Toward Nucleating the Concept of the Water Resource Recovery Facility (WRRF): Perspective from the Principal Actors

Zinc Recovery from a Water Supply by Reverse Osmosis Operated at Low Pressures: Looking for Sustainability in Water Treatment Advanced Processes

Achieving sustainability in life involves increasing efforts to recover resources. This research proposes the recovery of Zn from the Milluni lagoons, an important water supply for Bolivia, where high concentrations of Zn have been identified that exceed permitted limits, exposing a risk to health and ecosystems. The application of reverse osmosis (RO), operated with low pressures, is proposed as a first stage for the concentration of Zn and subsequent recovery of this metal through chemical precipitation. The aim was to maintain the separation efficiency of the RO operated at low pressures without presenting operational problems. As a result, 98.83% metal concentration was achieved with a laboratory-scale pilot system. The above means an important potential for large-scale Zn concentration, apart from orienting the RO toward sustainability by working with low pressures that reduce energy costs during its operation. This study can be used as a valuable reference for the advancement of sustainable technologies in the field of water treatment that simultaneously allow the recovery of resources to promote a circular economy. Finally, this study exposes an alternative for regions with heavy metal water contamination in Bolivia and worldwide.

Towards a sustainable transformation of municipal wastewater treatment plants into biofactories using advanced NH3-N recovery technologies: A review

Ammonia (NH3), as a prevalent pollutant in municipal wastewater discharges, can impair aquatic life and have a negatively impact on the environment. Proper wastewater treatment and management practices are essential to protect ecosystems and keep human populations healthy. Therefore, using highly effective NH3-N recovery technologies at wastewater treatment plants (WWTPs) is widely acknowledged as a necessity. In order to improve the overall efficiency of NH3 removal/recovery processes, innovative technologies have been generally applied to reduce its concentration when discharged into natural water bodies. This study reviews the current status of the main issues affecting NH3 recovery from municipal/domestic wastewater discharges. The current study investigated the ability to recover valuable resources, e.g., nutrients, regenerated water, and energy in the form of biogas through advanced and innovative methods in tertiary treatment to achieve higher efficiency towards sustainable wastewater and resource recovery facilities (W&RRFs). In addition, the concept of paradigm shifts from WWTP to a large/full scale W&RRF has been studied with several examples of conversion to innovative bio-factories producing materials. On the other hand, the carbon footprint and the high-energy consumption of the WWTPs were also considered to assess the sustainability of these facilities.

Impact of primary treatment methods on sludge characteristics and digestibility, and wastewater treatment plant-wide economics

Biogas production from anaerobic sludge digestion plays a central role for wastewater treatment plants to become more energy-efficient or even energy-neutral. Dedicated configurations have been developed to maximize the diversion of soluble and suspended organic matter to sludge streams for energy production through anaerobic digestion, such as A-stage treatment or chemically enhanced primary treatment (CEPT) instead of primary clarifiers. Still, it remains to be investigated to what extent these different treatment steps affect the sludge characteristics and digestibility, which may also impact the economic feasibility of the integrated systems. In this study, a detailed characterization has been performed for sludge obtained from primary clarification (primary sludge), A-stage treatment (A-sludge) and CEPT. The characteristics of all sludges differed significantly from each other. The organic compounds in primary sludge consisted mainly of 40% of carbohydrates, 23% of lipids, and 21% of proteins. A-sludge was characterized by a high amount of proteins (40%) and a moderate amount of carbohydrates (23%), and lipids (16%), while in CEPT sludge, organic compounds were mainly 26% of proteins, 18% of carbohydrates, 18% of lignin, and 12% of lipids. The highest methane yield was obtained from anaerobic digestion of primary sludge (347 ± 16 mL CH₄/g VS) and A-sludge (333 ± 6 mL CH₄/g VS), while it was lower for CEPT sludge (245 ± 5 mL CH₄/g VS). Furthermore, an economic evaluation has been carried out for the three systems, considering energy consumption and recovery, as well as effluent quality and chemical costs. Energy consumption of A-stage was the highest among the three configurations due to aeration energy demand, while CEPT had the highest operational costs due to chemical use. Energy surplus was the highest by the use of CEPT, resulting from the highest fraction of recovered organic matter. By considering the effluent quality of the three systems, CEPT had the highest benefits, followed by A-stage. Integration of CEPT or A-stage, instead of primary clarification in existing wastewater treatment plants, would potentially improve the effluent quality and energy recovery.

