Source: AGRICULTURAL RESEARCH SERVICE - US ARID-LAND RESEARCH CENTER submitted to
GROUNDWATER RECHARGE AND WASTEWATER IRRIGATION TO PROTECT CROPS AND GROUNDWATER
Sponsoring Institution
Agricultural Research Service/USDA
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0408631
Grant No.
(N/A)
Project No.
5347-13320-001-00D
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Jun 19, 2004
Project End Date
Jan 28, 2007
Grant Year
(N/A)
Project Director
WILLIAMS C F
Recipient Organization
AGRICULTURAL RESEARCH SERVICE - US ARID-LAND RESEARCH CENTER
21881 NORTH CARDON LANE
MARICOPA,AZ 85238
Performing Department
(N/A)
Non Technical Summary
(N/A)
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
0%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
4030210110040%
4030210202060%
Goals / Objectives
(1) To develop design and management practices for safe and sustainable groundwater recharge, including the recharge of treated sewage effluent; (2) to assess the microbiological safety of water reuse practices to include the evaluation of agricultural and turf irrigation with sewage effluent on soil and underlying groundwater, and (3) to develop practical and economical methods to handle and treat sewage effluent that will prevent transmission of pathogens to food, soil and water, and hence, reduce the risks to human health and the environment.
Project Methods
Large soil columns in the greenhouse will be irrigated with secondary sewage effluent to see how vegetation and irrigation efficiency affect the transport of pathogens, pharmaceuticals, and hormones through the columns as indications of potential contamination of underlying groundwater. Other columns will simulate artificial recharge of groundwater with sewage effluent and Colorado River water to determine the underground fate and potential contamination of groundwater with pathogens and organic compounds. In addition, samples of shallow groundwater from below fields with a long history of sewage irrigation and analyzed for pathogens and organics to evaluate long-term effects of sewage irrigation on groundwater. Combined projects 5344-13000-012-00D and 5344-32000-002-00D (6/04). Renumbered from 5344-13000-015-00D 06/24/2004. Formerly 5344-13320-001-00D (2/06).

Progress 06/19/04 to 01/28/07

Outputs
Progress Report Objectives (from AD-416) (1) To develop design and management practices for safe and sustainable groundwater recharge, including the recharge of treated sewage effluent; (2) to assess the microbiological safety of water reuse practices to include the evaluation of agricultural and turf irrigation with sewage effluent on soil and underlying groundwater, and (3) to develop practical and economical methods to handle and treat sewage effluent that will prevent transmission of pathogens to food, soil and water, and hence, reduce the risks to human health and the environment. Approach (from AD-416) Large soil columns in the greenhouse will be irrigated with secondary sewage effluent to see how vegetation and irrigation efficiency affect the transport of pathogens, pharmaceuticals, and hormones through the columns as indications of potential contamination of underlying groundwater. Other columns will simulate artificial recharge of groundwater with sewage effluent and Colorado River water to determine the underground fate and potential contamination of groundwater with pathogens and organic compounds. In addition, samples of shallow groundwater from below fields with a long history of sewage irrigation and analyzed for pathogens and organics to evaluate long-term effects of sewage irrigation on groundwater. Combined projects 5344-13000-012-00D and 5344-32000-002-00D (6/04). Renumbered from 5344-13000-015-00D 06/24/2004. Formerly 5344-13320-001-00D (2/06). Significant Activities that Support Special Target Populations This CRIS project terminated January 28, 2007. Research progress that occurred from Oct. 1, 2006 to Jan. 28, 2007 (previous CRIS period) is reported in CRIS project 5347-13000-002-00D annual report (covering Oct. 2006 - Sept. 2007).

