Brief Summary of Minutes of Annual Meeting

1. The NE 1545 meeting began at 2:30 pm. Sixteen individuals, representing twelve institutions, attended the meeting (see table below for list of attendees; member institutions indicated with an “*”).  Each representative institution delivered an update of NE1545 related activities for the reporting year October 1, 2017 to September 30, 2018.  Accomplishments from these research and outreach activities are noted in the Accomplishment section of this report.
2. Jose Amador from the University of Rhode Island updated the group on PhD student Bianca Ross’ research project evaluating treatment performance of N removal treatment technologies being used in Rhode Island.  
3. Sara Wigginton, PhD student from the University of Rhode Island, reported on her research investigating full-scale layered STAs in collaboration with the Massachusetts Alternative Septic System Testing Center (MASSTC). Sara presented a summary of the nitrogen removing performance and greenhouse gas emissions from a layered STA research site. Future plans for microbial analysis of the site was also discussed. Additionally, plans to monitor additional sites, including a seasonally used STA, was discussed.
4. Alissa Cox, PhD student from the University of Rhode Island, updated the meeting attendees about her research project related to OWTS and climate change – assessing the influence of sea level rise on groundwater tables and OWTS along the Southern RI Coast.
5. Sara Heger from the University of Minnesota provided an overview of septic system related education and research activities occurring in Minnesota and the Midwest.  The presentation focused on a recently completed evaluation of water softener contribution to chloride contamination in Minnesota.
6. Jennifer Cooper (currently at the University of Nebraska) reported on her continued research with the University of Rhode Island related to DNA sequencing methods to compare the microbial community composition in onsite wastewater treatment systems (OWTS) using intact soil mesocosms.
7. Younsuk Dong reported on research associated with Objectives 2 and 3. He provided a Hydrus Constructed Wetland (CW) 2D model of wastewater land application systems. The importance of mathematical modeling on wastewater land application system, and calibration and validation procedures, using bench-scale soil trenches, were discussed. The result of multiple scenarios including impact of dosing frequency, COD influent concentration, and hydraulic and organic loadings on carbon degradation and denitrification were discussed. In addition, he provided an update on research on the land treatment of food processing wastewater, the advantages relating to treatment energy cost and potential greenhouse gas emission were estimated. Outreach programs for wastewater professionals and homeowners were also discussed (details in Objective 4).
8. Brad Lee at the University of Kentucky reported on practitioner and homeowner outreach education activities being done to address OWTS issues in rural communities in Appalachia.
9. Daniel Delgado from University of South Florida described the projects currently being conducted along with Sarina Ergas related to hybrid adsorption biological treatment systems to reduce nitrogen removal from OWTS.
10. Details of the efforts noted above are included under Objectives 2 and 4 in the Outputs Section of this report.
11. The meeting concluded at 6:00 pm.

Project Objective 2 – Develop new OWTS design criteria for the purposes of climate change adaptation and mitigation

University of Minnesota findings –  Working with MnDOT OSTP is evaluating water tables and groundwater mounding at 20 existing systems with automated water level recorders between early April through mid-November.  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 four 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 soil treatment areas (STA) from one rest area was 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 after the system has been in operation for one year, and then at year two after pretreatment is added.

A study was conducted to characterize water softeners in five MnDOT rest area and assess their impacts on septic system chloride levels.  The objectives of this study were to compare facilities and evaluate the impacts of softener type, softener settings, softener age, and water quality on chloride levels in the septic system.  Chloride levels in the rest area septic systems were found to be high, ranging from 488-1730 mg/L.

Reuse of wash down water from salt truck washing is being evaluated for wastewater reuse at MnDOT facilities.   This project evaluated when reuse makes sense from a regulatory, environmental, economic and management perspective at truck washing/storage facilities and safety rest areas.  Sampling of various streams were collected in the winter of 2018.  Recommendations where provided on the most appropriate applications for reuse and the challenges with implementation. The possibility of reusing wastewater for anti-icing and pre-wetting after removal of sediment and oil was evaluated along with options for wastewater treatment. Moving forward a pilot treatment system is under design.