Denitrification performance and in-situ fermentation mechanism of the wastepaper-flora slow-release carbon source

Using wastepaper as external carbon sources is an optional way to achieve total nitrogen removal faced with low carbon to nitrogen ratio municipal sewage. Most of studies have primarily focused on using cellulose-rich wastes establishing the separate denitrification units to achieve in-situ fermentation, which can cause blockages and prolong the process chain. In response, a novel in-situ fermentation wastepaper-flora slow-release carbon source (IF-WF) was proposed using in the original denitrification unit. IF-WF could be efficiently utilized in situ and the denitrification rate increased with the increase of nitrate nitrogen. The fermentation products were highly available, but internal acidification of IF-WF inhibited fermentation. Moreover, IF-WF limited the growth of polysaccharides in the extracellular polymeric substances of denitrified sludge. IF-WF finally formed the structure dominated by nitrate-reduction bacteria outside and cellulose-degrading bacteria inside. These results provide guidance for understanding the mechanism of IF-WF for in-situ fermentation to promote nitrogen removal.

Performance of Anaerobic Membrane Bioreactor (AnMBR) with Sugarcane Bagasse Ash-based Ceramic Membrane treating Simulated Low-strength Municipal Wastewater: Effect of Operation Conditions

This study assesses the performance of waste sugarcane bagasse ash (SBA)-based ceramic membrane in anaerobic membrane bioreactor (AnMBR) treating low-strength wastewater. The AnMBR was operated in sequential batch reactor (SBR) mode at hydraulic retention time (HRT) of 24 h, 18 h, and 10 h to understand the effect on organics removal and membrane performance. Feast-famine conditions were also examined to evaluate system performance under variable influent loadings. An average removal of >90% chemical oxygen demand (COD) was obtained at each HRT and starvation periods up to 96 days did not significantly affect removal efficiency. However, feast-famine conditions affected extracellular polymeric substances (EPS) production and consequently the membrane fouling. EPS production was high (135 mg/g MLVSS) when the system was restarted at 18 h HRT after shutdown (96 days) with corresponding high transmembrane pressure (TMP) build-up; however, the EPS content stabilized at ~60-80 mg/g MLVSS after a week of operation. Similar phenomenon of high EPS and high TMP was experienced after other shutdowns (94 and 48 days) as well. Permeate flux was 8.8±0.3, 11.2±0.1 and 18.4±3.4 L/m² h at 24 h, 18 h and 10 h HRT, respectively. Filtration-relaxation (4 min - 1 min) and backflush (up to 4 times operating flux) helped control fouling rate. Surface deposits (that significantly attributed to fouling) could be effectively removed by physical cleaning, resulting in nearly complete flux recovery. Overall, SBR-AnMBR system equipped with waste-based ceramic membrane appears promising for treatment of low-strength wastewater with disruptions in feeding.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11270-023-06173-3.

Societal values, tensions and uncertainties in resource recovery from wastewaters

The recovery of resources, including water reuse, has been presented as a solution to overcome scarcity, and improve the economic and environmental performance of water provision and treatment. However, its implementation faces non-technical challenges, including the need to collaborate with new stakeholders and face societal acceptance issues. Looking at the prominence of the circular economy in current policy developments and the challenges to resource recovery, exploring these issues is urgently needed. In this work, we reviewed a broad range of literature to identify societal values relevant to the recovery of water and other resources from wastewaters, particularly urban and industrial wastewater and desalination brines. We discuss tensions and uncertainties around these values, such as the tension between socio-economic expectations of resource recovery and potential long-term sustainability impacts, as well as uncertainties regarding safety and regulations. For addressing these tensions and uncertainties, we suggest aligning common methods in engineering and the natural sciences with Responsible Innovation approaches, such as Value Sensitive Design and Safe-by-Design. To complement Responsible Innovation, social learning with a Sustainability Transitions or Adaptive Governance perspective is suggested.

