changing paradigms: from wastewater treatment...

Changing Paradigms: From Wastewater Treatment to Resource Recovery

Glen T. Daigger, Ph.D., P.E., BCEE, NAE

Senior Vice President and Chief Technology Officer

CH2M HILL

9191 South Jamaica Street

Englewood, CO 80112

303-771-0900

[email protected]

ABSTRACT

In spite of the availability of implementable technologies and approaches, adoption of energy

reduction and energy and nutrient recovery options by the used water profession has been slow.

This occurs for a number of reasons. Among them are the siloed nature of the educational and

regulatory systems, the professional organizations, and the relevant institutions. Codes and

standards also inhibit relevant changes. Economics have not historically encouraged greater

energy and nutrient recovery, but this factor is changing. Procedures for analyzing evolving and

innovative technologies and approaches compared to more conventional options often contain

biases against their adoption. Systematic barriers are also inherent in the innovation process,

including the time required by the technology learning curve and by the adoption process.

Understanding and addressing these barriers can lead to more rapid adoption of new, beneficial

technologies and approaches, creating significant societal benefits.

KEYWORDS

Energy, Nutrients, Recovery, Paradigms, Innovation, Adoption

INTRODUCTION

The municipal used water (also referred to as wastewater) stream contains a number of

constituents which can be extracted for useful purposes (Daigger, 2010, 2009, 2007). Water is

certainly one which is broadly addressed by the topic of water reclamation and reuse (Jimenez

and Asano, 2008). The used water stream also contains organic matter, nutrients, and heat which

can be extracted for a variety of purposes. Organic matter can be converted into biogas through

anaerobic processes, and the biogas can be recovered and used for energy (heat, electricity)

production through combined heat and power (CHP) systems. Microbial fuel cells can convert

the energy value of organic matter into electricity (Logan, et al., 2006). When concentrated

sufficiently, organic matter can be combusted and the heat energy recovered, for example again

for electricity production. Heat can be extracted directly from the used water stream and

upgraded for a variety of uses using heat pump technology. Nutrients can also be extracted.

While the specific technologies to accomplish energy and nutrient recovery are evolving,

practical technologies already exist and are applied in practice, although not in sufficient

magnitude relative to the existing potential.

Alternate approaches also exist which can facilitate greater recovery of energy and nutrients

from the municipal used water stream (Daigger, 2010, 2009, 2003). Source separation represents

one such approach where the relatively uncontaminated water (greywater), organic matter

(blackwater), and nutrients (yellowater) are separately collected. This separation can facilitate

the recovery of resources from the municipal used water stream. The application of

decentralized systems can also facilitate energy and nutrient recovery (Daigger and Crawford,

2007).

In spite of the availability of superior approaches to municipal used water management, their

potential application is often neglected during planning studies, or their potential advantages are

not reasonably assessed. As a result, the full potential of these approaches is not being delivered

to the public by the wastewater management profession (Guest, et al., 2009, 2010).

This paper addresses two topics. First, it provides a brief summary of available and developing

options to recover energy and nutrient from the municipal used water stream. Technologies and

management approaches will be briefly summarized, including a brief description of the

technology, its development status, and its potential contribution to increasing the sustainability

of municipal used water management systems.

Second, existing barriers to the more widespread application of these technologies by the used

water management profession will be addressed, along with approaches to address and reduce

these barriers (Daigger, 2010, 2009; Guest, et al., 2009, 2010). These barriers include factors

such as:

Lack of understanding of the available opportunities by practicing professionals, resulting

from the current structure of the educational system,

Regulatory barriers which resulted in “siloed” approaches to water, used water, and

resource management,

Institutional structures which reinforce the “silos” which restrain the implementation of

new approaches, and

Inappropriate methods of analysis which introduce biases against new approaches and

technologies.

These barriers will be addressed in the context of the existing, well developed, knowledge of the

adoption of innovations. These are factors which the profession can address, thereby allowing

more rapid implementation of alternate approaches which can contribute to greater overall urban

sustainability. The paper will not only identify these barriers but it will also present approaches

for overcoming them.