High chloride levels in surface waters and groundwater are an emerging concern in Minnesota, as they can negatively impact aquatic and plant life.  Previous research has shown that road salt is a major source of chloride, particularly in urban areas, but chloride discharge from water softener use, another major source, has not been quantified and therefore was evaluated. A mass budget was performed for wastewater treatment plants (WWTPs) with chloride monitoring data to estimate chloride discharged from household and commercial water softeners relative to other household, commercial, and industrial sources.  At the statewide level, household and commercial water softening were estimated to contribute 65% of WWTP chloride discharge.  Industries were also major sources, contributing 22% of the estimated chloride load of statewide WWTPs.  Human excreta, household product use, background chloride concentrations, chlorination, and other commercial processes contributed relatively small amounts of chloride, less than 5% of the chloride load.  The results of the chloride budget show that water softeners are major sources of chloride and indicate that increasing efficiency of water softener salt use could be a viable strategy to manage chloride levels in wastewater and receiving waters.

University of Rhode Island

The influence of climate change on OWTS in the coastal zone.  We are researching the impacts coastal storm events have on near-shore OWTS along the southern RI coast to better understand how groundwater table dynamics affect OWTS function. There are 17,760 OWTS in this coastal region. During the reporting period, using flood maps created by the USACE, we estimated that roughly 3,000 to 4,000 OWTS would be affected by a 1-in-25 Year to a 1-in-500 Year flood event, in which at least half of the affected OWTS would require repairs of some sort. Repairs would range from minor in nature to complete system replacements, costing anywhere between $1 to over $30K per system, depending on the nature of the damage.    Based on data extracted from regulatory agency OWTS permit applications, we determined that coastal groundwater tables are rising at an average rate of 14 mm per year, though a system’s relative landscape position (proximity to ocean or salt pond) and location along the coast (town) affect these rates significantly. Major drivers of rising groundwater tables include groundwater imports (via municipal water or out-of-basin imports), increased annual precipitation and sea level rise. Factors lowering groundwater tables include evapotranspiration, discharge to salt ponds and groundwater extraction, though these values are poorly constrained. Current coastal community resiliency plans are not adequately addressing either threat (storms or groundwater table rise) with respect to OWTS, which could result in significant environmental degradation and public health risks. The methods we used for our analyses could be applied to many coastal communities in the US and abroad, and present an important consideration for the sustainability of coastal communities and their adaptation to climate change.

Assessment of Non-proprietary Passive Nitrogen Removal Septic Systems.  In collaboration with partners in Massachusetts (MASSTC), we are conducting experiments to test the nitrogen removal potential of layered soil treatment areas (STA). These leaching systems increase sequential nitrification (in a sand layer) and denitrification (in a sand layer mixed with sawdust) as septic tank effluent percolates through to groundwater. Four layered systems, including one extensively instrumented system, are currently being monitored. The main objectives of this project are to: (1) Monitor layered STA effectiveness (2) Survey STAs for microorganisms involved in N transformations, and (3) Monitor STAs for greenhouse gas emissions to examine the sources of N₂O production.  During the reporting period, we intensively instrumented a research site where every 30 minutes we monitor temperature and moisture content at four depths in the layered STA using data loggers. We also collected five monthly subsurface greenhouse gas emissions and preliminary data analysis was performed. Additionally, greenhouse gas flux was collected at the ground surface over the layered and adjacent control STAs, and we collected four soil cores (2 control and 2 layered STAs) to perform microbial community, physical, and chemical analyses. The microbial community DNA extracts for initial media material, native soil, and the July sampling event have been performed. Additionally, we performed organic carbon analysis on soil cores. Analysis of the nitrogen removing performance data indicates that the layered STA removes 65-98% of total N, compared to 11-88% in the control STA.

Treatment Performance Optimization of Advanced Nitrogen Removal OWTS

N-removal OWTS are designed to facilitate nitrification and denitrification before effluent is applied to the soil treatment area. We selected 47 N-removal OWTS in the town of Charlestown, RI to determine the capacity of 6 different technologies (Orenco AX20, Orenco RX30, BioMicrobics FAST, and Norweco Singulair) to meet the RI regulatory standard for final effluent total N concentration of 19 mg/L or less.  Twenty-four of the systems (sampled quarterly) serve houses occupied year-round, while 23 systems (sampled monthly  4 times in summer) serve seasonally-occupied houses.  Investigating the impact of home occupancy pattern on effluent TN will allow us to assess if seasonal systems require any microbial “ramp-up” time before they are capable of N removal. 

