HR: 14:35h
AN: H32D-04    [PDF]
TI: Removing Phosphorus from Milkhouse Wastewater Using Vegetative Filter Strips
AU: * Geohring, L D
EM: ldg5@cornell.edu
AU: Kim, Y
AU: Steenhuis, T S
EM: tss1@cornell.edu
AB: Vegetative filter strips (VFS) are commonly used BMPs to control agricultural pollutants. In watersheds supplying drinking water to New York City, VFS are installed to remove phosphorus (P) from milkhouse wastewater and barnyard runoff to reduce P inputs to the drinking water reservoirs and minimize eutrophication. Monitoring wells were installed within two VFS and the application of chloride tracer was used to investigate flow paths and soluble reactive P (SRP) removal. The SRP concentrations in the wells were highest (generally over 10 mg/l) near the wastewater discharge point, while the Morgan's soil test P was high (over 60 mg/kg) in the downslope area of the VFS. Although P sorption isotherms indicate these soils (pH of 6.5) have high potential to remove P, the soil P accumulations were not occurring in the same area as the highest well water concentrations. Early chloride breakthroughs showed that milkhouse waste flowed preferentially in the VFS through locally saturated areas. The accelerated surface flow contributed to rapid transport of SRP in the wastewater to the downslope area of the VFS, resulting in less SRP removal. Although VFS of 33 to 40m long for the two sites, respectively, eventually reduced SRP to lower than 0.2mg/l in most cases, SRP was less effectively removed in areas where soil saturation occurred. The anaerobic condition of the locally saturated area apparently reduced opportunity for soil P sorption to Fe oxides in these sites. In order for the VFS to be more effective at P removal, efforts to distribute wastewater more uniformly to avoid soil saturation should be considered in new designs.
DE: 1871 Surface water quality
SC: Hydrology [H]
MN: 2003 Fall Meeting