestic Wastewater 
Disposal Through Class I Wells
    B. Comments on the Notice of Data Availability and the Relative 
Risk Assessment
    1. Appropriate Level of Wastewater Treatment Prior to Injection
    2. Feasibility of Hydrogeologic Demonstrations To Predict 
Movement of Fluids
    3. Class I or Class V
IV. Explanation of Today's Action
    A. Objectives and Approach
    B. Operating Requirements
    1. Selected Approach
    a. Rationale for Requiring Pretreatment of Wastewater
    b. Rationale for Requiring Secondary Treatment of Wastewater
    c. Rationale for Using Florida Definition of High-Level 
Disinfection
    d. Rationale for Not Requiring the Removal of Other Contaminants
    e. Rationale for Phasing In the New Treatment Over Time
    2. In-Depth Hydrogeologic Demonstrations
    C. Monitoring Requirements
    D. Rule Applicability
    1. How Will the New Rule Affect New Wells?
    2. What Florida Counties Are Covered by the Final Rule?
    E. Reclassification of Wells that Have Caused Fluid Movement
V. Cost of the Rule
VI. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With 
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From 
Environmental Health & Safety Risks
    H. Executive Order 13211: Actions That Significantly Affect 
Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Congressional Review Act

I. General Information

A. Who Are Regulated Entities?

    This regulation is limited in application to the owners and/or 
operators of existing Class I underground injection wells that inject 
domestic wastewater effluent in certain parts of Florida. It is limited 
geographically to wells in the following counties: Brevard, Broward, 
Charlotte, Collier, Flagler, Glades, Hendry, Highlands, Hillsborough, 
Indian River, Lee, Manatee, Martin, Miami-Dade, Monroe, Okeechobee, 
Orange, Osceola, Palm Beach, Pinellas, St. Johns, St. Lucie, Sarasota, 
and Volusia. These counties are included in this rule because they have 
the unique geologic conditions that are predominated by carbonate 
rocks. Such rocks commonly contain fractures, faults, and solution 
cavities that provide preferential paths for the movement of 
underground fluids.
    Class I injection wells are wells that inject fluids beneath the 
lowermost formation containing, within one-quarter mile of a well bore, 
a USDW (40 CFR 144.6(a)). Class I wells can be used to inject 
hazardous, industrial, or municipal wastes. Class I municipal disposal 
wells inject treated wastewater from publicly or privately owned and 
operated facilities that treat domestic wastewater (commonly referred 
to as sanitary wastewater or sewage), which is principally derived from 
dwellings, business buildings, and institutions. Treated wastewater 
from industrial facilities, often controlled through pretreatment 
standards, may also be found in this wastewater. Currently, Class I 
municipal disposal wells are located only in the State of Florida. 
Specific regulated categories and entities include:

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                Category                       Examples of entities
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Municipalities and Local Government....  Class I municipal disposal
                                          wells disposing of domestic
                                          wastewater effluent in certain
                                          parts of Florida
Private................................  Class I municipal disposal
                                          wells disposing of domestic
                                          wastewater effluent in certain
                                          parts of Florida.
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    This table is not intended to be exhaustive, but rather provides a 
guide for readers regarding entities likely to be regulated by this 
action. This table lists the types of entities that EPA is now aware 
could potentially be regulated by this action. Other types of entities 
not listed in the table could also be regulated. To determine whether 
your facility is regulated by this action, you should carefully examine 
the applicability criteria in 40 CFR 146.15 of the rule. If you have 
questions regarding the applicability of this action to a particular 
entity, consult one of the persons listed in the preceding FOR FURTHER 
INFORMATION CONTACT section.

B. Abbreviations and Acronyms Used in the Preamble and Final Rule

AWT Advanced Wastewater Treatment
BOD Biochemical Oxygen Demand
CFR Code of Federal Regulations
EPA Environmental Protection Agency
F.A.C. Florida Administrative Code
FDEP Florida Department of Environmental Protection
ICR Information Collection Request
MGD Million Gallons per Day
NDWAC National Drinking Water Advisory Council
NOA Notice of Availability
NODA Notice of Data Availability
NTTAA National Technology Transfer and Advancement Act
O&M Operations and Maintenance
OMB Office of Management and Budget
RCRA Resource Conservation and Recovery Act

[[Page 70515]]

RFA Regulatory Flexibility Act
SBREFA Small Business Regulatory Enforcement Fairness Act
SDWA Safe Drinking Water Act
TDS Total Dissolved Solids
TSS Total Suspended Solids
USDW Underground Source of Drinking Water
UIC Underground Injection Control
UMRA Unfunded Mandates Reform Act

