EPA's Proposed Policy on Wastewater Blending: Background and Issues

Order Code RL32384

CRS Report for Congress

Received through the CRS Web

EPA’s Proposed Policy on Wastewater Blending:

Background and Issues

Updated May 24, 2005

name redacted

Specialist in Resources and Environmental Policy

Resources, Science, and Industry Division

Congressional Research Service ˜ The Library of Congress

EPA’s Proposed Policy on Wastewater Blending:

Background and Issues

Summary

In November 2003 the Environmental Protection Agency (EPA) proposed a

policy concerning a wastewater treatment practice called blending. The policy was

intended to clarify when the practice can be allowed and still adhere to Clean Water

Act regulations and requirements. Some cities use blending to manage peak flows

of water and waste into wastewater treatment plants during and after storms as a way

to prevent conditions that otherwise result in raw sewage backups into homes and

other buildings or overflows into nearby waters. Blending involves routing excess

wastewater around the plant’s biological treatment processes and recombining this

excess flow with fully treated wastewater before discharging it to a stream or lake.

Although blending has been standard engineering practice for several decades

as a way to manage peak stormwater flows, controversy exists about the practice,

both among stakeholder groups and also internally at EPA, where enforcement

officials have challenged the practice and in some cases opposed allowing cities to

use it. Others at EPA believe that, with certain restrictions, the practice is legal and

environmentally protective. Controversies and uncertainties led EPA to announce

on May 19, 2005, that it will not finalize the policy that it proposed in 2003.

This report provides background on blending, why and how it is practiced, the

proposed policy that EPA now says it will not finalize, associated issues, and

congressional interest in the topic. It will be updated as warranted.

Criticism of blending focuses on three concerns: legality of the practice, impacts

on public health and the environment, and other policy issues. A number of groups

and interests weighed in on all of these issues, especially in comments on the

November 2003 proposed policy. Environmental advocates say that the practice of

blending is inconsistent with existing rules that prohibit intentional bypass of a

treatment facility. These groups have also raised substantial concern about public

health and environmental impacts from discharges of wastes that contain pathogenic

organisms. Many cities and municipal organizations supported the EPA policy and

practice of blending, saying that if cities are barred from blending, they are forced to

make costly infrastructure investments, with limited benefit. While a number of

states supported the EPA policy, others opposed it for reasons including concern that

the policy would undermine incentives for cities to remedy the infrastructure

problems that result in sewage overflows.

In Congress, these issues have drawn some attention. In January 2004,

Members with differing views wrote to EPA to express concerns about the proposed

policy. A House subcommittee held a hearing on the topic in April 2005.

Legislation intended to bar EPA from issuing blending rules or guidance has been

introduced in the 109th Congress (H.R. 1126). Also, in acting on FY2006

appropriations for EPA (H.R. 2361), the House adopted an amendment prohibiting

EPA from using funds to finalize or implement the 2003 proposed blending policy.

Contents

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Wastewater Treatment Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Federal Law and Regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Wet Weather Pollution Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Administrative Actions: CSO and SSO Policies . . . . . . . . . . . . . . . . . . . . . . 5

What Is Blending? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

EPA’s Blending Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Issues with Respect to Blending . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Legality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Public Health and Environmental Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Water Quality Criteria for Bacteria . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Other Policy Concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Congressional Interest and Status of the Proposal . . . . . . . . . . . . . . . . . . . . . . . . 15

List of Figures

Figure 1. Blending at a Sewage Treatment Facility During a Storm . . . . . . . . . . 7

EPA’s Proposed Policy on Wastewater

Blending: Background and Issues

Introduction

In November 2003, the Environmental Protection Agency (EPA) issued a

proposed policy concerning a wastewater treatment practice called blending. It is a

type of operational practice that is used to prevent conditions that result in sewage

backups into homes and other buildings, or overflows of untreated waste into nearby

waters. The proposal was intended to clarify when the practice can be allowed and

still adhere to Clean Water Act regulations and requirements. Blending has been

used for several decades to manage peak flows of water and waste into wastewater

treatment plants during storms, but it recently has become controversial. The

practice involves routing excess wastewater from domestic, commercial and

industrial sources around the plant’s biological treatment processes and recombining

this excess flow with fully treated wastewater before discharging it to a stream or

lake (see Figure 1, on page 7). On May 19, 2005, after reviewing nearly 100,000

public comments on the proposal — many favoring it, but many others opposing it

— EPA announced that it would not finalize the 2003 proposal and will continue to

work on alternatives.

This report provides background on blending, why and how it is practiced,

EPA’s proposed policy, associated issues, and congressional interest in the topic.

Controversy exists about whether the practice is lawful under water quality

regulations, whether it is harmful to human health or the environment, and whether

it is good from a policy perspective. Supporters of the proposed policy, including

many cities, municipal organizations and some states, say that if blending is restricted

or prohibited, cities will be forced to spend limited public resources on costly water

infrastructure improvements that are used infrequently. Such critics as environmental

advocates and other states say that blending allows treatment plants to discharge

wastewater that could contain harmful pathogenic microorganisms. Many critics also

said that EPA’s proposed policy would have allowed treatment plants to blend even

when other more environmentally protective technological options are available. A

key issue was whether the policy would have clarified EPA regulations to allow the

safe use of blending by cities, as EPA intended, or would have fostered wider use of

wastewater management practices that critics believe will harm public health and the

environment.

