Wastewater contains increasing amounts of pharmaceutical residues. Since the WWTPs are not designed to remove them from the water, the plants’ effluent frequently still contains pharmaceuticals. Many techniques for the removal of these pharmaceuticals, and other micropollutants, are not very effective because of the presence in the effluent of relatively large quantities of organic material. By first removing this organic material, the subsequent application of advanced oxidation does indeed prove to be effective.
Effective removal of pharmaceuticals from WWTP effluent
The objective of the project was to develop treatment methods to effectively and efficiently remove pharmaceuticals (and their breakdown products), and other organic micropollutants, from WWTP effluent. In principle, advanced oxidation techniques, such as UV/H2O2, are highly suitable, but the presence of organic matter in the effluent (EfOM) hinders the breakdown process. Through the use of ion exchange (IEX) or ozonation/biofiltration as a preliminary step to remove part of the EfOM, an affiliated treatment technique should become much more efficient.
First organic-material removal, then advanced oxidation
The research focused on the application of ion exchange (IEX) or ozonation/biofiltration for organic-material removal, as a preliminary step to three affiliated pharmaceutical-removal techniques, namely: activated carbon filtration (ACF), and advanced oxidation (AOP) with O3/H2O2 or with UV/H2O2. Then, in a pilot set-up at WWTP Panheel, several processes were tested: pre-treatment with either ozonation/biofiltration or IEX, and post-treatment with UV/H2O2.
More effective advanced oxidation process for pharmaceutical removal
The research showed that IEX followed by UV/H2O2 is a very robust process. The IEX removed practically all the humic acids, which led to an 84% drop in the energy consumption of the UV process. In this manner, a process was achieved which is particularly effective in the removal of organic micropollutants and of pharmaceuticals and their breakdown products, and is also economically feasible.