weftec® 2012 technical session proposal form...weftec® 2012 technical session proposal form...

WEFTEC® 2012 Technical Session Proposal Form Submitted by: Christopher W. Tabor, P.E. [email protected] Organizing WEF Committee (or Other Group): MWTDC – Wet weather Task Group and Government Affairs Supporting WEFTEC Program Committee Symposium: Municipal Wastewater Treatment Symposium SESSION DESCRIPTION Proposed Session Title: Managing Peak Wet Weather Flows in Municipal Treatment

Systems, Technically Speaking – What to do when it rains! Session Format: (check one): Platform

Panel Discussion Combination of Both �

Brief session description: The MWTDC and the Government Affairs committee is currently supporting the update to the WEF document, “Guide to Managing Peak Wet Weather Flows”. The work includes providing updated technical documentation to support many of the concepts presented within the document. As such, this technical session supports the WEF document revision and provides a compilation and forum to summarize the updated technical material. A panel discussion will close the session to solicit additional input from the audience for the work and determine if additional needs exist or if a course correction is required. Brief session approach:

• A regulatory perspective will be presented (history, pending issues, and how can utilities still manage through this process)

• An overview of sustainable collection system strategies for wet weather flow management

• Approach to managing wet weather flows inside the WWTP( the distinction between dry

and wet weather process selection approaches, a tour of treatment improvement approaches/technologies, case studies)

• Facilitated panel discussion

Is this session on a “hot” topic? YES NO Why? Currently EPA is establishing guidance for implementation of various treatment practices both inside treatment facilities and within our communities. There is a higher industry wide interest with stormwater management and treatment. Additionally, the GAC with support from MWTDC is revising the “Guide to Managing Peak Wet Weather Flows” and this provides a forum to highlight and promote the work and solicit additional input from the audience. How is the information in this session different or unique from what may come from the call for abstracts? Highlights WEF update to “Guide to Managing Peak Wet Weather Flows” and is topical in light of EPA regulatory activities and ongoing technical practices.

Session keywords: (List or select from attached list) Legislation (Policy, Legislation, Regulation) Wet Weather Operations and Maintenance CSOs/SSOs Stormwater

Green Infrastructure Disinfection Pathogens Infrastructure Process Design

AUDIENCE INFORMATION Who is the target audience for this session? (List or select from attached list) Regulators, facility management, engineers, operators, designers, Does this session apply to professionals in water, wastewater, or stormwater? (circle all that apply) WATER WASTEWATER STORMWATER Estimated Attendance: 100 SESSION DETAILS Will this session require different set up (standard is theater seating, podium, head table seating for 2 people, 1 LCD projector/screen)? YES NO If yes, why and what is needed? Is this a full session or half session? FULL HALF A full session consists of 3 hours of presentations with a ½ hour break in the middle; half sessions are 1 ½ hours with no break.

Will all speakers provide a manuscript for the proceedings? YES NO If no, please justify. Will any speaker require any assistance (registration for the session, etc.)? YES NO If yes, please justify. Proposed Moderator: Please note that we will send all future correspondence regarding this session to the moderator unless you specifically request here that someone else be included on all communication. Name: Christopher W. Tabor Email: [email protected] Proposed Assistant Moderator 1: Name: Julian Sandino, Ph.D. Email: [email protected]

Proposed Assistant Moderator 2: Name: James D. Fitzpatrick Email: [email protected] Proposed Speakers and Topics: Please list each speaker, and include a one to three page abstract in this proposal for each topic or speaker in the session. If this is a panel, please include the list of speakers and any more detail needed for their topics. Speaker 1: Name – Pat Bradley Affiliation – Limno-Tech Title of Presentation – Urban Wet Weather and Integrated Planning/Permitting: Past, Present, and Future Email: [email protected]

