Moving Toward Resource Recovery Facilities

By Water Environment Federation

Resource recovery is an emerging societal need around the globe. Due to the ever-increasing pressures on increasingly limited environmental resources, it is critical that recovery of resources (water, nutrients, and energy) from waste streams be implemented. Moving Toward Resource Recovery Facilities is about moving away from waste streams and moving toward values streams. First providing an overview of the fundamental drivers for resource recovery from wastewater and presenting the basic case for resource recovery, the text provides an overview of state-of-the-art technological approaches to resources recovery and provides general guidance on the applicability of recovery technologies for the cross section of facility types. This allows facilities to take steps towards recycling a greater number of otherwise lost resources.

• Language: English
• Publisher: Water Environment Federation
• Release date: Aug 1, 2014
• ISBN: 9781572783065

Book preview

Preface

The paradigm for clean water agencies is changing quickly across the globe. Historically, clean water agencies were tasked with one overriding goal: protecting water quality. As vital resources have become increasingly scarce, an acknowledgment of the potential value of wastewater has occurred. Viewing wastewater as not simply something that needs to be gotten rid of, but rather as a stream of potential resources to recover has stimulated a great deal of innovation and visionary thinking in the early part of the 21st century.

This Special Publication provides an overview of current resource recovery drivers; potential technologies to recover resources from wastewater; and some perspective on how to evaluate, plan, and implement resource recovery projects. A chapter of case studies highlights how several clean water agencies across the globe are already embracing the idea of resource recovery. While is it not an all-encompassing overview of every potential resource that could be recovered, the goal is to provide the industry with a starting point as clean water agencies begin their journey to becoming resource recovery facilities.

Authors’ and reviewers’ efforts were supported by the following organizations:

American University of Sharjah, Sharjah, United Arab Emirates

Associated Engineering, Edmonton, Alberta

Baxter & Woodman, Inc., Chicago, Illinois

Black & Veatch, Kansas City, Missouri

Brillion Iron Works, Brillion, Wisconsin

Brinjac Engineering

Brown and Caldwell, Milwaukee, Wisconsin

Carollo Engineers, Inc., Broomfield, Colorado; Walnut Creek, California; and Winter Park, Florida

CDM Smith, Cambridge, Massachusetts

CET-GHD Engineering Services, Doylestown, Pennsylvania

CH2M HILL, Chantilly, Virginia; Salt Lake City, Utah; Santa Ana, California; and Toronto, Ontario

City of Fort Worth, Texas

City of Reading, Pennsylvania

City of San José, California

Clean Water Services, Hillsboro, Oregon

DC Water, Washington, D.C.

Donohue and Associates, Sheboygan, Wisconsin

Effluential Synergies, LLC, Philadelphia, Pennsylvania

Erg Process Energy, LLC, New York, New York

Galardi Rothstein Group, Chicago, Illinois

Garver, Frisco, Texas

GHD, Inc., Doylestown, Pennsylvania

Government of the District of Columbia, Washington, D.C.

Greeley and Hansen LLC, Richmond, Virginia

Greenwood Metropolitan District, Greenwood, South Carolina

Gresham, Smith and Partners, Nashville, Tennessee

Harvest Power, Inc., Waltham, Massachusetts

Hazen and Sawyer P.C., Atlanta, Georgia; Fairfax, Virginia; and Raleigh, North Carolina HDR

Engineering, Inc., Cleveland, Ohio

Hemphill Water Engineering, LLC, West Linn, Oregon

IHS Energy, Cambridge, Massachusetts

InSinkErator, Racine, Wisconsin

Johnson Controls, Inc., Westerville, Ohio

Kent County WW Treatment Facilities, Milford, Delaware

Malcolm Pirnie, White Plains, New York

MWH Americas, Inc., Denver, Colorado

Orange County Sanitation District, Fountain Valley, California

Parsons Brinckerhoff, Orlando, Florida

P.M. Sutton & Associates, Inc., Campton, New Hampshire

Short Elliott Hendrickson, St. Paul, Minnesota

Spartanburg Water, Spartanburg, South Carolina

Stantec, Columbus, Ohio

Tennessee Technological University, Cookeville, Tennessee

United Water, Oradell, New Jersey

University of Illinois at Urbana-Champaign, Urbana, Illinois

University of Toronto, Toronto, Ontario

Utah State University, Logan, Utah

Village Creek Water Reclamation Facility, Fort Worth, Texas

1

What Resources Can We Recover?

