Brief Summary of Minutes of Annual Meeting

Summary of Meeting Minutes:

UTN - John Buchannan: Drip distribution applications and guidance

Ohio - Karen: Water reuse and high Salt concentrations

U. S. Al - Kevin: Black belt in AL and access to sanitation

URI - Alissa Cox, Sara Wigginton, Bianca Ross, Jose Amador

• Advanced N-Removing OWTS Technology
• Layered non-proprietary N-removing OWTS drainfields
• Climate change, sea level rise and coastal OWTS
• IRIS sensors and Greenhouse gas /climate change modeling

Virginia Tech – Leigh Anne Krometis: Straight pipes in Appalachia (recent publication)

University of North Carolina - Joe Brown: Part of Alabama Rural Consortium (microbio/public health focus)

Oklahoma State - Sergio Abit: Post-flooding septic extension info; Changes to soil loading rates in drainfields based on climate patterns in OK

University of Arizona - Kitt: Extension Training (point-of-sale inspection)

Rutgers University – Lilly Young & Abbie Porter: Pharmaceutical degradation

• Pharmaceuticals and personal care products are emerging contaminants that enter the environment through incomplete removal during the wastewater treatment process. 
• We stablished enrichment cultures with anaerobic digester sludge to grow pharmaceutical degrading microbes in the laboratory.
• Our group identified microbial transformation products of pharmaceuticals and personal care products, including naproxen, methylparaben, guaifenesin, and oxybenzone. Naproxen, guaifenesin, and oxybenzone were transformed to products that are not further degraded and could be a source of unrecognized pollutants.
• Further work will be done to examine the microbial communities involved in pharmaceutical transformation and identify additional biochemical or genetic biomarkers for pharmaceutical metabolism.

University of Alabama - Mark & Jillian: Alabama Black Belt Region and Part of Alabama Rural Water & Wastewater Consortium

• Black Belt efforts are collaboration between University of Alabama (Mark Elliott), University of South Alabama (Kevin White), Columbia University (Upmanu Lall), Auburn University and Auburn Rural Studio (Mark Barnett), UNC- Chapel Hill (Joe Brown) and UC- Irvine (Maura Allaire)
• Consortium members include universities, ADPH, ADEM, USDA, NGOs, Governor’s office, Rep. Terri Sewell’s Office, Sen. Doug Jones’ office, Sen. Richard Shelby’s office
• Current work: EPA Gulf of Mexico Program Cooperative Agreement, Columbia World Projects, Review of straight pipe documentation in USA published in Water Research (with Leigh-Anne Krometis from VT), EPA P3 project for modeling potential straight pipe locations using public data, EPA P3 project on time-integrated samples for Cryptosporidium in rural streams with known straight pipe discharge
• Mark also provided more background information about straight pipe surveys, media coverage of the issue, implications of straight pipes for health, and potential solutions (see slides in Google Drive)
• Path forward: find appropriate technologies (expand sewer, engineered septic systems, other onsite systems), identify clusters of homes, identify management entities, explore financial models, develop alternative regulatory strategies and develop a “how-to” guide to advise stakeholders of treatment options, management techniques, funding options, etc.

University of Kentucky - Chris Shepard: Soils education for aspiring registered sanitarians

North Carolina State University - Matt Ricker: digitized OWTS in coastal communities

University of Georgia – Mussie Habteselassie: Research updates

• Mussie Habteselassie from the University of Georgia informed the group about research efforts, including the evaluation of nutrient and bacteria transport from shoreline OWTS to Lake Lanier in GA and a newly started project to develop an ArcGIS toobox for automating digitization of septic systems in Jackson county in GA. The cooperative extension at UGA have also held educational and training activities for home owners and professionals. UGA is interested in monitoring water quality and assessing impacts of OWTS in Pike County, GA

University of South Florida - Sarina Ergas: Saline & fixed-film wastewater treatment

• Focus has been treatment of wastewater in water scarce coastal communities where seawater is used for toilet flushing using low cost biofilters.
• Current results show good Total N removal; however, DO limitations limit nitrification due to the decreased solubility of oxygen in saline wastewater.
• The Journal of Sustainable Water in the Built Environment published a Special Collection of articles on Onsite and Decentralized Wastewater. Members of the consortium were encouraged to submit to this journal in the future.
• Ergas presented a list of recent publications.