Speaker 2: Name – Dan Ott Affiliation – Johnson County Wastewater Title of Presentation – Water, Water Everywhere! – Overview of Sustainable Collection System Strategies for Effective Wet Weather Treatment. Email: [email protected] Speaker 3: Name – Julian Sandino Affiliation – CH2M Hill Title of Presentation – Is isn’t Cut and Dry – General Considerations in the Development of Wet Weather Flow Improvement Scenarios for Wastewater Treatment Facilities Email: [email protected] Speaker 4: Name – Jim Fitzpatrick Affiliation – B&V Title of Presentation – Preparing for a Rainy Day – Overview of Treatment Technology Options for Wet-Weather Flow Management Email: [email protected] Speaker 5: Name –Jamie Gellner Affiliation – Hazen and Sawyer Title of Presentation – What Happens When Everyone “Flushes” at the Same Time? – Case Studies on Management of Wet Weather Flow Events Email: [email protected] Speaker 6: Name –Chris Tabor, facilitator Affiliation – Hazen and Sawyer Title of Presentation – Facilitated Panel Discussion with prior speakers and audience Email: [email protected] ACKNOWLEDGEMENTS By submitting this, I agree that I have informed the proposed speakers that all are required to prepare a paper for the proceedings, meet all deadlines associated with the presentation, and are responsible for associated registration, transportation, and housing fees, unless an exception is specifically requested above and granted by WEF before final acceptance of this proposal. Moderators and Assistant Moderators have also been informed that they are responsible for their own registration, transportation, and housing fees. Submitter sign here:

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URBAN WET WEATHER AND INTEGRATED PLANNING/PERMITTING: PAST, PRESENT AND FUTURE

Patrick Bradley

Limno-Tech, Inc., 1705 DeSales St, NW, Suite 600, Washington, DC 20036 Discharges that result from rainfall and snowmelt (wet weather events) include storm water

runoff, combined sewer overflows (CSOs), sanitary sewer overflows (SSOs), and peak wet

weather flows at publicly-owned treatment works (POTWs). Wet weather discharges are

intermittent, somewhat unpredictable, and not easily characterized. They are extremely variable

from one wet weather event to the next with respect to frequency, duration, and volume. This

unpredictability and variability makes it difficult for local environmental agencies to manage wet

weather discharges. It is also makes it difficult for National Pollutant Discharge Elimination

System (NPDES) permitting authorities to draft permits to address wet weather discharges. In

order to assist local environmental agencies and NPDES authorities accomplish their missions in

an economical yet responsible manner, the Environmental Protection Agency (EPA) has

proposed a number of strategies over the years to address management of wet weather flows in a

holistic manner. EPA and its stakeholders have considered how municipal wet weather issues

could be better integrated on a watershed basis for close to 20 years (see USEPA 1994; USEPA

2002; USEPA 2003; USEPA 2007).

Addressing wet weather discharges in a holistic manner can provide for greater efficiency, more

comprehensive planning, and less redundancy among permitting requirements. Nontraditional

approaches may be required to address the challenges posed by wet weather discharges. Such

challenges must be addressed on several fronts:

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• Ensuring that the existing framework of regulation and policy is fully implemented for those

discharges covered by existing programs.

• Adjusting the existing regulation and policy framework to reflect the difficult decisions

municipalities face in controlling episodic, variable, and largely unpredictable wet weather

discharges.

• Supporting flexible local decision-making to achieve watershed objectives in the most cost-

effective manner.

This paper and accompanying presentation will consider innovative approaches that provide

flexibility for management of wet weather programs, including EPA's most recent strategy

related to "integrated permitting." First, it will provide a brief regulatory and policy background

on the principal wet weather discharges regulated under the NPDES program. Next, it will

discuss the recent announcement by EPA regarding work toward developing a strategy for

integrating wet weather programs and addressing the control of wet weather discharges (USEPA

2011). That is, storm water, CSOs, SSOs, and management of peak wet weather flows at

POTWS. The presentation and paper will review EPA’s most recent memo and the framework

that is expected to be issued during winter 2012. These documents will be reviewed and assessed

in relation to previous policies issued by EPA and what progress has been made over the years

and the issues that have arisen.

The issues that have arisen over the years related to integrated permitting on a watershed basis

will form the framework for the learning goals of the presentation. What has EPA attempted to

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achieve? What were obstacles that were encountered and problems permitting authorities faced

in working with the EPA? What constitutes the history of the overall issue and what attempts

have been made to address it? Based on the experience of some specific permitting authorities,

how might this move forward?

