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Dr. José A. Amador
Department of Natural Resources Science, University of Rhode Island, Kingston, RI, USA

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0 Biogeochemistry
0 Climate Change Impacts
0 Microbial Ecology
0 Soil Science
0 greenhouse gases

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onsite wastewater treatment systems
Soil Science
greenhouse gases

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Journal article
Published: 03 August 2021 in Water
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Non-proprietary N-removal onsite wastewater treatment systems are less costly than proprietary systems, increasing the likelihood of adoption to lower N inputs to receiving waters. We assessed the capacity of non-proprietary lignocellulose-amended soil treatment areas (LCSTAs)—a 45-cm-deep layer of sand above a 45-cm-deep layer of sand and sawdust—to lower the concentration of total N (TN) in septic tank effluent (STE) at mesocosm and field scales. The mesocosm received wastewater for two years and had a median effluent TN concentration of 3.1 mg/L and TN removal of 60–100%, meeting regulatory standards of 19 mg/L or 50% removal. Removal varied inversely with temperature, and was lower below 10 °C. Removal was higher in the mesocosm than in five field sites monitored for 12–42 months. Median effluent TN concentration and removal met the standard in three continuously-occupied homes but not for two seasonally-occupied homes. Sites differed in temporal pattern of TN removal, and in four of five sites TN removal was greater—and effluent TN concentration lower—in the LCSTA than in a control STA containing only sand. The performance of non-proprietary LCSTAs was comparable to that for proprietary systems, suggesting that these may be a viable, more affordable alternative for lowering N inputs to receiving waters.

ACS Style

Sara Wigginton; Jose Amador; Brian Baumgaertel; George Loomis; George Heufelder. Mesocosm- and Field-Scale Evaluation of Lignocellulose- Amended Soil Treatment Areas for Removal of Nitrogen from Wastewater. Water 2021, 13, 2137 .

AMA Style

Sara Wigginton, Jose Amador, Brian Baumgaertel, George Loomis, George Heufelder. Mesocosm- and Field-Scale Evaluation of Lignocellulose- Amended Soil Treatment Areas for Removal of Nitrogen from Wastewater. Water. 2021; 13 (15):2137.

Chicago/Turabian Style

Sara Wigginton; Jose Amador; Brian Baumgaertel; George Loomis; George Heufelder. 2021. "Mesocosm- and Field-Scale Evaluation of Lignocellulose- Amended Soil Treatment Areas for Removal of Nitrogen from Wastewater." Water 13, no. 15: 2137.

Article
Published: 05 November 2020 in Water, Air, & Soil Pollution
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Wastewater is a major source of nitrogen (N) to groundwater and coastal waterbodies, threatening both environmental and public health. Advanced N-removal onsite wastewater treatment systems (OWTS) are used to reduce effluent N concentration; however, few studies have assessed their effectiveness. We evaluated the total N (TN) concentration of effluent from 50 advanced N-removal OWTS in Charlestown, Rhode Island, USA for 3 years. We quantified differences in effectiveness as a function of N-removal technology and home occupancy pattern (seasonal vs. year-round use), and examined the relationship between wastewater properties and TN concentration. RX30 systems produced the lowest median TN concentration (mg N/L) (13.2), followed by FAST (13.4), AX20 (14.9), and Norweco (33.8). Compliance with the state’s regulatory standard for effluent TN concentration (19 mg N/L) was highest for RX30 systems (78%), followed by AX20 (73%), FAST (67%), and Norweco (0%). Occupancy pattern did not affect effluent TN concentration. Variation in TN concentration was driven by ammonium and nitrate for all technologies, and also by temperature for FAST and pH for Norweco. Median daily (g N/day) and annual (kg N/yr) N loads were significantly higher for year-round (5.3 and 2.3) than for seasonal (3.7 and 0.41) systems, likely due to differences in volume of wastewater treated. Our results suggest that advanced N-removal OWTS vary in their compliance with the state regulatory standard for effluent TN and can withstand long periods of non-use without compromising effectiveness. Nevertheless, systems used year-round do produce a higher daily and annual N load than seasonally-used systems.

ACS Style

Bianca N. Ross; Kevin P. Hoyt; George W. Loomis; Jose A. Amador. Effectiveness of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems in a New England Coastal Community. Water, Air, & Soil Pollution 2020, 231, 1 -10.

AMA Style

Bianca N. Ross, Kevin P. Hoyt, George W. Loomis, Jose A. Amador. Effectiveness of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems in a New England Coastal Community. Water, Air, & Soil Pollution. 2020; 231 (11):1-10.

Chicago/Turabian Style

Bianca N. Ross; Kevin P. Hoyt; George W. Loomis; Jose A. Amador. 2020. "Effectiveness of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems in a New England Coastal Community." Water, Air, & Soil Pollution 231, no. 11: 1-10.

Journal article
Published: 28 August 2020 in Water
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Advanced onsite wastewater treatment systems (OWTS) use biological nitrogen removal (BNR) to mitigate the threat that N-rich wastewater poses to coastal waterbodies and groundwater. These systems lower the N concentration of effluent via sequential microbial nitrification and denitrification. We used high-throughput sequencing to evaluate the structure and composition of nitrifying and denitrifying bacterial communities in advanced N-removal OWTS, targeting the genes encoding ammonia monooxygenase (amoA) and nitrous oxide reductase (nosZ) present in effluent from 44 advanced systems. We used QIIME2 and the phyloseq package in R to examine differences in taxonomy and alpha and beta diversity as a function of advanced OWTS technology, occupancy pattern (seasonal vs. year-round use), and season (June vs. September). Richness and Shannon’s diversity index for amoA were significantly influenced by season, whereas technology influenced nosZ diversity significantly. Season also had a strong influence on differences in beta diversity among amoA communities, and had less influence on nosZ communities, whereas technology had a stronger influence on nosZ communities. Nitrosospira and Nitrosomonas were the main genera of nitrifiers in advanced N-removal OWTS, and the predominant genera of denitrifiers included Zoogloea, Thauera, and Acidovorax. Differences in taxonomy for each gene generally mirrored those observed in diversity patterns, highlighting the possible importance of season and technology in shaping communities of amoA and nosZ, respectively. Knowledge gained from this study may be useful in understanding the connections between microbial communities and OWTS performance and may help manage systems in a way that maximizes N removal.