Technology type and/or home occupancy pattern does not appear to affect NO₃^- concentration, however, effluent NH₄⁺ is significantly influenced by technology type.  Specifically, Norweco systems reported higher NH₄⁺ levels and significantly higher   alkalinity and BOD₅ values than all other technologies, suggesting that Norweco systems are not nitrifying sufficiently.  Home occupancy pattern does not appear to significantly influence effluent TN, nor does there appear to be any microbial ramp-up time associated with seasonally-used systems.  However, effluent TN does vary across technologies.  Specifically, Norweco systems are reporting significantly higher TN concentrations than AX20 systems.  Sixty-eight percent of AX20, 50% of RX30, 67% of FAST, and 25% of Norweco systems have median TN values less than 19 mg/L.

Service providers are required to visit N-removal OWTS twice per year for O&M purposes.  These visits focus on operational function, and service providers are not required to quantify effluent TN concentrations.  Service providers need a quick and effective method of measuring effluent TN in order to ensure that the systems are not exceeding regulatory standards.  We evaluated a portable photometer as a reliable method for assessing real-time effluent N concentrations.  While the photometer is not capable of directly quantifying effluent TN, it can measure NH₄⁺ and NO₃^- concentrations.  By comparing measurements made using the photometer with those made using standard laboratory methods, we found that not only is the photometer accurately measuring NH₄⁺ and NO₃^- concentrations, but by summing these inorganic N concentrations, it is capable of reliably estimating effluent TN concentrations.  The photometer can be used indoors or outdoors as a quick and cost-effective “triage” method for identifying underperforming systems.

Nitrogen loading from OWTS in the Greater Narragansett Bay, RI Watershed

Knowledge of the N load from OWTS, an important part of water infrastructure in the USA, helps identify drivers of excess N and develop strategies to lower N inputs. We determined the mass N load from 42 advanced N removal OWTS (3 different technologies) and 5 conventional OWTS within the RI 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 5,150 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 kg 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.

University of Nebraska at Lincoln – Microbial Community Composition in OWTS.  We used high throughput DNA sequencing methods to compare the 16S (bacterial and archaeal) and 18S (eukaryotic) microbial community composition in OWTS using intact soil mesocosms from Kingston, RI.  We compared microbial communities between three different technologies: conventional pipe and stone (P&S), and alternative systems pressurized shallow narrow drainfield (SND) and Geomat ® (GEO).  We evaluated microbial communities under four different soil conditions:  native soil (no wastewater introduction), present climate and water tables (at current regulation levels and 20°C soil temperatures), climate change conditions (30 cm elevation in water table and 25°C  soil temperature), and a storm surge event (samples taken 48h after saturation with ocean water from the top of the columns).  Additionally, we sampled at various depths below the infiltrative surface (5 to 75 cm below) to quantify differences in microbial treatment at scales relevant to OWTS. 

Sterile soil samples were taken at each sample depth/technology/climate and stored at -80°C until analysis.  We performed DNA extraction using Mo-Bio Power Soil DNA kits, we amplified the DNA using polymerase chain reaction (PCR) using either 16S or 18S primers to amplify our selected region, and we performed gel electrophoresis to ensure proper amplification or our DNA fragment. Samples were sequenced using an Illumina MiSeq at the University of Rhode Island Genomics Sequencing Center in Kingston, RI.  To date, we have processed our sequencing data using the Qiime2 platform and are currently preparing the results for publication. 

