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Psychrophilic anaerobic digestion has often been examined with constant or minor temperature variations, with less focus on the greater temperature variations that characterize millions of ambient temperature digesters operating in temperate climates. This research examined the impact of organic loading rate (OLR) on digester performance under varying temperature conditions to improve management of ambient temperature digesters in temperate climates. Six lab-scale digesters (3 L) paired into three treatments with high (1.3 kg VS/m 3 /day), medium (0.8 kg VS/m 3 /day) and low (0.3 kg VS/m 3 /day) OLRs were assessed under a temperature regime that simulated an annual cycle of a temperate climate. Hydraulic retention times of the three treatments were 43, 71, and 188 days. After beginning the experiment at 27 °C for 14 days, the temperature was decreased from 27 to 10 °C over the course of 72 days, and held at 10 °C for 38 days before returning to 27 °C in the same manner. Digester performance of all treatments declined as temperature decreased, with pH decreasing from 7.8 to 7.2–5.5 and biogas production decreasing by 77–94%. As temperatures began to rise, the low OLR digesters recovered and began to produce biogas at levels similar to those before the temperature decrease (100–270 mL/day), but digesters with high and medium OLRs remained failed, with pH less than 6.5 and biogas production less than 100 mL/day. Laboratory results were used to inform the operation of an ambient temperature field-scale digester (∼1 m 3 ) fed with dairy manure. Low OLRs successfully maintained a viable microbial community that recovered during warmer periods for two successive years. Results highlight the effectiveness of low and/or variable OLRs for the management of ambient temperature digesters in temperate climates. [ABSTRACT FROM AUTHOR]

Selection of strategies that help reduce riverine inputs requires numerical models that accurately quantify hydrologic processes. While numerous models exist, information on how to evaluate and select the most robust models is limited. Toward this end, we developed a comprehensive approach that helps evaluate watershed models in their ability to simulate flow regimes critical to downstream ecosystem services. We demonstrated the method using the Soil and Water Assessment Tool (SWAT), the Hydrological Simulation Program–FORTRAN (HSPF) model, and Distributed Large Basin Runoff Model (DLBRM) applied to the Maumee River Basin (USA). The approach helped in identifying that each model simulated flows within acceptable ranges. However, each was limited in its ability to simulate flows triggered by extreme weather events, owing to algorithms not being optimized for such events and mismatched physiographic watershed conditions. Ultimately, we found HSPF to best predict river flow, whereas SWAT offered the most flexibility for evaluating agricultural management practices. [ABSTRACT FROM AUTHOR]

Abstract: The objective of ecological engineering is to design sustainable ecosystems that integrate human communities and their natural environment for the benefit of both. In this paper, we illustrate how social-ecological modeling can be used as a tool to clarify this objective at a landscape scale for freshwater systems. Coupled social-ecological systems (SESs) are open, dynamic systems subject to both ecological and socioeconomic perturbations. Here we demonstrate the interactive effects of social and technological uncertainties on SES dynamics over time. Additionally, we integrate research on ecosystem stability, social-ecological modeling, and ecological engineering to offer guidance for research at the human-environment interface. Based on a case study of Lake Erie''s Sandusky watershed, we use an integrated human-biophysical model to investigate the influence of two parameters on SES dynamics: (1) regional societal preferences that impact watershed management and (2) technological innovation that alters agricultural nutrient efficiency. Our results illustrate ways in which SES dynamics and optimum management strategies depend on societal preferences within the region, indicating a key area of uncertainty for future investigation. As guidance for SES restoration, our model results also illustrate the conditions under which technological change that increases nutrient efficiency on farms can and cannot create a win-win, or increase both human welfare and SES resistance to eutrophication simultaneously. Using these results, we elucidate the value of ecological engineering and offer guidance for assessments of ecological engineering projects using social-ecological modeling. [Copyright &y& Elsevier]

Abstract: A nine-month co-digestion investigation was conducted in Costa Rica to optimize animal wastewater treatment, renewable energy production, and fertilizer creation using 12 Taiwanese-model, plug-flow digesters (250 L each) constructed of tubular polyethylene and PVC piping, operating without mechanical or heating components. The experiment tested three replications of four treatment groups: the control (T0), which contained only swine manure, and T2.5, T5, and T10, which contained 2.5%, 5%, and 10% used cooking grease (by volume) combined with swine manure. T2.5 had the greatest methane production (45 L d−1), a 124% increase from the control. No adverse effects were observed from co-digesting 2.5% grease in terms of organic matter removal, pathogen reduction, grease removal, and pH. Chemical oxygen demand (COD) was reduced 94.7% to 1.96 g L−1, fecal coliforms and Escherichia coli were reduced 99.2 and 97.1%, respectively, and grease removal was 99.9%. The average effluent pH (7.05) and alkalinity in T2.5 was within the optimal range for methanogens and increased significantly during the nine-month experiment, likely due to adaptation of the methanogenic organisms to the influent grease concentrations. Total nitrogen concentration decreased 34.0%, and NH4-N increased 97.1% during digestion in T2.5, with no significant differences between T2.5 and T0. There was less phosphorus reduction with co-digestion, with 181 mg g−1 of total phosphorus (TP) in T2.5 and only 90.6 mg g−1 of TP in T0, resulting in lower N:P ratios in the grease treatment groups due to the greater concentration of phosphorus in the effluent. [Copyright &y& Elsevier]