The particular issues concerning blending also arise in the broader context of

policymakers’ efforts to control pollution associated with wet weather discharges that

happen only during and after major precipitation events. EPA believes that these

sources, including combined sewer overflow discharges, stormwater, separate

sanitary sewer overflows, and nonpoint source runoff, are the leading cause of water

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quality impairment in the United States.1 The nation’s initial efforts to control water

pollution focused on conventional point sources from municipal, commercial, and

industrial wastewater treatment plants that are typically characterized by predictable

flows and identifiable discharge points. Since the mid-1980s, policymakers have

turned attention to other, non-traditional wet weather pollution sources that are more

difficult to control because the sources are numerous and geographically dispersed,

and waste flows are intermittent and largely unpredictable. Managing these diverse

sources presents major policy and technological challenges.

Background

Wastewater Treatment Processes

In the United States, wastewater is discharged from sources such as homes or

industrial plants and is transported via collection systems consisting of sewers and

pumping facilities to a wastewater treatment facility. The wastewater components

of major concern are organic and inorganic materials that will deplete the oxygen

resources of the stream or lake to which they are discharged, those which may

stimulate undesirable growth of plants or organics (such as algae) in the receiving

water, or those with potential undesirable aesthetic effects or adverse health effects

on downstream water uses. Another important wastewater treatment concern is

removal of pathogenic bacteria and viruses that can cause disease.

Treatment plants generally work in two stages. Primary treatment mechanically

separates the coarser solids from the water, generally by screening and settling,

typically removing about 60% of solids and 35% of BOD from the untreated waste.2

The core element of wastewater treatment, called secondary treatment, follows

primary treatment; it typically involves biological processes. The biologic process

most often used today is the activated sludge process, which utilizes microorganisms

in an aerobic environment to remove a majority of the primary pollutants found in

wastewater. The microorganisms (bacteria and protozoa) use the remaining nutrients

and organic material in the wastewater as their food supply. Although secondary

treatment may remove more than 85% of the remaining BOD and suspended solids,

it fails to remove significant amounts of nitrogen, phosphorus, or heavy metals, nor

does it completely remove pathogenic bacteria and viruses. If further treatment such

as nutrient removal is required to meet water quality standards, tertiary biologic or

chemical treatment processes can be used. Following secondary or tertiary treatment,

1

U.S. Environmental Protection Agency. National Water Quality Inventory, 2000 Report.

EPA-841-R-02-001. August 2002. P. ES-3.

2

BOD, or biochemical oxygen demand, is a measure of the oxygen-consuming organic

matter and ammonia-nitrogen in wastewater and is used to determine how well a treatment

plant is working. The higher the BOD loading, the greater the resulting depletion of oxygen

in the waterway. The ability of a body of water to support life depends mainly on

maintaining a certain amount of dissolved oxygen (DO) because, for example, DO is what

fish breathe. Thus, federal regulations (and facility-specific permits that implement those

rules) specify maximum amounts of BOD that wastewater treatment plants may discharge,

as measured by the oxygen consumed in a stated period of time, usually five days (BOD5).

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the final effluent generally is disinfected before it is released to a receiving water,

most commonly by chlorination, ultraviolet irradiation, or ozonation.

Federal Law and Regulations

The 1972 Federal Water Pollution Control Act Amendments (P.L. 92-500,

commonly referred to as the Clean Water Act, or CWA) established a framework for

upgrading the nation’s wastewater infrastructure as one key element in the act’s

wide-ranging objective to restore the quality of the nation’s waters. The CWA

established a minimum pollution control standard for municipal wastewater

infrastructure, applicable nationwide, based on the application of secondary

treatment. It mandated application of more stringent treatment standards and

pollution control technology where necessary to protect local water quality and

established a permit program to ensure implementation of standards.

These requirements are implemented through regulations promulgated by the

EPA that define minimum levels of effluent quality for publicly owned treatment

works (POTWs) prior to discharge. The requirements of the secondary treatment

regulations are expressed as concentration limitations (seven-day and 30-day average

effluent concentration limits for total suspended solids (SS) and BOD5), percentage

removal requirements for both SS and BOD5, as well as a limitation on pH. For most

types of POTWs, the federal regulations establish a 30-day average percentage

removal requirement of 85% for SS and BOD5. The percent removal requirements

were established to achieve two basic objectives, according to EPA: (1) to encourage

cities to correct excessive infiltration and inflow I/I problems in their sanitary sewer

systems,3 and (2) to help prevent intentional dilution of influent wastewater as a

means of meeting permit limits.4

EPA regulations also define standard permit conditions to be included in all

Clean Water Act discharge permits. One of those standard conditions addresses

“bypasses,” which are defined as “the intentional diversion of waste streams from any

portion of a treatment facility” (40 CFR §122.41(m)). Under these rules, a bypass

is prohibited unless: it is unavoidable to prevent loss of life, injury, or severe

property damage; there are no feasible alternatives, such as use of auxiliary treatment

or backup facilities or retention of untreated wastes; and proper notice is provided to

the appropriate permitting authority. The bypass cannot cause effluent limitations to

be exceeded.

3

Infiltration occurs from too much rainfall or snowmelt percolating through the ground into

leaky sewers which are not intended to collect rainfall or to drain property. Infiltration can

also occur as a result of groundwater seeping directly into leaky sewers. Excess water can

also inflow through roof drains connected to sewers and broken or badly connected sewer

service lines.

4

68 Federal Register 216, Nov. 7, 2003, p. 63047.

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Wet Weather Pollution Problems

The collection system that conveys wastewater to the treatment plant is a key

element of the overall wastewater infrastructure system. Collection systems are

either combined sewer systems, which are designed to carry domestic and industrial

sanitary waste plus rainwater; or separate sanitary sewer systems, designed to collect

only domestic and industrial sanitary waste.5 Treatment plants and collection

systems are designed to handle the flows up to certain volumes under routine or

predictable operating conditions. A more difficult challenge is that of managing

flows that occur under peak flow conditions, during what is referred to as “wet

weather” events (rainfall, as well as snowmelt).