University of Tennessee Institute of Agriculture

Non-Steady State Operation of Subsurface Drip Dispersal Systems

The combination of using subsurface drip dispersal with the natural movement of water within the soil is a means of achieving uniform application and enhancing final treatment of wastewater.  Pressure-compensated (PC) emitters are the foundation of drip irrigation because of their ability to provide a constant water emission over a range of pressures.  Depending on the brand and model, emission rates range from under one-half gallon per hour to just over one gallon per hour per emitter.  When placed in the soil and operated in a dose/rest sequence, the application rate provided by a drip irrigation system is sufficiently low enough that the soil matrix potential can pull water away from the emitter and the soil surrounding the emitter becomes non-saturated before the next dose.   The design basis for a drip irrigation system used to disperse effluent is to determine a hydraulic loading rate that will minimize soil saturation and prevent effluent breakout on the soil surface.   Part of the design process is to select a combination of instantaneous loading (the emitter emission rate under steady state conditions) and resting time needed to redistribute the soil moisture.  An element that is frequently neglected in the design process is the water movement within the drip tubing during non-steady state conditions.   The hydraulic isolation of individual laterals prevents water from a higher lateral from moving down to a lower lateral when the pump is switched off.  However, there is still water movement within the individual laterals.  It is difficult, if not impossible, to place a drip lateral perfectly on contour – so there is a tendency for water remaining in the tubing to flow to the lowest point along the lateral.  The PC emitters are not rated for pressures less than 7 to 10 pounds per square inch (psi) and thus the flow rate from these emitters during drain-down conditions is unknown.  This project set out to determine how the emitters respond under low-pressure conditions and to estimate how this non-steady state water flow affects application uniformity.  Two types of drip lines were evaluated, a 0.6 gallon per hour PC emitter from Netafim (08WRAM.6-24V500) and a 1.02 gallon per hour PC emitter from Wasteflow PC by Geoflow (WFPC16-4-24).  These lines were suspended above ground so the water could be captured from the emitters and so that the lines could be placed on different slopes.  This research will open a dialog as to whether the differences that are found are significant to the design and operation of effluent dispersal using drip irrigation.

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.

Lab scale unsaturated sand/gravel columns were intermittently dosed, treating the high-strength wastewater in a single pass. Turkey processing wastewater served as the control, and 3 g/L, 6 g/L, 13 g/L and 35 g/L of salt were added to wastewater for treatments in duplicate laboratory columns. COD (94%) and ammonia (95%) removal was achieved and maintained over a 1 year period with sand/gravel bioreactors treating salt levels up to 13 g/L.  Clogging occurred in the 13 g/L and 35 g/l when bioreactors were loaded at 4 cm per day.

Another lab scale experiment is underway treating high salt septic tank effluent with sand bioreactors.  The experiment is examining the treatment of high and low ammonia wastewater to evaluate the use of seawater to flush toilets with and without urine diversion.  Early in the experiment TOC (96%) and ammonia (99%) removal was achieved with no system clogging at loading rates on 4 cm/day.

Michigan State University (MSU) findings – Land treatment of food processing wastewater can irrigate a crop, provide nutrients, recharge aquifers, reduce energy use, reduce greenhouse gas emissions, and save resources.  However, when excessive carbon is land applied, the soil becomes anaerobic and several metals become mobile when reduced.  Although aerobic conditions prevent metal mobilization, denitrification is inhibited under this condition.  Critical for land application is pretreatment and strategic organic and hydraulic loadings to maximize efficient waste management and minimize environmental impacts.  A long-term field study continues and includes direct soil oxygen and moisture monitoring using remote sensors to ensure aerobic conditions.  Finite element modeling using Hydrus Wetland Module is being conducted and is demonstrating the potential to simulate land application of wastewater under numerous scenarios.   Calibration and verification studies are ongoing.  The outcome is a change in action and condition in that careful operations and design allow food processors to continue using land application.  Additionally, onsite application of wastewater, as compared to treatment in a traditional activated sludge processes, reduces greenhouse gas emissions.  Reductions are achieved by not using energy for wastewater aeration, carbon dioxide uptake by the plants grown when using the wastewater, and reduced production of industrial nutrients for the crops.

Cornell University - Changes in agricultural land use, withdrawal and recharge to groundwater in watersheds affected by water and sewer line extensions.  Sewer and water extensions have impacts on ground and surface water recharge, with implications for water use with changing climate. Withdrawal and discharge of water within one basin helps maintain recharge to groundwater for subsequent in-basin uses. Extensions of water and sewer lines may have impacts on NYS Ag land use. We are studying agricultural land use trends with sewer/water extensions to gain a better estimate withdrawal/recharge rates in impacted basins.  During the report period we obtained water and wastewater data from the Genesee County Planning Department, including water and sewer plant locations, mapped water and sewer lines, and data layers such as aquifer and watershed boundaries. We have developed a procedure that will drive queries of the GIS project being developed with the County water and wastewater data and the lateral extensions mapping.  Going forward, we will obtain water and wastewater use data from selected plants in the County to use in calculations of withdrawal and discharge. We will develop and assess the results of queries of the GIS project on this limited number of service areas.

