Hydraulic parameters and statistical residence time distribution moments correlations–a lysimeter study for pesticides mitigation

Abstract

A lysimeter consisting of small tanks containing filtering solid mass is used to better understand and optimise constructed wetlands. The residence time distribution (RTD) representing the characteristics of a lysimeter is an essential tool for evaluating the hydraulic efficiency for optimal constituent removal. The moments of RTD function are used to determine the performance of a lysimeter, but the calculation process can be complicated. In this study, we focus on the correlations of some key experimental hydraulic parameters including the moments of RTD function. The tracer solution of sodium chloride was injected into the lysimeter to investigate hydraulic parameters affecting RTD characteristics. Tracer distribution at the outlet was measured and recorded using a conductometer with varying flow rates and different outlet heights during five independent experiments. Results indicate that the RTD moments and other hydraulic parameters which can be directly calculated or observed are strongly correlated. Understanding such results will help in the design and management of lysimeter and will facilitate further lab or field studies.

Keywords:

• correlation
• constructed wetland
• lysimeter
• RTD moments
• tracer experiment