Abstract: In coming years society will be forced to adapt to lower energy levels due to projected declines in non-renewable energies. This will increase the challenge to ecological engineers to design sustainable ecosystems, driven by renewable energies to benefit society and the environment. This paper introduces the field of Traditional Ecological Knowledge (TEK) as an important source of ideas, inspiration and designs to help our profession meet this challenge. TEK refers to ecological knowledge and practices of indigenous and local cultures. Because these practices originated and evolved prior to the era of fossil-fuel dominance, they were designed and have continuously adapted to utilize renewable energies and resources. TEK is also well suited to sustainable design due to philosophical differences with Western science and culture. While Western culture views society as apart from and controlling ecosystems, indigenous cultures routinely see themselves as embedded within ecosystems. Because TEK has declined as the influence of Western culture has spread, there is an urgent need to identify and apply this knowledge for future benefit. Collaboration with scientists can help raise the social standing of indigenous people and of TEK within their own communities, thus contributing to cultural survival while maintaining this information. Applications of TEK relevant to ecological engineering including water management and agriculture in the Americas are highlighted. [Copyright &y& Elsevier]

Abstract: A co-digestion investigation was conducted using small-scale digesters in Costa Rica to optimize their ability to treat animal wastewater and produce renewable energy. Increases in methane production were quantified when swine manure was co-digested with used cooking grease in plug-flow digesters that operated at ambient temperate without mixing. The co-digestion experiments were conducted on 12 field-scale digesters (250L each) using three replications of four treatment groups: the control (T0), which contained only swine manure and no waste oil, and T2.5, T5, and T10, which contained 2.5%, 5%, and 10% used cooking grease (by volume) combined with swine manure. The T2.5 treatment had the greatest methane (CH4) production (45L/day), a 124% increase from the control, with a total biogas production of 67.3L/day and 66.9% CH4 in the produced biogas. Increasing the grease concentration beyond T2.5 produced biogas with a lower percentage of CH4, and thus, did not result in any additional benefits. A batch study showed that methane production could be sustained for three months in digesters that co-digested swine manure and used cooking grease without daily inputs. The investigation proved that adding small amounts of grease to the influent is a simple way to double energy production without affecting other digester benefits. [Copyright &y& Elsevier]

Abstract: Ecological treatment systems, which rely on renewable resources, have successfully treated municipal and industrial effluents with reduced costs compared to conventional methods, but their capacity to treat dairy wastewater is unknown. In order for ecological treatment systems to be practical for agriculture they must be able to treat a significant portion of a dairy''s daily wastewater production. In this study, the impact of three strengths of dairy wastewater on effluent water quality was assessed. Three ratios of wastewater and city water—(1) one part wastewater:three parts city water, (2) one part wastewater:one part city water, and (3) two parts wastewater:one part city water—were each pumped into an ecological treatment system. Influent and effluent water samples were analyzed for PO4-P, TP, TN, NH4-N, NO3-N, total suspended solids (TSS), and carbonaceous biochemical oxygen demand (CBOD5). Influent dairy wastewater volumetric loading rates were much greater than those of municipal wastewater. Regardless of influent wastewater strength, concentrations of all measured variables were significantly reduced between the influent and effluent of the ecological treatment system. At the lowest wastewater strength, PO4-P was reduced 39%, TN 83%, and NH4-N 89%, while at the highest wastewater strength, PO4-P was reduced 41%, TN 79%, and NH4-N 70%. Increased wastewater strength required greater aerobic treatment volume to reduce concentrations of NH4-N and CBOD5. [Copyright &y& Elsevier]

Abstract: In southern Mexico, where rainforests are being degraded rapidly, the Lacandon Maya use an agroforestry system that both restores and conserves the rainforest. Their system cycles through field and fallow stages that produce food, medicines, and raw materials, and regenerates tall secondary forest. This investigation identified plants managed by Lacandon to restore soil fertility during fallow. Through interviews, Lacandon identified 20 plants managed for forest restoration. Leaf litter measurements and soil samples were taken near two of these species, Ochroma pyramidale and Sapium lateriflorum. Leaf litter increased quicker beneath O. pyramidales compared to other tree species (R =0.48, P =0.004), and total nematode concentrations increased with distance from this tree (R =0.71, P <0.001). Together, these two findings indicated an inhibition of degradation that permits accelerated soil organic matter accumulation. Available phosphorus (P) concentrations beneath S. lateriflorum were 16% higher than outside the canopy (P =0.03), and increased with age of the tree, indicating P recovery from subsoil. Our research shows that the Lacandon are cognizant of the natural abilities of certain species to fulfill the restoration needs in their systems. It demonstrates that Maya agroforestry and local knowledge could contribute to efforts to conserve and restore rainforests, and reduce deforestation by accelerating fallow in tropical agriculture. [Copyright &y& Elsevier]

Abstract: Ecological Treatment Systems (ETS) are composed of a series of anaerobic and aerobic reactors, clarifiers, and wetlands, and have been used for the removal of nutrients from municipal and industrial wastewaters. The design of ETS enhances nutrient removal by providing both aerobic and anaerobic environments and steep gradients between the two environments. The ability of an ETS to treat wastewater from a dairy farm was investigated with a 20-week study in Columbus, OH, USA. The Waterman Ecological Treatment System (WETS) had four replicate treatment lines. Together, the four lines treated 1310L/day of diluted wastewater from a dairy facility with over 99% removal of ammonium-nitrogen (NH4-N) and carbonaceous biochemical oxygen demand (CBOD), and 79% removal of orthophosphate (PO4-P). The average influent/effluent concentrations of NH4-N, CBOD, and PO4-P were 52.1/0.07mg/L, 517/5.2mgO2/L, and 21.0/4.4mg/L, respectively. Nitrate+nitrite (NO x -N) was produced and removed within the system, and had an average effluent concentration of 0.53mg/L. The multiple anaerobic–aerobic interfaces in the WETS design enhanced biological removal of nitrogen and phosphorus. NH4-N, CBOD, and NO x -N were consistently removed throughout the 20-week study, but PO4-P removal efficiency decreased over time in one of the four treatment lines. [Copyright &y& Elsevier]