ENERGY AND NUTRIENT RECOVERY OPTIONS

Energy use for the urban water management system (drinking water and used water) is on the

order of 15 to 20 Watts/person (Daigger, 2009). This includes the energy needed for drinking

and used water treatment, and also for water conveyance (water distribution and wastewater

collection). While the energy used for treatment is significant, nearly half is used for water

conveyance. This can be compared to the available energy. For instance, the energy available in

the organic matter and nitrogen contained in the used water stream is on the order of 35 to 40

W/person (Daigger, 2009). As illustrated in Figure 1, significant heat energy is also available in

the used water stream. Coupled with reductions in conveyance energy requirements through

more integrated system configurations, the potential exists to create urban water and used water

management systems which are energy-neutral (Daigger, 2009). Table 1 summarizes a range of

currently available energy and nutrient recovery options further described in this section.

Figure 1. Thermal Energy Available in Used Water (From Daigger, 2009).

Anaerobic treatment is well known and developed. Anaerobic treatment of sludge is a well

developed and long-standing process for biologically stabilizing these solids and reducing the

level of pathogens (Grady, et al., 2011, Tchobanoglous, et al., 2002). Other types of organic

matter, including fats, oils, and grease (FOG), food waste, and industrial waste, can be added to

digesters to increase biogas production. Produced biogas can be used, after appropriate cleaning,

in CHP systems or further cleaned to remove CO2, moisture, and impurities to produce natural

gas. Although less common, used water can also be treated directly using anaerobic processes

(Grady, et al., 2011; van Haandel and Lettinga, 1994), reducing the energy required for treatment

along with producing biogas. The stoichiometry, kinetics, and methods for implementing

anaerobic processes are well known and documented (Grady, et al., 2011; WEF, 2009; van

Haandel and Lettinga, 1994).

Organic matter removed from the used water stream or produced through treatment of it can also

be treated in thermal processes, producing excess heat energy which can be used directly or for

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electricity production. Energy production from these materials is constrained by their water

content, as some of the heat of combustion of the organic matter must be used to evaporate this

water. Thermal processes can also be used to gasify these solids, with the gas subsequently used

for energy production. Again, these are well known processes (WEF, 2009).

Microbial fuel cells are a developing approach for directly converting the chemical energy

content of the organic matter and nitrogen contained in used water directly into electrical energy

(Logan, et al., 2006). Bacteria extract electrons from organic matter and nitrogen and transfer

them to oxygen, producing water. Extensive laboratory-scale research has been completed with

this technology, and scale-up to practical application is on-going.

Heat can be extracted directly from the flowing used water stream for a variety of purposes, such

as district heating systems. As illustrated in Figure 1, significant energy is available with only a

modest change in water temperature. One may think of this as recovering the heat added by use

of the water. Heat is removed by heat exchange and can be converted into more useful forms

using heat pumps. Although applications are currently limited, use of these technologies is

increasing.

The various biosolids land application methods result in direct recovery and reuse of the

nutrients contained in the biosolids (Daigger, 2009). Nutrient recovery and reuse by these

approaches is limited by the quantity of biosolids reused and their nutrient content. Phosphorus

can be recovered directly by a variety of technologies, for example from incinerator ash using

conventional mining technologies (Sartorius, et al., 2011). It can also be extracted from the

sludge or the recycle streams from solids processing by precipitation as struvite (MgNH4PO4) or

calcium phosphate (Ca3(PO4)2). Struvite is a high quality slow release fertilizer, and calcium

phosphate is similar to phosphate ore. Ammonia-nitrogen can be stripped from these streams

and adsorbed, for example, into sulfuric acid to form ammonium sulfate, which can be used as a

fertilizer.

Daigger (2009) described how separate distribution of potable and non-potable water can reduce

water distribution energy requirements, especially if non-potable water is produced in a

distributed fashion by rainwater harvesting and/or water reclamation. Less energy is needed for

water distribution if water is produced close to the point of use. Energy may also be saved for

treatment to non-potable compared to potable water standards. Further energy savings and

significant energy production and nutrient recovery options are created by separation of

relatively uncontaminated greywater from blackwater (toilet and kitchen wastes) and yellowater

(urine). Because it is relatively uncontaminated but represents the bulk of the used water flow,

greywater can be treated to produce significant quantities of non-potable water with relatively

low energy input. Distributed treatment of greywater further allows non-potable water to be

produced close to its use, thereby reducing the energy required for water distribution.

Blackwater contains most of the organic matter and, because it is at a higher concentration due to

greatly reduced used water flow to transport it, blackwater can be treated using anaerobic

processes for direct energy production. Yellowater contains most of the nutrients, which can be

recovered directly. Public health would also be enhanced as a disproportionate proportion of

hormones and pharmaceuticals are contained in the yellowater (Ternes and Joss, 2006).