Andrew R. Shaw; James Barnard; Leon S. Downing, P.E., Ph.D.; and Darrin J. Harris, EIT

1.0  INTRODUCTION TO THE N-E-W PARADIGM

2.0  STRUCTURE OF THIS PUBLICATION

3.0  NUTRIENT RECOVERY

4.0  ENERGY

4.1  Introduction

4.2  Chemical

4.2.1  Biogas

4.2.2  Biofuels

4.2.3  Thermal Conversion (Combustion)

4.2.4  Electrochemical Conversion

4.3  Thermal

4.3.1  Heat Energy Recovery from Generators and Incinerators

4.3.2  Heat Energy Recovery from Biochemical Conversion Processes

4.3.3  Direct Heat Energy from Wastewater

4.4  Hydropower

4.5  Microbial Fuel Cells

5.0  WATER

5.1  Assessment of Approaches to Achieve Nationally Consistent Reclaimed Water Standards (WRF-08-01-1)

5.2  Low-Cost Treatment Technologies for Small-Scale Water Reclamation Plants (WRF-06-008)

5.3  An Economic Framework for Evaluating the Benefits and Costs of Water Reuse (WRF-03-006)

5.4  Marketing Nonpotable Recycled Water: A Guidebook for Successful Public Outreach & Customer Marketing (WRF-03-005) 12

5.5  Fit-for-Purpose Water

6.0  MATERIAL AND ENERGY BALANCES TO ASSESS INTERACTIONS AND TRADE-OFFS

6.1  Material Balance

6.2  Energy Balance

7.0  REFERENCES

1.0  INTRODUCTION TO THE N-E-W PARADIGM

The paradigm for clean water agencies is quickly evolving across the globe. Historically, clean water agencies were tasked with one overriding goal: protecting water quality. However, as vital resources have become increasingly scarce, the potential value of wastewater has been acknowledged. Indeed, viewing wastewater as not simply something that needs to be gotten rid of, but rather as a stream of potential resources to recover has stimulated a great deal of innovation and visionary thinking in the early part of the 21st century.

As part of this shift toward viewing wastewater as a resource stream, the term, utility of the future, has been used to describe the changing paradigm of operating wastewater treatment plants to operating water resource recovery facilities (WRRFs). As defined by The Water Resources Utility of the Future … A Blueprint for Action (NACWA et al., 2012), the water environment industry is now focusing on maintaining water quality protection at the least cost to society. This shift represents somewhat of a return to thinking of the past. As noted by Alleman (1984), when sanitary sewers were first installed in England in the mid-1850s, the newly devised waste conduits were subsequently recognized as a prime commodity for entrepreneurial gain, and a cottage industry of wastewater alchemists quickly emerged intent on extracting the nutrient essence of sewage for monetary gain.

The concept of the utility of the future has led to the idea of a N-E-W paradigm for water quality management, as proposed by the Water Environment Research Foundation (WERF). The N-E-W paradigm focuses on managing three key resources present in wastewater: nutrients, energy, and water. Managing these resources includes both conservation and recovery. Conservation efforts focus on reducing energy use within a utility through efficiency improvements and reducing overall water use and nutrient inputs to the municipal water cycle. Of particular interest to many utilities has been reducing the overall energy footprint of a facility (i.e., energy per volume of treated water) (WEF, 2009). These conservation efforts have been discussed in several other publications, including Water Environment Federation’s (WEF’s) Energy Conservation in Water and Wastewater Facilities (WEF, 2009).

Although these conservation efforts are critical to reducing the overall environmental footprint of a facility, the majority of these efforts can be accomplished under the existing paradigm for wastewater treatment. Therefore, the focus of this publication is on the recovery of resources from wastewater, which is the critical step in shifting wastewater facilities to the utility of the future. While the current focus in the industry is on recovering nutrients, energy, and water, other exciting avenues of resource recovery such as those for metals, bioplastics, and other materials will play an important role in the future. This chapter outlines the potential for nutrient, energy, and water recovery from wastewater and provides key references for each based on the current state of knowledge.

