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United States Department of Agriculture

Agricultural Research Service

Research Project: Reuse of Treated Municipal Waste Water for Irrigation as a Means to Increase Alternative Water Supplies

Location: Water Management and Conservation Research

2012 Annual Report

1a. Objectives (from AD-416):
Objective 1: Develop new and novel water quality indicators (biological and chemical) for assessment of reclaimed water quality. Objective 2: Determine the processes that govern the fate and transport of emerging contaminants, pathogens, and nutrients found in treated wastewater used for irrigation to provide a research basis for potential regulation of these constituents. Objective 3: Develop and optimize small on-site treatment systems to reduce emerging contaminants and pathogens found in domestic waste water used for irrigation.

1b. Approach (from AD-416):
Field data from sites where treated effluent has been used will be gathered and used to determine the presence and suitability of selected emerging contaminants and pathogens found in treated municipal wastewater as indicators. Qualitative and quantitative enzyme-linked immunosorbent assays (ELISA) will be developed for the identified wastewater indicators. Environmental samples will be taken and analyzed for nutrients, pathogens, and emerging contaminants. Distribution of nutrients, pathogens, and emerging contaminants will be used to determine which constituents may be accumulating in the environment for further investigations. Using a combination of lab studies fate and transport parameters will be determined for the identified constituents. Concurrently, a series of laboratory and field experiments will be conducted to determine the development of antibiotic resistance in native soil microbial populations. Finally, a small scale, low input treatment systems will be developed and validated to provide improvement in water quality and increased water supply by treating household wastewater.

3. Progress Report:
Project number 5347-13000-003-00D was initiated in February 2012 and is a continuation of project 5347-13000-002-00D which was completed in January 2012. Significant progress regarding emerging contaminants was achieved in objectives 1 and 2. However, progress regarding pathogens and indicator organisms was prevented due to a critical SY vacancy that occurred in November 2011. The vacancy was filled by another ARS SY without the microbial expertise to achieve the objectives of the project. The position was again vacated in March 2012 and has not been filled due to the agency wide hiring freeze. Primary and secondary antibodies have been acquired for a number of pharmaceuticals for the development of a new method of quantification for emerging contaminants in support of objective 1. ELISA development is proceeding and limits of detection and potential cross reactivity with interfering compounds are being determined. Accumulation of pharmaceutically active compounds found in treated effluent used for ground water recharge has been investigated in support of objective 2. There was no accumulation of ibuprofen and the antibiotic lincomycin over a three year period while, caffeine and the anti-seizure medication carbamazepine were observed to accumulate over the same three years. However, the total accumulated carbamazepine and caffeine was less than 5 parts per billion. The development of increased antibiotic resistance soil microorganisms from the same recharge facility was also investigated. The antibiotic content and resistance was measured from soil cores taken from the facility that has been used to recharge groundwater with treated municipal wastewater for 20 years. It was found that the maximum soil concentration of antibiotics was 0.035 ng/g with no accompanying increase in antibiotic resistance in the native gram positive soil microbial community. An alternative treatment system to remove pathogens and emerging contaminants is also being developed. A research is being developed with Foret Plasma Labs (a disabled veteran owned small business)to investigate a potentially new treatment system capable of providing treatment using solar energy. As part of the research, Foret Plasma Labs will provide a plasma system for evaluation. Potential removal of pathogens and emerging contaminants by the system will be evaluated based on energy used and maximum flow rates.

4. Accomplishments
1. The accumulation of pharmaceuticals from treated municipal wastewater during groundwater recharge. The accumulation of pharmaceuticals in environments receiving treated municipal wastewater is a growing concern. The accumulation of four pharmaceutically active compounds (PhAC’s) found in treated effluent was investigated at a groundwater recharge facility by researchers at the U.S. Arid Land Agricultural Research Center in Maricopa, AZ. Two PhAC’s, ibuprofen and the antibiotic lincomycin, were shown not to accumulate over a three year period while, caffeine and the anti-seizure medication carbamazepine did accumulate over the same three years. However, the total accumulated carbamazepine and caffeine was very small (1 part per billion and 4 parts per billion respectively). Distribution and accumulation of the PhAC's were found to be related to specific chemical properties of the pharmaceutical. Distribution was also related to soil chemical and physical properties such as texture and organic carbon content. Results are helping the Town of Gilbert, AZ evaluate the sustainability of the recharge facility.

2. Accumulation of the human drug Carbamazepine in soil irrigated with treated effluent. The reuse of sewage effluent for irrigation is an effective way to dispose of treated wastewater while protecting surface waters from contamination. The accumulation of the anti-epileptic drug carbamazepine was measured at a site that has been irrigated with treated waste water for over 25 years by researchers at the U.S. Arid Land Agricultural Research Center, Maricopa, AZ. Carbamazepine accumulation was greatest in the surface and in soils with the highest organic carbon content. The majority of the carbamazepine was found in the upper 30 cm of the profile suggesting that soils do adsorb carbamazepine at the field scale and may provide additional removal of carbamazepine from the wastewater as it percolates through the profile. The Pennsylvania State University is using the data to evaluate the operational parameters of the Living Filter treatment system to determine optimal operational parameters for disposing of treated sewage water while protecting the Chesapeake Bay from pollution.

3. Microbial content and activity in vegetative filter strips receiving antibiotics from soil applied animal manure. The use of vegetative filter strips has been proposed to prevent the runoff of antibiotics to surface water from manure amended fields. Vegetative filter strips are land areas of indigenous or planted vegetation that provide a buffer between agricultural land and surface water bodies and have been shown to improve water quality. However, the antibiotics in runoff water entering the filter strips may adversely affect soil microbial populations and interfere with the filter strips ability to provide long term treatment. The development of antibiotic resistance in soil microbial populations from existing vegetative filter strips was measured by scientists at the U.S. Arid Land Agricultural Research Center, Maricopa, AZ. It was shown that the presence of veterinary antibiotics did not affect soil microbial communities and that the use of vegetative filter strips may not be adversely affected by application of manures containing antibiotics to agricultural fields. These results provide further evidence that vegetative filter strips can provide sustainable improvements in surface water quality.

Review Publications
Walker, C.W., Watson, J.E., Williams, C.F. 2012. Occurrence of carbamazepine in soils under different land uses receiving wastewater. Journal of Environmental Quality. 41(4):1263-1267.

Williams, C.F., Mclain, J.E. 2012. Soil persistence and fate of carbamazepine, lincomycin, caffeine, and iburpofen from wastewater. Journal of Environmental Quality. 41(5):1473-1480.

Last Modified: 06/25/2017
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