BARRIERS TO ADOPTING ENERGY AND NUTRIENT RECOVERY OPTIONS

The question that arises from the above is, if we have all these approaches for energy reduction,

and energy and nutrient recovery, why are they not being adopted more quickly? This occurs for

several reasons, a principal one being the “siloed” nature of our educational and regulatory

systems and our institutions. Traditionally, water practitioners are educated and become

specialized in specific elements of the urban water cycle. Drinking water, storm water, used

water, and residuals management are taught separately, and it is possible for professionals to

complete their education without being learning about all elements of the urban water cycle.

This is reinforced by our professional associations which are also not comprehensive. The

regulatory framework is fragmented, with drinking water regulated separately from storm and

used water and components of the storm and used water regulations are separately and

independently implemented. Urban water management utilities are often single-purpose (water,

storm water, used water), or if they are integrated they are often internally siloed. Codes and

standards also institutionalize current practices and restrain the implementation of new practices.

It must be said, however, that these barriers are more significant with regard to water recovery

and recycling and less so with regard to energy and nutrient recovery and recycling. So, why has

progress on energy and nutrient recovery been slow?

Economic Factors

One factor has been economics. Anaerobic digestion of used water sludges with use of the

produced biogas was more widely practiced until the late 1960’s and early 1970’s when low

energy prices coupled with a focus on minimizing capital expenditures during the United States

Environmental Protection Agency (US EPA) construction grants program led to the increased

use of alternate sludge processing technologies. This situation is changing, however, as energy

prices are now increasing much faster than construction costs, making low energy using

processes more economically attractive. The economics of nutrient recovery are still generally

not favorable, although fertilizer costs are increasing more rapidly than construction costs so that

this situation is also changing. As expected, changing economics are making energy and nutrient

recovery options more cost-effective, resulting in increased adoption.

Quantifying Risks and Opportunities

The conservative nature of many engineers, coupled with the procedures used to evaluate

treatment options, constrain the application of newer technologies. The economics of various

options are typically evaluated using present worth (PW) analysis, which considers both the

capital and operation and maintenance (O&M) costs of options on an equivalent basis to select

the economically most attractive one. PW analysis is a deterministic method which assumes that

all of the cost factors are understood well enough so that the PW of each option can be estimated

comparable accuracy. This may not be the case, however for evolving and innovative

technologies and approaches compared to established ones, resulting in an inherent bias. In the

face of uncertainly about cost factors, the conservative engineer will often use conservative

values which understate the economic value of the advantages offered and overstate the

economic costs of the evolving and innovative technology or approach relative to more well

characterized conventional and proven technologies. This can be most easily thought about if

the PW analysis components are displayed as a benefit-cost ratio where the PW value of the

benefits is divided by the PW value of the costs. Understating the benefits and overstating the

costs can significantly and adversely alter the ratio compared to options where this bias is not

introduced.

The criticism here is not about recognizing the uncertainty associated with less well developed

options but the use of a deterministic analysis approaches to compare them to more well

established options. Deterministic analysis of options introduces an inherent bias when

comparing technologies and approaches at much different levels of development and also misses

the key point that the uncertainties inherent in evolving and innovative technologies and

approaches must be managed as they are being implemented. Thus, the level of risk associated

with an evolving or innovative technology or approach needs to be assessed when they are

compared to more well known and defined conventional technologies and approaches, and the

approach to implementing them refined to mitigate those risks while also maximizing the ability

to capture their inherent advantages.

Fortunately, tools are available to do this, principal among them being risk and opportunity

analysis. Risk is classically defined as the probability of occurrence of an event times its impact.

High risk elements are those which occur frequently and have large impacts, while low risk

elements occur infrequently and have small impacts. Risk and opportunity analysis also involves

determination of approaches to mitigate or take advantage of them, which can be used as the

basis for determining their economic value. Some of the key risks and opportunities of evolving

and innovative technologies and approaches are uncertain. Identification of both and

characterizing their likelihood (frequency) and economic impact allows the uncertainties inherent

in these less developed technologies and approaches to be rationally addressed.

