Transport and removal of coliphage PRD1 in constructed wetlands

Abstract

The Convection Dispersion Equation (CDE) was used to calculate PRD1 and Br⁻ transport parameters in a subsurface flow constructed wetland. Transport parameters from Br⁻ displacement were applied into the CDE to estimate a 0.96 day⁻¹ first order decay coefficient (k). The PRD1 breakthrough curves were also simulated to obtain effective cross-sectional area (Ac), longitudinal dispersion coefficient (D), convective velocity (v), and k. There was practically no difference between Ac and D for both tracers. However, the estimated convective velocity was higher for PRD1 than for Br⁻. Further simulations were conducted by taking experimental concentrations from prior research on surface and subsurface flow constructed wetlands. Dispersion number (d) was estimated to be between 0.17 and 0.029 by using PRD1 and Br⁻ transport parameters. These parameters were also used to calculate wetland dimensionless removal (K). An analytical solution for the zero moment of the observed breakthrough curves was applied to estimate PRD1 fraction recoveries in the wetland by using d and K. The results of the present study suggest that this analytical solution may be an alternative design tool for pathogen removal estimation in subsurface flow constructed wetlands.

Keywords:

• PRD1
• tracer
• virus removal
• wetlands
• detention time
• wastewater.