Impacts
(N/A)

Publications


    Progress 10/01/05 to 09/30/06

    Outputs
    Progress Report 1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? Why does it matter? Water demands in the western US currently exceed available supplies. Population growth and water shortages will increase the need to use treated wastewater effluent for irrigation, particularly in areas where fresh water resources are limited. The use of recycled water for municipal and crop irrigation will reduce groundwater pumping, which currently provides 37% of water for agricultural irrigation and is the largest user of groundwater nationwide. However, there are serious concerns about the long-term fate and transmission of toxic chemicals and pathogens from recycled municipal wastewater to irrigated land and crops and thus to human food and to groundwater. Using present technologies, municipal wastewater treatment may not completely disinfect recycled irrigation waters, allowing pathogenic microbial populations to re-grow in water storage and transmission systems. As a result, recycled water used for agricultural and municipal irrigation can contain enough pathogenic organisms to threaten human health once released into the environment. Moreover, the long-term environmental fate of synthetic organic compounds, including pharmaceutically active chemicals and disinfection byproducts, contained in recycled wastewater is largely unknown. Overall, the environmental and public health impacts of irrigation with reclaimed sewage effluent and the potential degradation of underlying groundwater are largely unknown. The aim of this research project is to develop novel methods to improve the chemical and microbiological safety of wastewater used for municipal and agricultural irrigation and directly supports National Program 201, Water Quality and Management. In addition, this work will aid in the development of wastewater irrigation management strategies aimed at protecting environmental and public health and at protecting our future groundwater resources. This project will utilize state-of-the-art soil chemical analyses, microbial cultivation, and molecular biology techniques to evaluate the transport of pathogens and pharmaceutically active chemicals in water distribution systems and in soils with a history of wastewater application. Studies will also examine factors affecting pathogen survival, chemical biotransformation, and transport. Novel methods of pathogen control in wastewater distribution systems will be examined using laboratory bioreactors, and methods for simplified detection of pathogens in surface soils will be developed. Taken together, this work will contribute to the development of management strategies to minimize the introduction of pathogens and emerging contaminant chemicals into the environment, thus reducing the risk to human health. The current project is the result of merging CRIS 5344-32000-002-00D and CRIS 5344-13000-012-00D in FY 2004. The combined CRIS has a two year duration and had redefined objectives as follows: Specific objectives for the project duration are: Objective 1: Develop methods for improved environmental detection of contaminants and pathogens using field studies in areas with a history of wastewater application. Objective 2: Determine the environmental fate and transport of contaminants and pathogens in following application using field lysimeter studies, and using focused studies in agricultural fields, municipal irrigated areas (golf courses, parks), and/or groundwater recharge areas with a long history of municipal wastewater application. Objective 3: Develop management strategies to minimize impacts of using treated effluent for irrigation, using laboratory reactor studies to develop novel methods to control bacterial growth and chemical transport in conveyance systems. All objectives fall under National Program 201, Water Quality and Management. Objectives 1 and 2 fall under Problem Area 2.5 (Waste Water Reuse), Goal 2.5.3 (Waste Water Standards). They address water conservation and integrated water management through water reuse. Objective 3 addresses Problem Area 2.3 (Water Conservation Management), Goal 2.3.1 (Water Conservation Technologies). It also addresses water conservation and integrated water management through water reuse. These issues occur or emerge in many parts of the U.S. and the rest of the world wherever there is not enough water to meet all demands for municipal, industrial, and agricultural (irrigation) purposes. 2. List by year the currently approved milestones (indicators of research progress) This project is in the second year following the combining of two independent projects (0404754 and 0405645). A final report was written previously for each project in FY 2004. The current project will expire in FY 2006 and will only span two years. Year 1 (FY 2005): Environmental Detection of Pathogens and Emerging Contaminants: 1) Verify procedures for determining microbial regrowth in the environment. 