Pivotal role of municipal wastewater resource recovery facilities in urban agriculture: A review

Urban agriculture provides a promising, comprehensive solution to water, energy, and food scarcity challenges resulting from the population growth, urbanization, and the accelerating effects of anthropogenic climate change. Their close access to consumers, profitable business models, and important roles in educational, social, and physical entertainment benefit both developing and developed nations. In this sense, Urban Water Resource Reclamation Facilities (WRRFs) can play a pivotal role in the sustainable implementation of urban agriculture. Reclaimed water as a recovered resource has less supply variability and in certain cases can be of higher quality than other water sources used in agriculture. Another recovered resource, namely, biosolids, as byproduct from wastewater treatment can be put to beneficial use as fertilizers, soil amendments, and construction material additives. The renewable electricity, heat, CO2, and bioplastics produced from WRRFs can also serve as essential resources in support of urban agriculture operation with enhanced sustainability. In short, this review exhibits a holistic picture of the state-of-the-art of urban agriculture in which WRRFs can potentially play a pivotal role. PRACTITIONER POINTS: Reclaimed water can be of higher quality than other sources used in urban agriculture. Biosolids can be put to beneficial use as fertilizers, soil amendments, and construction material additives. The renewable electricity, heat, CO2, and bioplastics produced can also serve as essential resources in support of urban agriculture.

Roadmapping the Transition to Water Resource Recovery Facilities: The Two Demonstration Case Studies of Corleone and Marineo (Italy)

The current exploitation of freshwater, as well as the significant increase in sewage sludge production from wastewater treatment plants (WWTPs), represent nowadays a critical issue for the implementation of sustainable development consistent with the circular economy concept. There is an urgent need to rethink the concept of WWTPs from the conventional approach consisting in pollutant removal plants to water resource recovery facilities (WRRFs). The aim of this paper is to provide an overview of the demonstration case studies at the Marineo and Corleone WRRFs in Sicily (IT), with the final aim showing the effectiveness of the resources recovery systems, as well as the importance of plant optimization to reduce greenhouse gas (GHG) emissions from WRRFs. This study is part of the H2020 European Project “Achieving wider uptake of water-smart solutions—Wider-Uptake”, which final aim is to demonstrate the water-smart solution feasibility in the wastewater sector. The main project goal is to overcome the existing barriers that hamper the transition to circularity through the implementation of a governance analysis tool. The preliminary actions in the two demonstration cases are first presented, while, subsequently, the water-smart solutions to be implemented are thoroughly described, highlighting their roles in the transition process. The achieved preliminary results underlined the significant potential of WRRF application, a great chance to demonstrate the feasibility of innovative solutions in the wastewater sector to overcome the existing social, administrative and technical barriers.

Integrating dairy manure for enhanced resource recovery at a WRRF: Environmental life cycle and pilot-scale analyses

The Twin Falls, Idaho wastewater treatment plant (WWTP), currently operates solely to achieve regulatory permit compliance. Research was conducted to evaluate conversion of the WWTP to a water resource recovery facility (WRRF) and to assess the WRRF environmental sustainability; process configurations were evaluated to produce five resources-reclaimed water, biosolids, struvite, biogas, and bioplastics (polyhydroxyalkanoates, PHA). PHA production occurred using fermented dairy manure. State-of-the-art biokinetic modeling, performed using Dynamita's SUMO process model, was coupled with environmental life cycle assessment to quantify environmental sustainability. Results indicate that electricity production via combined heat and power (CHP) was most important in achieving environmental sustainability; energy offset ranged from 43% to 60%, thereby reducing demand for external fossil fuel-based energy. While struvite production helps maintain a resilient enhanced biological phosphorus removal (EBPR) process, MgO₂ production exhibits negative environmental impacts; integration with CHP negates the adverse consequences. Integrating dairy manure to produce bioplastics diversifies the resource recovery portfolio while maintaining WRRF environmental sustainability; pilot-scale evaluations demonstrated that WRRF effluent quality was not affected by the addition of effluent from PHA production. Collectively, results show that a WRRF integrating dairy manure can yield a diverse portfolio of products while operating in an environmentally sustainable manner. PRACTITIONER POINTS: Wastewater carbon recovery via anaerobic digestion with combined heat/power production significantly reduces water resource recovery facility (WRRF) environmental emissions. Wastewater phosphorus recovery is of value; however, struvite production exhibits negative environmental impacts due to MgO₂ production emissions. Bioplastics production on imported organic-rich agri-food waste can diversify the WRRF portfolio. Dairy manure can be successfully integrated into a WRRF for bioplastics production without compromising WRRF performance. Diversifying the WRRF products portfolio is a strategy to maximize resource recovery from wastewater while concurrently achieving environmental sustainability.