ACS Style

Bianca N. Ross; Sara K. Wigginton; Alissa H. Cox; George W. Loomis; Jose A. Amador. Influence of Season, Occupancy Pattern, and Technology on Structure and Composition of Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems. Water 2020, 12, 2413 .

AMA Style

Bianca N. Ross, Sara K. Wigginton, Alissa H. Cox, George W. Loomis, Jose A. Amador. Influence of Season, Occupancy Pattern, and Technology on Structure and Composition of Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems. Water. 2020; 12 (9):2413.

Chicago/Turabian Style

Bianca N. Ross; Sara K. Wigginton; Alissa H. Cox; George W. Loomis; Jose A. Amador. 2020. "Influence of Season, Occupancy Pattern, and Technology on Structure and Composition of Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems." Water 12, no. 9: 2413.

Journal article
Published: 15 July 2020 in Science of The Total Environment
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Lignocellulose-amended, layered soil treatment areas (STAs) remove nitrogen (N) passively from wastewater by sequential nitrification and denitrification. As wastewater percolates through the STA, the top sand layer promotes nitrification, and the lower, lignocellulos-amended sand layer promotes heterotrophic denitrification. Layered STAs can remove large amounts of N from wastewater, which may increase their emissions of CO2, N2O, and CH4 to the atmosphere. We measured greenhouse gas (GHG) flux from sawdust-amended (Experimental) and sand-only (Control) STAs installed in three homes in southeastern Massachusetts, USA. The Experimental STAs did not emit significantly more GHGs to the atmosphere than Control STAs receiving the same wastewater inputs, and both Control and Experimental STAs emitted more CO2 and N2O – but not CH4 – than soil not treating wastewater. Median (range) flux (μmol m−2 s−1) for all homes for the Control STAs was 7.6 (0.8–23.0), 0.0001 (−0.0004–0.004), and 0.0008 (0–0.02) for CO2, CH4 and N2O, respectively, whereas values for the Experimental STAs were 6.6 (0.3–24.3), 0 (−0.0005–0.005), and 0.0004 (0–0.02) for CO2, CH4 and N2O, respectively. Despite the absence of differences in flux between Control and Experimental STAs, the Experimental STA had significantly higher subsurface GHG levels than the Control STA, suggesting microbial consumption of excess gas levels near the ground surface in the Experimental STA. The flux of GHGs from Experimental and Control STAs was controlled chiefly by temperature, soil moisture, and subsurface GHG concentrations. Total emissions (gCO2e capita−1 day−1) were higher than those reported by others for conventional STAs, with mean values ranging from 0 to 1835 for septic tanks, and from 30 to 1938 for STAs. Our results suggest that, despite a higher capacity to remove N from wastewater, layered STAs may have limited impact on air quality compared to conventional STAs.

ACS Style

Sara K. Wigginton; George W. Loomis; José A. Amador. Greenhouse gas emissions from lignocellulose-amended soil treatment areas for removal of nitrogen from wastewater. Science of The Total Environment 2020, 744, 140936 .

AMA Style

Sara K. Wigginton, George W. Loomis, José A. Amador. Greenhouse gas emissions from lignocellulose-amended soil treatment areas for removal of nitrogen from wastewater. Science of The Total Environment. 2020; 744 ():140936.

Chicago/Turabian Style

Sara K. Wigginton; George W. Loomis; José A. Amador. 2020. "Greenhouse gas emissions from lignocellulose-amended soil treatment areas for removal of nitrogen from wastewater." Science of The Total Environment 744, no. : 140936.

Journal article
Published: 20 June 2020 in Science of The Total Environment
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Septic systems represent a source of greenhouse gases generated by microbial processes as wastewater constituents are degraded. Both aerobic and anerobic wastewater transformation processes can generate nitrous oxide and methane, both of which are potent greenhouse gases (GHGs). To understand how microbial communities in the surface soils above shallow drainfields contribute to methane and nitrous oxide consumption, we measured greenhouse gas surface flux and below-ground concentrations and compared them to the microbial communities present using functional genes pmoA and nosZ. These genes encode portions of particulate methane monooxygenase and nitrous oxide reductase, respectively, serving as a potential sink for the respective greenhouse gases. We assessed the surface soils above three drainfields served by a single household: an experimental layered passive N-reducing drainfield, a control conventional drainfield, and a reserve drainfield not in use but otherwise identical to the control. We found that neither GHG flux, below-ground concentration or soil properties varied among drainfield types, nor did methane oxidizing and nitrous oxide reducing communities vary by drainfield type. We found differences in pmoA and nosZ communities based on depth from the soil surface, and differences in nosZ communities based on whether the sample came from the rhizosphere or surrounding bulk soils. Type I methanotrophs (Gammaproteobacteria) were more abundant in the upper and middle portions of the soil above the drainfield. In general, we found no relationship in community composition for either gene based on GHG flux or below-ground concentration or soil properties (bulk density, organic matter, above-ground biomass). This is the first study to assess these communities in the surface soils above an experimental working drainfield, and more research is needed to understand the dynamics of greenhouse gas production and consumption in these systems.