2) Develop procedures and analytical methods for quantifying organic contaminants found in treated effluent from environmental samples. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Establish long term lysimeters under effluent irrigation to determine the fate and transport of contaminants found in sewage effluent. 2) Establish methods to link hydraulic properties and nutrient status to the persistence of emerging contaminants and pathogens in passive effluent treatment systems. 3) Find new methods for directed sampling of effluent irrigated turf grass. 4) Determine fundamental fate and transport parameters for emerging contaminants for input into predictive models. Management Strategies to Minimize Untoward Impacts of Treated Effluent used for Irrigation: None planed for year 1 Year 2 (FY 2006): Environmental Detection of Pathogens and Emerging Contaminants: 1) Regular periodic sampling of model effluent systems. 2) Initiate source tracking of indicator organisms in open systems. 3) Continued long term monitoring of chemical and biological constituents capable of transport through the field lysimeters. 4) Continue monitoring of emerging contaminants in passive effluent treatment systems. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Determine if links between soil salinity and the presence of indicator organisms and other contaminants of interest exist. 2) Verify the experimentally determined fate and transport parameters with small scale leaching studies. Management Strategies to Minimize Untoward Impacts of Treated Effluent used for Irrigation: 1) Design and build a lab scale effluent treatment reactor. 4a List the single most significant research accomplishment during FY 2006. Determining detection accuracy of pathogen indicators: Supports National Program 201, Water Resources Management, Problem Area 2.3, Improved Irrigation and Cropping for Reuse of Degraded Waters Confirmatory testing at the U.S. Arid-Land Agricultural Research Center showed that a commonly used, commercially-available testing kit misidentified E. coli 25-40% of the time. This is of concern, given that the results of these same tests are often used in decision-making regarding public safety, for example, whether beaches should be closed due to high E. coli levels in recreation waters. Through support from the U.S. Bureau of Reclamation, scientists at the U.S. Arid-Land Agricultural Research Center collected microbial samples from a passive wetland treatment system that receives municipal wastewater from the City of Phoenix. These microbial samples were cultured in the laboratory to quantify the accuracy of analytical tests in identifying E. coli bacteria, and to determine whether the E. coli collected were pathogenic (i.e., harmful to humans). This work illustrates the critical need to ensure that tests used to detect pathogens in the environment be accurate to prevent misconceptions regarding the safety of using wastewater for irrigation. 4d Progress report. Treatment wetland monitoring for pathogens: Monthly sampling to evaluate microbial re-growth in treated wastewater effluent as it passed through a constructed wetland continued through February 2006 in support of National Program 201, Water Quality and Management problem area 2.5 (waste water reuse), goal 2.5.3 (waste water standards). The potential for human pathogens to survive wastewater treatment and to regrow in the environment is a concern to public health. Sampling was performed at the Tres Rios Constructed Wetland in Phoenix, Arizona, and analysis of collected samples was performed at the Microbial Ecology, Soil Chemistry and Water Quality Laboratories at the USDA-ARS, US Arid Land Agricultural Research Center. At present, little is known about the environmental processes controlling microbial growth and transport in open waters. Detailed, regular sampling of treated effluent waters and collection of related environmental data (e.g., water temperature, chemistry, pH) will contribute to the development of models that project areas of maximum pathogen re-growth. Ultimately, these models will be utilized to develop focused means of controlling pathogen growth and transport in open water systems. Treatment wetland monitoring for emerging contaminants: Monthly sampling to evaluate emerging contaminants and microbial re- growth in treated wastewater effluent as it passed through a passive treatment constructed wetland continued through February 2006 in support of National Program 201, Water Quality and Management problem area 2.5 (waste water reuse), goal 2.5.3 (waste water standards). Sampling