Project Objective 1 - Improve our understanding of the interactions among wastewater, soils, biogeochemical cycles and processes and treatment performance (contaminant removal) of existing and novel wastewater treatment technologies in different geographic regions and landscapes over time and considering climate change.

North Carolina State University (NCSU)

Understanding spatial relationships among existing on-site systems, soil types, and coastal zone flooding. Coastal climate change is predicted to cause increased flooding, salinization of soils, and

rising ground water tables. These factors will likely negatively affect the ability of existing septic systems to treat waste and protect water quality. We analyzed geospatial data from 7 coastal counties (Bertie, Brunswick, Camden, Chowan, Currituck, Pasquotank, Perquimans) in North Carolina to understand OWTS vulnerability to sea level rise. Our preliminary research has located 30,361 coastal systems that are within 500 m of the coastline and likely at risk because of sea level rise over the next century. Of these located systems, 328 are located within minimum required setback distances from coastal shorelines (50 feet) and most vulnerable to sea level rise.

Using soil survey data in GIS, we have mapped soil series and joined the data to the location of existing septic systems. We have found that 47% of existing permitted systems are located in soils that have seasonal high water tables within 100 cm of the soil surface. These systems are at most risk for shrinking vertical drainfield separation distances as groundwater tables in the coastal zone rise with sea level. The majority of coastal OWTS in our study counties are installed in mineral soils classified as Ultisols (61%) or Entisols (32%). Only 2.8% of existing systems were in problematic areas mapped as Histosols or “unknown” soil type. We have also acquired geospatial NOAA sea level rise projections through 2050 and 2100. Use of sea level rise projections and existing location of permitted OWTS showed that by 2100, with 3 feet of relative sea level rise, there would be 137 septic systems inundated or submerged. Geospatial products from our study can be used by land managers to predict problematic landscapes for future installation of OWTS or areas where failure of previously installed systems is more likely to occur.

University of Georgia (UGA)

Evaluation of nutrient and bacteria transport from shoreline OWTS to Lake Lanier in GA (2020, Dr. David Radcliffe). The study to determine if shoreline OWTS on Lake Lanier, the drinking water source for much of Metro Atlanta, contribute N, P, or E. coli to the lake is on its second year. The monitoring of groundwater wells along the shoreline at 7 home sites that vary in age of system, distance from the drainfield to the lake, and annual water use is continuing. Previously, a HYDRUS hillslope model that accurately predicts the Cl and N concentrations at one of the home sites was developed. Results so far indicate nitrate is between 4 to 6 mg/L range at homes with distances less than about 70 m. Concentrations of total P are below 0.1 mg/L and we have found no evidence of E. coli.

Developing An ArcGIS toolbox for Automating Digitization of Septic Systems (2020; Dr. Nandita Gaur). This is a new study that was started in 2020 and there are no results to report so far. While septic systems are often cited as a potential source of contamination of water bodies, counties seldom have digitized information on septic system location and ages. Since money is limited to generate such resources, we are developing an automated system based on GIS and Remote sensing to populate such a database for Jackson county, GA.

University of Minnesota (UMN)

The UMN is evaluating water tables and groundwater mounding at 25 existing systems with automated water level recorders year- round.   This data is being used to evaluating what level of vertical separation to a periodically saturated condition is maintained at each of these sites; and does the groundwater below these systems mound up either during high wastewater discharge times or wet climatic periods.

Chemicals of emerging concern (CEC) sampling is occurring at three highway safety rest areas and a land application site to determine design parameters affecting treatment.  Samples were collected prior to soil treatment, in the soil itself beneath the systems and in monitoring wells and evaluated for CECs.   The water samples were also analyzed for general wastewater contaminants.  The work will continue for 2 more years.

The soil treatment areas from two highway rest areas  are being sampled and analyzed to determine the soil microbial populations (metagenomics) using next generation (DNA) sequencing.  The goal is to compare STA microbiology, natural soil microbiology before use, after the systems has been in operation for one year with septic tank effluent, and then at year two after pretreatment is added.