Extreme wet weather events can introduce larger volumes of water and waste

than the plant and collection system can adequately manage, resulting in collection

system overflows and backups of sewage into buildings, and water quality problems

from discharges of inadequately treated waste. During storm events, both combined

and separate sewer systems can experience overflows when the capacity of a sewer

is exceeded as a result of blockages, bottlenecks and/or undersized pipes. The

discharge of untreated or partially treated sewage contains pathogenic organisms that

represent a health risk and also may contain toxic and/or oxygen-demanding

pollutants. Infiltration/inflow of rainwater into sewers is believed to be the primary

factor causing peak flows in sewers, especially separate sanitary sewers. Aging

infrastructure and associated maintenance challenges can also lead to excess water

in sanitary sewer systems. High levels of I/I that reach the treatment plant increase

the hydraulic load on the plant, which can reduce treatment efficiency, exceed the

capacity of components within the plant, and in extreme situations make biological

treatment facilities inoperable. Treatment plant operators use a combination of

strategies to manage these peak flows, including implementing operation and

maintenance programs, enlarging pipes, adding or increasing storage capacity,

building additional treatment facilities, or using alternative treatment techniques to

move peak flows through the treatment.

Operators of treatment plants and collection systems have long faced these

challenges, and for the last 15 years or so, policymakers have been addressing various

wet weather pollution issues, including developing strategies to reduce overflows and

backups, as well as establishing appropriate regulatory and enforcement policies.

By definition, sewer overflows are unauthorized discharge points that violate the

Clean Water Act’s prohibition on discharges that are not in compliance with the

limitations and conditions of a discharge permit issued pursuant to the CWA.

Nevertheless, municipal officials and sanitary engineers say that it is practically

impossible to design a system that will never overflow. Even under the best of

conditions, engineers say, natural disasters and even pipe failures will lead to

5

Combined sewer systems are remnants of the nation’s early infrastructure and are found

in about 900 communities, primarily in older cities in the Northeast, Great Lakes region, and

the Pacific Northwest. Most combined sewer systems were constructed before 1900 when

the necessity for separate wastewater treatment was not readily apparent.

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unavoidable releases of sewage. However, chronic overflows result from inadequate

system maintenance and deterioration, not unavoidable circumstances.

Recognizing the view that sewer overflows are unavoidable, at least to a degree,

some permitting authorities have issued Clean Water Act permits to POTWs

allowing overflow discharges — despite the statutory prohibition on discharges that

do not meet secondary treatment requirements. For example, some permits authorize

overflows when they are not feasible to avoid, such as circumstances beyond the

control of the system operator. In rare cases, other permits may allow discharges at

specified locations, when specific permit requirements are met, such as meeting

effluent limitations, monitoring, and reporting. However, in other cases, state and

federal enforcement officials have held to the view that overflow discharges are

inconsistent with the Clean Water Act and have brought actions against

municipalities for overflows from combined and separate sewers, thus raising

questions about the clarity of EPA regulations and consistency of enforcement.

Administrative Actions: CSO and SSO Policies

In part because of perceptions of inconsistent policy and rules, in 1994, after

lengthy consultations with stakeholder groups, EPA issued a national strategy on

controlling overflows from combined sewers (CSOs). Designed to reduce CSO

discharges that often contain high levels of organic and toxic wastes, it outlined

conditions under which combined sewer systems that overflow as a result of wet

weather events may be authorized through permits or other enforceable mechanisms,

including a requirement that systems adopt nine minimum controls and long-term

control plans.

Soon after issuance of the CSO policy, EPA and a group of stakeholders

initiated discussions for development of similar national policy on controlling

overflows from separate sanitary sewers (SSOs). The discussions about an SSO

policy were based on certain principles: desire to clarify a general prohibition on

overflows; to establish stringent but feasible standards and require specific actions

that would help eliminate avoidable overflows; and to define circumstances for

enforcement against unavoidable overflows.6 EPA officials and stakeholders were

unable to reach consensus on SSO policy issues, and eventually EPA decided to

move ahead with regulations to control SSO discharges. The Clinton Administration

approved an SSO rule proposal late in 2000. The proposal was not published in the

Federal Register before Inauguration Day in January 2001, and the incoming Bush

Administration suspended it for review. However, it was widely circulated and was

available to the public for some time on EPA’s website.

6

Combined sewer systems are, in fact, designed to discharge excess wastewater directly into

surface waters, when the capacity of the sewer system is exceeded during heavy rainfall or

snowmelt. In regulating CSOs, the key concern is first to eliminate overflows during dry

weather conditions and then to minimize impacts of storm-related discharges. The issues

involving SSOs are somewhat different, because separate sanitary sewers are not designed

to overflow. When storm sewer overflows occur, they usually are from undesigned outfall

points. Prohibiting and eliminating all overflows to the extent feasible is key.

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After several months of review, in November 2001 EPA officials announced the

intention to propose the SSO rule developed by the Clinton Administration, but with

revised preamble language. During the review EPA considered a number of options,

including separate publication of noncontroversial parts of the Clinton proposal.

Chief among the controversies raised was whether EPA would open discussion of

alternatives to prohibiting SSOs or would retain the policy detailed in the Clinton

rule calling for strict enforcement against any overflows, regardless of fault. It

appears that these and other controversies persist, because as of May 2005, EPA has

not proposed or published an SSO control regulation.