2.0  STRUCTURE OF THIS PUBLICATION

The goal of this publication is to provide the water environment industry with an overview of the drivers of resource recovery, the tools available, and guidance on how to move the industry from that of waste disposal to resource recovery. The following are brief summaries of chapters in this publication:

•  Chapter 1, What Resources Can We Recover?—this chapter provides an introduction to the N-E-W paradigm and information on the highest potential resources for recovery;

•  Chapter 2, The Case for Resource Recovery: Part 1—Global Mega trends in the Water, Energy, and Nutrient Landscape—this chapter provides an overview of the trends driving resource recovery around the world;

•  Chapter 3, The Case for Resource Recovery: Part 2—Regional Trends in the Water, Energy, and Nutrient Landscape—this chapter focuses on regional trends in North America driving resource recovery;

•  Chapter 4, Current State-of-the-Science in Recovery Technology Approaches and Opportunities—this chapter focuses on technologies and approaches available for N-E-W recovery;

•  Chapter 5, Case Studies of Recovery Technology Applications—this chapter introduces a range of case studies that have implemented several of the technologies and approaches discussed in Chapter 4;

•  Chapter 6, Resource Recovery: The Utility Management Perspective—shifting to WRRFs will require new methods for selection and evaluation of alternatives; this chapter introduces several approaches currently being used in the industry;

•  Chapter 7, Considerations for Selecting and Evaluating Resource Recovery Options—while most resource recovery discussion focuses on technical aspects, the shift will require several changes to utility management; this perspective is discussed in this chapter;

•  Chapter 8, Where Do We Go and How Do We Get There?—moving to resource recovery facilities will not be an overnight effort; this chapter provides guidance on the steps necessary to achieve this goal; and

•  Chapter 9, The Next Generation of Resource Recovery Technologies— the water environment industry is currently focused on the recovery of N-E-W products. However, there is a range of emerging areas of resource recovery, and this will be discussed in this chapter.

3.0  NUTRIENT RECOVERY

Typical wastewater comprises a complex mixture of materials produced from human wastes, food wastes, oil and grease, industrial food processing, industrial wastes, and many other sources. While every wastewater has its own characteristic, the main categories for compounds can be thought of as carbon, nutrients, and trace minerals. When nutrient recovery is considered, nitrogen and phosphorus are the main focus. However, the carbon and trace minerals present in wastewater products can often have value as well.

Chapter 2, Section 8, of Design of Municipal Wastewater Treatment Plants (WEF et al., 2010) contains detailed information on wastewater characteristics. Table 1.1 shows the typical characteristics of wastewater, on a per capita basis, and Table 1.2 shows concentration ranges for typical domestic wastewater.

Figure 1.1 shows a typical nutrient balance in a WRRF. Most phosphorus removed from influent is bound in the solids removed from the system, while most nitrogen removed is released to the atmosphere (note that in non-nutrient-removal facilities, nitrogen is mainly removed in the solids). The level of nutrient capture is highly dependent on the wastewater processes implemented by a facility, and regulatory drivers for nutrient management often dictate the level of nutrient accumulation in the solids. Water Environment Federation’s Nutrient Removal (WEF, 2011) contains detailed information on nutrient removal and nutrient recovery. The WERF (2011b) report, Nutrient Recovery State of the Knowledge, contains details of current efforts for nutrient recovery.

4.0  ENERGY

4.1  Introduction

Wastewater contains embedded energy that can be categorized as biochemical (i.e., chemical oxygen demand [COD] energy), thermal, and hydropower; the following sections characterize these in more detail. The WERF (2011a) fact sheet, Energy Production and Efficiency Research—The Roadmap to Net-Zero Energy, describes these different energy types and provides estimates of potential energy content for recovery (expressed as megajoules of energy per cubic meter of wastewater flow). Conversion of energy from one form to another results in energy losses that can be expressed as an efficiency for the conversion.

TABLE 1.1   Quantity of waste discharged by individuals on a dry-weight basis (Metcalf and Eddy, 2003).

TABLE 1.2   Typical composition of untreated domestic wastewaters (Metcalf and Eddy, 2003).