II. Background

A. Why Is EPA Taking This Regulatory Action?

    In the early 1980's EPA found that some Class I municipal wells in 
specific areas in Florida caused or may cause fluid movement into an 
Underground Source of Drinking Water (USDW). On July 7, 2000, EPA 
proposed a revision to the UIC regulations whereby continued injection 
would be allowed only if owners or operators met certain additional 
wastewater treatment requirements. EPA requested public comment on 
options for providing additional wastewater treatment at municipal 
disposal facilities in certain counties in Florida that have or may 
cause fluid movement.
    As part of EPA's FY 2000 appropriations bill, Congress asked EPA to 
conduct a relative risk assessment of deep well injection, ocean 
disposal, surface discharge, and aquifer recharge of treated effluent 
in South Florida. EPA published the Relative Risk Assessment of 
Management Options for Treated Wastewater in South Florida in April 
2003. In the Relative Risk Assessment, EPA reported that results from 
ground water monitoring around some Class I municipal disposal wells in 
Florida confirm that fluids have migrated out of the permitted 
injection zone and, in some cases, into USDWs. EPA also found that the 
full extent of USDWs contamination is not known because the fate and 
transport of pathogens contained in injected effluent is especially 
difficult to define even with the most sophisticated ground water 
modeling or monitoring.
    On May 5, 2003, EPA issued a Notice of Availability (NOA) 
announcing the availability of the Relative Risk Assessment and a 
Notice of Data Availability (NODA), requesting public comment on how 
the findings in the Relative Risk Assessment should inform this final 
rulemaking.
    Without today's rule, the no-fluid-movement requirement would 
remain the only available approach for regulating Class I municipal 
disposal wells in Florida, regardless of the level of wastewater 
treatment prior to injection. Enforcing this approach would, in effect, 
require owners and operators to shut these wells down because 
wastewater isolation from USDWs cannot be ensured. Shutting down the 
injection wells would, in turn, force the municipal wastewater to be 
managed by other means, which could increase the risks to surface water 
and coastal ecosystems.
    As an alternative, EPA has chosen, for Class I municipal disposal 
wells in certain parts of Florida, another approach that it believes 
will be as effective as confinement in protecting USDWs from the 
contaminants in the wastewater. This alternate approach involves the 
rigorous control of the quality of the injected fluids. Under this 
approach, the movement of fluids into USDWs, whether known or 
suspected, should not endanger the USDWs because the quality of the 
wastewater has been treated to a level that is no longer a threat to 
USDWs. Today's action shifts the endangerment protection strategy 
employed for Class I municipal disposal wells in certain parts of 
Florida from the no-fluid-movement standard to an alternate approach 
that relies on treatment of wastewater before it is injected. This 
shift, however, does not undercut the protection of USDWs or weaken the 
UIC Program requirements. Although facility owners and operators in the 
designated counties must meet new treatment requirements to continue 
injecting without violating the no-fluid-movement standard, they must 
also comply with all other applicable UIC requirements to ensure that 
their injection wells do not endanger USDWs.
    In the Relative Risk Assessment's evaluation of injection practices 
in Florida, pathogens were identified as the contaminant in municipal 
wastewater that presents the greatest risk to USDWs. High-level 
disinfection of this municipal wastewater is an effective method for 
inactivating these pathogens.
    Therefore, in today's rule, EPA amends the current Federal UIC 
regulations to allow owners and operators of Class I municipal disposal 
wells in specific areas of Florida to continue using their wells, even 
if they have caused or may have caused movement of fluid into a USDW, 
provided they meet new requirements to treat their municipal wastewater 
with pretreatment, secondary treatment, and high-level disinfection.

B. Statutory and Regulatory Framework

    Class I underground injection wells are regulated under the 
authority of Part C of the Safe Drinking Water Act (``SDWA'' or ``the 
Act'') (42 U.S.C. 300h et seq.). The SDWA is designed to protect the 
quality of drinking water sources in the United States and prescribes 
that:

    Underground injection endangers drinking water sources if such 
injection may result in the presence in underground water which 
supplies or can reasonably be expected to supply any public water 
system of any contaminant, and if the presence of such contaminant 
may result in such system's not complying with any national primary 
drinking water regulation or may otherwise adversely affect the 
health of persons. (Section 1421(d)(2) of the SDWA, 42 U.S.C. 
300h(d)(2).)

    Part C Protection of Underground Sources of Drinking Water of the 
Act specifically mandates the regulation of underground injection. The 
Agency has promulgated a series of UIC regulations under this authority 
at 40 CFR parts 144 through 147. The chief goal of any Federally 
approved UIC Program (whether administered by the State or EPA) is the 
protection of USDWs. This includes not only those aquifers which are 
presently being used for drinking water, but also those which can 
reasonably be expected to be used in the future. EPA has established 
through its UIC regulations that underground aquifers with less than 
10,000 mg/l total dissolved solids (TDS) and which contain a sufficient 
quantity of ground water to supply a public water system are USDWs. (40 
CFR 144.3)
    Section 1421 of the Act requires EPA to propose and promulgate 
regulations specifying minimum requirements for effective State 
programs to prevent underground injection that endangers drinking water 
sources. EPA promulgated administrative and permitting regulations, now 
codified in 40 CFR parts 144 and 146, on May 19, 1980 (45 FR 33290), 
and technical requirements, in 40 CFR part 146, on June 24, 1980 (45 FR 
42472). The regulations were subsequently amended on August 27, 1981 
(46 FR 43156), February 3, 1982 (47 FR 4992), January 21, 1983 (48 FR 
2938), April 1, 1983 (48 FR 14146), July 26, 1988 (53 FR 28118), 
December 3, 1993 (58 FR 63890), June 10, 1994 (59 FR 29958), December 
14, 1994 (59 FR 64339), June 29, 1995 (60 FR 33926), December 7, 1999 
(64 FR 68546), May 15, 2000 (65 FR 30886), and June 7, 2002 (67 FR 
39584). Section 1421(b)(3)(A) of the Act also provides that EPA's UIC 
regulations shall ``permit or provide for consideration of varying 
geologic, hydrological, or historical conditions in different States 
and in different areas within a State.''
    When EPA promulgated its UIC regulations, it defined five classes 
of injection wells in 40 CFR 144.6. Class I wells are defined as wells 
which inject

[[Page 70516]]

fluids beneath the lowermost formation containing, within one-quarter 
mile of the well bore, a USDW. Class I wells can be hazardous waste or 
other industrial or municipal disposal wells. (Hazardous waste 
injection must meet additional Resource Conservation and Recovery Act 
(RCRA) requirements. See 40 CFR part 148. Class I municipal disposal 
wells can be owned by public and private entities, as discussed above.
    Section 1422 of the Act provides that States may apply to EPA for 
national primary enforcement responsibility to administer the UIC 
program. Those States receiving such authority are referred to as 
``Primacy States.'' Florida received national primary enforcement 
responsibility for the UIC program for Class I, III, IV, and V wells on 
March 9, 1983. UIC regulations specific to Florida's primacy program 
are established in 40 CFR part 147, Subpart K. For the remainder of 
this preamble, reference to the UIC Program ``Director'' means the 
Secretary of the Florida Department of Environmental Protection (FDEP). 
Currently, all UIC Programs in Indian Country for Florida are directly 
implemented by EPA. It is EPA's intent that the provisions of this 
regulation apply to Class I municipal disposal wells in Indian Country 
within the counties identified in 40 CFR 146.15(f). At this time, there 
are no known Class I municipal disposal wells in Florida in Indian 
Country.

C. Requirements To Prevent Fluid Movement

    When EPA promulgated its regulations for the UIC program, it 
established different requirements for each class of wells, based upon 
the uses and risks of various types of wells. All classes of wells are 
required to comply with 40 CFR 144.12(a) which states:

    No owner and/or operator shall construct, operate, maintain, 
convert, plug, abandon, or conduct any other injection activity in a 
manner that allows the movement of fluid containing any contaminant 
into underground sources of drinking water, if the presence of that 
contaminant may cause a violation of any primary drinking water 
regulation under 40 CFR part 142 or may otherwise adversely affect 
the health of persons.

