Toward Nucleating the Concept of the Water Resource Recovery Facility

Mar 23, 2017 - Wastewater resource recovery has been advocated for decades; necessary structural pathways were long-ago articulated, and established a...
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Toward Nucleating the Concept of the Water Resource Recovery Facility (WRRF): Perspective from the Principal Actors Erik R. Coats*,† and Patrick I. Wilson‡ †

Department of Civil Engineering, University of Idaho, Moscow, Idaho 83844-1022, United States Department of Natural Resources and Society, University of Idaho, Moscow, Idaho 83844-1139, United States

‡

ABSTRACT: Wastewater resource recovery has been advocated for decades; necessary structural pathways were long-ago articulated, and established and emerging technologies exist. Nevertheless, broad wastewater valorization remains elusive. In considering implementation barriers, the argument is made that decision-makers focus on avoiding permit violations and negative publicity by embracing a conservative/safe approach−seemingly ignoring research on economic/environmental benefits. Conversely positing that economics is a primary barrier, we investigated, characterized, and described nontechnical socio-political barriers to realizing wastewater resource recovery. Principal actors in the Pacific NW region of the U.S. (representing a progressive populace facing stringent water quality regulations) were interviewed. Results revealed that economics were, indeed, the primary barrier to implementation/expansion of the WRRF concept. Consistent throughout interviews was a prevalent sense that the “cost of doing something (different)” was a principal consideration in resource recovery actions/policies. Moreover, “economics drives decisions,” and “95% the bottom line is money. Show return on investment, it will get people’s attention.” Who pays was also a concern: “Government isn’t going to pay. The states and Federal government won’t give any grants, and we can’t raise rates.” Applying business case evaluations was seen as a pathway to actualizing resource recovery. Most encouragingly, the consensus was that resource recovery is a necessary future paradigm, and that real barriers are surmountable. IWA,13 the Water Environment Federation (WEF), and the Water Environment and Reuse Foundation (WE&RF). WEF/ WE&RF have even rebranded wastewater treatment plants as water resource recovery facilities (WRRFs) to recognize and reinforce the significant resource recovery potential that exists in wastewater streams. To contextualize the opportunity, municipal WRRFs in the U.S. alone process an estimated 32 billion gallons of water daily14 that can be recovered as potable and nonpotable water. Energy use is another area of interest,15 as municipal WRRFs consume up to 3.4% of total electricity in the U.S.,14,16,17 and electricity use accounts for 25−40% of WRRF operating budgets.18 Significant energy potential exists in wastewater,15,19 and as a result the concept of energy neutral WRRFs has gained much attention.15,20 Beyond energy, wastewater contains value as a fertilizer. An estimated 8 million dry tons of nutrient-rich sludge is produced annually at municipal WRRFs and could be processed and used agronomically as a slow-release fertilizer (coupled with electricity production via AD); similar potential exists in the liquid wastewater stream.

1. INTRODUCTION Developed societies generate billions of tons of waste in the manufacture and use of products and commodities.1,2 Collectively, handling solid and liquid waste streams has historically emphasized a management concept, with a reactive contain-and-control legacy embedded in environmental regulations centered on the goal of protecting human health and the environment.1,3 While treatment has been implemented, the approach is most commonly applied to municipal wastewater, with resultant products (reclaimed water/treated effluent and biosolids) returned to the environment as a means to minimize containment requirements. Considering the complex and heterogeneous nature of waste streams and the potential adverse impacts of mismanagement, coupled with limited opportunities/technologies for otherwise recovering value, certainly the containment/treatment approach has indeed been sensible. However, looking to the future, we need to embrace an approach where maximum value of waste streams is realized. Sustainable solutions to waste management−namely resource recovery−have been advocated for decades,4−6 with necessary structural pathways long-ago articulated.7 Specifically focusing on municipal wastewater, the intrinsic value of this nutrient-rich stream is increasingly being realized.8−12 Indeed, resource recovery has been aggressively advocated by the © 2017 American Chemical Society