During the SSO rule review, EPA staff also began working on draft guidance

on other wet weather peak flow management issues that was envisioned as separate

from but related to the SSO rule. In December 2001, EPA circulated among

stakeholders a draft guidance document addressing permit requirements and

enforcement procedures applicable under existing rules to three specific wet weather

situations. One of the three addressed the use of alternative peak flow treatment

schemes at the POTW (in contrast, for example, to procedures governing discharges

from emergency overflow structures located outside the boundary of a treatment

plant) — a practice generally referred to as “blending.” The December 2001 draft

was never formally proposed or finalized (although it was circulated to states, EPA

regional offices, and multiple other stakeholders). It evolved into a single proposal

published by EPA in November 2003 that focused only on blending.7

What Is Blending?

Blending is a wastewater flow operational technique used by some treatment

plants during and after storm events. In order to manage high flows in the collection

system at such times, a POTW operator modifies the flow of wastewater through the

treatment plant. During blending, primary treatment is provided for all flows coming

into the facility, and secondary treatment is provided for flows up to the capacity of

the secondary biological treatment units. The latter typically are designed with less

capacity than primary treatment units, which can handle significant variations in flow

and concentration of pollutants, while the microorganisms in biological units are

more sensitive and can be negatively affected by such changes. The excess flows are

diverted around the secondary biological treatment units and then recombined, or

blended, with flows that have been treated by the secondary units. The blended

effluent is usually disinfected prior to discharge to a lake, stream, or coastal

waterbody — particularly if the discharge will affect bathing or fishing waters.

Figure 1 illustrates the process.8

Sanitary engineers and municipal officials say that blending is necessary because

if surges of excess flow from storm events enter the secondary treatment units, they

7

U.S. Environmental Protection Agency. “National Pollutant Discharge Elimination System

(NPDES) Permit Requirements for Municipal Wastewater Treatment Discharges During

Wet Weather Conditions.” 68 Federal Register 216, Nov. 7, 2003, pp. 63042-63052.

8

A typical sewage treatment system schematic showing flows during non-storm conditions

would look the same as Figure 1 but would not show part of the flow being diverted around

secondary treatment units.

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will wash out the bacteria which comprise the biological processes used during

secondary treatment. These bacteria are less tolerant of variations in flow volumes

and strength (i.e., more rainwater and more dilute/less sewage) than are systems used

in primary treatment units. If the bacteria are washed out, it can take weeks or

months for a biological treatment unit to recover by re-generating the necessary

microorganisms; in the mean time, excess pollutants may be discharged to the

environment. POTW officials say that it is not possible to build treatment plants to

a capacity where they could treat 100% of all wastewater during peak flows, because

during the more common dry periods, the biological component of the treatment

process would essentially starve to death.

Figure 1. Blending at a Sewage Treatment Facility During a Storm

Source: CRS.

As noted above, POTWs have a number of technological options for managing

peak wet weather flows beyond the boundary of the facility, ranging from correcting

infiltration and inflow in order to reduce the hydraulic load in the sewer system, to

constructing equalizing basins or storage tanks to hold rainwater off-line until flows

can be routed to the treatment plant. Milwaukee and Chicago, for example, have

built elaborate underground tunnel systems to temporarily hold peak flows. Some

cities also are investigating or constructing new or innovative technologies. One of

these is a high-rate clarification process with rapid settling of solids from the waste,

which both provides some initial treatment and reduces the volume of waste material.

Other technological options involve constructing secondary-equivalent treatment

units based on physical/chemical, not biological, processes, which can be started up

quickly and can sit idle between storm events. Depending on land availability, some

of these technologies may be used on-site at the POTW. Others are utilized remotely

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and can provide sufficient treatment to comply with EPA’s secondary treatment

discharge limits for suspended solids and BOD5.9

Treatment plant operators view blending as another technological option, one

that is preferable to overflow discharges of untreated waste or sewage backups in

basements. In 2002, the Association of Metropolitan Sewerage Agencies,

representing many of the nation’s large POTWs, conducted a survey on wet weather

management. Thirty percent (78) of AMSA’s members responded, and 37

respondents (47%) said they do blend during wet weather conditions, generally only

a few times per year. Of 41 who do not currently blend, 24 (58%) said that blending

would enable the POTW to meet permit limits all or a majority of the time.10

Proponents of blending argue that, if blending is restricted, municipalities are forced

to spend public resources to build structures with limited public benefit, because of

their infrequent use during occasional storm events. While EPA has not estimated

the national cost of providing sufficient treatment to preclude blending, it has

estimated that the cost of correcting sanitary sewer overflow occurrences nationwide

— a rough surrogate — is $88.5 billion.11 Groups representing municipalities

believe that the cost is likely to be higher, perhaps from $200 to $300 billion.

EPA’s Blending Policy

Blending has been standard engineering practice since the 1970s, engineers say,

as a way to manage peak flows during storm events to prevent conditions that result

in backups into homes and other buildings or overflows of untreated waste into

nearby waters. Nevertheless, controversy exists about the practice, both among

stakeholder groups and also between several of EPA’s regional offices and some at

EPA Headquarters. EPA’s Office of Water has generally supported the practice, but

the Office of Enforcement and Compliance Assistance (OECA) has challenged it.

Officials in OECA have argued that, without certain restrictions, the practice of

blending is not enforceable. With appropriate restrictions, they say, permits

authorizing blending are possible, but crafting permits to do so is complex and

confusing. Others in EPA believe it is possible to write permits that lawfully allow

for blending, and the policy that EPA proposed in November 2003 was intended to

clarify how existing Clean Water Act regulations and permit requirements apply to

wet weather blending scenarios.

9

It is more problematic for these alternative technologies to achieve the percentage removal

requirement of EPA’s secondary treatment rules, because wastes are more diluted in higher

volume wet weather flows than in normal dry weather flows.