Summary: The Lacandon Maya of Chiapas, Mexico practice a system of agroforestry that mimics the surrounding ecosystem and its successional stages. Their fields rotate through grass (milpa), and shrub (acahual) and forest fallow stages that regenerate soil, nutrients, and seed banks. Each successional stage, including the fallow stages, produces over 25 types of crops, raw materials, and medicines. Lacandon traditionally do not use fertilizers, pesticides, or herbicides. Nematodes were chosen to analyze soil ecology in the Lacandon system because they have been shown to be dynamic indicators of environmental conditions. Nematodes were classified by trophic level as plant parasite, fungivore, bacterivore, and omnivore-predator, and were found to be a function of management practice. In milpas where weeds were removed and applied to the field, plant parasites were reduced by 44% and fungivorous nematode concentrations were reduced by 50%. In these same fields, percentage of bacterivorous nematodes was positively related to soil organic matter concentration (, ). These results indicate that management practices reduced concentrations of plant parasites and delayed the nematode successional pathway from bacterivorous to fungivorous. This study demonstrates the potential for Lacandon Maya techniques to sustainably manage pests and maintain soil fertility in other tropical agroecosystems. [Copyright &y& Elsevier]

Abstract: Tools for modeling pulsed flows and constituent fluxes in wetlands, although well developed in theory, have not been well tested in practice. High-frequency monitoring of suspended solids and flows in a stormwater treatment wetland enabled application and analysis of these tools. A dynamic flow- and volume-weighted time variable, analogous to the retention time in steady-flow systems, is one important tool tested in this study. Cross-correlations with time lags demonstrated that the dynamic time variable was a better predictive variable of pulsed events than was the standard, static time variable. Although plug-flow models are typically used for steady-flow wetlands, residence time distribution (RTD) models are indispensable for describing pulsed flows and constituent fluxes in wetlands. This study demonstrated that RTD modeling with reaction kinetics of suspended solids during storm events produces a better explanation of outflow data than possible with steady, plug-flow models. Using only input and output data, an RTD model explained sedimentation rates with less unexplained variance than the standard, plug-flow model. The results of this study underscore the importance and utility of RTD modeling for complex flows. [Copyright &y& Elsevier]

Abstract: The residence time distribution (RTD) representing the hydraulics of a wetland is an important tool for modeling and designing treatment wetlands for optimal constituent removal. To correctly use RTD results, it is necessary to understand the conditions under which this distribution remains stable. Dye tracer experiments were conducted on a stormwater treatment wetland to investigate hydrologic factors affecting RTD characteristics. Dye was introduced into the inflow under normal flow conditions and during simulated storm flows, providing a range of flow rates and water levels. Dye distribution in the outlet was measured using an in situ fluorometer. Results indicate that flow rates did not have a significant effect on RTD characteristics. The RTDs normalized for volume and flow demonstrated a greater amount of short-circuiting and a larger mixing scale when water depth increased, demonstrating that water level can have a direct impact on the RTD of a wetland. This effect suggests that more than one RTD may be necessary for analyzing a wetland subject to changing water levels. For the wetland in this study, increasing the water depth elicited a decrease in hydraulic efficiency. Understanding such factors that affect hydraulic efficiency will aid in the design and management of wetlands. [Copyright &y& Elsevier]

River diversions within the Mississippi Delta deliver river water and associated sediments and nutrients to interior marshes that were previously isolated from river inputs by elevated levees. When isolated from river inputs, the marshes subside and deteriorate to open water, resulting in ecological and economic losses. River diversions are an ecological engineering method to reverse this trend by restoring controlled flows of river water through modified levees. This study compares the cost of constructing and operating the diversions with potential benefits to determine whether the diversions yield a net public benefit. The Caernarvon and Davis Pond river diversions were evaluated using emergy analysis to provide a common basis to quantify and compare economic and ecological costs and benefits. The analysis quantified high concentrations of natural resources inherent to deltas and demonstrated benefits produced by investing economic resources in river diversions to capture and utilize renewable resources. The diversions resulted in large net emergy yield ratios (33.2 and 9.36) that varied depending on the rate of marsh gain produced by the diversions. [Copyright &y& Elsevier]