We will also begin plans to expand the project to one other county in NY state  and to another state involved in the Multistate project.

University of South Florida (USF) findings - The goal of this research is to improve N removal performance and decrease reactor size requirements in OWTS using Hybrid Adsorption Biological Treatment Systems (HABiTS). Bench, pilot scale and modeling studies of a two stage HABiTS process were conducted at the University of South Florida as part of the EPA Center for Reinventing Aging Infrastructure for Nutrient Management.  Ion exchange materials, such as natural zeolites (e.g. chabazite and clinoptilolite), have the ability to adsorb NH₄⁺.  In this study, zeolite and scrap tires had a high ion exchange capacity for NO₃^- and provided consistent low effluent N concentration despite highly variable loading rates and long idle periods.  Recirculation was shown to improve Stage 1 ammonia removal and sulfur pellets were a good electron donor in Stage 2 denitrification. 

Project Objective 4 – OWTS Training and Outreach Education

University of Kentucky – The Cooperative Extension Service (CES) partnered with the Red River Watershed and Red Bird Watershed coordinators and the US Forest Service to deliver two educational programs to 63 Appalachia homeowners about proper septic system operation, maintenance and troubleshooting.  The CES also delivered a similar program to 22 homeowners in Campbell County, Kentucky, which includes several Cincinnati bedroom communities with decentralized wastewater treatment systems.  The University of Kentucky also trained 7 regional regulatory personnel in a week long introductory soils and septic system training course. 

University of Minnesota – UMN trained over 2,000 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 the 2017 annual Minnesota Onsite Wastewater Association conference.  In addition, staff assisted in organizing and delivering the National Onsite Wastewater Recycling Association annual conference in 2017. 

The H2OandM.com (developed through past NIFA grant) was used to develop customized septic system owner’s guides to deal with the complexity of the 52 MnDOT systems and sites.

Through work with MnDOT, researchers identified the rest areas best suited to educate the public about proper septic operation and maintenance. The OSTP team developed an education and outreach signage plan that discourages non-organic waste disposal into MNDot septic systems and educates the public about proper septic system treatment and use.

Through a grant from the Minnesota Department of Health, the UMN is developing and presenting education materials to increase the knowledge regarding chemical of emerging concern (CEC) for those served and managing septic systems.   A vast majority of these homes on a septic system use a private well for their drinking water.  There is the potential for CEC from septic systems to be affecting drinking water wells. This project focuses on educating septic system owners, septic system professionals and those managing wells with a source water protection plan.  During the reporting period, a factsheet was developed and 8 classes offered for homeowners (235 in attendance) and 6 for septic system professionals (420 in attendance).

University of Tennessee Institute of Agriculture - J. Buchanan was involved with 12 educational sessions during 2018 and spoke to 1,118 people about septic system installation, operation, and maintenance.   The scope of these events ranged from meeting with individuals seeking knowledge about their systems, community-level discussions about high septic system failure rates, state-level meetings with regulators, engineers and soil scientists, to presentations at national meetings.

Ohio State University – Three onsite wastewater workshops were presented reaching 68 watewater professionals and one workshop was conducted reaching 15 property owners.    

Michigan State University – The Michigan State University Extension Comprehensive Onsite Wastewater Management Education Program is a facilitated online program for designers and installers and approximately 13 professionals participated during this reporting period. Completion of the classes results in 1.6 continuing education credits and/or 16 septage waste education credits.  A homeowner OWTS program continues to be offered. A folder for homeowners defines onsite wastewater and provides important operational and maintenance procedures. Included in the homeowner folder is a grid to plot the location of structures, drives, and the onsite wastewater system and a maintenance log. In addition, a free webinar was offered for landowner, businesses, homeowners, and riparian owners to help educate them about how onsite wastewater systems work, the maintenance it requires, and how to keep the system operating at peak efficiency avoiding overloads, failure, and costly replacements.