ACS Style

Alissa H. Cox; Sara K. Wigginton; José A. Amador. Structure of greenhouse gas-consuming microbial communities in surface soils of a nitrogen-removing experimental drainfield. Science of The Total Environment 2020, 739, 140362 .

AMA Style

Alissa H. Cox, Sara K. Wigginton, José A. Amador. Structure of greenhouse gas-consuming microbial communities in surface soils of a nitrogen-removing experimental drainfield. Science of The Total Environment. 2020; 739 ():140362.

Chicago/Turabian Style

Alissa H. Cox; Sara K. Wigginton; José A. Amador. 2020. "Structure of greenhouse gas-consuming microbial communities in surface soils of a nitrogen-removing experimental drainfield." Science of The Total Environment 739, no. : 140362.

Journal article
Published: 20 June 2020 in Science of The Total Environment
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Advanced onsite wastewater treatment systems (OWTS) designed to remove nitrogen from residential wastewater play an important role in protecting environmental and public health. Nevertheless, the microbial processes involved in treatment produce greenhouse gases (GHGs) that contribute to global climate change, including CO2, CH4, N2O. We measured GHG emissions from 27 advanced N-removal OWTS in the towns of Jamestown and Charlestown, Rhode Island, USA, and assessed differences in flux based on OWTS technology, home occupancy (year-round vs. seasonal), and zone within the system (oxic vs. anoxic/hypoxic). We also investigated the relationship between flux and wastewater properties. Flux values for CO2, CH4, and N2O ranged from −0.44 to 61.8, −0.0029 to 25.3, and −0.02 to 0.23 μmol GHG m−2 s−1, respectively. CO2 and N2O flux varied among technologies, whereas occupancy pattern did not significantly impact any GHG fluxes. CO2 and CH4 – but not N2O – flux was significantly higher in the anoxic/hypoxic zone than in the oxic zone. Greenhouse gas fluxes in the oxic zone were not related to any wastewater properties. CO2 and CH4 flux from the anoxic/hypoxic zone peaked at ~22-23 °C, and was negatively correlated with dissolved oxygen levels, the latter suggesting that CO2 and CH4 flux result primarily from anaerobic respiration. Ammonium concentration and CH4 flux were positively correlated, likely due to inhibition of CH4 oxidation by NH4+. N2O flux in the anoxic/hypoxic zone was not correlated to any wastewater property. We estimate that advanced N-removal OWTS contribute 262 g CO2 equivalents capita−1 day−1, slightly lower than emissions from conventional OWTS. Our results suggest that technology influences CO2 and N2O flux and zone influences CO2 and CH4 flux, while occupancy pattern does not appear to impact GHG flux. Manipulating wastewater properties, such as temperature and dissolved oxygen, may help mitigate GHG emissions from these systems.

ACS Style

Bianca N. Ross; Brittany V. Lancellotti; Elizabeth Q. Brannon; George W. Loomis; Jose A. Amador. Greenhouse gas emissions from advanced nitrogen-removal onsite wastewater treatment systems. Science of The Total Environment 2020, 737, 140399 .

AMA Style

Bianca N. Ross, Brittany V. Lancellotti, Elizabeth Q. Brannon, George W. Loomis, Jose A. Amador. Greenhouse gas emissions from advanced nitrogen-removal onsite wastewater treatment systems. Science of The Total Environment. 2020; 737 ():140399.

Chicago/Turabian Style

Bianca N. Ross; Brittany V. Lancellotti; Elizabeth Q. Brannon; George W. Loomis; Jose A. Amador. 2020. "Greenhouse gas emissions from advanced nitrogen-removal onsite wastewater treatment systems." Science of The Total Environment 737, no. : 140399.

Journal article
Published: 12 June 2020 in Water
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Biological nitrogen removal (BNR) in centralized and decentralized wastewater treatment systems is assumed to be driven by the same microbial processes and to have communities with a similar composition and structure. There is, however, little information to support these assumptions, which may impact the effectiveness of decentralized systems. We used high-throughput sequencing to compare the structure and composition of the nitrifying and denitrifying bacterial communities of nine onsite wastewater treatment systems (OWTS) and one wastewater treatment plant (WTP) by targeting the genes coding for ammonia monooxygenase (amoA) and nitrous oxide reductase (nosZ). The amoA diversity was similar between the WTP and OWTS, but nosZ diversity was generally higher for the WTP. Beta diversity analyses showed the WTP and OWTS promoted distinct amoA and nosZ communities, although there is a core group of N-transforming bacteria common across scales of BNR treatment. Our results suggest that advanced N-removal OWTS have microbial communities that are sufficiently distinct from those of WTP with BNR, which may warrant different management approaches.

ACS Style

Sara K. Wigginton; Elizabeth Q. Brannon; Patrick J. Kearns; Brittany V. Lancellotti; Alissa Cox; Serena Moseman-Valtierra; George W. Loomis; Jose A. Amador. Nitrifying and Denitrifying Microbial Communities in Centralized and Decentralized Biological Nitrogen Removing Wastewater Treatment Systems. Water 2020, 12, 1688 .

AMA Style

Sara K. Wigginton, Elizabeth Q. Brannon, Patrick J. Kearns, Brittany V. Lancellotti, Alissa Cox, Serena Moseman-Valtierra, George W. Loomis, Jose A. Amador. Nitrifying and Denitrifying Microbial Communities in Centralized and Decentralized Biological Nitrogen Removing Wastewater Treatment Systems. Water. 2020; 12 (6):1688.