• Urban stormwater reflects anthropogenic contamination. • Bioretention cell treatment of stormwater does not increase microbial hazards. • Biofiltered stormwater microbiome indices correlate with rainfall and water quality. • Beta diversity community structure of stormwater changes after biofiltration. • Bioretention technology sustains microbial and improves physical water quality. Bioretention cells (BRCs) control stormwater flow on-site during precipitation, reducing runoff and improving water quality through chemical, physical, and biological processes. While BRCs are effective in these aspects, they provide habitats for wildlife and may face microbial hazards from fecal shedding, posing a potential threat to human health and the nearby environment. However, limited knowledge exists regarding the ability to control microbial hazards (e.g., beyond using typical indicator bacteria) through stormwater biofiltration. Therefore, the purpose of this study is to characterize changes in the bacterial community of urban stormwater undergoing bioretention treatment, with the goal of assessing the public health implications of these green infrastructure solutions. Samples from BRC inflow and outflow in Columbus, Ohio, were collected post-heavy storms from October 2021 to March 2022. Conventional culture-based E. coli monitoring and microbial source tracking (MST) were conducted to identify major fecal contamination extent and its sources (i.e., human, canine, avian, and ruminant). Droplet digital polymerase chain reaction (ddPCR) was utilized to quantify the level of host-associated fecal contamination in addition to three antibiotic resistant genes (ARGs): tetracycline resistance gene (tetQ), sulfonamide resistance gene (sul 1), and Klebsiella pneumoniae carbapenemase resistance gene (bla KPC). Subsequently, 16S rRNA gene sequencing was conducted to characterize bacterial community differences between stormwater BRC inflow and outflow. Untreated urban stormwater reflects anthropogenic contamination, suggesting it as a potential source of contamination to waterbodies and urban environments. When comparing inlet and outlet BRC samples, urban stormwater treated via biofiltration did not increase microbial hazards, and changes in bacterial taxa and alpha diversity were negligible. Beta diversity results reveal a significant shift in bacterial community structure, while simultaneously enhancing the water quality (i.e., reduction of metals, total suspended solids, total nitrogen) of urban stormwater. Significant correlations were found between the bacterial community diversity of urban stormwater with fecal contamination (e.g. dog) and ARG (sul 1), rainfall intensity, and water quality (hardness, total phosphorous). The study concludes that bioretention technology can sustainably maintain urban microbial water quality without posing additional public health risks, making it a viable green infrastructure solution for heavy rainfall events exacerbated by climate change. This is special type of abstract that is so short and could be inserted after main abstract of article, as a blurb or inserted as annotations into a Table of contents [Display omitted] [ABSTRACT FROM AUTHOR]

Mycosporine-like amino acids (MAAs) are UV-absorbing metabolites found in cyanobacteria. While their protective role from UV in Microcystis has been studied in a laboratory setting, a full understanding of the ecology of MAA-producing versus non-MAA-producing Microcystis in natural environments is lacking. This study presents a new tool for quantifying MAA-producing Microcystis and applies it to obtain insight into the dynamics of MAA-producing and non-MAA-producing Microcystis in Lake Erie. This study first developed a sensitive, specific TaqMan real-time PCR assay that targets MAA synthetase gene C ( mysC ) of Microcystis (quantitative range: 1.7 × 10 1 to 1.7 × 10 7 copies/assay). Using this assay, Microcystis was quantified with a MAA-producing genotype ( mysC + ) in water samples (n = 96) collected during March-November 2013 from 21 Lake Erie sites (undetectable − 8.4 × 10 6 copies/ml). The mysC + genotype comprised 0.3–37.8% of the Microcystis population in Lake Erie during the study period. The proportion of the mysC + genotype during high solar UV irradiation periods (mean = 18.8%) was significantly higher than that during lower UV periods (mean = 9.7%). Among the MAAs, shinorine (major) and porphyra (minor) were detected with HPLC-PDA-MS/MS from the Microcystis isolates and water samples. However, no significant difference in the MAA concentrations existed between higher and lower solar UV periods when the MAA concentrations were normalized with Microcystis mysC abundance. Collectively, this study’s findings suggest that the MAA-producing Microcystis are present in Lake Erie, and they may be ecologically advantageous under high UV conditions, but not to the point that they exclusively predominate over the non-MAA-producers. [ABSTRACT FROM AUTHOR]

Wetlands are known for providing important ecosystem services, such as reduction of eutrophication. However, less research has focused on public health service of wetlands: their ability to protect microbial quality of water for downstream while they attract wildlife populations. For urban surface water, transmission of antibiotic resistance is also an important concern. Under anticipated climate change scenarios, more extreme precipitation patterns are emerging. Thus, runoff and flooding from increased precipitation will impair surface water quality more significantly. The objectives of this study were to 1) evaluate the dynamics of bacteria of public health concern in urban wetlands, including: Escherichia coli , Campylobacter , Shiga toxin-producing Escherichia coli (STEC), Arcobacter , and two antibiotic resistance genes (sulfonamide, sul1 and tetracycline, tetQ ); and 2) identify the major fecal contamination sources using microbial source tracking (MST). Water samples were collected across the urban wetlands in central Ohio from June 2013 to June 2014 and tested with a culture-based ( E. coli ) and quantitative PCR (the rest) methods. Since Canada geese were the most observed wildlife at the study sites and they are known to carry an array of infectious disease agents, their fecal samples were also collected. From the water samples, E. coli (fecal indicator) had the highest occurrence in 99.2% of the total samples, followed by sul1 (98.3%), Arcobacter (94.9%), STEC (74.6%), tetQ (58.5%), and Campylobacter (1.7%). Overall reduction in E. coli was 22.3% across the wetlands, but variation was observed depending on the season. Microbial source tracking suggested a high prevalence of avian- (44.9%) and ruminant- (38.1%) originated fecal contaminations (e.g., Canada geese and deer). From the geese fecal samples, STEC (93.2%) and Arcobacter (4.5%) were detected, which could potentially compromise wetlands’ functions in reductions in bacteria of public health concern and antibiotic resistance. The results suggest that careful wildlife management together with long-term monitoring of microorganisms of concern are needed for making urban wetlands as a sustainable frontline safeguard of pathogen and antibiotic resistance spread in surface water. [ABSTRACT FROM AUTHOR]