Received: Revised: Accepted: Published: 4158

January 19, 2017 March 18, 2017 March 23, 2017 March 23, 2017 DOI: 10.1021/acs.est.7b00363 Environ. Sci. Technol. 2017, 51, 4158−4164

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Environmental Science & Technology

wastewater management−seemingly ignoring the research (i.e., life cycle assessment studies) that continue to document the potential economic and environmental benefits of resource recovery.17,22,40 Recognizing that the opportunities and benefits to wastewater resource recovery are indeed well established, yet real implementation examples remain relatively scarce, perhaps other variables or perspectives−beyond the well-described civic epistemology41 barriers1,3,9,39 − are in play that impede progress. In this regard, we posit that economics is the primary barrier to broad-scale wastewater resource recovery−specif ically, costs vs benef its and how they are shaped by business case considerations. Integrated with other articulated barriers, this economic context takes place within a collective dynamic relationship between decision makerspublic works managers, city managers, rate payers, and regulatorsthat is shaped by inherent caution and risk aversion. While economics might seem obvious or intuitive as a limiting factor, its potential centrality and critical influence as a pragmatic decision-making variable is seemingly not; and perhaps most importantly, for those developing alternative resource recovery technologies− particularly those in the academic sectoran enhanced understanding on the importance of economics (as expressed by technology adopters and decision makers) could help accelerate commercial applications. Clearly, the ultimate goal, collectively, is to realize the long-envisioned concept of resource recovery.4,5 Building from our hypothesis, the goal of this study was to investigate, understand, characterize, and describe nontechnical socio-political barriers to realizing broad-scale resource recovery from wastewater, with a specific emphasis at the local level where the WRRF concept must necessarily nucleate.

Given their centralized nature in receiving and processing wastewater, and the significant infrastructure already in place, municipal WRRFs can (and should) play a central role in the concept of waste resource recovery;9,17,21,22 industry professionals broadly agree WRRFs should evolve to become factories that manufacture products and commodities from the raw material that is wastewater.23 To such an end, an array of technologies have been developed to capture the intrinsic value in wastewater,9,23−25 including as (i) a slow-release fertilizer from wastewater (struvite22,26), (ii) a biomass-based fertilizer (as Class A or B biosolids), (iii) electricity via combustion of anaerobic digestion (AD) biogas (which could offset an estimated 40% of WRRF energy demand27), and (iv) reclaimed water. In addition, potential new technologies are being developed to capture even more of the intrinsic value in wastewater,23,25 with potential products including (i) bioplastics,28−31 (ii) methanol from anaerobic digester biogas,32 (iii) energy (e.g., anaerobic membrane bioreactors exhibit the potential to capture even more of the embodied carbon energy in wastewater33), and (iv) algae, which can be upcycled as both a fertilizer and energy source.15,25 Within the context of resource recovery, WRRF energy/carbon neutrality is also a potential targeted outcome (although not without challenges and potential limitations).34 Nevertheless, despite the intrinsic potential of these myriad technologies, limited resource recovery from wastewater has been implemented−even for the more established pathways. Indeed, much work remains to truly realize the envisaged concept.3,9 In the U.S. alone almost 98% of treated wastewater effluent is discharged into the water environment, with only a nominal fraction utilized for nonpotable or potable needs.35 Even in water-starved California the concept of water reuse remains underutilized.36 For energy, less than 10% of WRRFs where biogas-to-electricity is technically feasible employ such technologies19 − the majority of biogas produced is flared, while some is used to heat digesters.23 Regarding fertilizer, only half of collected sludge is used beneficially,35 with the residual being landfilled, while liquid stream phosphorus (and in some cases nitrogen) is more commonly discharged to the water environment. Considering the state of the global wastewater industry and the sizable financial commitments necessary to sustain its integrity,15,23,37 continued investment in traditional, treatmentcentric WRRF configurations is not sustainable.9,38 Instead, the industry must pivot and achieve broader integration of resource recovery technologies into existing infrastructure.9,15,20,23 To achieve this vision, however, the challenge is not one of technology (as described, an array of resource recovery technologies currently exist). Some researchers suggests the challenge is sociological and institutional,9,39 while others contend regulations (and to a lesser degree lack of policy drivers) are the primary impediment.1,3,23 Indeed, an argument can be made for all these potential barriers. Because WRRFs are (currently) in the business of producing effluent in compliance with regulatory-based permits (to protect human and aquatic system health), innovation failure, in whole or part, can lead to expensive fines. Moreover, decision-makers are often reluctant, given previous experiences, to confront potentially adverse public perceptions of resource recovery.9 Finally, fiduciary responsibilities are in play as well, with necessary concern about prudent use of public resources. So an argument is made that decision-makers focus principally on the avoidance of permit violations and negative publicity by embracing a conservative, safe approach to