REFERENCES

USEPA (U.S. Environmental Protection Agency). 1994. EPA NPDES Watershed Strategy. U.S.

Environmental Protection Agency, Washington, DC.

USEPA (U.S. Environmental Protection Agency). 2002. Committing EPA’s Water Program to

Advancing the Watershed Approach. U.S. Environmental Protection Agency: Washington, D.C.

USEPA (U.S. Environmental Protection Agency). 2003. Watershed-Based National Pollutant

Discharge Elimination System (NPDES) Permitting Implementation Guidance. EPA 833-B-03-

004; U.S. Environmental Protection Agency: Washington, D.C.

USEPA (U.S. Environmental Protection Agency). 2007. Watershed-Based National Pollutant

Discharge Elimination System (NPDES) Permitting Technical Guidance. EPA 833-B-07-004;

U.S. Environmental Protection Agency: Washington, D.C.

USEPA (U.S. Environmental Protection Agency). 2011. Achieving Water Quality Through

Integrated Municipal Stormwater and Wastewater Plans. Memorandum from N. Stoner and C.

Giles to EPA Regional Administrators, October 27, 2011.

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WATER, WATER EVERYWHERE! -- OVERVIEW OF SUSTAINABLE COLLECTION SYSTEM STRATEGIES FOR EFFECTIVE WET WEATHER FLOW MANAGEMENT

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WATER, WATER EVERYWHERE! -- OVERVIEW OF SUSTAINABLE COLLECTION

SYSTEM STRATEGIES FOR EFFECTIVE WET WEATHER FLOW MANAGEMENT

D. Ott1

1 Johnson County Wastewater (JCW), 4800 Nall, Mission KS 66202, [email protected]

Municipal utilities has been facing in recently years the need to provide significant

improvements on how they manage wet weather related flows in their wastewater collection and

treatment system as the result of increased regulatory and public pressures and aging

infrastructure. These wet weather flows, which result from combined sewer systems or separate

systems that have significant amounts of infiltration/Inflow (I/I), in many cases exceed the

original design capacity of existing sanitary sewer and treatment systems. The overall approach

necessary to identify, evaluate, and eventually select the “Best” combination of wet weather

improvements comprised of I/I reduction, increased conveyance capacity, remote storage,

satellite peak excess flow treatment facilities (PEFTFs), treatment plant improvements, and

system-wide operational strategies for a particular collection system is one that is unique to each

municipality.

This paper will provide an overview of sustainable collection system improvement and

operational strategies for effective wet weather flow management in order to encourage

engineers, planners, and designers developing improvement plans to take a holistic approach to

wet weather facility planning that includes all system components (collection system, treatment

facilities, and private service lines & connections). Some of the key items covered will be:

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WATER, WATER EVERYWHERE! -- OVERVIEW OF SUSTAINABLE COLLECTION SYSTEM STRATEGIES FOR EFFECTIVE WET WEATHER FLOW MANAGEMENT

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• I/I reduction strategies

• Synergies between Asset Management Programs and Wet Weather Flow Management

• Green infrastructure

• Integrated operation of collection and treatment systems

• Real Time Controls

Principles for collection system management provided in the July 2010 WEF/NACWA “Core

Attributes to an Effectively Managed Wastewater Collection Systems” and strategies provided in

the 2006 WEF “Guide to Managing Peak Wet Weather Flows in Municipal Wastewater

Collection and Treatment Systems” will be highlighted.

In light of the current regulatory and economic climate, utilities must stay focused on developing

sustainable real world plans that achieve water quality goals while at the same time allow

utilities to meet their customer’s level of service expectations. This paper is intended to provide

an overview of sustainable collection system strategies that will allow utilities to achieve these

objectives.