University of Rhode Island – The URI project team delivered 14 talks (2 of which were invited) and 7 posters to academic and professional audiences relative to OWTS and climate change at conferences in RI, CT, MA, CA, AZ, FL; reaching scientists, wastewater practitioners, board of health officials, regulatory decision makers and coastal resource managers.  In addition, we published 3 peer-reviewed papers, and one MS thesis, delivered a total of 31 workshops/ classes in 3 states in the region, reaching a total of nearly 750 practitioners, decision makers and students. These classes provided continuing education credits needed by over 540 licensed professionals to renew their professional licenses.  Three of the classes had qualifying exams.  We provided direct OWTS technical assistance to: Suffolk County Health Dept., NY and RI Department of Environmental Management.

University of South Florida -  USF staff conducted tours of their pilot OWTS for wastewater consultants, regulators, municipal utility staff, faculty and students, and FOWA members.  USF staff participated in 14 presentations, 4 posters, and a panel discussion at the WEF Nutrient Symposium in Ft. Lauderdale

Amador, J.A., J.H. Gorres, B.V. Lancellotti, and G. W. Loomis. 2018. Nitrogen loading from onsite wastewater treatment systems in the Greater Narragansett Bay (Rhode Island, USA) Watershed:  Magnitude and reduction strategies. Water, Air and Soil Pollution 229:65.

Conroy, K., L. Wang, O. Tuovinen, Z.T. Yu and K. Mancl. 2018. Microbial Communities in Sand Bioreactors Treating High Salt Content Food Industry Wastewater. WEFTEC 2018. 8 pages.

Conroy, K., F. Chen and K. Mancl. 2018. Sand Bioreactors for treatment of high salt content wastewater. Annual International Meeting ASABE. Publication Number 1800047.

Dong, Y., Safferman, S., Miller, S., Hruby, J., Bratt, D. 2017. Effectiveness of Food Processing Wastewater Irrigation. WEFTEC 2017, Chicago, IL, pp 3859-3866.

Dong, Y., and Safferman, S. 2018. Finite Element Modeling of Domestic and Food Processing Wastewater Land Application Treatment Systems. Annual International ASABE Meeting, Detroit, MI, July 31, 2018.

Dong, Y., Safferman, and S., Nejadhashemi, A.P. 2018. Computational Modeling of Wastewater Land Application Treatment Systems to Determine Strategies to Improve Carbon and Nitrogen removal. Journal of Environmental Science and Health, Part A, Submitted on August 19, 2018.

Griffin, J. and K. Mancl. 2017. Onsite reuse of reclaimed wastewater in winter to determine potential for pollutant runoff. Ohio Journal of Science. 117(2):74-84.

Heger, Sara and C. Gilbertson.  2018. Protecting our Water Takes Good Drinking Water and Septic Systems.  WRC Factsheet, St. Paul, MN Access online at:   https://septic.umn.edu/sites/septic.umn.edu/files/septic_and_wells_cec_final.pdf

Mancl, K., R. Kopp and O. Tuovinen. 2018. Treatment of meat-processing wastewater with a full-scale, low-cost sand/gravel bioreactor system. Applied Engineering in Agriculture. 34(2):403-409. Doi.org/10.13031/aea.12683.

Nelson, T. and S. Heger. 2017.  Water Use at Minnesota Rest Areas.  UMN Center for Transportation Studies:  CTS 17-01.

Ross, B. N., G. W. Loomis, K. P. Hoyt, and J. A. Amador. 2018. User-based photometer analysis of effluent from advanced nitrogen-removal onsite wastewater treatment systems. Water, Air Soil Pollution 229:389.

Rowan, M., K. Mancl, C. Bucy. 2018. On-site Sprinkler Irrigation of Treated Wastewater in Ohio. Extension Bulletin 912. The Ohio State University.

Safferman, S., Smith, J., Dong, Y., Saffron, C., Wallace, J., Binkley, D., Thomas, M., Miller, S., Bissel, E., Booth, J., Lenz, J. 2017, Resources from Wastes: Benefits and Complexity. Journal of Environmental Engineering.

Wigginton, S., E. Brannon, P. J. Kearns, B. Lancellotti, A. Cox, G.W. Loomis, and J.A. Amador. 2018. Nitrifying and denitrifying bacterial communities in advanced N-removal onsite wastewater treatment systems. Journal of Environmental Quality  47:1163-1171.

Zamalloa, C. and Heger. S. 2017. Biodegradability analysis of toilet paper under anaerobic conditions. National Onsite Wastewater Recycling Association Annual Conference Proceedings, Dover, Delaware.