Energy can be recovered from stillage from cellulosic biorefineries in different ways, including direct combustion and fast pyrolysis. These different energy conversion routes require different level of inputs from natural resources, non-renewable resources, and economic services. Due to the high energetic and economic costs of stillage recovery methods, it is essential to perform a sustainability analysis of these different options before commercial deployment. Thus, the main objective of this study was to assess the relative sustainability and environmental impact of fast pyrolysis and direct combustion systems for the beneficial use of waste stillage using emergy analysis. The estimated emergy sustainability indices of direct combustion and fast pyrolysis were 0.09 and 0.07, respectively, where the renewable fraction of stillage was the most influential input parameter. Additionally, the net product transformity for direct combustion and fast pyrolysis were 7.06E+05 and 2.61E+05 seJ/J, respectively. Overall, a 23% higher emergy sustainability index for the direct combustion compared to the fast pyrolysis and a 63% lower overall product transformity for the fast pyrolysis compared to the direct combustion suggests that both systems, at the current state of the technology, offer differing advantages for stillage utilization depending upon the desired end products and uses. [ABSTRACT FROM AUTHOR]

• Watershed-scale green infrastructure did not alter microbiome or resistome. • Stormwater microbiome and resistome shift with season and rainfall characteristics. • Fecal contamination is associated with stormwater microbiome and resistome shifts. • Stormwater carries potentially clinically relevant, antibiotic-resistant bacteria • Molecular methods and Escherichia coli results were not well correlated. Since stormwater conveys a variety of contaminants into water bodies, green infrastructure (GI) is increasingly being adopted as an on-site treatment solution in addition to controlling peak flows. The purpose of this study was to identify differences in microbial water quality of stormwater in watersheds retrofitted with GI vs. those without GI. Considering stormwater is recently recognized as a contributor to the antibiotic resistance (AR) threat, another goal of this study was to characterize changes in the microbiome and collection of AR genes (resistome) of urban stormwater with season, rainfall characteristics, and fecal contamination. MinION long-read sequencing was used to analyze stormwater microbiome and resistome from watersheds with and without GI in Columbus, Ohio, United States, over 18 months. We characterized fecal contamination in stormwater via culturing Escherichia coli and with molecular microbial source tracking (MST) to identify sources of fecal contamination. Overall, season and storm event (rainfall) characteristics had the strongest relationships with changes in the stormwater microbiome and resistome. We found no significant differences in microbial water quality or the microbiome of stormwater in watersheds with and without GI implemented. However, there were differences between the communities of microorganisms hosting antibiotic resistance genes (ARGs) in stormwater from watersheds with and without GI, indicating the potential sensitivity of AR bacteria to treatment. Stormwater was contaminated with high concentrations of human-associated fecal bacterial genes, and the ARG host bacterial community had considerable similarities to human feces/wastewater. We also identified 15 potential pathogens hosting ARGs in these stormwater resistome, including vancomycin-resistant Enterococcus faecium (VRE) and multidrug-resistant Pseudomonas aeruginosa. In summary, urban stormwater is highly contaminated and has a great potential to spread AR and microbial hazards to nearby environments. This study presents the most comprehensive analysis of stormwater microbiome and resistome to date, which is crucial to understanding the potential microbial risk from this matrix. This information can be used to guide future public health policy, stormwater reuse programs, and urban runoff treatment initiatives. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: An emergy analysis was performed to assess the relative sustainability and environmental impact of small-scale energy production using Taiwanese model plug-flow anaerobic digesters to treat livestock manure in Costa Rica. Emergy analysis quantifies all inputs to a system by converting them to solar energy equivalents, thus allowing for direct comparison of the diverse inputs of renewable energies, human labor and economic goods needed to construct and maintain anaerobic digestion systems. The digesters were located on the campus of EARTH University, Costa Rica, and the biogas was utilized to power a 40kW generator that supplies electricity for farm operations. Separate emergy analyses were performed for the biogas production and the combination of biogas production and generation of electricity. Manure was the largest input in both analyses, accounting for 85.3% of the annual emergy input for biogas production and 66.9% for electricity generation from the biogas. The fraction of emergy inputs from renewable sources (ΦR) was 66% for biogas production and 52% for electricity generation from the biogas. The transformities of biogas and electricity generation from the biogas were 5.23E+04sej/J and 1.01E+06sej/J respectively. The emergy yield ratios (EYR) were 2.93 for biogas production and 2.07 for electricity generation indicating that these digesters efficiently match purchased resources and renewable energies to produce energy from livestock manure. The generation of electricity from the biogas resulted in a decrease in the emergy sustainability index (ESI) from 5.67 to 2.22 and an increase in the environmental loading ratio (ELR) from 0.52 to 0.93. Using a generator to convert the biogas to electricity does decrease the sustainability of the system, largely due to the high emergy value associated with the electrical generation equipment and machinery, but these results demonstrate that the production of biogas and the generation of electricity from Taiwanese model digesters in Costa Rica are environmentally sustainable processes that result in the production of energy that is largely dependent on renewable and recycled energies. [Copyright &y& Elsevier]

Seven low-cost digesters in Costa Rica were studied to determine the potential of these systems to treat animal wastewater and produce renewable energy. The effluent water has a significantly lower oxygen demand (COD decreased from 2968mg/L to 472mg/L) and higher dissolved nutrient concentration (NH4-N increased by 78.3% to 82.2mg/L) than the influent water, which increases the usefulness of the effluent as an organic fertilizer and decreases its organic loading on surface waters. On average, methane constituted 66% of the produced biogas, which is consistent with industrial digesters. Through principle component analysis, COD, turbidity, NH4-N, TKN, and pH were determined to be the most useful parameters to characterize wastewater. The results suggest that the systems have the ability to withstand fluctuations in the influent water quality. This study revealed that small-scale agricultural digesters can produce methane at concentrations useful for cooking, while improving the quality of the livestock wastewater. [Copyright &y& Elsevier]