FIGURE 1.1   Nutrient mass balance in a typical WRRF (Metcalf and Eddy, 2003)

4.2  Chemical

Chemical energy is the energy content in organic chemicals in wastewater. The organic strength can be expressed as COD in milligrams per liter. Tchobanoglous (2009) calculated that the chemical energy content of COD is 12 to 15 MJ/kg (13 MJ/kg COD is typical), which equates to a range of 3 to 12 MJ/m³ (5.6 MJ/m³ is typical) for a COD range of 250 to 800 mg/L; this is typical for domestic wastewater. Facilities with high influent biochemical oxygen demand and/or volatile suspended solids concentrations (strong influent) will have high COD concentrations and, therefore, high chemical energy content. This energy content can provide greater opportunity to tap into this energy source through, for example, anaerobic treatment processes such as upflow anaerobic sludge blanket reactors (UASBs). Industrial wastes often have significantly higher COD values (in the 10 000-mg/L range) and, therefore, have much higher biochemical energy content, making them prime candidates for energy recovery.

For most domestic WRRFs that have relatively low influent COD concentrations, the most straightforward route to capture biochemical energy is in the form of biosolids either by settling out solids in a primary clarifier or converting the COD biologically into solids in secondary treatment. The following subsections outline ways in which biochemical energy can be converted into other, more useful energy forms.

4.2.1  Biogas

The most common approach to convert biochemical energy into a more useful form is to use a biological anaerobic process to convert the organics into biogas, which can then be used for heating or electricity generation. In domestic facilities, this is typically done using anaerobic digestion of solids. For facilities with high-strength waste, this also can be done using an anaerobic reactor such as a UASB or by adding the high-strength waste to a conventional anaerobic digester (i.e., co-digestion).

4.2.2  Biofuels

An alternative to producing biogas is to convert the organics into a liquid biofuel (e.g., biodiesel). However, this process is more complex. Similar to biogas production, the addition of high-strength organic wastes can be used to increase biofuel production through coconversion. Biogas can also be treated to increase methane content to natural gas quality that can then be used in natural gas vehicles or other conventional uses

4.2.3  Thermal Conversion (Combustion)

A third approach to tap into biochemical energy is to use an incinerator or other thermal process to burn the organics and produce heat directly. Many biosolids incinerators in the United States simply dissipate heat energy in a wet scrubber, thereby wasting this potential energy resource. A critical aspect of this approach is to reduce the water content of the feed material because conversion of water to steam adsorbs a significant amount of energy. This heat energy is produced by the thermal reduction of the biosolids mass. Incinerators have demonstrated autogenous conditions with feed characteristics of 28% total solids and 75% volatile solids. Similar to biogas and biofuel production, there is significant potential to combine sludge with other materials for co-incineration. There are many regulations pertaining to emissions and co-incineration of wastes that must be considered when evaluating thermal conversion.

4.2.4  Electrochemical Conversion

A final potential approach for tapping into biochemical energy is to use a fuel cell to convert this energy directly to electricity. Microbial fuel cells can be used to directly convert COD in wastewater to electricity. Alternatively, biogas can be used in a chemical fuel cell to produce electricity.

4.3  Thermal

Various process streams in a WRRF contain thermal energy that can potentially be captured and used for heating or converted to other energy forms. The following are three potential sources of thermal energy.

4.3.1  Heat Energy Recovery from Generators and Incinerators

Electricity generators produce significant waste heat that can be captured in a combined heat and power system to produce heating energy for other processes or heat for the building. Similarly, waste heat from incinerators and other thermal processing units can be used for site-heating applications.

4.3.2  Heat Energy Recovery from Biochemical Conversion Processes

Anaerobic digesters operate at elevated temperatures. Heat can be recovered from the digester, possibly to preheat incoming sludge. This is dependent on weather conditions, heating requirements, and digester temperature.

4.3.3  Direct Heat Energy from Wastewater

Heat pumps and direct heat exchangers can be used to recover energy directly from wastewater streams. The heat energy content in water dwarfs the other energy types; however, this heat energy is considered low grade because of the temperature of the water.