Chicago/Turabian Style

Sara K. Wigginton; Elizabeth Q. Brannon; Patrick J. Kearns; Brittany V. Lancellotti; Alissa Cox; Serena Moseman-Valtierra; George W. Loomis; Jose A. Amador. 2020. "Nitrifying and Denitrifying Microbial Communities in Centralized and Decentralized Biological Nitrogen Removing Wastewater Treatment Systems." Water 12, no. 6: 1688.

Article
Published: 03 March 2020 in Water, Air, & Soil Pollution
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Many coastal communities rely on individual onsite wastewater treatment (i.e., septic) systems to treat and disperse wastewater. Proper wastewater treatment in these systems depends on sufficient volume of unsaturated soil below the drainfield’s infiltrative surface. This is governed by the vertical separation distance—the distance between the groundwater table and the drainfield infiltrative surface—which is specified in (regulatory jurisdictions’ onsite wastewater system) regulations. Groundwater tables along the southern New England coast are rising due to sea-level rise, as well as changes in precipitation and water use patterns, which may compromise the functioning of existing septic systems. We used long-term shallow groundwater monitoring wells and ground-penetrating radar surveys of 10 drainfields in the southern Rhode Island coastal zone to determine whether septic system drainfields have adequate separation distance from the water table. Our results indicate that only 20% of tested systems are not impaired by elevated groundwater tables, while 40% of systems experience compromised separation distance at least 50% of the time. Surprisingly, 30% of systems in this study do not meet separation distance requirements at any time of the year. Neither age of system nor a system’s geographical relationship to a tidal water body was correlated with compromised separation distance. The observed compromised separation distances may be a result of inaccurate methods, specified by the regulations, to determine the height of the seasonal high water table. Our preliminary results suggest that enacting changes in the regulatory permitting process for coastal zone systems may help protect coastal drinking and surface water resources.

ACS Style

Alissa H. Cox; Deborah Surabian; George W. Loomis; Jim D. Turenne; Jose A. Amador. Temporal Variability in the Vertical Separation Distance of Septic System Drainfields Along the Southern Rhode Island Coast. Water, Air, & Soil Pollution 2020, 231, 1 -17.

AMA Style

Alissa H. Cox, Deborah Surabian, George W. Loomis, Jim D. Turenne, Jose A. Amador. Temporal Variability in the Vertical Separation Distance of Septic System Drainfields Along the Southern Rhode Island Coast. Water, Air, & Soil Pollution. 2020; 231 (3):1-17.

Chicago/Turabian Style

Alissa H. Cox; Deborah Surabian; George W. Loomis; Jim D. Turenne; Jose A. Amador. 2020. "Temporal Variability in the Vertical Separation Distance of Septic System Drainfields Along the Southern Rhode Island Coast." Water, Air, & Soil Pollution 231, no. 3: 1-17.

Article
Published: 24 October 2019 in Water, Air, & Soil Pollution
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Microbial removal of C and N in soil-based wastewater treatment involves emission of CO2, CH4, N2O, and N2 to the atmosphere. Water-filled pore space (WFPS) can exert an important control on microbial production and consumption of these gases. We examined the impact of WFPS on emissions of CO2, CH4, N2O, and N2 in soil microcosms receiving septic tank effluent (STE) or effluent from a single-pass sand filter (SFE), with deionized-distilled (DW) water as a control. Incubation of B and C horizon soil for 1 h (the residence time of wastewater in 1 cm of soil) with DW produced the lowest greenhouse gas (GHG) emissions, which varied little with WFPS. In B and C horizon soil amended with SFE emissions of N2O increased linearly with increasing WFPS. Emissions of CO2 from soil amended with STE peaked at WFPS of 0.5–0.8, depending on the soil horizon, whereas in soil amended with SFE, the CO2 flux was detectable only in B horizon soil, where it increased with increasing WFPS. Methane emissions were detectable only for STE, with flux increasing linearly with WFPS in C horizon soil, but no clear pattern was observed with WFPS for B horizon soil. Emissions of GHG from soil were not constrained by the lack of organic C availability in SFE, or by the absence of NO3 availability in STE, and addition of acetate or NO3 resulted in lower emissions in a number of instances. Emission of 15N2 and 15N2O from 15NH4 took place within an hour of contact with soil, and production of 15N2 was much higher than 15N2O. 15N2 emissions were greatest at the lowest WFPS value and diminished markedly as WFPS increased, regardless of water type and soil texture. Our results suggest that the fluxes of CO2, CH4, N2O, and N2 respond differently to WFPS, depending on water type and soil texture.

ACS Style

Faith L. Anderson; Jennifer A. Cooper; Jose A. Amador. Laboratory-Scale Evaluation of the Effects of Water-Filled Pore Space on Emissions of CO2, CH4, N2O, and N2 from Soil-Based Wastewater Treatment. Water, Air, & Soil Pollution 2019, 230, 245 .

AMA Style

Faith L. Anderson, Jennifer A. Cooper, Jose A. Amador. Laboratory-Scale Evaluation of the Effects of Water-Filled Pore Space on Emissions of CO2, CH4, N2O, and N2 from Soil-Based Wastewater Treatment. Water, Air, & Soil Pollution. 2019; 230 (10):245.

Chicago/Turabian Style

Faith L. Anderson; Jennifer A. Cooper; Jose A. Amador. 2019. "Laboratory-Scale Evaluation of the Effects of Water-Filled Pore Space on Emissions of CO2, CH4, N2O, and N2 from Soil-Based Wastewater Treatment." Water, Air, & Soil Pollution 230, no. 10: 245.