10

Association of Metropolitan Sewerage Agencies. “AMSA Wet Weather Survey, Final

Report.” May 2003. 37 p. Available at [http://www.amsa-cleanwater.org/advocacy/

wwsurvey/WetWeatherFinalReport.pdf]

11

U.S. Environmental Protection Agency. Clean Watersheds Needs Survey 2000, Report

to Congress. EPA-832-R-03-001, August 2003, pp. 4-1 - 4-3.

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The proposed policy set forth six criteria for managing peak flows, including

blended discharges:

!

!

!

!

!

!

The final blended discharge must meet effluent limitations based on

the secondary treatment regulation, including applicable percentage

removal requirements, or any more stringent limits necessary to

attain water quality standards.

The facility’s permit application must specify the treatment scenario

that would be used for peak flow management.

All flow must receive at least the equivalent of primary clarification.

Peak flow treatment should be operated as designed and only be

used when flows exceed the capacity of storage units and biological

treatment units.

The facility’s discharge permit must require sufficient monitoring to

ensure compliance with applicable Clean Water Act requirements.

The permit also must require that the permittee’s collection system

be properly operated and maintained.

In addition, the policy stated that, where physically possible and economically

achievable, blended effluent should not be discharged to sensitive receiving waters,

such as beaches, public drinking water intakes, waters with threatened or endangered

species, or designated Outstanding National Resource Waters and National Marine

Sanctuaries. EPA’s proposed policy assumed that if blending is done under the

limited terms of the policy, the practice would be fully protective of human health

and the environment.

Issues with Respect to Blending

Criticism of blending encompasses three areas: legality of the practice, impacts

on public health and the environment, and other policy concerns.

As discussed below, a number of groups and interests have weighed in on these

issues, especially in comments on the November 2003 proposed policy.

Environmental advocates oppose the practice on legal grounds, and they and public

health professionals have raised substantial concern based on public health and

environmental issues. Proponents include many cities and municipal and local

government organizations, including the National League of Cities, National

Association of Counties, and Association of Metropolitan Sewerage Agencies

(AMSA). Among states, views differ. Several states supported EPA’s proposed

policy, others supported it with additional restrictions or clarification (such as barring

blended discharges into impaired waters where water quality standards have not yet

been attained), and others opposed the practice based on a variety of policy concerns.

In some instances, individual cities commented in support of the policy, but agencies

of these cites’ home states opposed it (for example, the Miami-Dade Water and

Sewer Department supported it, while the Water Resources Management Division

of Florida’s Department of Environmental Protection opposed it).

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Legality

The focus of legal concerns over blending rests on whether the practice is

inconsistent with EPA’s existing “bypass” regulation which prohibits “intentional

diversion of waste streams from any portion of a treatment facility” and requires a

determination that “no feasible alternatives” to the bypass exist, including installation

of adequate backup facilities (40 CFR §122.41(m)). Critics argue that these

provisions preclude blending and mandate that POTWs provide larger plant

capacities, including temporary storage, so that all influent flows enter every

treatment process unit. Since secondary treatment units are clearly part of the

treatment unit, according to this view, blending violates the bypass rule’s prohibition

of intentional diversion. A bypass is allowed under EPA regulations when it is

unavoidable, but critics say that the proposed blending policy would have allowed

it as more routine practice. In the November 2003 proposed policy and guidance,

EPA interpreted the bypass rule to allow for blending that complies with the criteria

spelled out in the policy. Proponents of blending argue that, as long as the system is

operated as designed, and the planned operational regime is disclosed to the

permitting authority, it fully complies with the bypass regulation.

Concern over the legality of blending is the basis of actions brought by EPA

enforcement officials in several regions — especially Region III (Philadelphia),

Region IV (Atlanta) and Region VI (Kansas City) — challenging Clean Water Act

permits proposed by state permitting authorities that would allow for blending.12

These EPA regions, supported by states and environmental advocates, have declined

to authorize blending in discharge permits because they believe the practice violates

Clean Water Act rules mandating that all wastewater meet secondary treatment

standards. Some other EPA regions have not prohibited or limited blending in

POTW permits and have generally agreed with supporters of the practice that permits

could, under certain circumstances, authorize re-routing or recombination of waste

without being considered a bypass. For example, supporters say, if analysis of

feasible alternatives has been done and permitting authorities have been notified,

blending does not constitute a bypass. In 2002, a group of cities from Pennsylvania,

Tennessee, and Arkansas and AMSA brought legal action against EPA, alleging that

the prohibition on blending exercised by some EPA regions is not evenly applied

among its regional offices and is not supported by any national regulation. The

lawsuit was dismissed by a federal district court in November 2003, the court saying

that it lacked subject matter jurisdiction over regional guidance documents that do

not constitute final agency action by EPA Headquarters (Pennsylvania Municipal

Authorities Association v. Horinko, D.D.C., No. Civ. 02-01361, Nov. 20, 2003). An

appeal of the case is pending in the U.S. Court of Appeals for the District of

Columbia Circuit.

12

The Clean Water Act allows EPA to delegate permitting responsibility to qualified states,

and EPA has done so for 45 states and one territory. EPA issues permits in the remaining

states and territories. However, even after delegation, EPA retains oversight to ensure that

state-issued permits comply with the CWA’s requirements. If EPA objects in writing to a

permit, the permit may not be issued (§402(d)(2)).

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Some EPA enforcement officials reportedly were concerned that issuance of a

national policy would allow POTW operators to reopen consent decrees that now

prohibit blending among other wet weather management controls. Alternatively,

some were said to be concerned that POTWs could potentially sue EPA under the

Federal Tort Claims Act to receive compensation for having installed costly pollution

controls, or that they might petition EPA and states to revise their discharge permits.