4.4  Hydropower

At most facilities, energy available for recovery through hydropower is limited because the energy required to move the water in the first place is provided by pumps that should be sized to not waste energy, but provide just enough motive energy to move the water where it needs to be. In this respect, hydropower may be an opportunity to recuperate previously wasted energy caused by inefficient hydraulic design. Facilities with large elevation differences between the outfall and receiving waterbody may have the potential for hydropower recovery. Heat recovery is also a potential with many of the hydropower alternatives.

4.5  Microbial Fuel Cells

Microbial fuel cells (MFCs) represent an emerging technology for direct electricity production from wastewaters. Chapter 9 provides a more detailed discussion of MFCs.

5.0  WATER

Of all resources that can be recovered from a WRRF, the most obvious and arguably most significant from both environmental and economic perspectives is water itself. Water reuse is a well-established practice in many parts of the world, including many regions in North America, as discussed in the U.S. Environmental Protection Agency’s Guidelines for Water Reuse (U.S. EPA, 2012).

Reclaimed water is wastewater that is treated to remove solids and an array of impurities (depending on the level of treatment applied to the reclaimed water); it has a variety of uses ranging from irrigation of turf and crops to commercial and industrial applications such as cooling towers and process waters. Reclaimed water is also increasingly being used to recharge groundwater aquifers. Such uses promote sustainability and water conservation, rather than discharging the treated water to surface waters such as rivers, lakes, and oceans. In some cases, the effluent discharge itself maintains the local hydrology and, in extreme cases, can constitute the entire stream flow.

As pressures on local water supplies are exacerbated by climate change, droughts, and increased demand, communities are increasingly turning to reclaimed water as the new water resource in a community’s water resources portfolio.

There are a variety of important subjects to consider for use of reclaimed water. These include standards for reclaimed water treatment and use, technologies for the treatment of reclaimed water, the economics of such use, and management of communications regarding reclaimed water. Literally thousands of articles have been written on these subjects over the last 20 years as use of reclaimed water has increased. The WateReuse Association (and its affiliated WateReuse Research Foundation [WRF]) and WEF (and its affiliated WERF) are the definitive sources for primary research and education in the areas of treatment, distribution, and use of reclaimed water in the United States. Although there are a variety of commercial documents that discuss the various aspects of reclaimed water, the reports cited in the following sections summarize some of the important aspects of the subject of reclaimed water. The publications relate to reclaimed water standards, treatment technologies, the economics of water reuse, and communications.

5.1  Assessment of Approaches to Achieve Nationally Consistent Reclaimed Water Standards (WRF-08-01-1)

Standards for the production and use of reclaimed water are critical to its widespread acceptance. This study evaluated options to achieve nationally consistent reclaimed water standards because, currently, standards are written at the state level. Options for such consistent reclaimed water standards were evaluated in terms of their advantages and disadvantages, how they would be implemented, and potential obstacles to implementation. Preliminary information on five options were evaluated and refined by conducting a Web-based survey of stakeholders, including members of the water reuse community and state and federal regulators, and represent different geographical areas of the United States. Based on this information, a relative comparison of the options was performed using the following 10 factors: existing legal authority, ability to achieve national consistency, ability to promote reuse, will the option promote or inhibit reuse, time to implement, cost to implement, efficiency of development, funding to develop option, public acceptance, and acceptance by the reuse community.

5.2  Low-Cost Treatment Technologies for Small-Scale Water Reclamation Plants (WRF-06-008)

As the executive summary states, this study identifies and evaluates established and innovative technologies that provide treatment of flows of less than 1 million gallons per day. A range of conventional and innovative treatment processes and package systems were evaluated as part of this project. The primary value of this work is the extensive cost database, in which cost and operation data from existing small-scale wastewater treatment and water reuse facilities have been gathered and synthesized. Using this data, cost and maintenance issues for the various types of treatment technologies are compared and contrasted. Although this study focuses on smaller systems, most common treatment practices for reclaimed water are discussed, and cost estimates that are developed can easily be adjusted for larger systems based on data presented within the framework described.

