Author(s): Irene Salmeron; Silvia Venditti; Joachim Hansen

Linked Author(s):

Keywords: Contaminants of emerging concern; Pilot-scale system; Tertiary treatment; Urban wastewater; Water remediation

Abstract: The current growing concern about the presence and fate of micropollutants in the water bodies is promoting a huge increase in the research investment of new technologies (beside the mostly used ones such as ozonation and Activated Carbon Filtration) for their removal in Wastewater Treatment Plants (WWTPs) before discharge. In this context the strategic project CoMinGreat (EU-Interreg-GR) arises trying to bring together the know-how from different water management entities of the Greater Region (Luxembourg, Germany, Belgium and France) to find a technologically and economically viable solution to set national discharge standards in line with the European regulations. Until now, alternative technologies such as Advanced Oxidation Processes (AOPs) or natural-based technologies are only realized in lab- or early pilot-scale. For this reason, among the targets of the CoMinGreat project it is the implementation of a Demonstration-Center at the WWTP of Bliesen (Germany) (13 000 PE) to test the feasibility of AOP and natural-based technologies in comparison with the classical ones. One of the installed treatment lines consists of a Constructed Wetland (CW) of 1 m3 volume with two layers of gravel as drainage and filled with activated biocoal (15%) + sand (85%) mixed homogenously. The unit is planted at a density of 25 plants steams with common macrophytes Phragmites australis and Iris pseudacorusm distributed alternately. It will be irrigated 3 times per day during 30 min with clarifier effluent (intermittent mode). The maximum Hydraulic Loading Rate (HLR) will be 400 L day-1 m-2. The second line is a combination of photo-Fenton at neutral pH and CW. The photo-Fenton pilot consists of three 150W medium pressure lamps installed in cascade working in continuous mode feed directly with clarifier effluent. After that, a transition tank is installed to store the water pretreated by photo-Fenton for the ulterior watering of two CWs operated alternatively. Briefly, CW1 is irrigated 3 times for 24h while CW2 is not irrigated (rest mode). The following 24h CW2 is irrigated 3 times and CW1 is not irrigated. The maximum volume treated is 800 L day-1 meaning 400 L day-1 m-2 of HLR. Both lines are fully automatized and are remotely monitored. The comparison between the two lines allows to determine whether the combination of photo-Fenton and CW could increase the removal of highly-recalcitrant compounds while the energy needed to reach the 80% of micropollutant removal is reduced and CW lifetime ideally increased. Furthermore, the two types of irrigation (intermittent versus alternating operation mode) will be also evaluated. Outcomes of project will provide information about the applicability of investigated technologies as alternatives to the classical ones in rural areas, at small and medium-sized WWTP typical of the Greater Region, where their high cost compromise the viability of this last step.

DOI: https://doi.org/10.3850/IAHR-39WC252171192022794

Year: 2022