Hydrologic models are applied increasingly with climate projections to provide insights into future hydrologic conditions. However, both hydrologic models and climate models can produce a wide range of predictions based on model inputs, assumptions, and structure. To characterize a range of future predictions, it is common to use multiple climate models to drive hydrologic models, yet it is less common to also use a suite of hydrologic models. It is also common for hydrologic models to report riverine discharge and assume that nutrient loading will follow similar patterns, but this may not be the case. In this study, we characterized uncertainty from both climate models and hydrologic models in predicting riverine discharge and nutrient loading. Six climate models drawn from the Coupled Model Intercomparison Project Phase 5 ensemble were used to drive five independently developed and calibrated Soil and Water Assessment Tool models to assess hydrology and nutrient loadings for mid-century (2046–2065) in the Maumee River Watershed,the largest watershedsdraining to the Laurentian Great Lakes. Under those conditions, there was no clear agreement on the direction of change in future nutrient loadings or discharge. Analysis of variance demonstrated that variation among climate models was the dominant source of uncertainty in predicting future total discharge, tile discharge (i.e. subsurface drainage), evapotranspiration, and total nitrogen loading, while hydrologic models were the main source of uncertainty in predicted surface runoff and phosphorus loadings. This innovative study quantifies the importance of hydrologic model in the prediction of riverine nutrient loadings under a future climate. Unlabelled Image • No clear change in mid-century water quantity or quality in a Great Lakes watershed • Climate models are main source of uncertainty in discharge and nitrogen predictions. • Hydrologic models are main source of uncertainty in phosphorus loading predictions. [ABSTRACT FROM AUTHOR]

This study analyzes the environmental performance of two centralized clean coal technologies and localized biogas digester, biomass gasifier and a solar PV by joint use of life cycle assessment (LCA) and emergy analysis. We also calculate cost of electricity generation by each of these technologies. The resulting information is utilized to determine the optimum energy mix to meet the energy demand in Rampura Village, Uttar Pradesh, India by solving a linear programming (LP) problem. The LP problem is processed in two steps: first, it is solved for four scenarios involving different practical situations and constraints. After determining the suitable scenario, the optimum energy combination within this scenario is found. The scenario and energy combination analyses reveal that performing 70% of cooking by biogas cook stoves, 30% by improved biomass cook stoves in the traditional way, and converting rest of biogas to electricity to meet irrigation and lighting energy needs is the most environmentally benign, economically feasible and socially attractive option for the village. Direct utilization of biogas for cooking makes it possible to meet all the energy demand in Rampura with local resources. Importing energy from erratic and unreliable government grid is not needed, hence energy security and reliability are ensured. Additionally, the GHG and other emissions related to cooking with inefficient stoves are also significantly mitigated (88%) through the use of biogas and improved biomass cook stoves. Energy projection through 2031 to determine changing energy patterns in the project site shows that there will be enough biogas for cooking needs in Rampura until 2031. However, by 2016, the total energy demand (cooking + irrigation + lighting) will exceed what can be met with only biogas. Then either biogas potential will need to increase or electricity will have to come from biomass or solar resources. If these local sources of energy are not enough, importing energy from centralized energy options will be necessary. Thus, increasing energy demand in developing countries will necessitate utilization of centralized energy options even in rural areas. Utilizing centralized clean coal technologies to meet this demand could ease energy related environmental problems. Alternatively, if rural development can take place without rampant consumerism and energy-intensive lifestyles, then satisfying local needs with local resources with minimum environmental impact is much more likely. [ABSTRACT FROM AUTHOR]

Although necessary for complex problem solving, such as engineering design, team agility is often difficult to achieve in practice. The evolution of Artificial Intelligence (AI) affords unique opportunities for supporting team problem solving. While integrating assistive AI agents into human teams has at times improved team performance, it is still unclear if, how, and why AI affects team agility. A large-scale human experiment answers these questions, revealing that, with appropriately interfaced AIs, AI-assisted human teams enjoy improved coordination and communications, leading to better performance and adaptations to team disruptions, while devoting more effort to information handling and exploring the solution space more broadly. In sum, working with AI enables human team members to think more and act less. • Assistive AI boosts team agility with respect to both evolving and abrupt changes. • The AI-assisted teams outperform the human-only teams. • The AI assistance improves team action effectiveness and behavioral flexibility. • The AI assistance results in more information-intensive team coordination. • The AI-assisted teams explore the drone design and operations spaces more broadly. [ABSTRACT FROM AUTHOR]

Highlights: [•] We compared management and ecological outcomes on holistic and conventional ranches. [•] Holistic ranchers use rotational grazing, minimize purchased inputs and do not burn. [•] Their pastures have denser grass, deeper topsoil, and more earthworms. [•] Holistic management is leading to greater ecological and economic sustainability. [Copyright &y& Elsevier]