��IT ISN’T CUT AND DRY - GENERAL CONSIDERATIONS IN THE DEVELOPMENT OF WET WEATHER

FLOW IMPROVEMENTS SCENARIOS FOR WASTEWATER TREATMENT FACILITIES ��

IT ISN’T CUT AND DRY - GENERAL CONSIDERATIONS IN THE DEVELOPMENT

OF WET WEATHER FLOW IMPROVEMENTS SCENARIOS FOR WASTEWATER

TREATMENT FACILITIES

J. Sandino1, J. Fitzpatrick2, J. Gellner3, C. Tabor3

1 CH2M HILL, 13113 Melrose St., Overland Park, KS 66213 [email protected]

2 BLACK & VEATCH; 3 HAZEN & SAWYER

Municipal utilities has been facing in recently years the need to provide significant

improvements on how they manage wet weather related flows in their wastewater treatment

facilities as the result of increased regulatory and public pressures. These flows and loads, which

result from combined sewer systems or even separate systems that have significant amounts of

infiltration/Inflow (I/I), can in many cases exceed the treatment capacity of existing facilities.

However, the overall approach necessary to identify, evaluate, and eventually select the “Best”

wet weather improvement scenario in terms of facilities and operational requirements for a

particular treatment plant, is one that contrasts significantly from that normally used by the same

utilities in dealing with dry weather treatment needs.

This paper will argue for the need of a true “Paradigm Shift” in how our industry defines

improvement scenarios (i.e. establishing basis of design conditions and configuring treatment

process configurations) to address wet weather flow treatment requirements, and will propose an

alternative approach in dealing with the many factors that will end up influencing the evaluation

process. This will be done primarily my means of contrasting the differences between how a

particular issue/project constraint should be addressed depending whether it is looked from the

dry versus a wet weather point of view. Examples based on actual project experiences will be

��IT ISN’T CUT AND DRY - GENERAL CONSIDERATIONS IN THE DEVELOPMENT OF WET WEATHER

FLOW IMPROVEMENTS SCENARIOS FOR WASTEWATER TREATMENT FACILITIES ��

provided to illustrate these differences. Some of these key issues that will be discussed in this

“comparative” manner are presented in a simplified tabular form below.

Comparative Analysis in the Development of Dry versus Wet Weather Improvement Scenarios for Wastewater Treatment Facilities

Issue/ Constraint

Dry Weather Improvements Approach

Wet Weather Improvements Approach

Regulatory Drivers

Environmental primarily (Secondary Treatment; Nutrients in some cases); Public health secondarily (some plants do not require effluent disinfection).

Mainly public health driven - Goal of protecting public health, even when receiving stream water quality conditions during a storm event could be worse than the plant discharge.

Permit Structure

Primarily long terms averages – monthly/weekly. Requirements such as % removal and discharge concentrations can be calculated on the basis of a large set of individual values.

Event based – could be hours to a few days. Data set for calculating compliance tends to be limited. Often times, meeting % removal goals is difficult given low influent concentrations due to dilution.

Influent characteristics

Relatively constant flow and loading conditions, predicted with relatively confidence for long project planning horizons (quasi-steady state conditions). Relies upon historic data analysis to establish current conditions, which could then be extrapolated with reasonable certainty to the future by means of population growth estimates.

Highly variable flow and loading conditions, difficult to predict actual occurrence given probabilistic nature of storm events. Dynamic basis of design defined by hydrographs (flow vs. time) and pollutographs (loads vs. time). Problem compounded by climate change which undermines historic data analysis.

Anticipated Performance

Stable performance given quasi-steady state influent conditions. This makes systems inherently more reliable in meeting a particular effluent requirement.

Potentially variable performance given highly variable influent characteristics. Difficult to predict what would be treated effluent conditions (lower reliability).

Operational Optimization

Quasi-steady state nature of influent allows for the proactive development of long term (seasonal/annual) operational strategies. This reduces performance vulnerability.

Highly variable and unpredictable nature of influent makes it necessary for operators to “optimize” each wet weather event on a reactive basis. This increases performance vulnerability.

Cost Optimization

“Best” improvement scenario is established on the basis of considering both capital and O&M costs over long time periods (typical 20-yr present worth analysis).

Infrequent occurrence of wet weather events makes O&M costs irrelevant when compared to capital costs of improvements. Spending large amounts of money in facilities that are seldom used should be avoided, even at the expense of options with high operational cost, but lower capital costs.