The UMN conducted two small research projects to evaluate the impact of excess soda and coffee being deposed of at commercial properties and the impact of RV chemicals on wastewater characteristics. 

The UMN evaluate the wastewater characteristics of two state parks and the performance of two advanced treatment system at one of the of the parks with one serving a shower house with high nitrogen levels while the other treats waste from RVs. 

The UMN tested the effluent at home with a resident is undergoing in-home kidney dialysis to determine the potential impacts of this medical related waste stream. 

Ohio State University (OSU)

Reuse of reclaimed wastewater through onsite spray irrigation. Research on winter reuse of reclaimed wastewater was conducted in Ohio. Issues evaluated were impact on plants, equipment protection, pathogen control, and pollutant runoff potential from cold soil.

Treatment of high salt content wastewater. Salt levels in wastewater become an issue from food processors that use salt for curing or pickling.  With fresh water scarcity, the use of high salt-content water for toilet flushing is also an option. Research is looking at the impact of salt on wastewater treatment using sand bioreactors

University of Rhode Island

IRIS tubes as indicators of denitrification.  Indicator of Reduction in Soils (IRIS) films are visual sensors used to document weakly or moderately reducing conditions in soils based on the reduction and removal of manganese (Mn)- or iron (Fe)-oxide paints, respectively, from white PVC films. Paint removal is largely assumed to result from anaerobic microbial reduction using metal oxides on the films as electron acceptors. If true, IRIS films could indicate conditions favorable to other biogeochemical processes that occur at similar redox potentials to those facilitating paint removal. Our objective here was to assess the effects of selected abiotic soil properties on IRIS film paint removal to determine whether removal can accurately be attributed to biotic processes alone. Through field deployments and laboratory incubations using IRIS films, we investigated sulfide concentration and dissolved organic matter as two abiotic factors potentially capable of removing paint from Mn IRIS films. Our results showed that sulfide concentrations above a critical threshold cause rapid and extensive abiotic paint removal from Mn films, while ambient concentrations of dissolved organic matter in freshwater wetland porewater does not drive abiotic removal. Furthermore, we found that the visible formation of black iron sulfides on Fe films can be used to detect sulfide concentrations that will remove paint from Mn films. This study suggests that while some abiotic soil properties (e.g., sulfide concentration) can cause paint removal, IRIS films may be a viable tool to proxy biotic process rates where abiotic paint removal can be ruled out.

Performance of advanced N-removal onsite wastewater septic systems in Charlestown, RI.  Advanced N-removal OWTS facilitate nitrification and denitrification of wastewater before effluent is applied to the STA. We studied 48 advanced N-removal OWTS (21 year-round use and 27 seasonally-sued) to determine the capacity of 6 different OWTS technologies to meet the RIDEM N standard of 19 mg/L or less, and N removal “ramp up” time for seasonally-used systems.  We found that the median TN conc. varied among different OWTS technologies possibly due to differences in treatment train design, however, almost all of the systems were capable of meeting the standard at some point in the study.  We also found that certain wastewater properties (ammonium & nitrate) correlated as significant predictors for effluent TN concentrations for all technologies, and temp. & pH served as significant predictors for certain technologies. Home occupancy pattern does not significantly influence effluent TN concentration, suggesting that these systems are capable of withstanding long periods of non-use without compromising performance.  Our results suggest that mass N loading is important to adequately assess OWTS’ impact on receiving waters. 

Assessment of Non-proprietary Passive Nitrogen Removal Septic Systems.  In collaboration with partners in Massachusetts (MASSTC), we conducted experiments to test the N removal potential of layered soil treatment areas (LSTA). These systems promote the sequential nitrification (in a sand layer) and denitrification (in an underlying sand layer mixed with sawdust) as septic tank effluent percolates through the bottomless LSTA to groundwater. We monitored three LSTA for (1) N removal (2) microorganisms involved in N transformations, and (3) greenhouse gas emissions. All LSTA were constructed with a control (conventional) STA beside them filled only with sand and receiving the same wastewater; this design allowed us to make comparisons with a conventional STA like those currently installed in MA. Analysis of the N removing performance data at six homes indicates that the LSTA meet state N regulations in 83% of samples collected, compared to 40% of control samples. We observed no significant differences between GHG emissions from the layered and control STA. We found that the denitrifying microbial community in the sawdust amended layer was unique from those in the nitrification layer and the control STA.