    Then, for Class I, II, and III wells, 40 CFR 144.12(b) more 
specifically provides that:

    If any water quality monitoring of an underground source of 
drinking water indicates the movement of any contaminant into the 
underground source of drinking water, except as authorized under 40 
CFR part 146, the Director shall prescribe such additional 
requirements for construction, corrective action, operation, 
monitoring, or reporting (including closure of the injection well) 
as are necessary to prevent such movement.

    In contrast to subsection (a), which, for all classes of wells, 
prohibits fluid movement that may endanger USDWs, 40 CFR 144.12(b) 
requires for Class I, II, and III wells that a State or Federal UIC 
Program Director, upon detection of contaminant movement into a USDW, 
prescribe requirements to prevent any such movement, regardless of 
whether the movement may endanger the USDW.
    In addition to 40 CFR 144.12(b), EPA established technical and 
other requirements for specific classes of wells in Parts 144 and 146 
regulations. Parts 144 and 146 regulations address siting, 
construction, operation, and closure of wells. Parts 144.12(b) and the 
specific technical requirements of parts 144 and 146 regulate the 
activities through which fluid movement may result and impose 
requirements designed to ensure that Class I, II, and III wells will 
not endanger USDWs by prohibiting movement of any fluid into the USDW.

D. Domestic Wastewater Disposal in Florida Through Class I Wells

    Beginning more than 20 years ago, municipalities in Florida began 
to pursue the use of underground injection as an alternative to surface 
disposal of treated wastewater from domestic wastewater treatment 
facilities. Underground injection technology was employed to relieve 
stress to surface water environments because it was technologically 
feasible to inject large volumes of wastewater into deep permeable and 
transmissive formations. Through technical and monetary assistance, EPA 
supported construction of many of these facilities in an effort to 
safeguard surface waters. Through injection technology, domestic 
wastewater facilities have been able to dispose of large quantities of 
domestic effluent, with the resulting benefit of reducing impacts to 
surface ecosystems. Wells at facilities that inject domestic wastewater 
into wells below the lowermost USDW are considered to be Class I 
municipal disposal wells, and in Florida such wells inject into zones 
ranging from 650 to 3,500 feet below the land surface.
    The volumes of domestic wastewater permitted for injection at Class 
I municipal disposal well facilities presently range from one well with 
less than one million gallons per day (MGD) at the Gasparilla Island 
Water Utilities to 17 wells with about 110 MGD at Miami-Dade Water & 
Sewer Department, South District Wastewater Treatment Plant. Florida 
requires that domestic wastewater must, at a minimum, be treated to 
secondary wastewater treatment standards (see 40 CFR part 133). At the 
time Florida permitted the currently operating Class I municipal 
disposal wells, characterization of the geology indicated that there 
was adequate confinement to isolate the injection fluids from any 
USDWs. Because it was thought there was adequate confinement, it was 
believed that injection fluids would never migrate upwards into the 
shallower geologic formations containing USDWs.
    The current injection and confining zones in peninsular Florida 
exist in what is known as the Floridan Aquifer System. This system is 
made up of carbonate rocks. The uppermost geologic formations of the 
Floridan Aquifer System, as well as formations above the Floridan 
Aquifer, are USDWs. The porosity and permeability variations of the 
carbonate rocks of peninsular Florida and the existence of fractures 
within the formation determine their confining ability. The porosity 
varies greatly, even within the same horizon or geological deposit of a 
particular time. Monitoring of injection operations over the past 
several years has indicated that some deep geologic zones provide less 
confinement between formations than was originally thought.
    It now appears, from recent well monitoring data, that upward fluid 
movement from some Class I municipal disposal operations occurs in 
Florida because the injection fluid from Class I municipal disposal 
wells has a lower density (lower TDS) than the native formation fluids. 
This tends to cause the less dense injection fluids to rise to the top 
of the injection zone preferentially through fractures that may exist 
within the formations and above the injection zone if migration 
pathways, such as fractures, exist. Movement of injected fluid into 
USDWs either has been confirmed or is suspected at eight facilities, as 
evidenced by levels of nitrates and ammonia, as well as significant 
changes in dissolved solids concentrations. (The preferential flow that 
leads to the movement of fluid with nitrates and ammonia can also lead 
to the presence of pathogens.) At an additional eight facilities, there 
is evidence of movement outside of the injection zone, though not into 
USDWs.

E. July 7, 2000 Proposed Rule

    On July 7, 2000, EPA proposed revisions to the UIC regulations that 
would allow continued wastewater injection by existing Class I 
municipal disposal wells that have caused or may cause movement of 
contaminants into USDWs in specific areas of Florida (65

[[Page 70517]]