Risk and opportunity analysis begins with identifying the most significant inherent risks and

opportunities associated with the evolving or innovative technology or approach and listing them

in a risk register, as illustrated in Table 2. Note that all options actually have important

uncertainties associated with them. If risk and opportunity analysis is to be applied to only the

evolving or innovative technologies or approaches, then only those risks and opportunities

uniquely associated with them or which are greater for them should be identified in the risk and

opportunity register. Risks and opportunities are entered into the register by first assigning a title

or number to the individual element and providing a brief description. The frequency or

likelihood (chance) of occurrence of the item is then estimated, and the impact of its occurrence

is described. Finally, methods for mitigating the resultant impact are identified, along with the

economic cost. It may seem that identifying risks and opportunities and describing them may be

relatively straightforward but that the remainder of the analysis may be difficult to accomplish as

occurrence frequencies and economic impacts are not known. The key here is to use experience

and judgment in assembling the risk and opportunity register. The simple act of assembling the

register provides significant value because the risks and opportunities are explicitly recognized

rather than inherently and implicitly incorporated into a standard PW analysis where they are not

subject to scrutiny and evaluation. Identifying mitigation measures, and their economic value,

helps to frame the importance of the identified item. If a number of items are identified, they

can be analyzed to determine a range of potential economic outcomes as will be described

immediately below. If critical risks as identified which cannot be mitigated, these may represent

fatal flaws which would prevent selection and implementation of the particular technology or

approach at the current time. This, itself, is valuable information as it provides a rational basis

for rejecting it.

Developing a preliminary risk and opportunity register provides an initial assessment of the

uncertainties uniquely associated with the subject technology or approach. The result may be a

qualitative assessment that the risks clearly outweigh the opportunities, which provides a rational

basis for eliminating it at this point. If the qualitative analysis indicates sufficient potential

advantages compared to the risks, the next step can be a Monte Carlo analysis of the economics

of the technology or approach. A Monte Carlo analysis involves using the estimated frequency

of occurrence and economic impacts of the identified items to essentially “build and operate” the

option many (1,000 to 10,000) times, thereby quantifying the inherent uncertainty. When

conducting such an analysis it is important that the PW of the option be computed on an

“expected” basis, that is, with no bias reflecting the inherent uncertainties as these are accounted

for explicitly in the risk and opportunity register. The frequency of occurrence of the various

risks and opportunities and their economic impacts are then added randomly to the “expected”

PW analysis many times, resulting in PW values which are then tabulated and a probably

distribution of the expected PW is developed. Such analyses can be easily conducted these days

with modern spreadsheets and add-ins which allow Monte Carlo analyses to be automated. The

result can then be compare to the more conventional option(s) and a decision made.

The risk and opportunity register can also be used to develop the implementation plan if the

evolving or innovative technology or approach is selected. With the key risks and opportunities

identified, an implementation approach can be developed incorporating the identified mitigation

measures. Identification of the risks and opportunities also provides a rational basis for

assigning them to the party best able to manage them (owner, technology provider, contractor,

engineer), thereby maximizing the likelihood of successful implementation.

Systematic Barriers Inherent in the Innovation Process

Systematic barriers exist in the innovation process, as defined by researchers working in a wide

variety of disciplines. The classic work in this area is by Rogers (2003) where the classic S-

curve for the adoption of innovations (or technologies) is documented. As illustrated in Figure 2,

time is required for the adoption of an innovation, with the rate being initially slow, followed by

an acceleration phase and rapid growth, with the rate of adoption slowing as saturation is

approached. Different types of adopters are predominant in various phases of the adoption cycle.

The initial adopters are termed innovators, as they simply like new things and approaches. They

provide advantage to the developer of the innovation as they are more likely to participate in the

technology development process by funding research, pilot studies, and initial installations. Next

are the early adopters, who are key to introducing the innovation to the broader potential group

of adopters. They are continuously seeking advantage and are generally able to identify and

implement innovations which provide it to them. As a consequence, they are closely watched by

their peers and, when they select and successfully implement an innovation, adoption by the

early majority adopters often follows as they are also looking for advantages but generally let the

early adopters do the hard work of searching out and further developing beneficial innovations.

The late majority and laggards follow, but mainly out of necessity. The key point is that this

range of adopters exists in every population, including in the water profession.

Figure 2. The S-Curve for the Adoption of Innovations (Adapted from Rogers, 2003).

Christensen (2003) and Christensen and Raynor (2003) provide further insight into the

innovation process through their study of the adoption of technology in the electronics industry.