Impact of soil water-filled pore space on greenhouse (GHG) gas emissions from drainfield soil.  We examined the impact of WFPS on GHG emissions in soil microcosms receiving septic tank effluent (STE) or effluent from a single-pass sand filter (SFE), with deionized-distilled water (DW) as a control. Incubation of B and C horizon soil for 1 h with DW produced the lowest 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 GHG respond differently to WFPS, depending on water type and soil texture.

University of Tennessee Institute of Agriculture

Drip distribution. The engineering literature provides very little guidance on the design of drip system design for system that have the specific purpose of year-round effluent application.  There are many questions that need to be answered; however, for this project, three specific questions have been formulated.  The first is to determine an application rate for clay and silty clay soils that have weak, blocky structure; and the second question is whether there is any difference in the effluent application uniformity between a system that uses drip tubing spaced on two-foot centers versus a system that uses drip tubing placed on three-foot centers.  The third question investigates how water moves within the drip tubing after the dose, allowing more water to be emitted from lower portions of the distribution system and creating non-uniform application.

For the first question, a pilot-scale drip dispersal system was installed in the Central Basin (Wilson County, TN), in a Bradyville soil series.  The pilot-scale drip system was six-foot by six-foot with drip tubing spaced on 12-inch centers.  The emitters were spaced on 12-inch centers along the drip tubing, providing 36 emitters within the system.  Each emitter was rated for 0.58 gallon per hour.  Twelve soil moisture sensors were installed in and around the drip system.  Six of these sensors were located within the wetted area – two were placed four inches deep, two were placed eight inches deep and 2 were placed 12 inches deep.  The remaining six sensors were placed outside of the wetted area and at the same depths as the first set.  All of the soil moisture sensors were connected to a datalogger that took readings every 60 minutes. 

Water was applied in two, five-minute doses each hour for three days.  The application rate was 2.3 gallon per day per square foot (gpd/ft2).  The applied water infiltrated the soil with no observed ponding on the soil surface.  The soil moisture sensors within the wetted area indicated that the moisture moved through the soil profile.  The experiment needs to be replicated with varying climatic conditions before a definitive application rate for this soil can be determined.  However, preliminary results indicate that an application rate between 0.1 and 0.2 gpd/ft2 (less than 10% of the measured rate) may be applicable for this soil.

The second question addressed by this project investigated the appropriate spacing of the drip tubing within a drip distribution system.  An experimental drip system was installed at the Holston Unit of the East Tennessee Research and Education Center.  Four sets of three parallel drip tubes were installed in a clay soil.  The first set of tubes were installed 24 inches apart, the second set was spaced at 36 inches, the forth was set at 48 inches and the fifth was installed 60 inches apart.  Soil moisture sensors (installed 12 and 18 inches below the soil surface) were placed halfway between adjacent laterals to determine if moisture from the drip tubes was reaching the halfway point.  Preliminary results indicate that a three-foot drip tubing spacing can provide moisture to the area between the parallel tubes.  This investigation is ongoing and will be replicated in different soil types.

The third question investigated the hydraulic response of the drip distribution system after a dose.  This flow rate was needed in order to model the volume of water that will be produced by the lower emitters during depressurization.  An eight-foot vertical standpipe was used to provide water pressure to a single PC emitter.  As water moved through the emitter, the water column in the standpipe steadily decreases, lowering the pressure on the emitter.  The volumetric flow rate from the emitter was measured as the water column in the standpipe changed from eight to zero feet of head.  Results of this investigation strongly suggest that drip dispersal system designers need to work with the drip tubing manufacturers to understand how the system will operate during depressurization.  If the drip system is being installed in marginal soils, then the extra water volume produced at the lower end could be sufficient to saturate the soil and allow water to pond on the soil surface. 