2. MATERIALS AND METHODS 2.1. Description of Survey Area, Instrument, and Methodology. The focal point of this study was decisionmakers (and their advisors) who, operating in an environment shaped by external pressures and internal constraints, are cautious in embracing new technologies and management practices. This study was an exploration of the scope and substance of this caution. Is it caused by the practical realties of managing for the public interest and maintaining attention to ratepayer preferences for low rates? Is it the perceived balance of the cost (and risk) of embracing new technologies relative to the much more difficult challenge of measuring and explaining possible benefits? Is it related to a public unwillingness to embrace a new type of product (e.g., water supply) that transitions and differs from out of sight, out of mind uses? Or is it a product of professional training and experience, where intrinsic caution and conservatism in legacy management practices has produced stable, long-term system operations? The focus of this study was the Pacific Northwest (PNW) region (Idaho, Oregon, Washington) of the United States. This region was selected, in large part, because of a proactive and progressive approach to wastewater management and protection of the environment that is driven by a more environmentally conscious and engaged public (principally, but not exclusively, in the larger metropolitan areas) and stringent instreamwater quality criteria for many WRRFs. Regarding instreamwater quality, the presence of multiple endangered aquatic species (e.g., salmon, steelhead) coupled with low summertime in-streamflow conditions has yielded very stringent nutrient removal requirements (e.g., phosphorus is regulated in some water bodies at the μg/L level). As a result, 4159

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Survey questions generally framed the same categorical issues as a recent water reuse-focused study,36 albeit with a modified focus given this study explored resource recovery more broadly. When the interview process was complete the authors independently reviewed sets of transcripts and identified key themes. Consultation re-established collective agreement on theme definitions and further review led the authors to agree, given that new data no longer suggested new insights, that theoretical saturation of topics and responses had been achieved.44