5.3  An Economic Framework for Evaluating the Benefits and Costs of Water Reuse (WRF-03-006)

This research report develops an economic framework that is a tool to help water agencies and other water sector professionals conduct a benefit–cost analysis of reuse or desalination investments. The economic framework is designed to help water managers identify, estimate, and effectively communicate the full range of benefits associated with reuse projects or related activities. Having a reasonably complete recognition and accounting of the full range of benefits of a reuse or desalination project is important because the financial costs of building and operating such facilities are often high compared to those using conventional resources. Indeed, the question whether such expenses are justified is often asked.

5.4  Marketing Nonpotable Recycled Water: A Guidebook for Successful Public Outreach & Customer Marketing (WRF-03-005)

An abstract of this work, which was sponsored by both WERF and WRF, states that nonpotable and potable (principally indirect potable) water reuse initiatives in the United States have faced increasing public opposition. Several high-profile initiatives have been halted after several years of planning and tremendous expense. To understand why the public holds the perceptions they do and what public participation options exist to address water reuse more constructively, a team of social scientists, engineers, and water professionals conducted a multidisciplinary analysis. Through a comprehensive literature review, three in-depth case studies, and a 2-day interactive symposium, this framework was developed for water professionals. The framework summarizes five underlying principles that contribute to shaping public perception to guide water professionals in their selection of public outreach, education, and participation activities. Adhering to the principles outlined, this report contributes to building public confidence and trust, which, in turn, helps water utilities engage constructively with the public on challenging, contentious issues. The five principles are

(1)  Manage information for all,

(2)  Maintain individual motivation and demonstrate organizational commitment,

(3)  Promote communication and public dialog,

(4)  Ensure fair and sound decision making and decisions, and

(5)  Build and maintain trust.

No checklist of to dos exists for establishing public confidence and trust. Conversely, this research suggests that a one-size-fits-all model cannot work because the most appropriate ways to achieve the principles can vary from case to case. Thus, the framework includes an analytical structure to assess the community in which a water reuse initiative is underway. Using diagnostic questions and analytical techniques, a comprehensive picture of the community can be generated and monitored over time. Through application of the diagnostic tools and a commitment to the aforementioned principles, water professionals can build the public confidence and trust they need to engage with the public on difficult water reuse issues.

5.5  Fit-for-Purpose Water

An important concept in reclaiming and reusing water is that the water quality produced should be fit-for-purpose; that is, it should be treated to a standard suitable for the proposed end use. Producing reclaimed water that is of a significantly higher quality than is required will require additional energy, equipment, and chemicals, which reduce the overall sustainability of the project. Conversely, inadequate treatment will cause significant problems for downstream processes using the water. Table 1.3 lists some common reuse water opportunities and considerations to ensure that the reused water is fit-for-purpose.

6.0  MATERIAL AND ENERGY BALANCES TO ASSESS INTERACTIONS AND TRADE-OFFS

Shifting the paradigm from wastewater treatment plant to WRRF requires a holistic view of the treatment process. Material and energy balances allow synergies and conflicts between the different aspects of resource recovery to be understood better while ensuring that effluent discharge and other regulations are not violated.

TABLE 1.3   Reuse opportunities by end use and fit-for-purpose considerations.

FIGURE 1.2   Energy balance example.

6.1  Material Balance

Assessment and design of WRRFs can be best carried out using whole-plant modeling, which enables engineers and operators to understand the interactions between all unit processes. Both Design of Municipal Wastewater Treatment Plants (WEF et al., 2010) and Wastewater Treatment Process Modeling (WEF, 2013) contain descriptions of whole-plant modeling.

6.2  Energy Balance

The Water Environment Research Foundation’s Project ENER1C12 (WERF, 2014) (ongoing) investigates the energy balance (i.e., the energy required for reuse treatment technologies, conveyance energy, and net benefit) for many different treatment facility configurations. As part of this work, energy diagrams were developed to look at the flow of COD energy and the use of electrical energy. Figure 1.2 presents an example output from the study.

7.0  REFERENCES

Alleman, J. A. (1984) The Genesis and Evolution of Activated Sludge Technology. http://www.elmhurst.org/DocumentView.asp?DID=301 (accessed Feb 2014).

Metcalf and Eddy, Inc. (2003) Wastewater Engineering: Treatment and Reuse, 4th ed.; Tchobanoglous, G., Burton, F. L., Stensel, H. D., Eds.; McGraw-Hill: New York.