Rutgers University

Microbial Metabolomics and Genetics Associated with Biodegradation of Pharmaceuticals and Personal Care Products During Wastewater Treatment. Our work examines the removal of micropollutants to improve water quality and produce tools for monitoring water quality. Micropollutants are chemicals that are found at very low concentrations and include household chemicals like pharmaceuticals and personal care products. These chemicals are either washed down the drain or flushed down the toilet and end up as components in wastewater. If these chemicals are not fully degraded by the microorganisms in wastewater treatment systems, they may be released into the environment.

To examine this problem, we established cultures using anaerobic digester sludge as a source of microorganisms and supplied the cultures with pharmaceuticals and personal care products that have similar chemical structures.  Our studies have shown that these pharmaceutical and personal care products are transformed by the microorganisms into products that are slow to degrade. This is important, because these partial transformation products have not yet been examined for pharmaceutical activity or environmental prevalence. Therefore, the potential toxicity and environmental impact is unknown. Our results provide evidence of metabolites that could be used as targets when screening water samples and biosolids, which are key modes of micropollutant entry into the environment. Ultimately, this leads to a better understanding of micropollutant removal for future improvements to wastewater treatment systems and improved monitoring of water quality.

We plan to continue to monitor our enrichment cultures for pharmaceutical biodegradation activity. Cultures will be periodically transferred to fresh media to maintain activity and further enrich for biodegrading populations. We will genetically characterize these enriched microbial communities to gain a better understanding of the types of processes these microorganisms may be involved in. Additionally, we will use genetic biomarkers to determine the presence of the benzoyl-CoA pathway in cultures that show degradation of the aromatic ring. Finally, we will continue to identify biodegradation products.

Project Objective 2 - Examine watershed-level impacts of septic systems on water quality and other environmental parameters in suburban, rural and coastal areas.

University of Rhode Island (URI)

The influence of climate change on OWTS in the coastal zone: Groundwater tables are compromising separation distance for a majority of coastal septic systems. We investigated how groundwater tables in the southern RI coast impact the separation distance from the drainfield’s infiltrative surface to the groundwater table in near-shore areas using long-term groundwater monitoring wells and ground-penetrating radar surveys of 10 different drainfields. Our results showed that only 20% of systems had adequate separation distance throughout the year, except during unusually large storm events. At least half of the system experienced compromised separation distance at least some of the time over the course of a year, and 30% of systems never have adequate separation distance. In some cases, the groundwater table intercepted the drainfield infiltrative surface, suggesting significant groundwater contamination potential.

Modeling effects of storms on septic systems along the southern RI coast. We developed a simple geospatial model using existing flood maps for different storm recurrence interval probabilities and parcel elevations to predict which septic systems would be affected to what extent by different flood or storm conditions along the southern RI coast. Systems were predicted to face serious (complete replacement required), moderate (minor repairs required to restore function) or ephemeral impacts (no long-term effects), based on proximity to the ocean and parcel elevation. The model was validated using descriptions of system damage during Hurricane Sandy in 2012 in Charlestown and Westerly, RI. During any given storm event approx. 2,000 to 4,000 systems are expected to experience flooding, with damages and repair costs in the aftermath ranging from about $1K to over $30K per system, and additional threats to human and environmental health from pollution by untreated wastewater.

Project Objective 3 – Develop educational materials and tools to acquaint the public and practitioners about management, operation, maintenance and health issues related to OWTS in light of system performance, and the need for adaptation to climate change.

University of Georgia

A study update from Dr. Gary L. Hawkins (2020). In Georgia, the following workshops/field days were held: A). Two workshops for homeowners via Zoom (40 attendants), B). A field day for industry, GA Department of Public Health (DPH) personnel and manufacturers (85 attendants). The field day was designed and co-sponsored by the Georgia On-Site Wastewater Association (GOWA). The participants received updates on Georgia Regulations (1.5 hours) and an outdoor portion where DPH personnel and manufacturers explained different parts of OWTS and distribution systems including: pump trucks, ATU units, dosing systems and floats, installation of different Georgia approved distribution systems, and how the different distribution systems operate.  There were 85 attendants. Additionally, Dr. Hawkins participated and presented in National Onsite Wastewater and Recycling Association annual meetings, Gwinnett County Septic Systems Workshop and UGA Extension Conference.