As illustrated in Figure 3, both customer expectations for improved functionality of the

technology or innovation and the capabilities of the technology evolve with time. Expectations

are often first dominated by interest in performance, but as performance is established and

becomes expected differentiating factors for the subject technology evolve from reliability to

convenience to price (at which time the subject technology has become a commodity). Early in

the cycle for a sustaining technology or innovation the difference between the functionality

provided and that desired by the user drives (funds) further development. As also illustrated in

Figure 3, not all users are the same and have different desires with regard to performance,

reliability, convenience, and price. This is an important factor which allows different “products”

to co-exist in the marketplace at any given time – different products serve the desires of different

customers. However, the functionality of the product can evolve to where it begins to exceed

that desired by the customer. As this happens, the opportunity to enter the marketplace is created

for an alternative technology or innovation which begins to meet the needs of some of the

customers and establishes itself in this set of applications.

Figure 3. Sustaining and Disruptive Innovations.

The technology development, or learning, curve has been quantified for a number of

technologies, but some of the most consistent data are available for the energy sector. Figures 4

and 5 provide illustrations, using the unit cost of various energy production technologies as the

performance metric. Figure 4 illustrates the classic observation that performance improves

exponentially with increased installed capacity, reflecting the learning which occurs with use of

the technology. The rate is greatest during the initial development phases (described in greater

detail below), and then decreases as the technology proceeds into the commercialization phase.

Figure 4. Decrease in Costs for Gas Turbines with Installed Capacity (From Grübler, et

al., 1999).

As illustrated in Figure 5, competing technologies follow similar learning curves, and that

learning can occur at similar rates for competing technologies. Given the relationships presented

in Figure 5 one may wonder how competing technologies, such as photovoltaics, become

established when their unit costs are systematically higher than competing technologies such as

windmills and gas turbines. The answer is that, initially, the various technologies fill various

niches. Thus, photovoltaics may initially be used in remote installations where their passive

operation is an advantage. More on this later as well.

Figure 6 illustrates that competing technologies may evolve for an extended period, filling

specific niches but not becoming a significant contributor to meet the overall need for some time.

The term that is applied to this phenomenon is materiality – meaning when the contribution of a

particular technology to meeting industry-wide demands becomes material from a quantitative

perspective. That time is needed for a technology (or innovation) to become material results

from a number of factors. One is the fact that time is needed for the technology to evolve

through the learning curve. The second is that, in some industries, the life of the installed

infrastructure is quite long and, unless the new technology is sufficiently superior to existing

technologies to justify its early replacement, existing technology must reach its useful life before

it is replaced by newer approaches. These constraints certainly apply to the water industry.

Figure 5. Evolution of Unit Costs for a Variety of Competing Energy Technologies as a

Function of Installed Capacity (Grübler, et al., 1999).

Table 3 is abstracted from Grübler, et al., 1999 and summarizes and extends the concepts

presented thus far. The processes of invention and innovation are first distinguished. Invention

is the discovery of some unique and fundamental phenomenon that may have no practical value

in and of itself but which forms the basis for value-added practical applications. Invention is a

random and unpredictable process which is often the result of basic research. The cost can be

high, it does not lead directly to a marketable product (or usable result), and little learning occurs

relative to practical applications. In contrast, innovation is the process of applied research,

development, and demonstration (RD&D) which builds on the invention but seeks to develop a

useful product or result. Again, costs are high, and no marketable or useful result is produced.

Innovation leads to the development of prototype products which begin to fill niche applications,

as illustrated in Figure 3. This represents the initial phase of adoption by the innovators, as

illustrated in Figure 2. This phase is characterized by a high rate of learning by doing and close

collaboration between technology suppliers and users. Development costs are still high but are

declining, and revenue from sales begins to help finance some of the development costs. The

practical learning rate is high.

Figure 6. Time is Required for Niche Technologies to Become Material Relative to the

Needs of the Entire Industry (From Kramer and Haight, 2009).

Once niche applications are established, learning by doing progresses, leading to progressive

improvements which expand the available market, as illustrated in Figure 3, and adoption

proceeds as characterized in Figure 2. Costs decline rapidly as market share grows quickly, but

the learning rate declines as the technology matures. The rapid growth phase is followed by

market saturation and finally by senescence as it begins to be replaced by higher performing

technologies.