was performed at the Tres Rios Constructed Wetland in Phoenix, Arizona, and analysis of collected samples was performed at the Water Quality and Soil Chemistry Laboratories at the USDA-ARS, US Arid Land Agricultural Research Center. The fate, transport and persistence of emerging contaminants found in treated wastewater are a growing concern. Distribution of emerging contaminants throughout the wetland has been monitored over time. The changes throughout the season have been observed and environmental factors linked to the persistence of emerging contaminants within the wetland. This data will be used to determine seasonal changes that may contribute to potential increases in emerging contaminants found in irrigation water and possible methods of remediation. Long term chemical and biological monitoring: A long-term research study to assess the biological and chemical changes that may occur in soils irrigated with wastewater is ongoing in support of National Program 201, Water Quality and Management problem area 2.5 (waste water reuse), goal 2.5.3 (waste water standards). The long term environmental fate of chemical and biological contaminants found in treated effluent used in irrigation is of concern. Previously installed lysimeters continue to be monitored. Results to date indicate that irrigation is an effective method for reducing potential environmental contamination from treated wastewater when compared to direct disposal in surface waters. Six additional monitoring lysimeters have been installed and instrumented to collect soil moisture, temperature, and salinity data continuously. Data gathered from the lysimeters will help elucidate the long-term environmental fate and transport of pathogens and synthetic organic compounds, including pharmaceutically active chemicals and disinfection byproducts contained in recycled wastewater. Thus, the data gathered from the field lysimeter studies will contribute to the development of best management practices in reusing sewage effluent. 5. Describe the major accomplishments to date and their predicted or actual impact. The project Groundwater Recharge and Wastewater Irrigation to Protect Crops and Groundwater addresses needs in National Program 201, Water Quality and Management problem area 2.5 (waste water reuse), goal 2.5.3 (waste water standards). The fate and persistence of pathogens and emerging organic contaminants found in treated sewage effluent needs to be understood so that water supplies in the arid Southwestern United States can be supplemented. Two important uses of large quantities of water in arid regions are maintaining stream flow and irrigation. Treated effluent is ideal for both of these purposes as long as the constituents found in the effluent will cause no harm to downstream users. Understanding the basic fate and transport of pathogens and emerging contaminants that this research focuses on is essential in ensuring that treated effluent is used in a safe and sustainable manner. One major accomplishment of the project was to determine that soil organic matter is capable of adsorbing pharmaceutically active compounds. The sorption indicated that soil from the root zone of turfgrass will significantly retard the leaching of these pharmaceuticals. Monitoring of field lysimeters has also shown that the same pharmaceutically active compounds have not leached through a 1 m soil profile in 2 years of monitoring. Little is known about the long-term environmental fate of synthetic organic compounds, including pharmaceutically active chemicals and disinfection byproducts contained in recycled wastewater, and this research has increased our ability to predict the fate and transport of contaminants found in treated effluent. Thus, the data gathered from these studies will contribute to the development of best management practices in reusing sewage effluent. Our laboratory has shown that a commonly used, commercially-available testing kit misidentified E. coli 25-40% of the time. Previous microbiological work has shown the survival and regrowth potential of bacteria present in tertiary-treated effluent as it passed through a model distribution system. Present microbiological work has brought into question these results. This research has shown that the results of common testing for pathogen indicators my result in erroneous conclusions and that more definitive tests are needed. This work illustrates the critical need to ensure that tests used to detect pathogens in the environment be accurate to prevent misconceptions regarding the safety of using wastewater for irrigation. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Williams, CF. Increased Water Supplies Through Water Reuse. 2006. Science in Action. American Society of Agronomy, Madison, WI, September, 2006.

