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

   https://doi.org/10.1002/wer.1574  

   Bryant, Casey; Coats, Erik R. (April 2021, Water Environment Research)

   Abstract 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, MgO₂production 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 pointsWastewater 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 MgO₂production 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. 

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2. Perceptions of high-tech controlled environment agriculture among local food consumers: using interviews to explore sense-making and connections to good food

   https://doi.org/10.1007/s10460-021-10261-7  

   Broad, G.M. (August 2021, Agriculture and human values)

   In recent years, new forms of high-tech controlled environment agriculture (CEA) have received increased attention and investment. These systems integrate a suite of technologies – including automation, LED lighting, vertical plant stacking, and hydroponic fertilization – to allow for greater control of temperature, humidity, carbon dioxide, oxygen, and light in an enclosed growing environment. Proponents insist that CEA can produce sustainable, nutritious, and tasty local food, particularly for the cities of the future. At the same time, a variety of critics raise concerns about its environmental impacts and energy use, high startup costs, and consumer accessibility challenges, among other issues. At this stage, however, relatively little research has explored actual consumer knowledge and attitudes related to CEA processes and products. Guided by theories of sense-making, this article draws from structured interviews with local food consumers in New York City to examine what people know and think about high-tech CEA. From there, it explores the extent to which CEA fits into consumer conceptualizations of what makes for “good food.” Key findings emphasize that significant gaps in public understanding of CEA remain, that CEA products’ success will depend on the ability of the industry to deliver on its environmental promises, and that concerns about “unnatural” aspects of CEA will need to be allayed. Given the price premium at which high-tech CEA products are currently sold, the industry’s expansion will depend in large part on its ability to convince value-oriented food consumers that the products meet the triple-bottom-line of economic, social, and environmental sustainability goals. 

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3. The Intersection of Wastewater Treatment Plants and Threatened and Endangered Species in California, USA Watersheds

   https://doi.org/10.1029/2022WR033976  

   Cassady, Anna; Anderson, Kurt E.; Schwabe, Kurt A.; Regan, Helen M. (August 2023, Water Resources Research)

   Abstract A changing climate and often unregulated water extractions have exposed over 2 billion people to water stress worldwide. While water managers have explored a portfolio of options to reduce this stress, supply augmentation through reuse of treated municipal wastewater is becoming increasingly attractive. Wastewater treatment plants protect water quality and prevent sewage from contaminating waterways. Increasingly, this resource is utilized for numerous human (e.g., irrigation, drinking water, groundwater recharge) and conservation (e.g., stream and river recharge) needs in water stressed regions. To understand the role treated municipal wastewater plays in impacting conservation objectives we identified the intersection of wastewater treatment plant locations and occurrences of threatened and endangered (T&E) species in California and compared the permitted contribution of effluent to baseflow quantities of the receiving waterbody to assess the degree to which changes in effluent could affect instream waterbodies. We found a positive correlation between the presence of treatment plants and T&E species in California watersheds—a quarter of species have 100% of their range in watersheds with at least one treatment plant. This correlation is greatest for species associated with terraces and riparian habitat, followed by aquatic habitat and aquatic emergent vegetation. One‐third of watersheds in our analysis can receive most of their cumulative watershed baseflow from effluent and are characterized by dense urbanization or agriculture. Our analysis demonstrates that the fates of T&E species and effluent are interconnected in ways important for water policy, suggesting that species conservation goals should be considered when making decisions about effluent reuse. 

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4. Sustainability of lettuce production: A comparison of local and centralized food production

   https://doi.org/10.1016/j.jclepro.2023.139224  

   Maynard, Reid; Burkhardt, Jesse; Quinn, Jason C (November 2023, Journal of Cleaner Production)

   Communities are considering local food production in response to the pressing need to reduce food system greenhouse gas (GHG) emissions. However, local food systems can vary considerably in design and operation, including controlled environment agriculture (CEA), which refers to agricultural production that takes place within an enclosed space where environmental conditions, such as temperature, humidity, and light, are precisely controlled. Such systems require a considerable amount of energy and thus emissions; therefore, this study seeks to quantify these environmental impacts to determine how local CEA systems compare to alternative systems. For this study’s methods, we apply life cycle assessment methodology to quantify the cradle-to-storeshelf GHG emissions and water consumption of four lettuce production systems: local indoor plant factory, local greenhouse, local seasonal soil, and conventional centralized production in California with transportation. Using geographically specific inputs, the study estimates the environmental impact of the different production systems including geospatially resolved growth modeling, emissions intensity, and transportation distances. The results include the major finding that baseline CEA systems always have higher GHG emissions (2.6–7.7 kg CO2e kg−1) than centralized production (0.3–1.0 kg CO2e kg−1), though water consumption is significantly less owing to hydroponic efficiency. In contrast, local seasonal soil production generally has a lower GHG impact than centralized production, though water consumption varies by crop yield and local precipitation during growing seasons. Scenario analyses indicate CEA facilities would need to electrify all systems and utilize low-carbon electricity sources to have equivalent or lower GHG impacts than California centralized production plus transportation. We conclude that these results can inform consumers and policy makers that local seasonal production and conventional supply chains are more sustainable than local CEA production in near-term food-energy-water sustainability nexus decision making. 

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5. Nutrient recovery from treated wastewater by a hybrid electrochemical sequence integrating bipolar membrane electrodialysis and membrane capacitive deionization

   https://doi.org/10.1039/C9EW00981G  

   Gao, Fei; Wang, Li; Wang, Jie; Zhang, Hongwei; Lin, Shihong (February 2020, Environmental Science: Water Research & Technology)

   The growing needs for sustainable nutrient management and pollution control have motivated the development of novel technologies for nutrient recovery from wastewater. However, most of the existing technologies require extensive use of chemicals and intensive consumption of energy to achieve substantial recovery of nutrients. Herein, we present a hybrid electrochemical sequence integrating two relatively novel electrochemical processes, bipolar membrane electrodialysis (BMED) and membrane capacitive deionization (MCDI), for simultaneous removal of phosphorus and nitrogen. Specifically, the BMED process is employed to alkalify the wastewater to facilitate struvite precipitation and the MCDI process is used to further reduce the ammonia concentration in the effluent and concentrate the excess ammonia to a small stream. The electrochemical sequence is demonstrated to remove ∼89% of phosphorus and ∼77% of ammonia, recovering ∼81% of wastewater as a high-quality effluent that can be discharged or reused. This electrochemical treatment train minimizes chemical use and has competitive energy consumption as compared to electrochemical processes for nutrient recovery from wastewater. 

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