Dow-Evides Wetland Study
Internship Evides-Dow at DECO (Terneuzen)
Subject: Treatment of industrial wastewater effluent via constructed wetland and desalination
Research topic: Fate and impact of polyol constituents
Period: Sept 2019 – Jan 2020
Internship description
Biologically treated process water still contains low levels of difficult to degrade organic components like “polyols” and other chemical and biological polymers. When recycled as make-up for industrial cooling towers these constituents are suspect to give rise to undesired foaming phenomena and fouling on heat exchanger surfaces. Total concentration of these constituents is in the range 0-10 mg/L, expressed as Total Organic Carbon.
At the DECO location of Evides, adjacent to the chemical I-Parc of Dow Terneuzen, two pilot systems are in operation, both fed with treated process water. One of the pilots is a constructed wetland, where adsorption/degradation processes take place – the objective is to determine whether the residual organics from the Dow Wastewater treatment plant are captured or degraded in the wetland and/or impacts its vegetation. In a parallel pilot the same stream is treated by a variety of membrane and ion exchange units – behavior of the organic constituents in these systems is unknown yet – they may be retained or form biofilms at the surface of membranes or resin particles.
The internship is part of a dual internship – a chemistry student will focus on developing the appropriate analytical techniques for determining polyol fractions and concentrations. The water management student task will monitor whether residual polyols are captured or degraded in the wetland and/or impacts its vegetation. Samples will be collected and analyzed in cooperation with the chemistry student. Conditions in the wetland will vary over the entire period, since a number of tests will be executed with varying levels of oxygen supply (creating aerobic or more anoxic environments). In a parallel pilot the same stream is treated by a variety of membrane and ion exchange units – behavior of polyols in these systems is unknown yet – they may be retained or form biofilms at the surface of membranes or resin particles. The task of this internship is to picture the fate and impact of polyols in both pilot systems.
More information: Emma McAteer, Hans Cappon