Perspective article
Published: 27 August 2019 in Frontiers in Environmental Science
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Traditional passive approaches to teaching, such as lectures, are not particularly effective at promoting student learning, or at developing the qualities that employers seek in graduates from soil science programs, such as problem-solving and critical thinking skills. In contrast, active learning approaches have been shown to promote these very qualities in students. Here, I discuss my use of active learning approaches to teach soil science at the introductory and advanced levels, with particular focus on problem-based learning (PBL), and combined just-in-time teaching (JITT) and peer instruction (PI). A brief description of the each pedagogical approach is followed by evidence of its impact on student learning in general and, when available, its use in soil science courses. I describe and discuss my experiences using these approaches teaching introductory soil science (face-to-face and online), soil chemistry and soil microbiology courses, and provide examples of some of the problems I use. I have found the benefits to student learning in terms of student engagement, ownership of learning, and development of critical thinking and problem-solving skills easily outweigh the additional effort required, and are clear relative to traditional, passive approaches to teaching.

ACS Style

Jose A. Amador. Active Learning Approaches to Teaching Soil Science at the College Level. Frontiers in Environmental Science 2019, 7, 1 .

AMA Style

Jose A. Amador. Active Learning Approaches to Teaching Soil Science at the College Level. Frontiers in Environmental Science. 2019; 7 ():1.

Chicago/Turabian Style

Jose A. Amador. 2019. "Active Learning Approaches to Teaching Soil Science at the College Level." Frontiers in Environmental Science 7, no. : 1.

Article
Published: 23 November 2018 in Water, Air, & Soil Pollution
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Advanced nitrogen-removal onsite wastewater treatment systems (OWTS) are used to reduce total nitrogen (N) levels in domestic wastewater. Maintaining system performance requires regular monitoring and in situ rapid tests can provide an inexpensive option for assessing treatment performance. We used a portable photometer to measure ammonium and nitrate concentrations in final effluent from 46 advanced N-removal OWTS, sampling each site at least three times in 2017. To assess photometer accuracy, we compared measurements made using the photometer with those determined by standard laboratory methods using linear regression analysis and a two-tailed t test to compare regression parameters to those for a perfect linear relationship (slope = 1, intercept = 0). Our results show that photometer-based analysis reliably estimates inorganic N (ammonium and nitrate) concentration in field and laboratory settings. Photometer-based analysis of the sum of inorganic N species also consistently approximated the total N concentration in the final effluent from the systems. A cost-benefit analysis indicated that the photometer is a more cost-effective option than having samples analyzed by commercial environmental testing laboratories after analysis of 8 to 33 samples. A portable photometer can be used to provide reliable, cost-effective measurements of ammonium and nitrate concentrations, and estimates of total N levels in advanced N-removal OWTS effluent. This method can be a viable tool for triaging system performance in the field, helping to identify systems that are not functioning properly and may need to be adjusted or repaired by an operation and maintenance service provider in order to meet treatment standards.

ACS Style

Bianca N. Ross; George W. Loomis; Kevin P. Hoyt; Jose A. Amador. User-Based Photometer Analysis of Effluent from Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems. Water, Air, & Soil Pollution 2018, 229, 389 .

AMA Style

Bianca N. Ross, George W. Loomis, Kevin P. Hoyt, Jose A. Amador. User-Based Photometer Analysis of Effluent from Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems. Water, Air, & Soil Pollution. 2018; 229 (12):389.

Chicago/Turabian Style

Bianca N. Ross; George W. Loomis; Kevin P. Hoyt; Jose A. Amador. 2018. "User-Based Photometer Analysis of Effluent from Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems." Water, Air, & Soil Pollution 229, no. 12: 389.

Journal article
Published: 01 September 2018 in Journal of Environmental Quality
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Advanced N-removal onsite wastewater treatment systems (OWTS) rely on nitrification and denitrification to remove N from wastewater. Despite their use to reduce N contamination, we know little about microbial communities controlling N removal in these systems. We used quantitative polymerase chain reaction and high-throughput sequencing targeting nitrous oxide reductase (nosZ) and bacterial ammonia monooxygenase (amoA) to determine the size, structure, and composition of communities containing these genes. We analyzed water samples from three advanced N-removal technologies in 38 systems in five towns in Rhode Island in August 2016, and in nine systems from one town in June, August, and October 2016. Abundance of nosZ ranged from 9.1 × 103 to 9 × 108 copies L−1 and differed among technologies and over time, whereas bacterial amoA abundance ranged from 0 to 1.9 × 107 copies L−1 and was not different among technologies or over time. Richness and diversity of nosZ—but not amoA—differed over time, with median Shannon diversity indices ranging from 2.61 in October to 4.53 in August. We observed weak community similarity patterns driven by geography and technology in nosZ. The most abundant nosZ- and amoA-containing bacteria were associated with water distribution and municipal wastewater treatment plants, such as Nitrosomonas and Thauera species. Our results show that nosZ communities in N-removal OWTS technologies differ slightly in terms of size and diversity as a function of time, but not geography, whereas amoA communities are similar across time, technology, and geography. Furthermore, community composition appears to be stable across technologies, geography, and time for amoA. Copyright © 2018. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Sara Wigginton; Elizabeth Brannon; Patrick J. Kearns; Brittany Lancellotti; Alissa Cox; George W. Loomis; Jose A. Amador. Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen‐Removal Onsite Wastewater Treatment Systems. Journal of Environmental Quality 2018, 47, 1163 -1171.

