Household chemicals and prescription drugs are considered emerging wastewater contaminants. These compounds often resist conventional wastewater treatments, leading engineers to consider advanced treatment solutions such as UV/H2O2 advanced oxidation. One of the drawbacks of advanced oxidation is the formation of transformation products, following contaminants' oxidation. These products are occasionally more toxic than the parent compound, in particular if the active part of the molecule remains unmodified.  The present study demonstrates the results from a pilot system (installed at Boulder CO wastewater treatment plant), aiming to provide a holistic treatment solution for emerging contaminants and transformation products. The treatment is composed of a UV/H2O2 oxidation process followed by a biological aerated filter (BAF). The goal of the UV/H2O2 process is to oxidize primary contaminants, generating transformation products. These products are subsequently removed by the BAF system.  Figure 1 presents the UV/H2O2 results from the pilot, demonstrating effective contaminants degradation in secondary effluent, using (a) medium pressure (MP) or (b) low pressure (LP) UV reactors, at 10 mg/L H2O2 and UV dose of up to 1500 mJ/cm2. Different transformation products were identified during the oxidation process. These intermediates were often generated up to a maximum concentration, after which their concentration decreased with increasing of the UV fluence (due to oxidation). The BAF system could remove a significant amount of iopromide and carbamazepine transformation products; however, at relatively high retention time.

Demonstrating advanced oxidation/biofiltration to remove emerging contaminants from wastewater: A pilot study

248th National Meeting (2014)

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