• Mitigation of phosphorus, sediment and Escherichia coli losses in runoff from a dairy farm roadway

      McDowell, R.W.; Daly, Karen M.; Fenton, Owen; Environment Bay of Plenty; Our Land and Water National Science Challenge; Environmental Protection Agency; Department of Agriculture, Food and the Marine; C10X1507; 2018-W-MS-38 (Compuscript Ltd.Teagasc, 2020-11-30)
      Dairy cow deposits on farm roadways are a potential source of contaminants entering streams. Phosphorus (P), suspended sediment (SS) and Escherichia coli (E. coli) loads in 18 runoff events over 12 mo from two-halves of a section of dairy farm roadway that spilt into an adjacent P-impacted stream were measured. The runoff from one half was untreated while the other half was directed through a filter of steel melter slag [termed aluminium chlorohydrate (ACH)-altered slag] sprayed with 1% ACH solution to improve P sorption capacity. An uncertainty analysis was conducted to ascertain potential loads of P lost from roadways considering variation in deposit weight, number and P content. Over the monitoring period, the total load decreased P (92%), SS (98%) and E. coli (76%) from the ACHaltered slag roadway compared to the control. However, uncertainty analysis showed that the amount of dung-P deposited on the roadway could be 10-fold greater.