Fitzpatrick Page 1 of 4 Preparing for a Rainy Day – Overview of Treatment Technology Options for Wet-Weather Flow Management

Preparing for a Rainy Day – Overview of Treatment Technology Options for Wet-Weather Flow Management J. Fitzpatrick1*, J. Gellner2, J. Sandino3, C. Tabor2 1 Black & Veatch Corporation 2 Hazen and Sawyer 3 CH2MHILL * [email protected] Introduction

When faced with the need to increase wet-weather flow treatment capacity, municipal

utilities now have a large variety of process and technology alternatives to consider. In fact,

many of today’s state-of-the-art technologies were not considered feasible alternatives a

generation ago when most of North America’s clean water regulations and policies were crafted.

However, significant advances have been made since then, both in terms of treatment

technologies and in terms of the profession’s understanding of wet-weather problems. This paper

will provide an overview of wet-weather flow treatment technologies, compare their potential

advantages and disadvantages, and describe how each might fit into an existing treatment works

and contribute to a utility’s water quality goals.

Treatment Challenges

Wet-weather flows tend to be intermittent and unpredictable, but in many cases they

cause significant and rapid increases (and decreases) to the hydraulic loading of a treatment

facility. However, after the “first-flush” of solids during the initial flow ramp-up, the subsequent

wet-weather flows are generally found to be very dilute with pollutant loadings usually falling

within a facility’s design average capacity range. Each facility may have unique water quality

goals that need to be further considered, but the most prevalent concern for wet-weather

discharges is the protection of public health from water borne pathogens.


Technology Alternatives

As with any optimal treatment solution, wet-weather alternatives should be geared to

solve the problem at hand in a sustainable fashion; therefore, it should not be too surprising that

the first priority of most wet-weather flow treatment technologies is to produce an effluent that is

reliably amenable to disinfection processes over a wide range of flow rates. Before adding more

treatment infrastructure, a thorough evaluation should be conducted to determine if it is feasible

for the existing facilities to provide additional wet-weather treatment capacity by changing

certain operational settings or by using an alternate configuration or flow arrangement. If more

treatment capacity is still needed, then additional auxiliary treatment facilities generally rely on a

solids/liquids separation process that is capable of efficiently and consistently producing effluent

with relatively low concentrations of suspended solids. This core process is generally

accompanied by another process to inactivate or destroy potential pathogens and complete the

disinfection process. The core process may be preceded by preliminary treatment units

(screening facilities are fairly common) aimed at the removal of floatables and relatively large

debris and solids that could cause downstream equipment failures or maintenance problems.

The profession has historically understood that excess wet-weather flows generally

require the equivalent of sedimentation along with effluent disinfection to meet Clean Water Act

requirements. This is reflected in the “Presumption Approach” of EPA’s CSO Control Policy

(USEPA, 1994) and is the technology standard that was assumed when the regulatory definitions

of “bypass” and the practice of “blending” were developed. Examples that would generally be

expected to meet this technology standard include the following:

• Conventional sedimentation basin followed by chlorine contact basin

• Retention treatment basin with simultaneous sedimentation and chlorination


• Extraneous flow basin with chlorination

• Vortex separators (a.k.a. swirl concentrators) with chlorination

Over the past decade or so, some utilities have opted for auxiliary treatment technologies

that offer a higher effluent quality than the above examples, improving the efficiency and

reliability of the disinfection process. Such technologies have recently been called enhanced (or

advanced) high-rate treatment (EHRT) and generally involve some variation of a chemically

enhanced sedimentation (CES) process or filtration process along with a disinfection process.

CES processes (sometimes referred to as high-rate clarification or HRC) use gravity

settling as in conventional sedimentation, but enhance the removal of discrete suspended solids,

colloidal material and certain soluble materials through chemical coagulation, precipitation and

flocculation. Lamella settlers can be used to decrease the required settling tank size. Solids

contact, sludge recirculation or ballasted flocculation can also be used to enhance and stabilize

the floc settling characteristics and further decrease the required settling tank size. Examples

range from non-proprietary CES designs to systems such as DensaDeg®, ACTIFLO®, CoMag™

or RapiSand™. A couple of these have recent full-scale applications demonstrating their ability

to be used in a high-rate activated sludge configuration (Bio ACTIFLO® and BioMag™).