Public Health and Environmental Impacts

The largest area of disagreement about blending rests on the issue of public

health and environmental impacts. Supporters of the practice contend that, so long

as the ultimate discharge from a POTW complies with EPA’s secondary treatment

rule or more stringent local water quality limits — as the proposed policy would have

required — public health and the environment are adequately protected.

Disease-causing pathogens, including bacteria, parasites and viruses, can be

found in domestic sewage, and may cause both chronic and acute illnesses, ranging

from cholera, gastroenteritis, infectious hepatitis, and shigellosis to respiratory and

skin infections. Outbreaks of waterborne diseases are associated both with exposures

to contaminated drinking water supplies (resulting from inadequate treatment,

disrupted treatment processes, or cross-contamination of wastewater and water

supplies lines) and exposure to contaminated recreational waters. According to

surveillance data compiled by EPA and the Centers for Disease Control and

Prevention (CDC), states report, on average, approximately 20 such outbreaks per

year linked to drinking water supplies and 30 per year linked to recreational water

exposure, in total causing illness in several thousand persons annually. Since 1989,

the number of gastroenteritis-related outbreaks involving recreational waters has been

gradually increasing.13 The concern of public health and environmental advocates

about blending and other peak flow management issues is whether effluent

containing pathogens is being adequately treated prior to discharge.

EPA’s secondary treatment rules do not specifically limit pathogens. While

primary wastewater treatment processes may remove about one-half of the suspended

solids and BOD from raw wastewater, these processes are not effective in removing

microbial pollutants. Secondary treatment removes about 85% of the organic matter

in sewage and is considerably more effective at removing microorganisms —

including up to 99% of viruses, which are known to cause a significant percentage

of all gastrointestinal illnesses, and 99% of bacteria and parasites.14 Two Canadian

studies reported that primary wastewater treatment removes on average 76% and

27%, respectively, of Cryptosporidium and Giardia lambia, parasites associated with

13

Lee, Sherline H., Deborah A. Levy, Gunther F. Craun, Michael J. Beech, Rebecca L.

Calderon. “Surveillance of Waterborne-Disease Outbreaks — United States, 1999-2000.”:

Nov. 22, 2002/(appears in Morbidity and Mortality Weekly Report) 51 (SS08);1-28.; online

at [http://www.cdc.gov/mmwr/preview/mmwrhtml/ss5108a1.htm].

14

U.S. Environmental Protection Agency. Office of Research and Development. Design

Manual: Municipal Wastewater Disinfection. EPA/625/1-86-021, 1986, Table 2-3, p. 6.

CRS-12

waterborne illness in the United States, and that secondary treatment was needed to

achieve 90% or greater reduction of both.15

When primary treatment alone is provided, very high doses of chlorine are

required to remove viruses or parasites. Moreover, when extra doses of chlorine are

needed to disinfect the primary-treated waste, the chlorine combines with certain

organic matter in the wastewater, creating compounds such as trihalomethanes,

which are hazardous chemicals. These disinfection by-products are carcinogenic and

may increase risk of cancer to humans, thus creating a secondary set of health

hazards.

Supporters of blending respond to the arguments about public health impacts by

acknowledging that primary treatment alone does not remove all pathogens, but also

by pointing to the paucity of data to actually link human health impacts to discharges

of raw or partially treated sewage. For example, to understand the relative magnitude

of major sources to water contamination, a project by the Water Environment

Research Federation studied occurrence of the parasite Cryptosporidium in two

Wisconsin watersheds and found that contributions of Crypto oocysts from POTW

effluents were nearly insignificant compared with contributions from other sources,

especially wastes in uncontrolled runoff from farm lands and urban/suburban lands.16

While supporters and critics disagree on a number of issues, they are in broad

agreement on one point: more monitoring and investigation are needed to determine

the frequency of sewer overflows and assess the number of people made ill from

waterborne diseases related to such discharges. Data on the incidence of waterborne

diseases in the United States (and other impacts, such as closing of beaches and

shellfish beds) frequently are unable to pinpoint the source or sources of

contaminating agents. Both environmental advocates and groups representing

POTW operators want more study of the possible health problems — the latter saying

that, if there are only limited scientific studies documenting a problem, it is unwise

for the nation to spend scarce public resources to address it. Environmental

advocates say that the lack of data linking wastewater discharges to waterborne

illnesses does not mean that the connection does not exist — the problem is in

quantifying the health risk.

These questions were partly addressed in an August 2004 EPA report to

Congress that was mandated by the Wet Weather Water Quality Act of 2000 (P.L.

106-554) concerning human health and environmental impacts of CSOs and SSOs.

In that report, EPA said that there is an absence of direct cause-and-effect data

relating the occurrence of CSO and SSO discharges to specific human health impacts,

due to factors such as under-reporting of waterborne illness and the presence of

pollutants from other sources. But, based on data from a subset of the nation’s

swimming areas, EPA estimated that between 3,448 and 5,576 illnesses occur

15

Katonak, Rachel and Joan B. Rose. “Public Health Risks Associated with Wastewater

Blending.” Department of Fisheries and Wildlife, Michigan State University, Final report,

Nov. 17, 2003, pp. 22-23.

16

Water Environment Research Foundation. Sources and Variability of Cryptosporidium

in the Milwaukee River Watershed. Stock no. 99HHE2. 2003. 132 p.

CRS-13

annually in people exposed to waters contaminated with bacteria and viruses from

sewer overflows. That estimate, the report said, captures only a portion of the likely

number of annual illnesses attributable to CSO and SSO contamination of

recreational waters.17 Uncertainty about public health impacts was a key factor that

affected finalization of EPA’s proposed policy, as critics contended that the bypass

of secondary treatment in a blending scenario may not adequately protect human

health and that current monitoring strategies do not accurately assess the amount of

harmful bacteria present in surface water after blending.