FR 42234). Continued injection would be allowed only if owners or 
operators met certain additional requirements that provide adequate 
protection for USDWs. EPA co-proposed two primary options for the 
additional requirements:
1. Option 1: Advanced Wastewater Treatment (AWT) With a Non-
Endangerment Demonstration
    The authorization to inject under Option 1 would have required that 
the owner and/or operator of a Class I municipal disposal well 
injecting domestic wastewater effluent treat the wastewater by advanced 
treatment methods and high-level disinfection and demonstrate that 
injection would not cause fluids that exceed the national primary 
drinking water regulations or other health-based standards to enter the 
USDW. The non-endangerment demonstration would focus on any 
contaminants that still exceed national drinking water regulations or 
other health-based standards after wastewater treatment. In the 
proposal, EPA solicited public comment on the appropriateness of this 
option, as well as the appropriate level of wastewater treatment, 
nutrient removal, and high-level disinfection that should be required 
if Option 1 is selected. The alternatives proposed were:
    Treatment to 10-24 mg/l biochemical oxygen demand (BOD) with 
disinfection;
    Treatment to 10-24 mg/l BOD with disinfection and nutrient removal;
    Treatment to <10 mg/l BOD with disinfection;
    Treatment to <10 mg/l BOD with disinfection and nutrient removal.
2. Option 2: In-Depth Hydrogeologic Demonstration and Advanced 
Treatment, as Necessary
    The authorization to inject under Option 2 would have required that 
the owner and/or operator of a Class I municipal disposal well 
injecting domestic wastewater effluent provide a hydrogeologic 
demonstration that the injection operation would not cause the USDW to 
exceed national primary drinking water regulations or other health-
based standards. EPA anticipated that this hydrogeologic demonstration 
would be an extensive evaluation, similar in detail to those required 
for a RCRA land ban no-migration petition, and consist of an analysis 
of the contaminants in wastewater prior to injection, include 
monitoring data from deep wells at the base of the USDW, and also 
include detailed hydrogeologic modeling of vertical and horizontal 
fluid transport in the injection zone and USDWs. If it was anticipated 
that the fluids may enter the USDW, the demonstration would have to 
show that the fluids would not cause the USDW to exceed primary 
drinking water regulations in 40 CFR part 141 or other health-based 
standards. Operators who could not successfully demonstrate that the 
injection operation meets these criteria would have been required to 
treat their injectate to address the contaminants of concern and 
satisfy additional requirements proposed to be added in a new 40 CFR 
146.15(d). This second option also proposed a provision whereby all 
facilities qualifying for authorization to inject under this option 
would be required to install advanced wastewater treatment and high-
level disinfection by 2015.
    EPA proposed to limit the applicability of the rule to existing 
Class I municipal disposal wells that have caused or may cause fluid 
movement into USDWs in specific counties and under certain geologic 
conditions in Florida. The proposed counties were: Brevard, Broward, 
Charlotte, Collier, Flagler, Glades, Hendry, Highlands, Hillsborough, 
Indian River, Lee, Manatee, Martin, Miami-Dade, Monroe, Okeechobee, 
Orange, Osceola, Palm Beach, Pinellas, St. Johns, St. Lucie, Sarasota, 
and Volusia. These counties were targeted in the proposal because they 
have the unique geologic conditions that are predominated by carbonate 
rocks discussed previously. The counties were selected using a map 
adapted from Florida Geological Survey map series 94 ``Potential 
Subsurface Zones for Liquid-Waste Storage in Florida,'' created by 
James A. Miller of the United States Geological Survey in 1979. The 
proposed geological conditions were those where the injection and 
confining zones are both in the Floridan Aquifer, and no clastic 
confining unit separates the injection zone from the lowermost USDW. 
See United States Geological Survey's Web site for specific information 
on Florida's geology at https://www.usgs.gov or at https://
www.dep.state.FL.us/geology/.
    EPA requested comment on a range of issues associated with this 
proposal, including the following: (1) Should the Agency select Option 
1 or 2, or, if it would be more appropriate, select a combination of 
both options? (2) What is the appropriate level of wastewater 
treatment, if Option 1 were selected? (3) What is the need to require 
pretreatment as an additional condition of authorization under the 
rule, and is it necessary to extend the pretreatment standards 
presently required by the State to injection facilities with less than 
5 MGD? (4) Are owners and operators able to provide the kind of 
hydrogeologic and other information necessary for a successful 
hydrogeologic demonstration under Option 2? (5) Is there a need for any 
additional monitoring requirements for the final rule? (6) Is it 
appropriate to make the rule applicable only to existing wells (not new 
wells) and only to the proposed list of counties? (7) Is the Florida 
geology suitable for domestic wastewater disposal through Class I 
injection wells?
    Following publication of the proposed rule, EPA held a series of 
public meetings during the comment period. These meetings provided an 
opportunity for interested parties to submit oral comments on the 
proposal. Two public meetings were held on August 22, 2000, in Tampa, 
Florida, and an additional two meetings were held on August 24, 2000, 
in West Palm Beach, Florida.
    The written comments submitted on the proposed rule and the oral 
comments provided during the public meetings mirror each other. EPA has 
carefully considered all of these comments and has responded to them in 
full in the comment response document for the proposal, which is part 
of the record for this final rule. These comments are also summarized 
in Section III.A and factored into the Agency's final decisionmaking 
discussed in Section IV of today's preamble.

F. 2003 Relative Risk Assessment

    As noted previously, following the July 7, 2000, proposal, Congress 
included the following provision as part of EPA's fiscal year 2000 
appropriations bill: ``Within available funds, the conferees direct EPA 
to conduct a relative risk assessment of deep well injection, ocean 
disposal, surface discharge, and aquifer recharge of treated effluent 
in South Florida, in close cooperation with the Florida Department of 
Environmental Protection and South Florida municipal water utilities.'' 
Because this directive came at a time when EPA's work on the July 7, 
2000, proposal was substantially complete, the Agency decided to 
proceed with the proposal and the relative risk assessment along 
separate but converging paths. EPA initiated and conducted the relative 
risk assessment with the intent of using relevant findings from the 
assessment to inform the final rulemaking. EPA published the Relative 
Risk Assessment of Management Options for Treated Wastewater in South 
Florida (EPA 816-R-03-010) in April 2003.
    The methodology for the assessment involved a process of 
investigating the

[[Page 70518]]