High-rate filtration (HRF) technologies that lend themselves to wet-weather flows

include deep-bed granular media, cloth media and compressible media filters. Full-scale

examples include the Schreiber Fuzzy Filter™ and WWETCO FlexFilter™. Recent research has

included investigations into the potential for filter biofilm treatment mechanisms.

The full paper will further describe these EHRT technologies, provide performance

expectations and design considerations, and compare and contrast their similarities and

differences.


Figure 1. A few of the advanced high-rate treatment technologies available in today’s wet-weather treatment market are depicted in this figure. The base facility design shown in the isometric drawing is for chemically enhanced sedimentation (CES) using conventional rectangular sedimentation basins, but other CES alternatives or non-chemical filtration alternatives may offer advantages. The final selection will depend largely upon various site-specific considerations (dual storage/capture needs, treatment capacity requirements, footprint constraints, dual dry-weather use, coordination with existing treatment process units, operational staffing, etc.).

Gellner Page 1 of 5 What Happens When Everyone “Flushes” at the Same Time? – Case Studies on Management of Wet Weather Flow Events

What Happens When Everyone “Flushes” at the Same Time? – Case Studies on Management of Wet Weather Flow Events * J. Gellner1, J. Sandino2, J. Fitzpatrick3, C. Tabor1 1 Hazen and Sawyer 2 CH2MHILL 3 Black & Veatch Corporation * [email protected] Introduction

Many utilities are faced with the challenge of providing additional peak wet weather

treatment capacity at their wastewater treatment plants and within the collection system. This

need is being driven by a host of factors, the most significant of which is the focus by regulators

on overflows and “bypasses”. If improvements are not required by a consent decree or other

regulatory order, they are increasingly being mandated by conditions in permit renewals. Unlike

in the past where most of the focus has been placed on larger utilities, the need is now extending

to small to mid size utilities.

There are a host of challenges associated with accommodating significant flows beyond

average capacities, including the following:

• Capture of first flush – The initial time period of a storm event is often

accompanied by a period of very high influent loading, particularly suspended

solids. A plant or facility must be designed to accommodate this loading, but

usually requires bringing on additional treatment units or operating existing

equipment at much higher rates. First flush loading and removal is often focused

on screening and grit removal facilities.


• Hydraulic capacity – Often, when plant upgrades are considered, the hydraulic

capacity of interprocess piping and flow management structures is simply

inadequate. Therefore, utilities must consider either upgrades to this conveyance

infrastructure or other options for treatment.

• Maintenance of biomass and protection of sensitive biology - The active

biomass of the treatment system must be maintained throughout and normal

conditions must be returned as soon as possible after storm events so that

consistent permit compliance can be achieved. If biomass is lost from the

secondary system during a storm event, permit compliance will be a significant

challenge as the biomass population is “restored” within the system. In many

facilities with nutrient removal limits, this challenge has become even greater as

specialized biological communities must continue to be protected.

• Operational transition between dry and wet weather operations – Operation

for wet weather typically requires that the plant develop a transitional strategy for

bringing process units on line, for changing the flow paths in the secondary

system, and for potentially storing part of the incoming flow. This transitional

strategy must accomplish two objectives. First, the transition must maintain

consistent treatment throughout. Second, the transition must return the plant to

normal operations and regular permit compliance as soon as possible.

There is much that can be learned from the experiences of existing utilities in the overall process

of planning, implementing, and then operating wet weather treatment systems. This paper will

focus on several utilities where varying strategies and systems have been used to accommodate

wet weather. The utilities and examples were chosen to cover a broad range of capacities,


treatment technologies, and overall strategies. The case studies presented will include the

following:

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The paper and presentation will provide a summary of each installation and will compile and present information on the following:


• Description of wet weather strategy and why it was selected • Lessons learned from operations staff on the use of the strategy, including how plant

operations have been modified since the system was put on line. • Operational strategy used for initiation of wet weather treatment, operation during high

flow events, and the return to normal flows.

weftec® 2012 technical session proposal form...weftec® 2012 technical session proposal form...

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