Water Quality Criteria for Bacteria. In the Federal Register Notice

announcing the proposed blending policy, EPA said that it encourages states to adopt

protective water quality criteria for bacteria in their water quality standards, since

standards based on scientifically sound methods are needed as indicators for

determining the human health risk from pathogenic microorganisms in waste

discharges.18 The likelihood of states doing so voluntarily is uncertain, however.

EPA publishes water quality criteria which consist of scientific information on

the concentrations of specific constituents in water which protect aquatic life or

human health. The issue concerning water quality criteria for bacteria stems from the

fact that, in the early years following enactment of the 1972 Clean Water Act, EPA’s

recommended water quality criteria were based on specific levels of fecal coliform

to be used as the indicator organism to protect bathers from gastrointestinal illness

in recreational waters, and consequently most state-adopted water quality standards

have been based on that indicator since the 1970s. In 1986, EPA recommended that

states adopt criteria based on Escherichia coli (E. coli) and enterococci to

demonstrate the presence of fecal pollution, because newer epidemiological studies

have found a stronger correlation between swimming-associated gastroenteritis and

these organisms than with fecal coliform or other indicator organisms.

In the Beaches Environmental Assessment and Coastal Health Act of 2000

(BEACH Act, P.L. 106-284), Congress required the 30 coastal and Great Lakes states

to adopt EPA’s 1986 water quality criteria for pathogens by April 2004. As required

by that law, in July 2004 EPA proposed federal water quality criteria for 20 states

that missed the deadline for adopting more up-to-date criteria for pathogens in their

water quality standards. At that time, EPA said that 16 states were in the process of

adopting revised criteria, while four states had not moved forward on the criteria.

Most of the 20 states had standards in place, but EPA did not think they were

adequately protective of human health because they rely on fecal coliforms as the

pathogen indicator, rather than incorporating limits for E. coli. However, wastewater

treatment officials and some in the scientific community have questioned use of the

1986 criteria document because it relies on data that are more than 20 years old. EPA

acknowledges that problem and is working on additional epidemiological studies of

pathogen indicators of illnesses at beaches in order to develop new water quality

criteria to protect swimmers in recreational waters by October 2005, as mandated by

17

U.S. Environmental Protection Agency. Office of Water. Report to Congress, Impacts

and Control of CSOs and SSOs. EPA 833-R-04-001. August 2004. p. 6-9.

18

68 Federal Register 216, Nov. 7, 2003, p. 63051.

CRS-14

the BEACH Act. In the mean time, the law requires EPA to press states to adopt

standards based on the existing criteria for pathogens.

Other Policy Concerns

Critics of EPA’s November 2003 proposed policy, including environmental

advocates and a number of states, believe that the proposal would not have

definitively restricted blending to wet weather events only. Some state officials, for

example, said that allowing blending undermines the POTW’s incentive for

removing wet weather infiltration and inflow and otherwise improving the collection

system.19 These and other critics asserted that the policy would allow bypasses to

become routine and would relieve treatment plant operators from analysis to

determine if there are feasible alternatives to bypass/blending. According to these

critics, blending succeeds in meeting permit discharge limits by virtue of dilution

(mixing), not technological pollution control. Further, blending in effect shifts the

cost of treating wet weather flows to drinking water suppliers, who become

responsible for removing residual microorganisms or harmful disinfection byproducts

that enter the water supply after discharge by the POTW. Others recognize the need

for POTWs to blend wastewater in certain temporary circumstances but say that it

should not be used as a long-term solution in order to avoid treating peak and base

flows when treatment is feasible and can be done according to standard engineering

practice.

Yet, while some were critical that the proposed policy would be too flexible,

others believed that it would be too restrictive. Some of these critics, including

municipal officials and sanitary engineering professionals that support blending,

believed that the proposal contained a number of vague or excessively broad terms

that needed to be further refined, such as what is “generally accepted good

engineering practice” for design and operation of a POTW. They also charged that

the policy sought to restrict discharge of blended wastes into sensitive receiving

waters and that it would have required the system operator to utilize all peak flow

capacity of sewers and other storage devices before commencing blending. These

restrictions, they say, amount to EPA dictating design and operations of the treatment

facility, which is contrary to the Clean Water Act. They argued that ambiguities

would allow different EPA regions to interpret the policy differently, resulting in

inconsistencies much like those that EPA had hoped to resolve by issuing the policy.

These critics urged EPA to require that the policy be binding in all regions. On the

other hand, a number of commenters urged EPA to do the opposite: to clarify that

the final policy, as in the proposal, would allow states and regions the option to not

authorize POTWs to blend, if that is their preference.

A number of critics of EPA’s proposal — both those who oppose blending and

others who favor it — asserted that the policy represented more than just

interpretation of current rules, that it fundamentally would have changed existing

19

See, for example, Letter from Larson, Jeffrey H., Manager, Permitting, Compliance and

Enforcement Program, Environmental Protection Division, Water Protection Branch,

Georgia Department of Natural Resources. EPA Docket ID No. OW-2003-0025-0482, Jan.

9, 2004, 6 p.

