ENVIRONMENTAL AND SOURCE WATER QUALITY EFFECTS OF MANAGEMENT PRACTICES AND LAND USE ON POORLY DRAINED LAND
Location: Soil Drainage Research
Title: Nutrient and Pesticide Removal From Laboratory Simulated Tile Drainage Discharge
Submitted to: Transactions of the ASABE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 2, 2010
Publication Date: May 1, 2010
Citation: King, K.W., Mcdonald, J., Moore, J., Agrawal, S.G., Fischer, E.N., Balogh, J. 2010. Nutrient and Pesticide Removal From Laboratory Simulated Tile Drainage Discharge. Transactions of the ASABE. 53(3):769-777.
Interpretive Summary: Excess nutrients in drainage waters have been implicated in the creation and growth of harmful algal blooms and hypoxic areas worldwide. Additionally, public water utilities spend millions of dollars annually to purify waters prior to distribution. Treatment of the drainage waters prior to their entry into streams or waterways would provide a cleaner, safer water supply for downstream uses. It was determined that implementation of an end-of-tile cartridge filter system containing natural and by-product materials could significantly reduce the amount of soluble phosphorus and selected pesticides exiting into streams and waterways. The findings lay the foundation for the use of by-products for filtering nutrients and pesticides from large scale surface and subsurface drainage waters. The beneficiaries of this research are all downstream water users that rely on surface water for drinking, recreation, and navigation.
Excess nutrient and pesticide transport through subsurface tile drainage is well documented. One approach receiving consideration for reducing the amount of nutrients and pesticides in subsurface drainage waters is end-of-tile filters. The filters are often comprised of industrial wastes or by-products that have a significant capacity for binding or sorbing nutrients and pesticides. A laboratory study was conducted to test the efficacy of an activated carbon, zeolite (clinoptilolite), and activated alumina filter to reduce nitrate-nitrogen, dissolved reactive phosphorus, metalaxyl, and chlorothalonil in simulated drainage waters. Hydrographs having peak flow rates of 0.63, 1.26, and 1.89 liters per second (lps) were simulated. The simulated drainage waters were spiked with two nutrients (nitrate-nitrogen introduced into solution as potassium nitrate and dissolved reactive phosphorus introduced as sodium phosphate) and two fungicides (chlorothalonil and metalaxyl). Across all flow rates, the cartridge filter system produced reductions in nitrate-nitrogen loading of 4.7%, dissolved reactive phosphorus, 51.6%, chlorothalonil, 58.2%, and metalaxyl, 28.8%. The effectiveness of the filters was dependent on flow rate and position on the hydrograph. The findings from this study suggest that the end-of-tile filter approach could be adapted as a best management practice to reduce nutrient and pesticide transport in subsurface tile drainage where the contributing area and flow rates are relatively small. Additionally, the findings support further investigation into alternative sorbent materials and delivery designs that permit larger drainage areas and greater flow rates to be filtered.