four very different wastewater disposal options: deep well injection, 
aquifer recharge, discharge to ocean outfalls, and discharge to other 
(non-ocean) surface water bodies. Each option has its own specific 
stressors (hazards), exposure pathways, receptors, and potential 
effects. Parameters that are relevant to one particular disposal option 
are not necessarily relevant to the other three. Therefore, a strictly 
quantitative comparison between the four options was not possible.
    Instead, EPA conducted what is termed a relative risk assessment to 
both assess the risks associated with each disposal method and allow 
comparisons. Individual risk assessments were completed for each 
wastewater disposal option and the risks associated with each were 
characterized. The risks and risk factors identified for each specific 
disposal option were then evaluated and described. Overall comparisons 
and conclusions were then presented as relative risk assessment 
matrices.
    The Relative Risk Assessment addresses five key questions 
specifically related to deep well injection: (1) What level of 
treatment and disinfection is provided for deep well injection? (2) 
What stressors remain (after treatment) that may be a concern for deep 
well injection? (3) What exposure pathways are (or may be) of 
significance for deep well injection? (4) What is the overall estimate 
of risk for deep well injection? (5) What are the important data or 
knowledge gaps for deep well injection? The significant findings of the 
Relative Risk Assessment pertaining to deep well injection are 
contained in the report and are summarized below. (See the Relative 
Risk Assessment document for details on the other disposal options.)
1. Relative Risk Assessment Question 1: What Level of Treatment and 
Disinfection Is Provided for the Management Options of Treated 
Wastewater in South Florida?
    All facilities that manage municipal wastewater by deep well 
injection in Florida are required by Florida law to provide at least 
secondary treatment of the wastewater prior to injection. In addition, 
utilities that employ deep well injection must maintain, as a 
contingency, disinfection capability, per F.A.C 62-500.540(1), but many 
do not disinfect treated effluent prior to injection. For example, 
treatment of wastewater that is injected by Class I municipal disposal 
wells in Miami-Dade and Brevard Counties consists of secondary 
treatment with no disinfection, although backup disinfection capability 
is required. In contrast, in Pinellas County, wastewater is treated to 
more stringent reclaimed water standards before being discharged into 
Class I municipal disposal wells, because the Class I wells are used to 
dispose of reclaimed water during periods of wet weather. Reclaimed 
water standards, as specified by the State of Florida, include 
secondary treatment plus a variety of techniques to remove 
microorganisms, including filtration and high-level disinfection. 
Filtration before disinfection serves to increase the ability of the 
disinfection process to inactivate viruses and other pathogens. 
Filtration also serves as the primary means for removing protozoa, such 
as Cryptosporidium and Giardia.
2. Relative Risk Assessment Question 2: What Stressors Remain (After 
Treatment) That May Be a Concern for the Management Options of Treated 
Wastewater in South Florida?
    ``Stressors'' include chemical or biological agents that may cause 
adverse effects if exposure levels are high enough. The Relative Risk 
Assessment describes the human health and ecological health stressors 
that may be found in wastewater effluent after it has been treated and 
that may pose a risk.
    In cases where injectate has received secondary treatment only, 
microorganisms are generally not inactivated prior to deep well 
injection in Florida. When used, disinfection serves to inactivate 
bacteria and viruses, especially when the wastewater is sufficiently 
filtered prior to disinfection. Protozoan pathogens (e.g., 
Cryptosporidium and Giardia) may still be present if the wastewater is 
not filtered. Disinfection (or chlorination) byproducts such as 
trihalomethanes may also be present in some wastewater, although no 
data are available to suggest that such byproducts are a serious 
concern for deep well injection or any of the other wastewater 
management options studied.
    Nutrients (e.g., nitrogen and phosphorus) can potentially stimulate 
the production of algae, which can lead to adverse side effects such as 
eutrophication, should the stressors reach surface water. Nitrogen is 
the primary nutrient of concern for Class I injection, because of its 
mobility in ground water.
3. Relative Risk Assessment Question 3: What Exposure Pathways Are (or 
May Be) of Significance for the Management Options of Treated 
Wastewater in South Florida?
    An ``exposure pathway'' is the course a stressor takes from a 
source of release to an exposed organism. It is defined by the 
different environmental media through which a stressor migrates (e.g., 
air, surface water, ground water) as well as the mechanism by which an 
organism is actually exposed (e.g., inhalation, drinking, topical 
contact).
    There are documented impacts to USDWs resulting from deep well 
injection in Florida, which raise concerns about potential human 
exposures via the drinking water pathway. Beginning in the late 1980s, 
ground water monitoring wells at 16 of the 42 municipal facilities that 
utilize Class I deep well injection in Florida began to detect the 
movement of fluid outside of the permitted injection zones. As 
previously mentioned, movement of contamination into USDWs either has 
been confirmed or is suspected at eight facilities.
    There is also the potential for contaminants released by deep well 
injection to migrate through the subsurface and discharge into marine 
and/or surface waters, where they could pose risk via other pathways if 
loadings were sufficiently large. However, the risk assessment 
concluded that it is unlikely that stressors would migrate from the 
deep injection zone to surface water.
4. Relative Risk Assessment Question 4: What Is the Overall Estimate of 
Risk for the Management Options of Treated Wastewater in South Florida?
    Although the report does not quantify risks, it offers conclusions 
about the relative risks of the four wastewater management options 
studied and about the various factors that influence risks to human and 
ecological health.
What Is the Human Health Risk?
    The human health risks associated with deep well injection (as well 
as the other three wastewater management options studied in the risk 
assessment) were found to be generally low. However, the degree of 
wastewater treatment, and in particular the level of disinfection and 
filtration of pathogenic microorganisms, is a major risk driver. There 
is greater potential risk associated with wastewater that is not 
filtered and then disinfected to inactivate bacteria and viruses, and 
not filtered to remove protozoan pathogens, such as Cryptosporidium and 
Giardia. This suggests higher relative risks for deep well injection 
operations that do not filter and disinfect wastewater and the risk is 
highest in situations where the injectate migrates through fractures, 
and solution cavities. The risk associated with microorganisms being 
released by deep well injection would be mitigated somewhat in 
situations where the

[[Page 70519]]

injection is dominated by porous media flow, characterized by long 
travel times to current or potential drinking water sources and fine 
pore spaces capable of retaining microorganisms.
    Once microorganisms and other stressors are released to the 
environment, the level of risk they pose to human health depends 
largely on how likely they are to enter drinking water supplies. The 
Relative Risk Assessment suggests that deep well injection has a higher 
risk than the other wastewater management options because current UIC 
regulatory requirements for pathogen removal/inactivation are less 
stringent.
What Are the Ecological Health Risks?
    Overall, the risk to surface water ecosystems is low when treated 
wastewater is managed by deep well injection. The potential for damage 
may be higher where treated wastewater is released in proximity to 
surface water with previously impaired water quality, which is the case 
for many surface water bodies in Florida. Deep well injection could 
also pose a risk to marine ecology if contaminants can readily migrate 
and discharge to offshore waters. Although some uncertainty remains, 
the potential for this actually to happen in Florida and pose a real 
threat in the ocean is believed to be unlikely. Two potential 
ecological effects of particular concern, should surface or ocean 
waters be sufficiently contaminated, include harmful algal blooms and 
bioconcentration of toxic contaminants in the food web. Algal blooms 
can cause a variety of toxic symptoms (including death) in aquatic 
organisms as well as nontoxic adverse effects such as clogging of gills 
and smothering of coral reefs and sea grass beds. Food web 
bioconcentration of metals and other contaminants can also cause a 
variety of toxic effects.
5. Relative Risk Assessment Question 5: What Are the Important Data or 
Knowledge Gaps for the Management Options of Treated Wastewater in 
South Florida?
    For all four wastewater management options that were considered in 
the Relative Risk Assessment, EPA found that there is a lack of 
definitive studies in Florida that use a physical or chemical tracer or 
indicator to identify the source and transport pathways of stressors 
detected in the environment. Without more definitive tracer studies for 
each wastewater management option, it is difficult to assess the 
potential effects of local conditions on the fate and transport of 
treated wastewater after being released into the environment. While 
results from ground water monitoring around some Class I municipal 
disposal wells in Florida confirm that fluids have migrated out of the 
permitted injection zone, the full areal extent of USDW contamination 
is not known. The unknown degree of migration is not only because of 
limited availability of monitoring data, but also because the location 
and connectivity of natural conduits for fluid flow (fractures and 
solution cavities in underground formations) are difficult to predict. 
In addition, the rates of microbial survival, inactivation, and 
transport are difficult to predict. Also uncertain are the rates of 
microbial straining or filtration by geological materials under 
different fluid flow scenarios, including porous media and conduit 
flow. The fate and transport of pathogens is especially difficult to 
verify for deep well injection, even with the most sophisticated 
modeling or with expensive monitoring, since the receiving formations 
are thousands of feet underground.