in the U.S. the PNW region is broadly viewed as a leader in utilizing advanced WRRF solutions. Moreover, a select few WRRFs in the region have more aggressively, yet selectively, embraced enhanced resource recovery.42 Yet, within the context of wastewater treatment and management, broadscale resource recovery has not been widely embraced in the PNW, and most WRRFs have focused on permit compliance in some cases without pause in the associated chemical and energy intensity. As a result, the Pacific Northwest can be conceptualized, spatially and socially, as an optimal region for this study. The starting point for this study was a purposive sampling approach, where participants were selected in a strategic way “so that those sampled are relevant to research questions.”43 Using a form of generic purposive sampling, we began by using professional networks to identify key informants and decisionmakers representative of the wastewater industry in the PNW region. A semistructured interview protocol was used, and 28 professionals from the PNW WRRF industry were interviewed. The interviewees were all senior professionals actively working in the wastewater management field and engaged at the decision-making level; interviewees included consulting engineers, public works/city administrators/decision-makers, and regulators. All interviewees are actively involved in the permitting, planning, design, and operation of WRRFs, and thus the resource recovery arena. Interviewees well represented (geographically) the three-state PNW region, included regional and national consulting engineers actively practicing in (and outside) the region (and consulting to small, medium, and large WRRFs), and included medium and large cities/WRRFs. Technology developers were not included in the survey. Following consideration and assessment of the entire set of completed interviews, we concluded the population was well represented and there was limited gain from increasing the sample size or expanding the portfolio of professionals. Experience in the design, implementation, operation, and ownership of WRRFs varied, with most having extensive experience with WRRF operations and infrastructure design and development. Interviewees represented a range of actors working in major metropolitan areas to local, smaller scale WRRFs. Included were representatives from the heavily populated, surface water dependent, coastal wet side of the region and the arid, sparsely populated, groundwater dependent, dry side. 2.2. Survey Questions. Although the wording of questions evolved as the survey progressed, all interviewees were asked a close version of the following questions: • Based on your experiences, how socially acceptable is using recovered products (direct or indirect) from wastewater for human use/consumption? • How effective are campaigns to educate the public about the positive benefits of recovered products? • Have communities found success in “branding” of products recovered from wastewater? • How do current rules and regulations shape or limit the broad application of resource recovery technologies and use of products recovered from wastewater? • What changes in regulation would have the biggest effects; would make the biggest differences toward wider acceptance and use of recovered wastewater? • How do financial considerations act as a barrier to deployment of resource recovery technologies?

3. RESULTS 3.1. Wastewater Resource Recovery Economics. Indeed, the economics of wastewater resource recovery was a prominent theme in this study. Consistent throughout interviews was a prevalent sense that the “cost of doing something (different)” was a principal consideration in resource recovery actions and policies. Of the 28 professionals interviewed, 23 directly noted costs of action and the balance of costs-benefits as a primary challenge in enhanced wastewater resource recovery. As one succinctly noted, “economics drives decisions,” while a second contended “95% the bottom line is money. Show return on investment, it will get people’s attention.” A commonly expressed opinion in interviews was a need for business case evaluations that monetize costs and benefits specific to the implementation of resource recovery technologies, rather than the more conventional cost-benefit analysis focused on treatment. The importance of relative costs to benefits in shaping decision making was explained by one interviewee, “companies love (water) reuse and the technology really isn’t the problem, but it’s the cost and distribution of the reclaimed water that is the challenge.” However, a number of interviewees noted the challenge of measuring and weighing costs and benefits. The “benefits (of resource recovery technologies and products),” observed one, “are hard to monetize.” Decision-makers, as a result, are confronted with a significant challengeis there a solid business case for the water resource recovery investment? “The money” concluded an interviewee, “has to be good. It doesn’t have to be great, but the money has to be good. When I say money, I mean the business case, the return on investment.” Noted another, “Always the biggest challenge at this point is the business case, there to be some financial motivation to do it. It just can’t be because is the right thing to do, that only gets us so far. It has to be a solid business case.” The attention to costs and benefits took shape in another important way−the question of who pays for infrastructure investments, and the associated return on investment. As one interviewee contended when surveying potential payees, “Government isn’t going to pay. The states and Federal government won’t give any grants, and we can’t raise rates.” Concluded another, “if there was funding for waste recovery, regardless of end use, you would see it done everywhere.” Concern was also expressed about quantifying noneconomic benefits and whether the potential noncash and indirect benefits from wastewater resource recovery can justify “hard dollar” investments in new or improved infrastructure. “The manager,” claimed one interviewee, “won’t necessarily support the initial capital and operating investment in resource recovery unless they can see a financial return on investment.” Finally, the “big picture” interrelating all fiduciaries was well captured by one interviewee, who noted: “I think that capital investment 4160