Simple Preparation Method for Hydrophilic/Oleophobic Coatings

This work provides a simple method to prepare a hydrophilic/oleophobic coating using polyester filter cloth as the substrate, a mixture of three hydrophilic polymers (poly(aspartic acid), poly(acrylic acid), and poly(vinyl alcohol)); SiO₂ with an average particle size of 30 nm is used to improve the surface roughness of the filter cloth. Then, a long fluorocarbon chain of 1H,1H,2H,2H-perfluorooctyltriethoxysilane is grafted onto the surface by a vacuum silanization coupling reaction to obtain hydrophilic/oleophobic properties. The water and hexadecane contact angles of the treated filter cloth are 3 and 99.8°, respectively. A separation efficiency of 98% was achieved in hexadecane/water separation. The durability test shows that the separation efficiency of toward hexadecane-water mixture remains more than 98% after 20 cycles. The obtained material also presents a strong underwater antipollution property when using hexane, rapeseed oil, mineral oil, and pump oil as model pollutants. For oils with higher viscosity, the separation efficiency remains above 97%. However, the separation efficiency is ∼80% when treating emulsions.

A framework for resource recovery from wastewater treatment plants in megacities of developing countries

In developing countries, there is often a lack of a comprehensive data set that supports the development of coherent policies on resource recovery from wastewater treatment. This paper aims to contribute to the elaboration of resource recovery projects by providing accurate and updated data from wastewater treatment plants such as those located in the region of the Macrometropolis of Sao Paulo. The authors discuss possibilities of improvement of resource recovery for this illustrative example. Comprehensive analyses were performed based on data from 143 municipal wastewater treatment plants to understand the situation regarding resource recovery implementation in this region. The results show that just 26% of the plants perform at least one resource recovery practice. The predominant resource recovery practice is internal water reuse, and recovery is concentrated more in large plants than in medium and small ones. The sludge is disposed in landfills except for three plants, which perform sludge recycling for compost. Some plant managers reported interest in recovering energy from biogas, in expanding water reuse and in recovering sludge for fertilizer production or for building materials. Several aspects that have been regarded as relevant to the implementation of resource recovery processes in previous literature are discussed, such as the size of the plant, related legislation as well as treatment technologies and configurations. Finally, the authors propose a generic framework with several steps that can help to achieve resource recovery implementation. Therefore, the results can provide support for planning of resource recovery projects for large cities in developing countries.

Wastewater Reclamation in Major Jordanian Industries: A Viable Component of a Circular Economy

Water scarcity remains the major looming challenge that is facing Jordan. Wastewater reclamation is considered as an alternative source of fresh water in semi-arid areas with water shortage or increased consumption. In the present study, the current status of wastewater reclamation and reuse in Jordan was analyzed considering 30 wastewater treatment plants (WWTPs). The assessment was based on the WWWTPs’ treatment processes in Jordan, the flowrates scale, and the effluents’ average total dissolved solid (TDS) contents. Accordingly, 60% of the WWTPs in Jordan used activated sludge as a treatment technology; 30 WWTPs were small scale (<1 × 104 m3/day); and a total of 17.932 million m3 treated wastewater had low TDS (<1000 ppm) that generally can be used in industries with relatively minimal cost of treatment. Moreover, the analysis classified the 26 million m3 groundwater abstraction by major industries in Jordanian governorates. The results showed that the reclaimed wastewater can fully offset the industrial demand of fresh water in Amman, Zarqa, and Aqaba governorates. Hence, the environmental assessment showed positive impacts of reclaimed wastewater reuse scenario in terms of water depletion (saving of 72.55 million m3 groundwater per year) and climate change (17.683 million kg CO2Eq reduction). The energy recovery assessment in the small- and medium-scale WWTPs (<10 × 104 m3/day) revealed that generation of electricity by anaerobic sludge digestion equates potentially to an offset of 0.11–0.53 kWh/m3. Finally, several barriers and prospects were put forth to help the stakeholders when considering entering into an agreement to supply and/or reuse reclaimed water.

Phosphorus recovery from municipal wastewater treatment: Critical review of challenges and opportunities for developing countries