OVERCOMING BARRIERS TO ADOPTING ENERGY AND NUTRIENT RECOVERY

OPTIONS

As noted, economics are becoming more favorable for the adoption of innovative and evolving

energy reduction and energy and nutrient recovery technologies and approaches. While

systematic barriers restrain the adoption of energy and nutrient recovery options by the water

profession, systematic changes could reduce these barriers, as follows:

1. Revise the educational system so that urban water management is taught in a more

complete and holistic fashion. The recently published Body of Knowledge (BOK) by the

American Academy of Environmental Engineers (AAEE) should help to accelerate this

(AAEE, 2009).

2. Greater collaboration by the relevant professional societies, including the American

Water Works Association (AWWA) and the Water Environment Federation (WEF).

3. Aggressively working through the relevant professional societies to revise codes and

standards to make them less prescriptive and more performance-based.

4. Working with regulators and legislatures to develop more holistic environmental

legislation and translating both existing and revised legislation into more holistic

environmental regulations which encourage innovation. Transitioning from prescriptive

regulations which dictate practices to performance-based regulations which dictate what

must be accomplished illustrate the types of changes that can be made. Incentives would

ideally be incorporated into revised regulations which encourage new, higher performing

technologies and approaches and reward innovators and early adopters.

5. Revise the procedures typically used to evaluate evolving and innovative technologies

and approaches relative to the more well established and defined conventional

technologies to explicitly reflect the greater uncertainty inherent with evolving and

innovative technologies and approaches.

6. Recognize the inherent nature of the innovation process and the steps that are necessary

for new inventions and innovations to become commercially viable. One of the inherent

constraints to innovation in the water industry is the long life for infrastructure and

equipment conventionally used. A higher rate of innovation would occur if it was

recognized that a greater rate of obsolescence would allow beneficial technologies and

approaches to become available more quickly, which in the long-run would improve

performance and lower costs more rapidly.

REFERENCES

American Academy of Environmental Engineers (2009) Environmental Engineering Body of

Knowledge, American Academy of Environmental Engineers, Annapolis, MD.

Christensen, C. M. (2003) The Innovator’s Dilemma: The Revolutionary Book That Will Change

the Way You Do Business, HarperCollins Publishers Inc., NY.

Christensen, C. M. and R. E. Raynor (2003), The Innovator’s Solution: Creating and Sustaining

Successful Growth), Harvard Business School Publishing, Boston.

Daigger, G. (2010) Integrating Water and Resource Management for Improved Sustainability In

Water Infrastructure for Sustainable Communities, Hao, X., V. Novotny, V. Nelson, Ed., IWA

Press, London.

Daigger, G. T. (2009) State-of-the-Art Review: Evolving Urban Water and Residuals

Management Paradigms: Water Reclamation and Reuse, Decentralization, Resource Recovery.

Water Environment Research, 81(8), 809-823.

Daigger, G.T. (2007) Wastewater Management in the 21st Century. Journal of Environmental

Engineering, 133(7), 671-680.

Daigger, G. T. and Crawford, G. V. (2007) Enhanced Water System Security and Sustainability

by Incorporating Centralized and Decentralized Water Reclamation and Reuse Into Urban Water

Management Systems. J. Environ. Eng. Manage., 17(1), 1-10.

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Guest, J. S., S. J. Skerlos, G. T. Daigger, J. R. E. Corbett, and N. G. Love (2010) The Use of

Qualitative System Dynamics to Identify Sustainability Characteristics of Decentralized

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Grady, C. P. L., Jr., G. T. Daigger, N. G. Love, and C. D. M. Filipe (2011) Biological

Wastewater Treatment, CRC Press, Boca Raton, FL.

Guest, J. S.; Skerlos, S. J.; Barnard, J. L.; Beck, M. B.; Daigger, G. T.; Hilger, H.; Jackson, S. J.;

Karvazy, K.; Kelly, L.; Macpherson, L.; Mihelcic, J. R.; Pramanik, A.; Raskin, L.; van

Loosdrecht, M. C. M.; Yeh, D.; Love, N. G. (2009) A New Planning and Design Paradigm to

Achieve Sustainable Resource Recovery From Wastewater. Environmental Science &

Technology. 2009, 43(16).

Grübler, A. N. Nakićenović, D. “G. Victor (1999) Dynamics of Energy Technologies and Global

Change, Energy Policy, 27, 247-280.

Jimenez, B. and T. Asano (2008) Water Reuse: An International Survey of Current Practice,

Issues and Needs, IWA Publishing, London.

Kramer, G. J. and M. Haight (2009) No Quick Switch to Low-Carbon Energy, Nature, 462(3),

568-569.