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3.2. Regulations and Enhanced Wastewater Resource Recovery. As would be expected, considering the highly regulated state of the wastewater industry, regulatory actions and actors (who, how much, type) were a consideration for nearly all of the interviewees. However, unlike the centrality of cost and benefits and the need to weigh both in resource recovery actions, interviewee responses on regulations and their effects were more varied. Some noted that regulations did not limit wastewater resource recovery innovation, and that “Regulations have always meant open doors for new technology, not limits.” Indeed, it can be argued that WRRF permits prescribe effluent quality only, giving owners the ability to select and implement technologies that achieve compliance (and thus allowing for resource recovery). Overall, however, many interviewees expressed concern that existing regulations limit resource recovery, lack consistency, and need to evolve to meet contemporary opportunities. The permitting process as related to potential resource recovery technologies was identified as often too timeconsuming or burdensome (similar to concerns expressed by Novak et al.3). One interviewee commented “the permitting process is potentially a bit onerous. I think certain parts of it are maybe a bit too onerous, and are a hurdle for an entity to take on.” Of particular interest, a commonly expressed sentiment was a perceived mismatch between the purpose of existing regulations and the possibilities and challenges of wastewater resource recovery. This was captured by an interviewee who concluded: “Current clean water act regulations do not address resource recovery; indeed, regulations are designed to do other things. They are very conservative and overly restrictive. Everything is driven by pursuing a very narrow result based on overly conservative assumptions all seem to happen at the same time. This is where our current regulations are restrictive.” Indeed, water quality regulations and associated permits are arguably bifurcated depending on the desired end-use of the wastewater. The act of “returning” water to the environment as treated effluent simply requires compliance with permitted water quality criteria. However, repurposing reclaimed water or biosolids (and, in some cases, struvite45) for a higher use invokes prescriptive permitting processes and criteria that can be (perceived or not) as onerous; ultimately, lack of consensus3 on how resources recovered from wastewater must be regulated, and how they must be produced to achieve regulatory compliance, unfortunately adds another layer of economic uncertainty to the decision-making process. Interviewees further noted the inherent caution of regulations, regulators, and regulatory agencies and, to a certain degree, WRRF operators. “Regulators,” said one, “are going to be reluctant to do anything perceived to harm public health.” Regulations are also generally designed to prevent pollution rather than promote resource recovery, and often are implemented in a “site specific” way that inhibits development of broad approaches to recovery. This was most apparent when interviewees noted the lack of consistency across state lines, agency overlap (both in jurisdiction and regulations), and the potential for “things to get politically charged” and foster stakeholder distrust: “The more consistency you have across the regulatory framework,” contended an interviewee, “the easier it is to implement these programs.” Regarding WRRF operations staff, it was observed that “an operator won’t support resource recovery, it has nothing to do with financial return, just permit compliance.”