AMA Style

Sara Wigginton, Elizabeth Brannon, Patrick J. Kearns, Brittany Lancellotti, Alissa Cox, George W. Loomis, Jose A. Amador. Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen‐Removal Onsite Wastewater Treatment Systems. Journal of Environmental Quality. 2018; 47 (5):1163-1171.

Chicago/Turabian Style

Sara Wigginton; Elizabeth Brannon; Patrick J. Kearns; Brittany Lancellotti; Alissa Cox; George W. Loomis; Jose A. Amador. 2018. "Nitrifying and Denitrifying Bacterial Communities in Advanced Nitrogen‐Removal Onsite Wastewater Treatment Systems." Journal of Environmental Quality 47, no. 5: 1163-1171.

Article
Published: 13 February 2018 in Water, Air, & Soil Pollution
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Onsite wastewater treatment systems (OWTS) are an important part of the water infrastructure in the USA. Advanced OWTS are used instead of conventional OWTS to lower nitrogen (N) inputs to coastal ecosystems and groundwater sources used for drinking. Knowledge of the N load from OWTS helps identify drivers of excess N and develop strategies to lower N inputs. We used wastewater flow and effluent total N (TN) concentration to determine the mass N load from 42 advanced N-removal OWTS technologies (Orenco Advantex AX-20®, BioMicrobics MicroFAST®, SeptiTech D® series) and 5 conventional OWTS within the Rhode Island, USA, part of the Greater Narragansett Bay watershed. The median N load (g N/system/day) followed the order: conventional systems (31.1) > AX-20 (10.8) > FAST (10.1) > SeptiTech (9.6), and was positively correlated with flow. Results of a Monte Carlo simulation estimated the N load from the current distribution of conventional and advanced systems (105,833 systems total; Current scenario) to the watershed at 1,217,539 kg N/year. Compared to the Worse Case scenario (100% conventional OWTS), advanced OWTS currently prevent 53,898 kg N/year from entering the watershed. The per capita N load (kg N/capita/year) from OWTS under the current scenario is 4.68, and 1.47 for a local wastewater treatment plant (WTP) with biological N removal (BNR). Replacing 5150 conventional OWTS yearly with the most effective OWTS technology would result in a per capita N load from OWTS equivalent to that for a WTP with BNR after ~15 years, with a yearly cost of $174.24 per additional kilogram of N removed. Increasing the proportion of advanced OWTS that achieve the final effluent standard of 19 mg TN/L—through monitoring and recursive adjustment—would reduce the time and cost necessary to achieve parity with the WTP. Advanced N-removal OWTS are an important part of the water infrastructure that can lower N load to the Narragansett Bay watershed.

ACS Style

Jose A. Amador; Josef H. Görres; George W. Loomis; Brittany V. Lancellotti. Nitrogen Loading from Onsite Wastewater Treatment Systems in the Greater Narragansett Bay (Rhode Island, USA) Watershed: Magnitude and Reduction Strategies. Water, Air, & Soil Pollution 2018, 229, 65 .

AMA Style

Jose A. Amador, Josef H. Görres, George W. Loomis, Brittany V. Lancellotti. Nitrogen Loading from Onsite Wastewater Treatment Systems in the Greater Narragansett Bay (Rhode Island, USA) Watershed: Magnitude and Reduction Strategies. Water, Air, & Soil Pollution. 2018; 229 (3):65.

Chicago/Turabian Style

Jose A. Amador; Josef H. Görres; George W. Loomis; Brittany V. Lancellotti. 2018. "Nitrogen Loading from Onsite Wastewater Treatment Systems in the Greater Narragansett Bay (Rhode Island, USA) Watershed: Magnitude and Reduction Strategies." Water, Air, & Soil Pollution 229, no. 3: 65.

Article
Published: 19 September 2017 in Water, Air, & Soil Pollution
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Advanced nitrogen (N)-removal onsite wastewater treatment systems (OWTS) are installed in coastal areas throughout the USA to reduce N loading to groundwater and marine waters. However, final effluent total nitrogen (TN) concentration from these systems is not always routinely monitored, making it difficult to determine the extent to which they contribute to N loads. We monitored the final effluent TN concentration of 42 advanced N-removal OWTS within the Greater Narragansett Bay Watershed, Rhode Island between March 2015 and August 2016. The compliance rate with the State of Rhode Island final effluent standard (TN ≤ 19 mg N/L) was 64.3, 70.6, and 75.0% for FAST, Advantex, and SeptiTech systems, respectively. The median (range) final effluent TN concentration (mg N/L) was 11.3 (0.1–41.6) for SeptiTech, 14.9 (0.6–61.6) for Advantex, and 17.1 (0.6–104.9) for FAST systems. Variation in final effluent TN concentration was not driven by temperature; TN concentrations plotted against effluent temperature values resulted in R2 values of 0.001 for FAST, 0.007 for Advantex, and 0.040 for SeptiTech systems. The median effluent TN concentration for all the systems in our study (16.7 mg N/L) was greater than reported for Barnstable County, MA systems (13.3 mg N/L), which are monitored quarterly. Depending on technology type, ammonium (NH4+), nitrate (NO3−), alkalinity, forward flow, biochemical oxygen demand (BOD), and effluent temperature best predicted effluent TN concentrations. Service providers made adjustments to seven underperforming systems, but TN was reduced to 19 mg N/L in only two of the seven systems. Advanced N-removal OWTS can reduce TN to meet regulations, and monitoring of these systems can enable service providers to proactively manage systems. However, improvement of performance may require recursive adjustments and long-term monitoring.