Logan, B. E., Hamelers, B., Rozendal, R., Schroder, U., Keller, J., Freguia, S., Aelterman, P.,

Verstraete, W., and Rabaey, K. (2006) Microbial Fuel Cells: Methodology and Technology

Envir. Sci. Tech., 40(17), 5181-5192.

Rogers, E. M. (2003) Diffusion of Innovation, 5th

Edition, Free Press, NY.

Sartorius, C., J. van Horn, and F. Tettenborn (2011) Phosphorus Recovery From Wastewater –

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and Reuse, McGraw Hill, Boston.

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Ltd., London.

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Edition, Alexandria, VA.

Table 1. Summary of Select Energy and Nutrient Recovery Options.

Technology Description Development Status Contribution to Sustainability

Anaerobic Treatment

Wastewater Raw municipal used water or a

component of it is treated directly in a

high-rate anaerobic process.

Technology developed and

applied in warm climates but not

in colder climates

Energy for treatment reduced and

collected biogas usable for energy

production

Sludge Sludges from conventional used water

treatment stabilized in anaerobic

digesters

Conventional mesophilic

digestion well established;

advanced digestion processes

evolving

Biogas production from treatment

residuals

Thermal

Treatment

Residuals from conventional used water

treatment treated in thermal processes

with excess heat captured for direct use

and/or energy production

Thermal destruction technology

well established; gasification

technology established but

evolving

Thermal energy used directly and/or

for energy production

Microbial

Fuel Cells

Chemical energy in used water directly

converted to electricity by combined

biological and electrochemical

processes

Science well developed; scale-up

to pilot and eventually to

commercial scale on-going

Energy for treatment avoided and

electrical energy produced directly

Heat

Recovery

Heat exchangers used to collect heat

from used water and heat pumps used,

when necessary, to produce usable

heated source

System components well proven;

limited but growing number of

full-scale applications

Heat energy removed from used water

provides direct domestic, commercial,

and industrial functions

Biosolids

Land

Application

Residuals from conventional used water

treatment processed into wide variety of

products which are applied to land as

fertilizer and/or soil conditioner

Wide variety of well developed

and widely used processes such

as land application of digested

biosolids, composting, thermal

drying

Nutrients contained in applied

biosolids provide nutrients for plant

growth and off-set use of conventional

fertilizer

Phosphate

Recovery

Phosphate recovered from used water,

sludge, or solids handling recycle stream

in reusable form

Evolving set of technologies

generally applied to sludge or

solids handling recycle streams

Use of recovered phosphate replaces

use of phosphate produced from

mined phosphate ore

Nitrogen

Recovery

Ammonia-nitrogen is removed from

liquid stream by air stripping and

subsequently adsorbed into sulfuric acid

Well established process which is

little applied today due to

unfavorable economics

Produced ammonium sulfate usable

directly or as component of

commercial fertilizer

Dual

Distribution

Potable and non-potable water

separately produced and distributed to

the customer

Well developed approach which

is widely used in water short

locations

Less energy required to produce non-

potable water from compromised

sources

Source

Separation

Greywater, blackwater, and yellowater

separately collected and processed

Evolving approach which is being

applied in increasing number of

locations

Water, energy, and nutrients in used

water separately collected and

recovered

Decentralized

Systems

Used water treated locally for

reclamation and reuse

Evolving approach which is

increasingly being applied

Energy for reclaimed water

distribution reduced

Table 2. Example Risk and Opportunity Register.

Item

Description

Frequency or Chance

of Occurrence

Impact Mitigation Method Economic Impact of

Mitigation

#1 Item #1 Description Chances for Item #1 Impact of Item #1 Item #1 Mitigation Cost to Mitigate Item #1




Table 3. Stages of the Innovation Process (Abstracted from Grübler, et al., 1999)

Stage Mechanism Cost Market

Share

Learning

Rate

Invention Random Breakthroughs and Basic Research High 0 % -

Innovation Applied Research, Development, and Demonstration (RD&D) High 0% -

Niche

Market

Niche Applications, Learning by Doing, Suppliers and Users Have

Close Relationship

High But

Declining

0-5% 20-40%

Pervasive

Diffusion

Standardization, Mass Production, Economies of Scale, Network

Effects

Rapidly Declining 5-50% 10-30%

Saturation Commodity, Intense Competition Low and Declining Up to 100 % 0-5%

Senescence Few Improvements Possible Low and Declining Declining 0-5%

changing paradigms: from wastewater treatment...

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