is always an issue. It’s only recently that were are taking a more focused look at lifecycle costs and capital. These things are capital intensive. It is hard for people to foot the bill for a large capital project today that will have a payoff over 20 years.” Comparative and competitive costs were identified as a concern, specifically related to producing reclaimed water and the potential to recover investments ultimately being limited by viability relative to other water supply alternatives. For example, a number of interviewees noted that if costs for producing Class A or B reclaimed water exceeded the price of other sources of potable and nonpotable water, resource recovery was not economically viable. As one observed, at the moment and in their geographic location “reclaimed water is more expensive than plentiful groundwater.” In contrast, there was often concern expressed that this was too “narrow” a way to measure relative cost. Observed one interviewee: “It’s a whole lot cheaper to pump water out of the ground than it is to reclaim it, but it’s not necessarily the right thing to do. We have to pick and choose the alternatives that seem like we could actually accomplish them, then we have to view them on cost, and figure out what the lowest cost alternatives are.” A particularly interesting perspective offered by some interviewees was how recycled water produced at WRRFs would, or could, compete with that available from wellentrenched public and private water supply utilities. Established water providers with successful (albeit tenuous) business models, and which are heavily regulated by state and local officials, operate based on predictable supply/delivery costs to, and generally predicable demand by, captured users at fixed rates. Such entities pose challenges to making recovered water a viable alternative, given reclaimed water is (or can be viewed as) a threat to sustained economic viability of these conventional water purveyors (by displacing traditional water supplies). In some cases the same utility may be providing both services, while in other cases the WRRF is a separate, and thus competing, utility. Nevertheless, offset demand for traditional water supplies by WRRFs providing reclaimed water could imperil the economics of these conventional purveyors. Moreover, established, legacy regulatory regimes (or traditionally accepted wastewater management approaches) may pose an additional (often unspoken) economic challenge if, as one interviewee noted, it is less expensive to “comply with ecological regulations about putting wastewater into the river” than to recycle water. In short, if it is less costly to discharge treated effluent into the ecosystem than to produce reclaimed water (that could then be used to displace traditional water supplies), the incentive for water resource recovery can be limited. The challenge of relative costs was also evident in the potential to generate marketable power associated with organic carbon recovery from wastewater (e.g., via anaerobic digestion). This is especially problematic in the Pacific Northwest, where low cost hydropower yields the lowest electricity rates in the U.S. One interviewee observed that low electricity rates “mean it’s hard to justify cogeneration because it takes so long to pay off.” Moreover, the sharp collapse of natural gas prices across the U.S. has only magnified the concern. Noted one interviewee: “Natural gas prices are so low, that its tough (for methane) to compete with that. I have seen very few projects where it pencils out financially to do recovery of a resource, other than some luxury. If you have methane, put it in a boiler and burn it versus firing it. But it’s probably not going to be cost effective.” 4161

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noting that scarcity (e.g., drought) was a large consideration (and driver) in public acceptance. “It depends on what it is and where you are if you’re in SoCal (southern California) and you want water, then wastewater is more acceptable. It also depends on what it looks like, the social acceptability of sewage sludge is low, but the social acceptability of struvite is much higher.”

Finally, a shared theme among interviewees was captured by one, who suggested regulatory regimes “need to evolve” to maximize the potential for resource recovery. This sentiment was stated more forcefully by another who concluded: “The regulatory conditions associated with water reuse need to be revisited and taken a hard look at with the data. I think that there is a lot of work that can be done in the water reuse regulation field.” 3.3. Social Acceptance of Wastewater Resource Recovery Products. On the topic of social acceptance, the principal resource recovery product of “concern” is most commonly water reuseranging from use as irrigation water to direct potable reuseand to a lesser degree biosolids. In this regard, for many interviewees the often noted “yuck factor” is a problematic challenge to widespread adoption of resource recovery (most commonly related to water reuse, including direct potable reuse; and to a certain degree on biosolids reuse). However, it was also a strong, though often implicit, sentiment that if the public was better informed, if it “just knew what we know,” there would be far less unwillingness to embrace resource recovery. It was also clear from interviews that the type of product and potential use loomed large in public acceptance of using recovered resources. Referring to general wastewater resource recovery, an interviewee suggested that “on a scale of 1−10 (1 being not acceptable; 10 being acceptable), I would probably guess a 5 right now. There is the stigma of the toilet to tap campaignthe “yuck factor” is still there.” However, another interviewee, discussing acceptance of recovered water more specifically for irrigation purposes (i.e., less potential public impact), put public acceptance at 8 on a similar 1−10 scale. A second prominent theme in this area was the perceived divide between the public and the professionals. The “regular public finds it negative,” claimed one interviewee, while “professionals find it positive.” Another offered similar sentiments: “For the most part we are fairly comfortable, we have the scientific backing. [There is an]“Ick” factor for people who are not connected. [But] Kids have had exposure and are much more open to it.” The importance of communication and public education in bridging this gap was well captured by one interviewee: “As long as there is an education process that fronts it is reasonably accepted, without it is skeptical at best.” Said another, “It varies, generally speaking if the public is informed usually they’re very accepting.” The complexity of bridging an information/education gap was highlighted in one interview: “There is huge gap in communication, a long way to go in how we communicate to the public, the value of recycling, and the yuck factor. A lot of people still have a hard time getting over. The continued perception of pathological risk and a lot of people are not sure about total eradication of pathogens.” A third and final theme that emerged in exploration of social acceptance was the importance of location and use. As noted by one interviewee, rural irrigation use is viewed as more acceptable: “It also varies from a rural environment to a town environment. Farmers and ranchers are more accepting; they see the value that it can bring.” The greater acceptance of reuse in rural agricultural communities was also true for biosolids. “I think with regards to biosolids land application,” said an interviewee, “at least from our experience, it’s very well accepted amongst the ag(ricultural) culture that we interface with.” Finally, locations as related to resource scarcity was seen as an important consideration, with a number of interviewees