ACS Style

Brittany V. Lancellotti; George W. Loomis; Kevin P. Hoyt; Edward Avizinis; Jose A. Amador. Evaluation of Nitrogen Concentration in Final Effluent of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems (OWTS). Water, Air, & Soil Pollution 2017, 228, 383 .

AMA Style

Brittany V. Lancellotti, George W. Loomis, Kevin P. Hoyt, Edward Avizinis, Jose A. Amador. Evaluation of Nitrogen Concentration in Final Effluent of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems (OWTS). Water, Air, & Soil Pollution. 2017; 228 (10):383.

Chicago/Turabian Style

Brittany V. Lancellotti; George W. Loomis; Kevin P. Hoyt; Edward Avizinis; Jose A. Amador. 2017. "Evaluation of Nitrogen Concentration in Final Effluent of Advanced Nitrogen-Removal Onsite Wastewater Treatment Systems (OWTS)." Water, Air, & Soil Pollution 228, no. 10: 383.

Journal article
Published: 01 September 2016 in Ecological Engineering
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Jennifer A. Cooper; Iván Morales; José A. Amador. Nitrogen transformations in different types of soil treatment areas receiving domestic wastewater. Ecological Engineering 2016, 94, 22 -29.

AMA Style

Jennifer A. Cooper, Iván Morales, José A. Amador. Nitrogen transformations in different types of soil treatment areas receiving domestic wastewater. Ecological Engineering. 2016; 94 ():22-29.

Chicago/Turabian Style

Jennifer A. Cooper; Iván Morales; José A. Amador. 2016. "Nitrogen transformations in different types of soil treatment areas receiving domestic wastewater." Ecological Engineering 94, no. : 22-29.

Journal article
Published: 01 September 2015 in Journal of Environmental Quality
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Bacteria removal efficiencies in a conventional soil-based wastewater treatment system (OWTS) have been modeled to elucidate the fate and transport of E. coli bacteria under environmental and operational conditions that might be expected under changing climatic conditions. The HYDRUS 2D/3D software was used to model the impact of changing precipitation patterns, bacteria concentrations, hydraulic loading rates (HLRs), and higher subsurface temperatures at different depths and soil textures. Modeled effects of bacteria concentration shows that greater depth of treatment was required in coarser soils than in fine-textured ones to remove E. coli. The initial removal percentage was higher when HLR was lower, but it was greater when HLR was higher. When a biomat layer was included in the transport model, the performance of the system improved by up to 12.0%. Lower bacteria removal (<5%) was observed at all depths under the influence of precipitation rates ranging from 5 to 35 cm, and 35-cm rainfall combined with a 70% increase in HLR. Increased subsurface temperature (23°C) increased bacteria removal relative to a lower temperature range (5–20°C). Our results show that the model is able to effectively simulate bacteria removal and the effect of precipitation and temperature in different soil textures. It appears that the performance of OWTS may be impacted by changing climate. Copyright © 2015. . Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

ACS Style

Ivan Morales; José A. Amador; Thomas Boving. Bacteria Transport in a Soil-Based Wastewater Treatment System under Simulated Operational and Climate Change Conditions. Journal of Environmental Quality 2015, 44, 1459 -1472.

AMA Style

Ivan Morales, José A. Amador, Thomas Boving. Bacteria Transport in a Soil-Based Wastewater Treatment System under Simulated Operational and Climate Change Conditions. Journal of Environmental Quality. 2015; 44 (5):1459-1472.

Chicago/Turabian Style

Ivan Morales; José A. Amador; Thomas Boving. 2015. "Bacteria Transport in a Soil-Based Wastewater Treatment System under Simulated Operational and Climate Change Conditions." Journal of Environmental Quality 44, no. 5: 1459-1472.

Journal article
Published: 01 May 2015 in Journal of Environmental Quality
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Shallow narrow drainfields are assumed to provide better wastewater renovation than conventional drainfields and are used for protection of surface and ground water. To test this assumption, we evaluated the water quality functions of two advanced onsite wastewater treatment system (OWTS) drainfields-shallow narrow (SND) and Geomat (GEO)-and a conventional pipe and stone (P&S) drainfield over 12 mo using replicated ( = 3) intact soil mesocosms. The SND and GEO mesocosms received effluent from a single-pass sand filter, whereas the P&S received septic tank effluent. Between 97.1 and 100% of 5-d biochemical oxygen demand (BOD), fecal coliform bacteria, and total phosphorus (P) were removed in all drainfield types. Total nitrogen (N) removal averaged 12.0% for P&S, 4.8% for SND, and 5.4% for GEO. A mass balance analysis accounted for 95.1% (SND), 94.1% (GEO), and 87.6% (P&S) of N inputs. When the whole treatment train (excluding the septic tank) is considered, advanced systems, including sand filter pretreatment and SND or GEO soil-based treatment, removed 99.8 to 99.9% of BOD, 100% of fecal coliform bacteria and P, and 26.0 to 27.0% of N. In contrast, the conventional system removed 99.4% of BOD and 100% of fecal coliform bacteria and P but only 12.0% of N. All drainfield types performed similarly for most water quality functions despite differences in placement within the soil profile. However, inclusion of the pretreatment step in advanced system treatment trains results in better N removal than in conventional treatment systems despite higher drainfield N removal rates in the latter.

ACS Style

Jennifer A. Cooper; George W. Loomis; David V. Kalen; José A. Amador. Evaluation of Water Quality Functions of Conventional and Advanced Soil-Based Onsite Wastewater Treatment Systems. Journal of Environmental Quality 2015, 44, 953 -962.