    Impacts
    (N/A)

    Publications

    • Williams, C.F., Williams, C.F., Adamsen, F.J. 2006. Sorption/desorption of carbamazepine from irrigated soils. Journal of Environmental Quality. 35(5) :1779-1783.


    Progress 10/01/04 to 09/30/05

    Outputs
    1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Water demands in the western US currently exceed available supplies. Population growth and water shortages will increase the need to use treated wastewater effluent for irrigation, particularly in areas where fresh water resources are limited. The use of recycled water for municipal and crop irrigation will reduce groundwater pumping, which currently provides 37% of water for agricultural use and is the largest user of groundwater nationwide. In addition, large quantities of water in arid regions are used for maintaining critical stream flows. Treated effluent is ideal for both of these purposes as long as the constituents found in the effluent will cause no harm to downstream users. This research, focused on understanding the basic fate and transport of pathogens and emerging contaminants, is essential to ensure that treated effluent is used in a safe and sustainable manner. Using present technologies, municipal wastewater treatment may not completely disinfect recycled irrigation waters, allowing pathogenic microbial populations to re-grow in water storage and transmission systems. As a result, recycled water used for agricultural and municipal irrigation can contain enough pathogenic organisms to threaten human health once released into the environment. Moreover, little is known about the long-term environmental fate of synthetic organic compounds, including pharmaceutically active chemicals and disinfection byproducts, contained in recycled wastewater. Overall, the environmental and public health impacts of irrigation with reclaimed sewage effluent and the potential degradation of underlying groundwater are largely unknown. The aim of this research project is to develop novel methods to improve the chemical and microbiological safety of wastewater used for municipal and agricultural irrigation. This project will utilize state-of-the-art soil chemical analyses, microbial cultivation, and molecular biology techniques to evaluate the transport of pathogens and pharmaceutically active chemicals in water distribution systems and in soils with a history of wastewater application. Studies will examine factors affecting pathogen survival, chemical biotransformation, and microbial and chemical transport in soils, and methods of pathogen control in wastewater distribution systems will be tested using laboratory bioreactors and field studies. Taken together, this work will contribute to the development of wastewater irrigation management strategies to minimize the introduction of pathogens and emerging contaminant chemicals into the environment, thus reducing the risk to human health and to groundwater. The current project is the result of merging CRIS 5344-32000-002-00D and CRIS 5344-13000-012-00D in FY 2004. The combined CRIS has a two year duration and has redefined objectives as follows: Objective 1: Develop methods for improved environmental detection of contaminants and pathogens using field studies in areas with a history of wastewater application. Objective 2: Determine the environmental fate and transport of contaminants and pathogens using focused studies in agricultural fields, municipal irrigated areas (golf courses, parks), and/or groundwater recharge areas with a long history of municipal wastewater application. Objective 3: Examine novel methods to control bacterial growth and chemical transport in conveyance systems using laboratory reactor studies, to aid in development of management strategies to minimize environmental impacts of using treated effluent for irrigation. This research directly addresses the national and global problem of food safety in agricultural areas that have been irrigated with sewage effluent or with effluent contaminated water. The research also addresses issues of water conservation and integrated water management through water reuse. These issues now occur or are emerging in many parts of the US and the rest of the world wherever there is insufficient water to meet competing demands for municipal, industrial, and agricultural irrigation. All objectives fall under National Program 201, Water Quality and Management. By addressing water conservation and integrated water management through water reuse, Objectives 1 and 2 fall under Problem Area 2.5 (Waste Water Reuse), Goal 2.5.3 (Waste Water Standards). Objective 3 addresses Problem Area 2.3 (Water Conservation Management), Goal 2.3.1 (Water Conservation Technologies). 2. List the milestones (indicators of progress) from your Project Plan. This is a new project resulting from the combining of two previously independent projects (0404754 and 0405645). A final report for each of the independent projects was written in FY 2004. The combined project will expire in FY 2006 and will span only two years; therefore, the current report will begin with year one (FY 2005) and will document milestones for FY 2005 and projected milestones for the final year of the project (FY 2006). Project Plan Milestones, Year 1 (FY 2005): Environmental Detection of Pathogens and Emerging Contaminants: 1) Verify laboratory and field procedures for determining microbial re- growth in environmental samples. 2) Develop procedures and analytical methods for quantifying organic contaminants in treated effluent from environmental samples. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Establish long-term lysimeter studies under effluent irrigation to determine the fate and transport of contaminants and pathogens found in sewage effluent. 2) Establish methods to link hydraulic properties and nutrient status to the persistence of emerging contaminants and re-growth of pathogens in passive effluent treatment systems. 3) Develop new methods for directed sampling of effluent irrigated turf grass. 4) Determine fundamental fate and transport parameters for emerging contaminants for predictive model input. Management Strategies to Minimize Adverse Impacts of Using Treated Effluent for Irrigation: None planned for year 1 Project Plan Milestones, Year 2 (FY 2006): Environmental Detection of Pathogens and Emerging Contaminants: 1) Regular periodic sampling of model effluent systems. 