CRS-15

requirements, such as the bypass rule and the ability of operators (not EPA) to design

and operate plants in order to meet permit requirements. Some of these critics shared

the view that in the 2003 proposal, EPA had transformed the policy into a

rulemaking. As presented, the proposal was not a formal rulemaking (which would

be subject to the notice and comment procedures of the Administrative Procedure Act

(APA), although EPA did solicit public comments that it compiled in a docket), nor

did it contain changes to current regulations. EPA characterized the policy as an

interpretation of current rules and a draft guidance to implement such an

interpretation. In addition, so long as the policy was not considered by EPA to be a

rule, it was unlikely to be seen by EPA as subject to provisions of the Congressional

Review Act (CRA, 5 U.S.C. §§801-808), which requires that before a rule can

become final, it must be filed with the House and Senate and the General Accounting

Office. The CRA allows Congress to disapprove agencies’ rules by enacting a joint

resolution of disapproval.20

Congressional Interest and Status of the Proposal

In Congress, the issues and practice of blending have drawn some Members’

attention. In January 2004, during the public comment period on the proposed

policy, Members with differing views on the proposal wrote to EPA to express

concerns about it. In one letter, four House committee and subcommittee chairmen

urged EPA to issue the policy, but said that the draft needed to clarify inconsistent

regional enforcement. As drafted, the proposal would overstep federal authority and

bypass the role of states in clean water decisionmaking, the lawmakers said. Further,

they asserted that the proposal would establish “new back-door regulatory-type

requirements to be imposed at the discretion of the permitting authority [that] will

lead to less, not greater, national consistency.”21 These Members called for EPA to

revise the guidance to make clear that blending is an acceptable practice and to make

sure that the policy is implemented in a reasonable and consistent manner nationally.

At the same time, a bipartisan letter from 64 House Members of the

Congressional Coastal Caucus criticized the draft policy as an environmental rollback

that would endanger public health. Focusing on the concern that blending may lead

to discharges of microbial pathogens into waterways, the letter faulted the draft

policy for not ensuring that disinfection be required when a POTW blends its

20

For additional information, see CRS Report RL32240, The Federal Rulemaking Process:

An Overview, by Curtis Copeland. It should be noted, however, that the CRA has a broad

definition of the term “rule” that encompasses not only formal notice and comment

proceedings under the APA but also policy statements, guidance, and other agency issuances

that may have a legal or practical binding effect on the regulated public. See CRS Report

RL30116, Congressional Review of Agency Rulemaking: An Update and Assessment After

Nullifcation of OSHA’s Ergonomics Standard, by Mort Rosenberg, pp. 2-3.

21

Letter from Don Young, Chairman, Committee on Transportation and Infrastructure, John

J. Duncan, Jr., Chairman, Subcommittee on Water Resources and Environment, Tom Davis,

Chairman, Committee on Government Reform, Doug Ose, Chairman, Subcommittee on

Energy Policy, Natural Resources, and Regulatory Affairs. EPA Docket No. ID OW-20030025-0533, Jan. 7, 2004, 3 p.

CRS-16

effluent. This letter recognized the problem of excess flows during storms, but said

that blending sewage is an unacceptable alternative and that treatment facilities

should consider building additional capacity or short-term storage until all the sewage

can be treated with biological processes.22

Several developments have followed in the 109th Congress. On April 13, 2005,

the House Transportation and Infrastructure Committee’s Water Resources and

Environment Subcommittee held a hearing about the practice of blending and

received testimony from a number of municipal officials who support blending and

environmental advocates who discussed their opposition to it. Also, legislation has

been introduced that is intended to prohibit EPA from issuing rules or guidance that

would authorize blending, unless necessary to prevent loss of life, personal injury,

or severe property damage (H.R. 1126). (Congress took no action on a similar bill

that was introduced at the end of the 108th Congress, H.R. 5421.)

Further, in approving legislation providing FY2006 appropriations for EPA

(H.R. 2361), the House adopted an amendment that would prohibit EPA from

finalizing, issuing, implementing, or enforcing the 2003 proposed blending policy.

Supporters of the amendment, which the House approved by voice vote on May 19,

2005, said that the provision in the bill was not intended to have any impact on

existing policies of EPA regions and states that currently allow blending, or on any

Clean Water Act permit that allows blending. The amendment’s sponsor,

Representative Stupak, said it would maintain the status quo by preventing EPA from

adopting policies that would weaken environmental standards.23

After publication of the proposed policy in November 2003, EPA solicited

public comments for a 120-day period, compiling a docket with more than 98,000

comments. Many observers had expected EPA to issue a final version of the policy

in mid- or late-2004, but the agency did not do so. Issues that reportedly continued

to be unresolved included whether the policy would apply only to future CSO

settlements or also to past enforcement settlements (if applied retroactively, the

guidance could force the re-opening of consent decrees in a number of cases) and

whether the guidance must require municipalities to conduct a “no feasible

alternatives” analysis to prove that blending is necessary. On May 19, 2005 (the

same day that the House adopted the Stupak amendment to H.R. 2361), EPA officials

announced that, after reviewing the public comments and testimony presented to

Congress, the agency had decided to withdraw the November 2003 proposal and not

finalize the policy. The announcement said that EPA will continue to review

alternatives (i.e., a revised policy or perhaps a rulemaking) to develop the most

feasible approaches to treating wastewater and protecting communities.

Not surprisingly, environmental advocates were pleased with EPA’s decision

to abandon the proposal. On the other hand, municipal groups and other supporters

of blending and the proposed policy were disappointed. They indicated that EPA’s

failure to issue a definitive policy continues to leave communities in an uncertain

22

“Competing Hill Critiques Hand EPA Tough Choices on Blending Policy.” Inside EPA,

vol. 25 no. 5, Jan. 30, 2004, p. 16.

23

Congressional Record, daily ed., May 19, 2005, p. H3665.

CRS-17

position about whether and, if so, when treatment plant operators may use blending.

Until the agency clarifies these issues, these groups say, municipalities are unsure

about EPA’s legal interpretation and what treatment plant improvements cities must

make to ensure their compliance with the law.

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