Abstract: A new hydraulic index was derived according to residence time distribution theory. The approach quantifies hydraulic inefficiencies according to the juxtaposition of the hold back parameter relative to the residence time distribution. The index was evaluated for its ability to detect variation, for conformity with qualitative assessments, and for correlation to effluent pollutant fractions in order to assess its suitability as a predictor of treatment. The moment index overcomes many of the weaknesses inherent in existing indices. The index can be computed from a dataset considering just one volume exchange so arbitrary truncation of data due to the finite nature of data collection has no impact on the moment index. The moment index appears to be more sensitive than existing indices in detecting attenuation of a residence time distribution as well. The new index demonstrated excellent correlation to the effluent pollutant fraction predicted by a first-order reduction implying the index could be the good predictor of treatment. In addition to correlation with treatment, the moment index matched qualitative assessment precisely for eight specific cases considered. The moment index could substantially aid in the design and management of treatment wetlands for balancing cost and efficacy by resolving some of the uncertainty associated with residence time. The index could be used to help identify the optimal wetland configuration for maximizing residence time. Not only would it be useful in quantifying the effects of vegetation, bathymetry, and wetland shape on residence time; it could have utility in supplying the bounds for pollutant reduction. [ABSTRACT FROM AUTHOR]

Abstract: Conventional ranching in Chiapas, Mexico typically includes annual pasture burns and agrochemical use that decrease the biodiversity and forest cover of ranch lands. Members of a holistic ranching “club” in the Frailesca region of Chiapas, Mexico have moved away from this conventional management by eliminating burns and agrochemicals from their systems after decades of use because they believed that the land and their production process were growing unhealthy; they were further motivated by extension courses on holistic ranching. They have also implemented sophisticated systems of rotational grazing and diversified the use of trees. For this study all seven holistic ranchers and 18 neighboring conventional ranchers were interviewed about their cattle ranches and production strategies. An emergy analysis was conducted to compare the resource use, productivity and sustainability of the conventional and holistic ranches. Holistic ranches were found to have double the emergy sustainability index (ESI) values of conventional ranches, and the emergy yield ratio was 25% higher in holistic systems. Government assistance programs were found to have a negative impact on the ESI and were variably administered among holistic ranchers during the year of emergy evaluation. Overall improved emergy sustainability did not decrease milk nor cattle productivity. Transformities and specific emergies, the emergy of one type required to make a unit of energy (transformity) or mass (specific emergy) of another type, did not differ between conventional and holistic systems. Transformities for milk production ranged between 3.4E5 and 1.2E7 solar emjoules/joule (sej/J). Specific emergy for cattle production ranged from 3.5E10 to 1.5E11sej/g. To improve the ESI assistance programs could be re-targeted toward incentive programs for increased forest cover in ranching systems and startup costs for holistic ranching. The results from this study show that productivity can be maintained as the sustainability of rural dairy ranches is increased. These results also show that local knowledge and understanding of the surrounding ecosystem can drive positive environmental change in production systems. [Copyright &y& Elsevier]

Abstract: Methane production, electricity production, and wastewater transformations were quantified for a digestion system that combines biogas from a swine digester and dairy digester in Costa Rica. The low-cost, plug-flow digesters were not heated and were operated in the lower portion of the mesophilic range (25–27°C). The dairy digester produced 27.5m3/day of biogas with 62.6% methane and reduced organic matter (COD) by 86%. The swine digester produced 6.0m3/day of biogas with 76.4% methane and reduced COD by 92%. Combining biogas from a swine and dairy digester, increased electricity production due to the higher biogas production rate of the dairy farm and the higher quality biogas obtained from the swine farm. The farm’s 2-h peak electricity demand (12.9kW/day) was 81.8% met. The electricity was produced using manure equivalent to the quantity excreted by 5 dairy cows and 40 pigs remaining in corrals 100% of the time. The $21,000 capital cost of the digester project will be recovered in 10.1 years through electricity savings and reductions in wastewater fines. If the generator were more appropriately sized for the farm, the capital recovery time would have been 7.6 years. [Copyright &y& Elsevier]

• A SWAT model was used to assess targeting conservation practice adoption pathways. • Field and/or farmer characteristics were drivers of conservation practice adoption. • Targeting adoption by field-level nutrient losses was the most efficient pathway. Conservation identities of farmers in the Maumee River watershed, derived from farmer surveys, were embedded into a SWAT watershed model. This was done to improve the representation of the heterogeneity among farmers in the decision-making process related to the adoption of conservation practices. Modeled farm operations, created with near field-level Hydrologic Response Units (HRUs) within the SWAT model, were assigned a modeled primary operator. Modeled primary operators held unique conservation identities driven by their spatial location within the watershed. Five pathways of targeting the adoption of subsurface placement of phosphorus and buffer strips to HRUs within the watershed were assessed. Targeting pathways included targeting by HRU-level phosphorus losses, conservation identity of model operators, a hybrid approach combining HRU-level phosphorus losses and conservation identity of the model primary operator managing the HRU, and a proxy measure for random placement throughout the watershed. Targeting the placement of subsurface phosphorus application to all agricultural HRUs resulted in the greatest reduction in total phosphorus losses (32%) versus buffer strips (23%). For both conservation practices, targeting by HRU-level total phosphorus losses resulted in the most efficient rate of phosphorus reduction as measured by the ratio of phosphorus reduction to conservation practice adoption rates. The hybrid targeting approach closely resembled targeting by phosphorus losses, indicating near optimal results can be obtained even when constraining adoption by farmer characteristics. These results indicate that by developing management strategies based on a combination of field-level information and human-operator characteristics, a more efficient use of limited resources can be used while achieving near-maximal environmental benefits as compared to managing environmental outcomes solely based on field-level information. [Display omitted] [ABSTRACT FROM AUTHOR]