AMA Style

Jennifer A. Cooper, George W. Loomis, David V. Kalen, José A. Amador. Evaluation of Water Quality Functions of Conventional and Advanced Soil-Based Onsite Wastewater Treatment Systems. Journal of Environmental Quality. 2015; 44 (3):953-962.

Chicago/Turabian Style

Jennifer A. Cooper; George W. Loomis; David V. Kalen; José A. Amador. 2015. "Evaluation of Water Quality Functions of Conventional and Advanced Soil-Based Onsite Wastewater Treatment Systems." Journal of Environmental Quality 44, no. 3: 953-962.

Journal article
Published: 31 March 2015 in Open Journal of Water Pollution and Treatment
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Ralph Rozier; José A. Amador; Dave S. Bachoon; Jessie Dyer. Evaluation of microbiological water quality in Point Judith Pond (Rhode Island, USA): Quantitation of fecal pollution and presence of human pathogenic bacteria. Open Journal of Water Pollution and Treatment 2015, 2015, 25 -32.

AMA Style

Ralph Rozier, José A. Amador, Dave S. Bachoon, Jessie Dyer. Evaluation of microbiological water quality in Point Judith Pond (Rhode Island, USA): Quantitation of fecal pollution and presence of human pathogenic bacteria. Open Journal of Water Pollution and Treatment. 2015; 2015 (1):25-32.

Chicago/Turabian Style

Ralph Rozier; José A. Amador; Dave S. Bachoon; Jessie Dyer. 2015. "Evaluation of microbiological water quality in Point Judith Pond (Rhode Island, USA): Quantitation of fecal pollution and presence of human pathogenic bacteria." Open Journal of Water Pollution and Treatment 2015, no. 1: 25-32.

Journal article
Published: 01 November 2014 in Journal of Environmental Quality
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Optimization of N removal in soil-based wastewater treatment systems requires an understanding of the microbial processes involved in N transformations. We examined the fate of NH in intermittently aerated leachfield mesocosms over a 24-h period. Septic tank effluent (STE) was amended with NHCl to help determine N speciation and distribution in drainage water, soil, and headspace gases. Our results show that 5.7% of the N was found in soil, 10.0% in drainage water, and 84.3% in the gas pool. Ammonium accounted for 41.7% of the soil N pool, followed by NO (29.2%), organic N (21.7%), and microbial biomass N (7.5%). In drainage water, NO constituted ∼80% of the N pool, whereas NH was absent from this pool. Nitrous oxide was the dominant form of N in the gas phase 6 h after addition of NH-amended STE to the mesocosms, after which its mass declined exponentially; by contrast, the mass of N was initially low but increased linearly with time to become the dominant form of N after 24 h. Analysis based on the isotopic enrichment of NO and N indicates that nitrification contributed 98.8 and 23.1% of the NO flux after 6 and 24 h, respectively. Our results show that gaseous losses are the main mechanism for NH removal from wastewater in intermittently aerated soil. In addition, nitrification, which is generally not considered a significant pathway for N loss in soil-based wastewater treatment, is an important source process for NO.

ACS Style

John T. Richard; David A. Potts; José A. Amador. Mechanisms of Ammonium Transformation and Loss in Intermittently Aerated Leachfield Soil. Journal of Environmental Quality 2014, 43, 2130 -2136.

AMA Style

John T. Richard, David A. Potts, José A. Amador. Mechanisms of Ammonium Transformation and Loss in Intermittently Aerated Leachfield Soil. Journal of Environmental Quality. 2014; 43 (6):2130-2136.

Chicago/Turabian Style

John T. Richard; David A. Potts; José A. Amador. 2014. "Mechanisms of Ammonium Transformation and Loss in Intermittently Aerated Leachfield Soil." Journal of Environmental Quality 43, no. 6: 2130-2136.

Journal article
Published: 02 April 2014 in Water
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Segmented mesocosms (n = 3) packed with sand, sandy loam or clay loam soil were used to determine the effect of soil texture and depth on transport of two septic tank effluent (STE)-borne microbial pathogen surrogates—green fluorescent protein-labeled E. coli (GFPE) and MS-2 coliphage—in soil treatment units. HYDRUS 2D/3D software was used to model the transport of these microbes from the infiltrative surface. Mesocosms were spiked with GFPE and MS-2 coliphage at 105 cfu/mL STE and 105–106 pfu/mL STE, respectively. In all soils, removal rates were >99.99% at 25 cm. The transport simulation compared (1) optimization; and (2) trial-and-error modeling approaches. Only slight differences between the transport parameters were observed between these approaches. Treating both the die-off rates and attachment/detachment rates as variables resulted in an overall better model fit, particularly for the tailing phase of the experiments. Independent of the fitting procedure, attachment rates computed by the model were higher in sandy and sandy loam soils than clay, which was attributed to unsaturated flow conditions at lower water content in the coarser-textured soils. Early breakthrough of the bacteria and virus indicated the presence of preferential flow in the system in the structured clay loam soil, resulting in faster movement of water and microbes through the soil relative to a conservative tracer (bromide).

ACS Style

Ivan Morales; Janet A. Atoyan; José A. Amador; Thomas Boving. Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling. Water 2014, 6, 818 -838.

AMA Style

Ivan Morales, Janet A. Atoyan, José A. Amador, Thomas Boving. Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling. Water. 2014; 6 (4):818-838.

Chicago/Turabian Style

Ivan Morales; Janet A. Atoyan; José A. Amador; Thomas Boving. 2014. "Transport of Pathogen Surrogates in Soil Treatment Units: Numerical Modeling." Water 6, no. 4: 818-838.