G. May 5, 2003, Notice of Availability and Notice of Data Availability

    On May 5, 2003, EPA issued a Notice of Availability (NOA) (68 FR 
23673) announcing the availability of the Relative Risk Assessment and 
a Notice of Data Availability (NODA) (68 FR 23666), requesting public 
comment on how the Relative Risk Assessment informs this rulemaking.
    Following publication of the NOA and NODA, EPA held a series of 
public meetings on the Relative Risk Assessment. These meetings, held 
during the comment period, provided an opportunity for interested 
parties to submit oral comments on the Relative Risk Assessment. Two 
public meetings were held, one in West Palm Beach, Florida on June 24, 
2003, and a second in Tampa, Florida on June 25, 2003.
    The comments provided at the meetings address the same issues as 
those submitted in writing. EPA has considered the comments provided in 
the meetings along with the written comments submitted during the 
comment period following publication of the NODA. The comment response 
document for the NODA, which is part of the record for this rule, 
summarizes all of these comments and provides EPA's responses. These 
comments are also summarized in Section III.A and factored into the 
Agency's final decisionmaking discussion in Section IV of today's 
preamble.
    In the NODA, EPA summarized the findings of the Relative Risk 
Assessment, highlighting those that are most relevant findings to 
informing the final regulatory action, and requested comment on three 
issues: The appropriate level of wastewater treatment required for 
continued deep well injection; the feasibility of hydrogeological 
demonstrations for showing that injection will not cause fluids to 
enter USDWs; and whether some of the Class I municipal disposal wells 
in Florida are actually misclassified Class V wells.
1. NODA Question 1: What Is the Appropriate Level of Wastewater 
Treatment Prior to Injection?
    In the NODA, EPA requested comment on an alternative option for 
defining the appropriate level of wastewater treatment required for 
continued injection in deep municipal disposal wells in Florida 
(instead of the four options included in the July 7, 2000, proposal, as 
listed in Section II.D above). Based on comments received on the 
proposed rule related to wastewater treatment, as well as findings from 
the Relative Risk Assessment, the NODA solicited comments on 
prescribing wastewater treatment requirements that conform with 
relevant State requirements. Under this alternative, the Agency would 
simply adopt, in lieu of the standards considered in the proposal, the 
Florida standards in Rule 62-610.460, F.A.C. (for waste treatment and 
disinfection applicable to reclaimed water that may come into contact 
with people) or the standards in Rule 62-600.540(2), F.A.C. (for ground 
water disposal by underground injection in Class V wells) and Rule 62-
600.440(5), F.A.C. (for design and operational criteria for high-level 
disinfection). Specifically, EPA would require wastewater treatment 
that results in injected water meeting, at a minimum, secondary 
treatment and high-level disinfection as defined in the Florida 
regulations. Also, filtration would be required for total suspended 
solids (TSS) control prior to disinfection, which would specify that 
the treated wastewater not contain more than 5.0 mg/l of TSS before the 
application of the disinfectant. As discussed in the NODA, EPA believes 
that this treatment standard might offer some important advantages over 
the alternatives proposed on July 7, 2000. In particular, it might 
better address the risks associated with pathogens and it would be 
consistent with the standards already adopted and implemented in 
Florida for reclaimed water and wastewater disposed through Class V 
injection wells, which are part of domestic wastewater treatment 
systems.
    In the NODA, EPA asked commenters whether this standard for 
advanced

[[Page 70520]]