2) Initiate source tracking of indicator organisms in open systems. 3) Continue long term monitoring of chemical and biological constituents capable of transport through the field lysimeters. 4) Continue monitoring of emerging contaminants in passive effluent treatment systems. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Determine the existence of links between soil salinity and the presence of indicator organisms and other contaminants of interest. 2) Verify experimentally determined fate and transport parameters with small scale leaching studies. Management Strategies to Minimize Adverse Impacts of Using Treated Effluent for Irrigation: 1) Design and build a lab (benchtop-scale) effluent treatment reactor. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Verify field collection procedures and laboratory methods for determining microbial re-growth in the environment. Milestone Fully Met 2. Develop procedures and analytical methods for quantifying organic contaminants found in treated effluent from environmental samples. Milestone Fully Met 3. Establish long-term lysimeters under effluent irrigation to determine the fate and transport of emerging contaminants and pathogens found in sewage effluent. Milestone Fully Met 4. Establish methods to link hydraulic properties and nutrient status to the persistence of emerging contaminants and pathogens in passive effluent treatment systems. Milestone Fully Met 5. Find new methods for directed sampling of effluent irrigated turf grass. Milestone Substantially Met 6. Determine fundamental fate and transport parameters for emerging contaminants for input into predictive models. Milestone Substantially Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Expected Milestones, FY 2006: Environmental Detection of Pathogens and Emerging Contaminants: 1) Regular periodic sampling of model effluent systems. 2) Initiate source tracking of indicator organisms in open systems. 3) Continued long-term monitoring of chemical and biological constituents capable of transport through the field lysimeters. 4) Continued monitoring of emerging contaminants in passive effluent treatment systems. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Determine the existence of links between soil salinity and the presence of indicator organisms and other contaminants of interest. 2) Verify the experimentally determined fate and transport parameters with small scale leaching studies. Management Strategies to Minimize Adverse Impacts of Using Treated Effluent for Irrigation: 1) Design and build a lab scale effluent treatment reactor. Expected Milestones, FY 2007: Environmental Detection of Pathogens and Emerging Contaminants: 1) Develop and use source tracking methods to establish origin of indicator organisms found in open, passive effluent treatment systems. 2) Continued long term monitoring of chemical and biological constituents capable of transport through the field lysimeters. 3) Identify additional sites in different climates where lysimeters can be installed under effluent irrigation for long-term monitoring under various climatic conditions. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Expand sampling locations to verify links between soil salinity mapping and pathogen and contaminant accumulation. 2) Develop methods to use salinity mapping for directed sampling for environmental fate and transport of pathogens and other contaminants. 3) Expand fate and transport studies to include greater numbers of emerging contaminants to increase data input into predictive models. 4) Develop and maintain a database of fate and transport parameters needed for predictive fate and transport models for emerging contaminants. Management Strategies to Minimize Adverse Impacts of Using Treated Effluent for Irrigation: 1) Operate and validate lab scale system for microbial and chemical disinfection. Expected Milestones, FY 2008: Environmental Detection of Pathogens and Emerging Contaminants: 1) Validate methods that use salinity mapping for directed sampling for environmental fate and transport of pathogens and other contaminants. 2) Continue to maintain and expand a database of fate and transport parameters needed for predictive fate and transport models for emerging contaminants. 3) Continued long term monitoring of chemical and biological constituents capable of transport through the field lysimeters. Environmental Fate and Transport of Pathogens and Emerging Contaminants: 1) Begin new long-term column studies to assess the leaching potential of pathogens and emerging contaminants through soil. 2) Determine links between root zone nutrient status and persistence of contaminants found in effluent used for irrigation. Management Strategies to Minimize Adverse Impacts of Using Treated Effluent for Irrigation: 1) Expand lab scale system for microbial disinfection to field applications. 2) Develop adaptive management tools for the safe use of effluent in irrigation. 4a What was the single most significant accomplishment this past year? Developed and validated a three-dimensional sampling array for surface waters that significantly increases sampling efficiency by increasing the number of environmental samples that can be obtained and decreasing time required for sample collection. Detailed environmental monitoring is fundamental to environmental protection, but typically the expense and time required for sample collection limits the number of sampling locations and sampling events. The three-dimensional array provides an inexpensive means by which limited manpower is needed to sample multiple locations within surface water bodies. By decreasing time required for sample collection and transport to the laboratory, this sampling array effectively reduces the uncertainty associated with environmental monitoring and increases the confidence in management methods developed using this technology. 