Constructed wetlands for the removal of water treatment additives from saline industrial wastewater.
Constructed wetlands (CWs) are man-made wetland systems, isolated from the natural environment, that employ the natural treatment capacity of natural systems for the removal of contaminants from water streams. Throughout the world, CWs have been employed as an alternative for or in addition to different forms of domestic- and industrial wastewater treatment. CWs are often considered to be a suitable (secondary) wastewater treatment option because of their low maintenance effort and costs, low energy requirements and their integration in the landscape. Various contaminant removal processes occur in simultaneously in CWs: anaerobic and aerobic biodegradation, photodegradation, plant uptake and adsorption to the soil matrix.
The dominating removal process in a CW depends on its design. For instance, photodegradation occurs mainly in surface flow constructed wetlands, while aerobic and anaerobic biodegradation can be found in batch fed vertical subsurface flow CW. In addition, the removal efficiency of CWs are influenced by the choice of substrate, vegetation, hydraulic retention time and the climatological circumstances.
The removal efficiency of CWs for various emerging contaminants is well studied. However, no information on the removal of water treatment additives from saline industrial waste water streams in constructed wetlands is available. In my PhD-project, I will study the feasability of a constructed wetland for the removal of this compounds from saline industrial waste water streams and develop the most optimal CW design to do this. To perform this study, I chose various representative water treatment chemicals for different industries :
With this chemicals, I will perform different batch scale studies to elucidate their fate in CWs :
In addition, I will design pilot scale CWs in which the removal efficiency for a (synthetic) wastewater spiked with the chemicals of interest will be tested. Because it is hypothesized that a combination of different CW designs will likely result in the highest removal efficiency, these pilot scale CWs will consist out of different sequences of CW designs in order to find the most optimal CW sequence (Fig 1).