University of Minnesota (UMN)

UMN had to make a large change due to COVID 19 and first cancel many classes and then move to an online platform to training over 1,000 septic professionals in Minnesota in over 50 training events and delivered training in numerous other states with over 1,000 attendees.  Staff planned and organized the educational program for 2020 annual Minnesota Onsite Wastewater Association conference.  In addition, staff assisted in organizing and delivering the National Onsite Wastewater Recycling Association virtual annual conference in 2020.

Through a grant from the Minnesota Department of Health, the UMN presented education materials to increase the knowledge regarding chemical of emerging concern for those served and managing septic systems both in the classroom and through virtual events.   During the reporting period 12 classes offered for homeowners (300 in attendance) and 6 for septic system professionals (500 in attendance).

University of Rhode Island (URI)

URI project members published 10 peer-reviewed papers, 3 dissertations, delivered 17 workshops in the region reaching 225 practitioners, decision makers and students. These classes provided continuing education credits needed by practitioners to renew their professional licenses. We provided direct technical assistance to Suffolk Co. Health Dept., NY and RIDEM.

University of Tennessee Institute of Agriculture

As part of PI-Buchanan’s Extension appointment, he has been involved in the training of engineers and installers in the mechanics of subsurface drip dispersal systems.  During these training events, he has discussed the potential impacts that climate variability may have on the operation of decentralized wastewater management systems.  During this project, Buchanan conducted trainings in Tennessee, North Carolina, Pennsylvania, Connecticut, Minnesota, Colorado, Missouri, Indiana, Texas, Ohio, Idaho, Iowa, Alberta, Canada, and Shenzhen, China.

University of Georgia (UGA)

Capps, K. A., Bateman McDonald, J. M., Gaur, N., & Parsons, R. (2020). Assessing the Socio-Environmental Risk of Onsite Wastewater Treatment Systems to Inform Management Decisions. Environ Sci Technol, 54(23), 14843-14853. doi:10.1021/acs.est.0c03909

Fox, J., Batzer, D., Franklin, D., & Hawkins, G. (2020). Using macroinvertebrates as indicators of septic system density: an initial review. In National Onsite Wastewater and Recycling Association (NOWRA) annual Meeting. Virtual: NOWRA. Retrieved from http://www.nowra.org/.  November 16, 2020. 

Ohio State University (OSU)

Conroy, KM, F Chen, OH Tuovinen and KM Mancl. 2020. Effect of sodium chloride concentration on removal of chemical oxygen demand and ammonia from turkey processing wastewater in sand bioreactors. Applied Engineering in Agriculture. 36(1):33-37. doi.org/10.13031/aea.13632

Mancl, K. 2020. Household Water Use.  AEX 420. Ohio State University Extension. AEX-420.  https://ohioline.osu.edu/factsheet/AEX-420

Liu, K, E Park, KM Mancl, J Lee and OH Tuovinen. 2020. Batch UV disinfection for small flow onsite wastewater treatment. Applied Engineering in Agriculture. 36(5):717-725. doi.org/10.13031/aea.13398

Guo, YT, K Mancl, and R Moore. 2020. Water quality trading mechanisms enhances willingness to upgrade rural household septic systems in the western Lake Erie basin, northwest Ohio. Journal of Environmental Health. 82(6):8-15.

University of Minnesota (UMN)

Overbo, A., Heger. S., and Gulliver, J.  2020.  Evaluation of Chloride Contributions from Major Point and Nonpoint Sources in a Norther U.S. State.  Science of the Total Environment 764 (144179).