4d Progress report. A study was initiated to evaluate pathogen re-growth in treated wastewater effluent. Collected pathogens are being cultured in the laboratory to utilize in source tracking studies to quantify pathogen sources (human vs. other mammal vs. avian). At present, little is known about the environmental processes controlling pathogen growth and transport in open waters, and how effluent (human-derived) pathogens vs. natural (avian-derived) pathogens contribute to the total pathogen load of these systems. Detailed, regular sampling of treated effluent waters and collection of related environmental data will contribute to the development of models that project areas of maximum pathogen re-growth. Ultimately, these models will be utilized to develop focused means of controlling pathogen growth and transport in open water systems. Studies to determine the fate of organic contaminants found in treated sewage effluent used for irrigation continued. Soil sorption studies were conducted using two compounds typically found in treated sewage effluent. It was found that soils treated with biosolids increased sorption, and therefore retention, of these compounds in the soil. This data will contribute to a comprehensive database of environmental fate parameters for emerging contaminants. This database will eventually be available for inputs into predictive fate and transport models. A number of pieces of laboratory equipment have been acquired, and existing equipment has been refurbished, to provide the necessary analytical capabilities to investigate most of the emerging contaminants found in treated effluent. In addition, a laboratory has been established to process and store samples for microbiological analysis, culture pathogens of interest, and utilize molecular analyses to validate microbiological results. These expanded analytical capabilities will aid in the development of databases detailing environmental controls on the fate and transport of emerging contaminants and human pathogens. Resulting databases will be made available to other researchers for development, calibration and validation of predictive models used in management of agricultural and municipal systems where treated effluent is used for irrigation. Survival of Bulrush in Constructed Wetland Treatment System for Sewage Effluent as Affected by Redox, pH and Microbes Constructed wetlands are potentially an important means of treating sewage effluent before release to surface water bodies. The Tres Rios Constructed Wetlands Demonstration Project at the Phoenix, Arizona 91st Avenue Sewage Treatment Plant experienced a failure of the bulrush population. The Bureau of Reclamation funded a study to evaluate chemical and biological conditions that may have lead to the decline of the wetland plants. A series of oxidationreduction potential (ORP) and pH sensors have been maintained throughout the wetland for 18 months. Results continue to show that the ecology of the overlying water column is responsible for much of the observed seasonal patterns in pH and ORP. Diurnal patterns were present in the ORP readings only in the spring. The diurnal patterns observed in pH were predominantly in the sediment surface and to a lesser extent at depth. The ORP readings were highest in spring and lowest during summer. The seasonal patterns of both pH and ORP appear to be driven more by floating vegetation and bottom growing algae than by the emergent vegetation. The sustainability of the vegetation at the Tres Rios Wetland is a function of nutrient content and availability. Two hydraulic tracer studies conducted using the three dimensional sampling array indicate that there is bypass flow occurring within the wetland. In addition, one detailed nutrient distribution sampling event was conducted. Water samples were analyzed for essential nutrients, dissolved oxygen, pH, and total salinity as well as type and quantity of dissolved salts. Preliminary results indicate that the distribution of nutrients throughout the wetland correlate with the hydraulic characteristics. Collected samples were also analyzed for microbiological indicator organisms, and their distribution was also highly correlated with the nutrients and hydraulics of the system. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. This is a new project resulting from the combination of two previously independent projects (0404754 and 0405645). A final report for each of the independent projects was written in FY 2004. Each of the independent projects had major accomplishments that contributed to the objectives and goals of the combined project. One major accomplishment of the earlier projects was determining that soils treated with biosolids reduced the potential mobility of pharmaceutical compounds in field lysimeters. Little is known about the long-term environmental fate of synthetic organic compounds, including pharmaceutically active chemicals and disinfection byproducts contained in recycled wastewater, and the lysimeter work increased our ability to predict the fate and transport of contaminants found in treated effluent. Thus, the data gathered from the initial field lysimeter studies will contribute to the development of best management practices in reusing sewage effluent. Microbiological work in the earlier projects included a laboratory study to assess the survival and regrowth potential of bacteria present in tertiary-treated effluent as it passed through a model distribution system. The results demonstrated that population numbers of indicator bacterial organisms increased by three to four orders of magnitude over the 11-day length of the experiment. This research established that although the reclaimed water met EPA standards for irrigation at the treatment plant, there is great potential for bacterial regrowth during transport that could place the water out of compliance at the point of intended use. This work illustrated the critical need to understand the environmental fate of microorganisms and the potential for bacterial regrowth in reclaimed water used for crop irrigation so that future problems of food and groundwater contamination via wastewater irrigation can be prevented. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). C. Williams. 2005. Is irrigated agriculture sustainable? The battle to counteract salinity. Southwest Hydrology. Volume 4, July/August 2005: 22- 23. F.C. Williams and C. Williams. 2005. Conservation-minded guidelines for establishing and maintaining a beautiful and healthy lawn. Information leaflet distributed by the South Davis Sewer District, West Bountiful, UT.

    Impacts
    (N/A)

    Publications