treatment and high-level disinfection should be specified in the final 
rule. EPA also requested that commenters describe the type of treatment 
that would be necessary to achieve the performance standards (i.e., 
national primary drinking water regulations and other health-based 
standards) and provide any information they have on the costs of this 
option.
2. NODA Question 2: Is It Feasible To Predict Movement of Fluids 
Through Hydrogeologic Demonstrations?
    In the NODA, EPA requested comment on whether the findings from the 
Relative Risk Assessment regarding deep well injection suggest anything 
about the practicability and feasibility of the approach outlined under 
Option 2 in the July 7, 2000, proposal. As summarized above, Option 2 
would allow owners and operators to conduct hydrogeologic 
demonstrations to show that injection will not cause fluids that exceed 
any national primary drinking water regulations or other health-based 
standards to enter any USDW.
    Based on the added findings in the Relative Risk Assessment 
regarding the Florida geology, EPA posed several questions in the NODA 
related to the uncertainties of hydrogeologic demonstrations that would 
be required under Option 2. In particular, EPA asked whether facilities 
should be granted the opportunity to conduct the demonstrations; how 
the UIC Program Director should address anticipated technical 
difficulties in his/her review of a demonstration; and how a 
satisfactory hydrogeological demonstration would be conducted.
3. NODA Question 3: Have Some Deep Wells Been Misclassified as Class I, 
When They Are Actually Class V?
    Given the extent of fluid movement documented at some sites, as 
well as information concerning the geology and the construction of some 
municipal disposal wells in Florida, it is possible that some wells may 
have been misclassified as Class I, when they are actually Class V. 
According to the Federal UIC regulations, Class I wells ``inject fluids 
beneath the lowermost formation containing, within one quarter mile of 
the well bore, an underground source of drinking water'' (40 CFR 
144.6(a)(2)). Class V wells are defined as wells that are not included 
in Class I, II, III, or IV. Typically, Class V wells release 
nonhazardous fluids into or above formations containing USDWs.
    Separate from the issue of how Class I and Class V wells are 
defined, the Federal Class I and Class V UIC programs differ in their 
basic approach to protecting USDWs. As previously described in Section 
II.B, the basic standard of protection in the Class I program is to 
ensure that there is no movement of any contaminant into USDWs. This 
standard is achieved through a Class I regulatory program that focuses 
on the development and enforcement of stringent permit requirements, 
including, but not limited to, criteria for well siting, construction, 
and operation and maintenance. A key component of the Class I program 
is ensuring that adequate confinement exists between the permitted 
injection zone and USDWs at a given site.
    Since most Class V wells release fluids either directly into or 
above USDWs, they by definition cause the movement of fluid, which may 
contain contaminants, into or above USDWs. Therefore, the basic 
standard of protection in the Class V program is to prevent any 
contaminants in the fluid from endangering USDWs. Protection efforts in 
the Class V program mainly focus on regulating and monitoring injectate 
quality to ensure that the movement of injected fluid will not contain 
any contaminants that may endanger USDWs. This standard is achieved 
through inventory and assessment requirements, additional reporting 
requirements, closure requirements, and other requirements (possibly 
including permitting requirements) believed by UIC Program staff to be 
necessary to protect drinking water supplies.
    Information collected for the Relative Risk Assessment raises a 
question as to whether certain Florida municipal disposal wells should 
have been classified as Class V at the time they were first permitted. 
In particular, all of the lithologic units of the upper Floridan 
Aquifer in Pinellas County and the lower Floridan Aquifer in Miami-Dade 
consist of limestone and dolomite that have shown evidence of solution 
cavities and fractures. These natural conduits for fluid flow raise a 
question as to whether lithologic units in these aquifers are effective 
confining layers and whether the injection zones and overlying USDWs 
are in different and distinct formations, as they were believed to be 
when the wells were originally sited, constructed, and permitted as 
Class I wells.
    Based on this information, the NODA requested comment on whether 
the findings from the Relative Risk Assessment suggest that some 
Florida wells may have been misclassified as Class I wells. EPA also 
asked whether the findings suggest that some wells in Florida may, in 
fact, discharge directly to (and not below) formations containing a 
USDW, and if the findings suggest that this misclassification should be 
accepted for the entire group of Florida municipal disposal wells, or 
only a subset.

III. Summary of Public Comments

A. Comments on the July 7, 2000, Proposed Rule

    EPA received 1,181 comments in response to the proposed rule. The 
following sections summarize the more significant public comments on 
the seven main issues raised in the proposal. These comments are 
addressed in more detail in the comment response document available for 
review in the Florida UIC docket as well as in Section IV of today's 
preamble.
1. Selection of Option 1, Option 2, or a Combination of Both
    In the proposal, EPA solicited comment on whether to select Option 
1 (advanced wastewater treatment (AWT) with a non-endangerment 
demonstration), Option 2 (in-depth hydrogeologic demonstration and 
advanced treatment, as necessary), or a combination of both options.
    Commenters who favor Option 1 explained that, although initially 
more costly, this option offers the advantage of allowing 
identification and avoidance of potential drinking water contamination, 
which would be more cost-effective than ground water remediation. One 
commenter offered that Option 1 should be required only if needed to 
meet the non-endangerment requirement. A commenter opposed to Option 1 
said that even with AWT, the proposed requirements may not prevent 
violations of drinking water standards in USDWs.
    Those commenters favoring Option 2 argued that it would be 
burdensome to require utilities to employ AWT immediately. They 
therefore suggested that AWT either should not be required at all or 
should be phased-in. One commenter opposing Option 2 said that 
facilities already perform analyses to demonstrate compliance, and 
geochemical modeling should be required only where actual data are not 
available. Another commenter opposing Option 2 said that it is unclear 
what geochemical modeling would accomplish.
2. Appropriate Level of Wastewater Treatment
    In the proposed rule, EPA requested comment on which treatment 
alternative to specify in the final rule, if Option 1 were selected. 
Comments were

[[Page 70521]]