The aim of this paper is to provide guidance in selecting phosphorus recovery options within the municipal wastewater treatment sector regarding developing countries. This critical review includes a brief contextualization of the resource-oriented sanitation paradigm, the discussion of processes for phosphorus recovery based on methods at full-scale, pilot-scale and laboratory-scale, and a concise discussion of the environmental impacts and benefits associated with phosphorus recovery strategies. Finally, the main challenges related to the implementation of resource recovery strategies, especially for phosphorous, were identified and discussed. According to the results, some of the main drivers for phosphorus recovery are the limited availability of phosphorus, increasing cost of phosphate fertilizers and reduction of maintenance costs. Currently, most of the operational processes are based on crystallization or precipitation from the digester supernatant. Struvite is the most common recovered product. The recovery rate of phosphorus from the liquid phase is lower (10-60% from wastewater treatment plant influent), than from sludge (35-70%) and from sludge ashes (70-98%). Phosphorus recovery remains challenging, and some barriers identified were the integration between stakeholders and institutions, public policies and regulations as well as public acceptance and economic feasibility. In developing countries, the implementation of nutrient recovery systems is challenging, because the main concern is on the expansion of sanitation coverage. Resource recovery approaches can provide benefits beyond the wastewater treatment sector, not only improving the sustainability of wastewater treatment operations, but generating revenue for the utility provider.

Comparative energy and carbon footprint analysis of biosolids management strategies in water resource recovery facilities

Biosolids or sludge management has become an environmental and economic challenge for water resource recovery facilities (WRRFs) and municipalities around the world. The electric energy and operational costs linked to the solid processing stage can account for 20% and 53% of the overall treatment respectively, and as such they are primary factors among utilities which must be considered while working toward more efficient strategies with less energy use. As part of the growing awareness of greenhouse gas (GHG) emissions, municipal wastewater treatment plants have begun reporting their GHG emission inventories. However, there is not yet a standardized or fully comprehensive CFP analysis for the biosolids management. In this paper, two major metropolitan WRRFs in China and the USA with two different biosolids management approaches were compared in terms of energy and carbon footprint (CFP). Site-specific equipment inventories coupled with state-of-the-art methodologies were used for the carbon and energy intensity assessment. Tailored biosolids management strategies and scenarios were included in the analysis to provide a venue for the reduction of their environmental impact. Co-digestion with food waste (FW) and the economic feasibility of its implementation were proposed as a GHGs mitigation strategy to highlight the energy recovery potential. Although both plants had similar energy intensity, Plant A (Shanghai) exhibited three times larger CFP primarily due to site-specific limitations on their biosolids management. The study showed the potential to improve CFP by 28.8% by selecting convenient strategies (i.e., incineration with AD). Energy recovery with its concurrent environmental benefits can be further enhanced by implementing FW co-digestion. This study shows the economic and environmental relevance of selecting adequate biosolids processing strategies and energy recovery practices in WRRFs.

Sustainability metrics for assessing water resource recovery facilities of the future

The recovery of water, energy, and nutrients from water resource recovery facilities (WRRFs) is needed to address significant global challenges, such as increasing water demand and decreasing availability of nonrenewable resources. To meet these challenges, innovative technological developments must lead to increased adoption of water and resource recovery processes, while addressing stakeholder needs (e.g., innovators, practitioners, regulators). A test bed network of over 90 partner facilities within the United States and abroad will help accelerate innovation and widespread adoption of novel processes through multiscale testing and demonstration of technologies. In this paper, we define a common set of environmental, economic, technical, and social performance metrics for innovative technologies, that will meet the needs of multiple stakeholders in the decision-making process. These triple bottom line performance metrics can be used to track the sustainability of technologies in a consistent and transparent manner, while aiding the decision-making process for WRRFs. PRACTITIONER POINTS: The Facilities Accelerating Science and Technology (FAST) Water Network includes over 90 test bed facilities dedicated to accelerating innovation and adoption of water energy, and nutrient recovery systems. A common set of environmental, economic, technical, and social performance metrics should be measured and reported when a new technology is evaluated in the FAST Water Network. Performance metrics can aid sustainable decision-making at WRRF, while meeting the needs of multiple stakeholders.

Carbon dioxide sequestration and methane production promotion by wollastonite in sludge anaerobic digestion

This study investigated the feasibility and performance of simultaneous in-situ CO₂ sequestration and CH₄ production promotion by wollastonite addition in sludge AD. A maximum CH₄ yield increment of 30.8% and maximum methane production rate increment of 64.9% with wollastonite addition at dosage of 16.25 g/L were achieved. CO₂ was efficient sequestered by wollastonite addition and resulted in a higher CH₄ content of 81.7%-82.4%. The mechanism of CO₂ sequestration by wollastonite was confirmed as Ca²⁺ release and subsequently carbonation based on cation and precipitates analysis. The results demonstrated that wollastonite could be applied as an effective additive for simultaneous in-situ CO₂ sequestration and CH₄ production promotion of sludge AD.