4. DISCUSSION Resource recoverythat is, the manufacture of products and commodities of economic value from wastewateris the envisioned and advocated for evolution from the current wastewater management paradigm that is focused on containment and treatment within a stringent regulatory framework.9,23 While not a new concept,4−7 certainly the need to recapture value from waste streams is arguably more prominent than when first envisaged decades ago. In advancing the WRRF concept more universally, current literature suggests a lack of understanding of civic epistemology is the central barrier.41 And, if only sociological challenges were overcome (with a commensurate methodology to execute sustainable solutions), resource recovery would become more prevalent.9 Regulations and policy are commonly identified as secondary barriers.3,9,46 However, results from this studywhich focused on understanding the perspective of the core decision-makers and adopters of resource recovery technologiesdemonstrate that achieving broad-scale wastewater resource recovery will require recognition of the organic and local nature in which such advancements nucleate, and commensurately consider the principal actors who will recommend, financially support, and implement such decisions. Considering perspectives gained from interviewees on realizing resource recovery, in contrast to the prevailing perceptions, in this study economic issues were clearly articulated as a primary and principally motivating consideration. Moreover, the issue of “economics” was more than simply a question of net positive revenue or addressing unpriced/underpriced elements.46 Instead, establishing a fundamental business case proposition in favor of resource recovery was a priority among those interviewed. Nuanced within the context of a positive business case was the need of financial support that did not adversely affect ratepayers. “It is hard,” contended one interviewee, “for people to foot the bill for a large capital project today that will have a payoff over 20 years.” Also noted was a need to sufficiently monetize benefits (economic and noneconomic) while addressing the potential challenge of producing commodity resources that compete against more conventional sources of water resources. In considering the central findings from this study, two case studies exemplify how economics are driving resource recovery implementation in the PNW; in both of these case studies, the utilities generally embraced a business case evaluation approach as related to sustainable phosphorus recovery from wastewater,40 for direct economic valorization of the wastewater P, and indirect cost savings through reduced WRRF maintenance/ repair. While these two case studies well align with the findings of our research, it must be noted that these two utilities are more progressive than most. The Clean Water Services’ Durham WRRF (Tigard, OR) has a seasonal 0.10 mg L−1 total P discharge limit which is achieved through a combination of Enhanced Biological Phosphorus Removal (EBPR) and chemical polishing. Anaerobically digested sludge results in a centrate rich in P and ammonia (N)internally increasing the loading of these respective 4162

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case evaluations was seen as a pathway to successful actualization of wastewater resource recovery. Although regulations, the permitting process, and the intrinsic caution of regulators (transferred to permittees) were identified as a concern, the regulatory environment was not viewed as a significant barrier. In fact, in a positive twist, as one interviewee summarized, “Regulations have always meant open doors for new technology, not limits.” Indeed, most wastewater discharge permits are written on a compliance, not prescriptive basis; in other words, utilities are able to adopt whatever technology desired to achieve permit compliance. While this “open door” perspective was not universal, it does suggest regulatory “fixes”3 may not need to be substantive. Pertaining to the “yuck” factor, which historically has impeded progress in resource recovery (most commonly for water reuse (and specifically direct potable reuse); also pertinent for biosolids), again nucleating from the local level, study results suggest communication and public education can overcome the stigma (coupled with a broader commitment to sustainability at the utility/city level). Perhaps most encouragingly, the consensus was that enhanced resource recovery is a necessary future paradigm for wastewater management, and that the real barriers are surmountable.

