Review of experimental procedures and modelling techniques for flow behaviour and their relation to residence time in constructed wetlands

Accurate modelling of constructed wetlands is vital for furthering the use of these systems. Constructed wetlands can treat various types of wastewater, including domestic wastewater, agricultural wastewater, industrial and mining wastewater and stormwater runoff. Physical, chemical and biological processes all take place simultaneously to breakdown the contaminants in wastewater, and while the combination of so many processes makes them an effective wastewater treatment system, it can also make the modelling of these systems intricate. The modelling technique used is dependent on the goal of the model, whether it is for design or scientific research. The extent to which contaminants are broken down by these processes is highly dependent on the time the water spends in the system, and this time is dependent on and can be quantified by the understanding of the hydraulic behaviour of the constructed wetland. Tracer studies are the most common way to determine the hydraulic behaviour of the system and the data from these studies can be used in various ways to quantify time in the system. There are three aims of this paper, the first is to give wetland researchers an idea of what hydraulic modelling techniques are available, the second is to indicate the connection between accurate hydraulic modelling and the modelling of kinetic processes, and the third is to guide the researchers in determining which model is best suited for their needs based on research needs and characteristics of the wetland.

Automated summary

Accurate modelling of constructed wetlands is crucial for their effective use in wastewater treatment. The modelling technique used depends on the goal of the model, and the time contaminants spend in the system is highly dependent on the hydraulic behaviour of the wetland, which can be quantified through tracer studies.