Development of Methane-Utilizing Mixed Cultures for the Production of Polyhydroxyalkanoates (PHAs) from Anaerobic Digester Sludge

The fundamental components required for scaling up the production of biogas-based biopolymers can be provided through a single process, that is, anaerobic digestion (AD). In this research, the possibility of enriching methane-utilizing mixed cultures from the AD process was explored as well as their capability to accumulate polyhydroxyalkanoates (PHAs). For almost 70 days of operation in a fed-batch cyclic mode, the specific growth rate was 0.078 ± 0.005 h^-1 and the biomass yield was 0.7 ± 0.08 mg-VSS/mg-CH₄. Adjusting the nitrogen levels in AD centrate resulted in results comparable to those obtained with a synthetic medium. The enriched culture could accumulate up to 51 ± 2% PHB. On the other hand, when the culturing medium was supplemented with valeric acid, the enriched bacteria were able to produce polyhydroxybutyrate- co-valerate (PHBV) up to 52 ± 6% with an HV percentage of 33 ± 5%. Increasing the valeric acid concentration in the culturing medium above 100 mg/L decreased the overall amount of PHBV by 60%, whereas the number of HV units incorporated was not affected. Changing the methane-to-oxygen ratio (M/O) from 1:1 to 4:1 caused an almost 80% decline in PHB accumulation. In addition, M/O had a significant effect on the fraction composition of PHBV at different valeric acid concentrations.

Can Sanitation Technology Play a Role in User Perceptions of Resource Recovery? An Evaluation of Composting Latrine Use in Developing World Communities in Panama

There remains a large unmet need for sanitation access throughout the world that compromises both human and environmental health. Opportunities exist to employ sanitation systems that better utilize and recover scarce resources from excreta such as water, energy, and nutrients. However, technologies such as a composting latrine may require more maintenance and close handling of feces compared to other sanitation technologies. This study aims to evaluate how use of on-site composting latrine technology and other demographic characteristics are associated with users' perceptions of excreta for resource recovery. Field observations and interviews of composting latrine users ( N = 201) and 200 perceptions surveys were administered to composting and non-composting latrine users in Indigenous and Latino communities in Panama. Of the completed composting latrines, 78% were in use and 65% of these were used properly. Compost latrine design and operational factors identified to improve were: anal wash capability, desiccant supply, children usage, and clogging urine tubes. Demographic categories associated with positive perceptions toward resource recovery ( p < 0.05) were ethnicity (14 out of 16 total statements) and sanitation type (11) then community origin (7), occupation (5), education (4), age (3), and gender (1).

Modeling and Optimization of Recycled Water Systems to Augment Urban Groundwater Recharge through Underutilized Stormwater Spreading Basins

Infrastructure systems that use stormwater and recycled water to augment groundwater recharge through spreading basins represent cost-effective opportunities to diversify urban water supplies. However, technical questions remain about how these types of managed aquifer recharge systems should be designed; furthermore, existing planning tools are insufficient for performing robust design comparisons. Addressing this need, we present a model for identifying the best-case design and operation schedule for systems that deliver recycled water to underutilized stormwater spreading basins. Resulting systems are optimal with respect to life cycle costs and water deliveries. Through a case study of Los Angeles, California, we illustrate how delivering recycled water to spreading basins could be optimally implemented. Results illustrate trade-offs between centralized and decentralized configurations. For example, while a centralized Hyperion system could deliver more recycled water to the Hansen Spreading Grounds, this system incurs approximately twice the conveyance cost of a decentralized Tillman system (mean of 44% vs 22% of unit life cycle costs). Compared to existing methods, our model allows for more comprehensive and precise analyses of cost, water volume, and energy trade-offs among different design scenarios. This model can inform decisions about spreading basin operation policies and the development of new water supplies.

Accelerating Innovation that Enhances Resource Recovery in the Wastewater Sector: Advancing a National Testbed Network

This Feature examines significant challenges and opportunities to spur innovation and accelerate adoption of reliable technologies that enhance integrated resource recovery in the wastewater sector through the creation of a national testbed network. The network is a virtual entity that connects appropriate physical testing facilities, and other components needed for a testbed network, with researchers, investors, technology providers, utilities, regulators, and other stakeholders to accelerate the adoption of innovative technologies and processes that are needed for the water resource recovery facility of the future. Here we summarize and extract key issues and developments, to provide a strategy for the wastewater sector to accelerate a path forward that leads to new sustainable water infrastructures.