Detection of Carbamazepine, Diclofenac, and Ketoprofen via a SPE-HPLC-PDA Method in a Municipal Wastewater Treatment Plant in East Texas, USA

Abstract

Increased demand for water reuse, recycling and reclamation heightens the need for improvements in the design of wastewater treatment plants that minimize or remove toxic pollutants or their metabolites. In this study, solid-phase extraction (SPE) technique utilizing C-18 cartridge was used for separation of three commonly used pharmaceuticals, namely, carbamazepine (CBZ), diclofenac (DF), and ketoprofen (KT) in wastewater samples. High performance liquid chromatography-photodiode array detector (HPLC-PDA) method was used for detection of CBZ, DF, and KT along the treatment stages (aeration, clarifier, raw activated sludge (RAS), chlorine contact chamber (CCC), and sulfur dioxide chamber) from Nacogdoches wastewater treatment plant (NWWTP), in East Texas, USA. Highest concentrations were found in the RAS followed by influent aeration stage. Pharmaceutical concentrations detected from the influent or RAS samples were 2.115 × 10⁻³ mg/L, 8.95 × 10⁻⁴ mg/L and 8.55 × 10⁻⁴ mg/L for CBZ, KT and DF, respectively. Highest detected total concentrations of pharmaceuticals were: carbamazepine (1.285 – 2.117 μg/L), diclofenac (0.600 – 0.865 μg/L), and ketoprofen (0.815 – 0.885 μg/L). The calculated % removal efficiencies along the treatment stages follow the order; CBZ: RAS > SO₂ > clarifier ≈ aeration > CCC; KT: RAS > SO₂ > aeration > CCC > clarifier; DF: RAS ≈ aeration ≈ CCC > clarifier > SO₂. Determined removal efficiencies follow the order carbamazepine (∼ 39.2%) > diclofenac (∼ 30.6%) > ketoprofen (∼8.8%). Removal efficiencies of pharmaceuticals in the NWWTP may be affected by the human body, transition through activated wastewater treatment processes, and their metabolism and/or usage by humans.

GRAPHICAL ABSTRACT

Keywords:

• Wastewater treatment plant
• pharmaceuticals
• HPLC-PDA
• removal efficiency
• emerging pollutants