nutrients to the WRRF by 25 and 30%, and increasing the risk of struvite precipitation in the anaerobic digesters and ancillary systems. It was determined that utilizing additional metal salts to capture the P would defeat the point of removing P biologically and result in increased operating costs. Ultimately the utility implemented the Ostara Nutrient Recovery Technologies (Vancouver, BC) Pearl struvite recovery process; the technology was selected based on an economic evaluation that projected a 7-year payback on the investment. The economic analysis considered the value of the struvite, reduction in WRRF operating costs, and reduction in chemical solids produced. The success of this resource recovery project reinforces the results from our studyeconomics as a primary driver in technology selection. However, regulations were not an impediment; rather, it could (ironically) be suggested that the regulations instigated consideration of the resource recovery technology (i.e., the seasonal P limit). As a second case study, associated with a TMDL conducted by the Idaho DEQ, the city of Boise, ID faced wastewater P removal requirements prior to effluent discharge into the Boise River. Implementing EBPR at the W. Boise WRRF was selected to achieve the first phase of phosphorus removal. To recover P from internal wastewater streams, Boise implemented the Multiform Harvest (Seattle, WA, USA) struvite production resource recovery process. The decision to implement struvite production was driven by a city philosophy to become more sustainable, which includes realizing resource recovery at city WRRFs. Economics played a role in the decision-making process as well, in that the city recognized the potential to generate revenue from the struvite; the lack of any economic return on investment associated with the commercial sale of struvite would have undermined support for the struvite process. Ultimately, a combination of revenue potential and other qualitative (e.g., sustainability) attributes factored into monetization of resource recovery and implementation of the struvite process at the W. Boise WRRF. Related to regulations, and in contrast with the experience of Clean Water Services, Boise elected to demonstrate that the produced struvite met EPA Class A biosolids criteria before they sold the product; this decision was made as a risk management effort driven by regulatory uncertainty, as it was unclear how the EPA might rule on the matter, since Idaho does not have regulatory primacy. Thus, regulations entered the equation, although only in post facto compliance manner and not associated with the decision-making process to implement resource recovery.

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AUTHOR INFORMATION

Corresponding Author

*Phone: (208) 885-7559; e-mail: [email protected]. ORCID

Erik R. Coats: 0000-0003-2796-9949 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS This material is based upon work supported by the National Science Foundation under Grant Number CBET-1235885, amendment #006. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.

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REFERENCES

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5. CONCLUSIONS Numerous established technologies to capture value from wastewater are available for use at water resource recovery facilities, and new, advanced technologies are on the horizon. However, maximum valorization of wastewaterand realization of the true WRRF conceptremains elusive. This study focused on local-level, front-line principal actors (decisionmakers; advisors) in the Pacific NW region of the U.S. to explore how expanded resource recovery might nucleate and to understand potential barriers. In contrast to published studies that suggest regulatory and/or sociological barriers are dominant factors in the decision making process, in this study economics was viewed as the primary barrier to implementation/expansion of the WRRF concept. Within the context of economics was the view there is (currently) mostly downside to deploying new technologies, with little perceived upside, and thus significant risk. In this regard, utilizing business 4163

DOI: 10.1021/acs.est.7b00363 Environ. Sci. Technol. 2017, 51, 4158−4164

Policy Analysis

Environmental Science & Technology

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DOI: 10.1021/acs.est.7b00363 Environ. Sci. Technol. 2017, 51, 4158−4164