Heger, S. and S. Larson  2019.  Assessment of a Minnesota Residential Septic System Affected by Home Hemodialysis.  https://septic.umn.edu/sites/septic.umn.edu/files/report_final_kidney.pdf

Larson, S. and S. Heger.  2020.  Wastewater Characteristics Analysis of Coffee and Soda Products.  Water Resource Center available online at:  https://septic.umn.edu/sites/septic.umn.edu/files/coffee_soda_report_final.pdf

Larson, S. and S. Heger.  2020. Analysis of Recreation Vehicle Holding Tank Treatment Products.  2020.  Water Resources Center available online at:  https://septic.umn.edu/sites/septic.umn.edu/files/dnr_report_final_approved.pdf

Heger, S. and S. Larson  2019.  Wastewater Treatment Assessment at Two Minnesota State Parks.  https://septic.umn.edu/sites/septic.umn.edu/files/dnr_report_final_approved.pdf.

University of Rhode Island (URI)

Wigginton, S. K., and J. A. Amador. 2020. Soil: Microbial Ecology. In Landscape and Land Capacity, 2nd ed. (Y.Q. Wang, Ed.) CRC Press, Boca Raton, FL.

Ross, B. N, S. K. Wigginton, A. H. Cox, G. W. Loomis, and J. 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 12:2413

Ross, B. N., K. P. Hoyt, G. W. Loomis, and J. A. Amador. 2020. Effectiveness of advanced nitrogen-removal onsite wastewater treatment systems in a New England coastal community. Water, Air and Soil Pollution 231(11): 1-10.

Ross, B. N., B. V. Lancellotti, E. Q. Brannon, G. W. Loomis,  and J. A. Amador. 2020. Greenhouse gas emissions from advanced nitrogen-removal onsite wastewater treatment systems.  Science of the Total Environment https://doi.org/10.1016/j.scitotenv.2020.140399

Wigginton, S. K, G. W. Loomis, and J. A. Amador. 2020. Greenhouse gas emissions from lignocellulose-amended soil treatment areas for removal of nitrogen from wastewater. Science of the Total Environment https://doi.org/10.1016/j.scitotenv.2020.140936

Wigginton, S. K., E. Q. Brannon, P. J. Kearns , B. V. Lancellotti, A. Cox*, S. Moseman-Valtierra, G. W. Loomis, and J. A. Amador. 2020. Nitrifying and denitrifying microbial communities in centralized and decentralized biological nitrogen removing wastewater treatment systems. Water 12, 1688.

Cox, A. H., S. K. Wigginton, and J. A. Amador. 2020. Structure of greenhouse gas- consuming microbial communities in surface soils of a nitrogen-removing experimental drainfield. Science of the Total Environment https://doi.org/10.1016/j.scitotenv.2020.140362

Cox, A. H., D. Surabian, G. W. Loomis, J. D. Turenne, and J. 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, 107. https://doi.org/10.1007/s11270-020-04488-z

Cox, A. H., M. Dowling, G. W. Loomis, S. E. Engelhart, and J. A. Amador. 2020. Geospatial modeling suggests threats from stormy seas to Rhode Island’s coastal septic systems. Journal of Sustainable Water in the Built Environment 6(3) https://doi.org/10.1061/JSWBAY.0000917

Anderson, F. L., J. A. Cooper, and J. 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 230:245.

Wigginton, S.K. 2020.  NITROGEN-REMOVING WASTEWATER TREATMENT SYSTEMS: MICROBIAL COMMUNITIES AND GREENHOUSE GAS EMISSIONS. Doctoral Dissertation. University of Rhode Island.  https://digitalcommons.uri.edu/oa_diss/1165/

Cox, A. H. 2020. Coastal New England septic system drainfields: groundwater table and greenhouse gas cycling dynamics. Doctoral Dissertation. University of Rhode Island https://doi.org/10.23860/diss-cox-alissa-2020

Rutgers University

Porter, A.W., S. J. Wolfson, L. Y. Young. 2020. Pharmaceutical transforming microbes from wastewater and natural environments can colonize microplastics. AIMS Environmental Science.7(1):99-116. DOI: 10.3934/environsci.2020006

Porter, A.W., S. J. Wolfson, M. Häggblom, and L. Y. Young. 2020.  Microbial transformation of widely used pharmaceutical and personal care product compounds [version 1; peer review: 2 approved]. F1000 Research. 9 (F1000 Faculty Rev):130. DOI: 10.12688/f1000research.21827.1