solicited on the appropriate level of BOD treatment and the need for 
disinfection and nutrient removal.
    Commenters who favored higher levels of BOD treatment (to less than 
10 mg/l) asserted that these standards would protect the environment 
and can be met with available cost-effective technologies. Commenters 
opposed to requiring BOD treatment said that it is not possible to meet 
the disinfection requirement with BOD levels of 10 to 24 mg/l, or that 
there is no technical basis for requiring those levels, since the 
treated wastewater is being discharged to an anaerobic environment 
without plant life.
    Commenters who supported nutrient removal requirements said that 
such treatment would have environmental benefits, including protecting 
wetlands and endangered species. Commenters who opposed nutrient 
removal explained that it could adversely impact water reuse programs. 
These commenters also opposed setting phosphorus limitations, saying 
that there are no human health benefits associated with phosphorus 
removal.
    Commenters who favored requiring AWT said that injected fluids can 
move into surficial aquifers or near shore surface waters, and AWT is 
thus needed to protect aquatic species. Commenters opposed to requiring 
AWT asserted that imposing health-based standards as discharge 
requirements is inconsistent with the SDWA and not supported by 
scientific data. These commenters added that injection provides 
effective source separation that has protected water supplies for many 
years and that requiring AWT would jeopardize the viability of this 
practice going forward. Other commenters thought that AWT is 
insufficient to prevent endangerment of USDWs. These commenters 
expressed concern that the proposal does not adequately protect USDWs 
from many of the substances that may be found in municipal wastewater.
3. Need for Pretreatment
    EPA solicited public comment on the need for pretreatment as an 
additional condition of the authorization to inject, and on whether to 
extend the pretreatment requirements presently required by the State of 
Florida to injection facilities with flows of less than 5 MGD.
    Commenters advocating pretreatment requirements suggested that 
requiring industrial users to pretreat their wastewater would reduce 
the chance of contaminating USDWs and reduce the costs to municipal 
treatment works. Several commenters advocated extending pretreatment 
requirements to facilities with flows of less than 5 MGD.
    Commenters opposed to the pretreatment requirements cited concerns 
about the ineffectiveness of pretreatment programs to prevent fluid 
movement or protect public health.
4. Feasibility of Hydrogeologic Demonstrations To Predict Movement of 
Fluids
    EPA solicited comment on the ability of injection well owners and 
operators to provide the kind of hydrogeologic and other information 
necessary for a successful hydrogeologic demonstration that their 
injectate will not cause a USDW to exceed any primary drinking water 
regulations or other health-based standards.
    Commenters opposed to the proposed hydrogeologic demonstrations 
asserted that they could not accurately reflect flow responses after 
prolonged injection, and that EPA should not rely on them to protect 
USDWs. These commenters cited limitations in available knowledge of the 
subsurface geology of Florida and the fate of contaminants.
5. Monitoring Requirements
    EPA requested comments on the proposed monitoring requirements 
(which would include, at a minimum, effluent monitoring and an analysis 
of any such contaminants following injection), and asked whether any 
additional monitoring requirements should be included in the final 
rule.
    Some commenters challenged the proposed monitoring requirements, 
claiming that they are not adequate to prevent endangerment of ground 
water quality. Two commenters suggested a need to monitor for 
pathogens, viruses, and pharmaceuticals. Several commenters requested 
an increased monitoring frequency, believing that annual monitoring is 
insufficient to characterize the injected fluids.
    Many commenters requested that EPA clarify certain aspects of the 
proposed monitoring requirements, including what is meant by ``other 
health-based standards.''
6. Rule Applicability
    EPA requested comment on whether the rule should apply to existing 
wells only or also to new wells. Some commenters suggested that the 
rule apply to new and existing wells, as well as to replacement wells, 
and recommended that the rule apply in all counties where fluid 
migration could or does occur. Those commenters who opposed applying 
the rule to facilities that have not shown movement of fluid to USDWs 
expressed concern that such an approach would limit the future 
application of injection as a disposal technology.
    In the proposal, EPA also requested comment on whether any 
additional (or fewer) counties in Florida should be included within the 
scope of the rule. No comments requesting the addition or removal of 
any counties were received.
7. Suitability of Florida Geology for Domestic Wastewater Disposal 
Through Class I Wells
    Commenters provided information and background on the geology of 
Florida, fluid migration, and the appropriateness of wastewater 
injection in Florida.
    Some commenters expressed concern about injection operations 
contaminating drinking water aquifers with a virus or pathogen, citing 
evidence that effluent is leaking into the Floridan Aquifer that is 
hydrogeologically connected to the Biscayne Aquifer, the sole source of 
Miami-Dade's drinking water. These commenters said that there are many 
unknowns about the geology of Florida and that the behavior of injected 
fluids cannot be accurately predicted.
    Other commenters asserted that injection is a safe practice that 
has been taking place in Florida for decades without any documented 
adverse impacts to USDWs. They indicated that the injected fluid is 
``freshening'' the highly saline receiving waters, and that the 
availability of injection as a disposal alternative has resulted in 
significant improvements to surface water quality in Florida. Some 
commenters added that, in the proposal, EPA did not adequately 
characterize the subsurface geology in Florida. Some commenters 
recognized that fluid movement is occurring, but support a rule that 
allows fluid movement if it is accompanied by a non-endangerment 
policy. These commenters added that a strict no movement policy would 
eliminate all injection and supply wells in the region.

B. Comments on the Notice of Data Availability and the Relative Risk 
Assessment

    EPA received 203 comments in response to the NODA and its summary 
of the Relative Risk Assessment. The paragraphs below summarize the 
more significant comments on the three main issues raised in the NODA. 
The complete comment response document available for review in the 
Florida UIC docket addresses these comments in more detail.

[[Page 70522]]

1. Appropriate Level of Wastewater Treatment Prior to Injection
    In the NODA, EPA asked for comment regarding the level to which 
wastewater should be treated before it is injected into deep wells that 
have caused or may cause fluid movement into a USDW. Some commenters 
advocated requiring treatment to drinking water standards before 
injection, citing concerns about pathogens migrating to aquifers and 
the inability of modeling to identify all pathways by which 
contamination could occur. Some commenters also expressed concern about 
the potential migration of viruses, pathogenic bacteria, and protozoa. 
They asserted that data show that injected fluids are migrating and, 
without disinfection, pathogens may survive, especially where the 
travel times to USDWs are short.
    Some commenters advocated requiring denitrification as well. 
Commenters opposed to requiring advanced wastewater treatment said that 
current treatment requirements are adequate, and that the cost of 
requiring AWT all the time would be excessive. Some commenters 
cautioned against a ``one-size-fits-all'' approach, and suggested 
including case-by-case treatment requirements in permits. They added 
that, at most facilities, drinking water standards are already met 
within the aquifer and that, given the salinity of the injection zone, 
any water from the USDW would require reverse osmosis treatment before 
it is usable for drinking.
    EPA also asked commenters whether treatment consistent with 
corresponding Florida requirements (i.e., treatment that meets the 
State's secondary treatment and high-level disinfection standards) is 
appropriate. Some commenters advocated requiring AWT in accordance with 
Florida's standards. Other commenters said that Florida sets differing 
standards based on the quality of the receiving waters, and that simply 
adopting the Florida standard would not resolve the issue where fluid 
migration is occurring.
2. Feasibility of Hydrogeologic Demonstrations To Predict Movement of 
Fluids
    As previously described in Section II.F.2, the NODA requested 
comment on the practicality and feasibility of allowing facilities to 
conduct hydrogeologic demonstrations, given the inherent difficulties 
and uncertainties regarding the extent, location, and connectivity of 
possible natural conduits for flow identified in the Relative Risk 
Assessment.
    Commenters who advocated the use of hydrogeological demonstrations 
said that such demonstrations would provide utilities needed 
flexibility, given the hydrogeologic variability in Florida. They added 
that this approach would be in line with the intent of Congress and the 
SDWA. These commenters added that monitoring shows that contaminants 
are not moving into USDWs, and that the critical point to consider is 
whether the USDW is endangered (rather than just that fluids are moving 
into USDWs).
    C