The need for effective water quality models to help guide management and policy, and extend monitoring information, is at the forefront of recent discussions related to watershed management. These models are often calibrated and validated at the basin outlet, which ensures that models are capable of evaluating basin scale hydrology and water quality. However, there is a need to understand where these models succeed or fail with respect to internal process representation, as these watershed-scale models are used to inform management practices and mitigation strategies upstream. We evaluated an ensemble of models—each calibrated to in-stream observations at the basin outlet—against discharge and nutrient observations at the farm field scale to determine the extent to which these models capture field-scale dynamics. While all models performed well at the watershed outlet, upstream performance varied. Models tended to over-predict discharge through surface runoff and subsurface drainage, while under-predicting phosphorus loading through subsurface drainage and nitrogen loading through surface runoff. Our study suggests that while models may be applied to predict impacts of management at the basin scale, care should be taken in applying the models to evaluate field-scale management and processes in the absence of data that can be incorporated at that scale, even with the use of multiple models. Unlabelled Image • Internal watershed processes depend on model inputs, parameters, and structure • These model variations were captured through use of multiple models • Edge of field data was used to evaluate internal watershed process simulation • Calibration at watershed outlet did not ensure accurate simulation upstream • Model structure limited accurate internal partitioning of P transport [ABSTRACT FROM AUTHOR]

How anticipated climate change might affect long-term outcomes of present-day agricultural conservation practices remains a key uncertainty that could benefit water quality and biodiversity conservation planning. To explore this issue, we forecasted how the stream fish communities in the Western Lake Erie Basin (WLEB) would respond to increasing amounts of agricultural conservation practice (ACP) implementation under two IPCC future greenhouse gas emission scenarios (RCP4.5: moderate reductions; RCP8.5: business-as-usual conditions) during 2020–2065. We used output from 19 General Circulation Models to drive linked agricultural land use (APEX), watershed hydrology (SWAT), and stream fish distribution (boosted regression tree) models, subsequently analyzing how projected changes in habitat would influence fish community composition and functional trait diversity. Our models predicted both positive and negative effects of climate change and ACP implementation on WLEB stream fishes. For most species, climate and ACPs influenced species in the same direction, with climate effects outweighing those of ACP implementation. Functional trait analysis helped clarify the varied responses among species, indicating that more extreme climate change would reduce available habitat for large-bodied, cool-water species with equilibrium life-histories, many of which also are of importance to recreational fishing (e.g., northern pike, smallmouth bass). By contrast, available habitat for warm-water, benthic species with more periodic or opportunistic life-histories (e.g., northern hogsucker, greater redhorse, greenside darter) was predicted to increase. Further, ACP implementation was projected to hasten these shifts, suggesting that efforts to improve water quality could come with costs to other ecosystem services (e.g., recreational fishing opportunities). Collectively, our findings demonstrate the need to consider biological outcomes when developing strategies to mitigate water quality impairment and highlight the value of physical-biological modeling approaches to agricultural and biological conservation planning in a changing climate. Unlabelled Image • How climate change will affect present-day conservation efforts remains uncertain. • We projected the effects of climate and land use change on Lake Erie stream fishes. • Anticipated climate change will modify fish responses to agricultural conservation. • Shifts in species and trait composition may lead to ecosystem service tradeoffs. • Our results highlight the value of biophysical modeling in conservation planning. [ABSTRACT FROM AUTHOR]

Non-point stormwater runoff is a major contamination source of receiving waterbodies. Heightened incidence of waterborne disease outbreaks related to recreational use and source water contamination is associated with extreme rainfall events. Such extreme events are predicted to increase in some regions due to climate change. Consequently, municipal separate storm sewer systems (MS4s) conveying pathogens to receiving waters are a growing public health concern. In addition, the spread of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria in various environmental matrices, including urban runoff, is an emerging threat. The resistome and microbiota profile of MS4 discharges has yet to be fully characterized. To address this knowledge gap, we first analyzed the relationship between rainfall depth and intensity and E. coli densities (fecal indicator) in stormwater from four MS4 outflows in Columbus, Ohio, USA during the spring and summer of 2017. Microbial source tracking (MST) was conducted to examine major fecal contamination sources in the study sewersheds. A subset of samples was analyzed for microbial and resistome profiles using a metagenomic approach. The results showed a significant positive relationship between outflow E. coli density and rainfall intensity. MST results indicate prevalent fecal contamination from ruminant populations in the study sites (91% positive among the samples tested). Protobacteria and Actinobacteria were two dominant bacteria at a phylum level. A diverse array of ARGs and potentially pathogenic bacteria (e.g. Salmonella enterica Typhimurium), fungi (e.g. Scedosporium apiospermum), and protists (e.g. Acanthamoeba palestinensis) were found in urban stormwater outflows that discharge into adjacent streams. The most prevalent ARGs among samples were β-lactam resistance genes and the most predominant virulence genes within bacterial community were related with Staphylococcus aureus. A comprehensive contamination profile indicates a need for sustainable strategies to manage urban stormwater runoff amid increasingly intense rainfall events to protect public and environmental health. Unlabelled Image • Extreme precipitation contributed to high concentrations of E. coli in stormwater. • Stormwater-derived microbiome and resistome was profiled with metagenomics. • Among antibiotic resistance (AR) genes, β-lactam resistance was ubiquitously detected. • Ruminant (deer)- and human-associate fecal bacteria contamination was dominant. • Stormwater can contribute to pathogen and AR transmission in nearby surface water. [ABSTRACT FROM AUTHOR]