National Association of Clean Water Agencies; Water Environment Federation; Water Environment Research Foundation (2012) The Water Resources Utility of the Future … A Blueprint for Action https://www.werf.org/c/PressReleases/2013/02012013_Blueprint_for_Action_pdf.aspx (accessed May 6, 2014).

Tchobanoglous, G.; Leverenz, H. (2009) Impacts of New Concepts and Technology on the Energy Sustainability of Wastewater Management. Paper presented at Conference on Climate Change, Sustainable Development and Renewable Resources in Greece, Oct 17, 2009.

Water Environment Federation (2009) Energy Conservation in Water and Wastewater Facilities; WEF Manual of Practice No. 32; Water Environment Federation: Alexandria, Virginia.

Water Environment Federation (2011) Nutrient Removal; WEF Manual of Practice No. 34; Water Environment Federation: Alexandria, Virginia.

Water Environment Federation (2013) Wastewater Treatment Process Modeling, 2nd ed.; WEF Manual of Practice No. 31; Water Environment Federation: Alexandria, Virginia.

Water Environment Federation; American Society of Civil Engineers; Environmental & Water Resources Institute (2010) Design of Municipal Wastewater Treatment Plants, 5th ed.; WEF Manual of Practice No. 8, ASCE Manuals and Reports on Engineering Practice No. 76; Water Environment Federation: Alexandria, Virginia.

Water Environment Research Foundation (2011a) Energy Production and Efficiency Research—The Roadmap to Net-Zero Energy; http://www.werf.org/c/2011Challenges/Energy_Optimization_.aspx (accessed May 6, 2014); Water Environment Research Foundation: Alexandria, Virginia.

Water Environment Research Foundation (2011b) Nutrient Recovery: State of the Knowledge; http://www.werf.org/c/2011Challenges/Nutrient_Recovery.aspx (accessed May 6, 2014); Water Environment Research Foundation: Alexandria, Virginia.

Water Environment Research Foundation (2014) Energy Balance and Reduction Opportunities, Case Studies of Energy-Neutral Wastewater Facilities and Triple Bottom Line (TBL) Research Planning Support; Project ENER1C12; Water Environment Research Foundation: Alexandria, Virginia.

WateReuse Research Foundation (2006a) An Economic Framework for Evaluating the Benefits and Costs of Water Reuse; WRF-03-006; WateReuse Research Foundation: Alexandria, Virginia.

WateReuse Research Foundation (2006b) Marketing Nonpotable Recycled Water: A Guidebook for Successful Public Outreach & Customer Marketing; WRF-03-005; WateReuse Research Foundation: Alexandria, Virginia.

WateReuse Research Foundation (2010a) Assessment of Approaches to Achieve Nationally Consistent Reclaimed Water Standards; WRF-08-01-1; WateReuse Research Foundation: Alexandria, Virginia.

WateReuse Research Foundation (2010b) Low Cost Treatment Technologies for Small Scale Water Reclamation Plants; WRF-06-008; WateReuse Research Foundation: Alexandria, Virginia.

U.S. Environmental Protection Agency (2012) Guidelines for Water Reuse; EPA-600/R-12-618; U.S. Environmental Protection Agency: Washington, D.C.

2

The Case for Resource Recovery: Part 1—Global Megatrends in the Water, Energy, and Nutrient Landscape

Andrew R. Shaw; James Barnard; Leon S. Downing, P.E., Ph.D.; and Darrin J. Harris, EIT

1.0  GENERAL GLOBAL TRENDS AFFECTING RESOURCES

1.1  Population Growth

1.2  Urbanization

1.3  Global Climate Change and Variability

1.4  Environmental Sustainability (Life-Cycle Thinking)

2.0  GLOBAL NUTRIENT TRENDS

2.1  Global Phosphorus

2.2  Nitrogen Cycle and Recovery

3.0  GLOBAL ENERGY TRENDS

3.1  Global Energy

3.2  Primary Energy Sources

3.3  Carbon Accounting

3.4  Energy and Wastewater

4.0  GLOBAL WATER TRENDS

5.0  DRIVERS OF RESOURCE RECOVERY

6.0  REFERENCES

7.0  SUGGESTED READINGS

1.0  GENERAL