Photolysis and advanced oxidation treatment of pharmaceuticals in tap water and treated sewage

Abstract

The aim of this study was to investigate the removal efficiency of six phannaceuticals by
photo-degradation and the advanced oxidation process (AOP), UV/H2O2. The six
phannaceuticals were the four NSAIDs ibuprofen, diclofenac, naproxen and ketoprofen, the
pharmacological active metabolite of the lipid lowering agent, clofibrin, clofibric acid, and the
anticonvulsant and mood stabilizing drug, carbamazepine.
Treatment experiments were perfom1ed using a UV lamp optimized for photochemical
treatment in a flow through set-up. For the AOP experiments 60 mg/L H2O2 was added to the
water before treatment. The treatment effectiveness is evaluated based on the Electrical
Energy per Order (EEO) (unit kWh!m\ which is defined as the electrical energy consumed
per unit volume of water treated required for 90% removal of the investigated compound.
It was found that four of the six phannaceuticals were completely removed in tap water by
both UV treatment and the AOP. The exceptions were ibuprofen and carbamazepine, which
exhibited a relationship between UV dose and removal. The electrical energy per order, EEO
was detennined to 8.2 kWh/ml (UV) and 3. 7 kWh/ml (UV /H2O2 ) for ibuprofen.
In the wastewater effluent the removal by UV irradiation was almost complete for ketoprofen,
while the other compounds show dependency of flow rate/UV dose. Ibuprofen was the
compound that needed the highest UV dose to remove 90% (EEO = 33.4 kWh/ml
) where
naproxen and clofibric acid required 9.6 kWh/ml and 5.5 kWh/ml
, respectively. Ketoprofen
and diclofenac needed considerable less energy than clofibric acid. Ibuprofen and naproxen is
biodegradable and will be removed in biologically treated wastewater. Therefore, the relevant
estimate of the needed treatment is the energy use for removal of clofibric acid which required
5.5 kWh/ml for 90% removal.