1a. Objectives (from AD-416):
(1) Assess the environmental impacts of land-applying different rates of municipal biosolids on the production of forage and biofuel grasses and on water quality at Austin Water Utility's Hornsby Bend Municipal Biosolid Recycling Facility. (2) Identify and quantify the composition, concentration, and distribution of nutrients (carbon, nitrogen, phosphorus), micronutrients (trace metals), and endocrine disrupting compounds (EDCs) in biosolids, soils, waters, and plants. (3) Measure the potential mobility of nutrients, micronutrients, and EDCs in surface run-off and in water infiltrating through the soil profile using rainfall simulations in the field. (4) Use empirical field data to develop and test new model components for SWAT (phosphorus, EDCs) to further validate and improve model code. (5) Provide risk assessment to the City of Austin regarding the potential watershed impacts of Austin's municipal waste recycling program.
1b. Approach (from AD-416):
We will conduct a broad survey of the Hornsby Bend site to assess the presence and concentrations of nutrients, micronutrients, and EDCs in biosolids, soils, waters, and plants. Ten-meter-wide strips of switchgrass will be established within the existing forage production system (coastal bermudagrass) receiving Class B biosolid applications. Rainfall simulations will be conducted in forage production plots and in biofuel production plots to quantify the movement of nutrients, micronutrients, and EDCs in surface run-off and in water infiltrating the soil profile. Crop productivity and soil microbial activity will also be measured across different biosolid application rates (0, 10, 20, and 30 dry tons/acre/year).
3. Progress Report:
Soil samples from two sites (Austin and Belton, TX) used in the NIFA-awarded project were collected and shared with scientists at the University of Arizona for identification of nanomaterials in land-applied biosolids and in soils exposed to different management histories of land-applied biosolids. Also, soil samples from Austin were shared with scientists at the University of Arizona to score for antibiotic resistance in soil bacteria in soils exposed to different management histories of land-applied biosolids. A SWAT (Soil and Water Assessment Tool) workshop was presented to scientists and graduate students from Baylor University, Texas A&M University, Louisiana State University, and the University of Nebraska who are collaborating on the project. After the workshop, we discussed research gaps and a conceptual modeling framework for the fate and transport emerging contaminants. After the discussion, we distributed funds to each university to develop and validate models of emerging contaminant transport.