Journal of Hazardous Materials B112 (2004) 105–113 Pre-treatment of penicillin formulation effluent by advanced oxidation processes Idil Arslan-Alaton ∗ , Serdar Dogruel Department of Environmental Engineering, Faculty of Civil Engineering, Istanbul Technical University, 34469 Maslak, Istanbul, Turkey Received 20 June 2003; received in revised form 16 February 2004; accepted 5 April 2004 Available online 7 June 2004 Abstract A variety of advanced oxidation processes (AOPs; O 3 /OH - ,H 2 O 2 /UV, Fe 2+ /H 2 O 2 , Fe 3+ /H 2 O 2 , Fe 2+ /H 2 O 2 /UV and Fe 3+ /H 2 O 2 /UV) have been applied for the oxidative pre-treatment of real penicillin formulation effluent (average COD 0 = 1395 mg/L; TOC 0 = 920 mg/L; BOD 5 , 0 ≈ 0 mg/L). For the ozonation process the primary involvement of free radical species such as OH • in the oxidative reaction could be demonstrated via inspection of ozone absorption rates. Alkaline ozonation and the photo-Fenton’s reagents both appeared to be the most promising AOPs in terms of COD (49–66%) and TOC (42–52%) abatement rates, whereas the BOD 5 of the originally non-biodegradable effluent could only be improved to a value of 100 mg/L with O 3 /pH = 3 treatment (BOD 5 /COD, f = 0.08). Evaluation on COD and TOC removal rates per applied active oxidant (AOx) and oxidant (Ox) on a molar basis revealed that alkaline ozonation and particularly the UV-light assisted Fenton processes enabling good oxidation yields (1–2mol COD and TOC removal per AOx and Ox) by far outweighed the other studied AOPs. Separate experimental studies conducted with the penicillin active substance amoxicillin trihydrate indicated that the aqueous antibiotic substance can be completely eliminated after 40 min advanced oxidation applying photo-Fenton’s reagent (pH = 3; Fe 2+ :H 2 O 2 molar ratio = 1:20) and alkaline ozonation (at pH = 11.5), respectively. © 2004 Elsevier B.V. All rights reserved. Keywords: Penicillin formulation effluent; Advanced oxidation processes; Ozonation; H 2 O 2 /UV; Fenton and photo-Fenton processes 1. Introduction Since the late 1980s a variety of pharmaceuticals have been reported to be present in surface water and effluent of sewage treatment plants (STPs) indicating their poor biodegradability in municipal sewage and STPs [1,2]. Be- cause of their toxicity to various microorganisms, poor microbial elimination efficiencies are particularly expected for antibiotics and various countries regulate the level of antibacterial residues in agricultural, veterinary, dairy, and meat-based food products [2–4]. As a consequence, separation and pre-treatment of antibi- otic synthesis and formulation effluent from the total phar- maceutical wastewater should be considered since biological activated sludge processes are practiced at STPs and most pharmaceutical industries [5,6]. For example, during the for- mulation stage of antibiotics, highly diluted but still toxic ∗ Corresponding author. Tel.: +90-212-285-65-76; fax: +90-212-285-65-87. E-mail address: arslanid@itu.edu.tr (I. Arslan-Alaton). and/or recalcitrant liquid effluent is generated for which alternative chemical treatment methods (i.e. granular acti- vated carbon adsorption, ozonation, Fenton’s oxidation and co-precipitation) have to be employed for pre-treatment and biodegradability improvement. Until now, only few studies dealing with the advanced oxidation of antibiotic substances found in water or wastewater have been reported in the sci- entific literature [7–12]. Advanced oxidation processes (AOPs) have been defined as aqueous phase oxidation processes which are based pri- marily on the intermediacy of the hydroxyl radical (OH • ) attacking aggressively and almost non-selectively inorganic as well as organic compounds, including a variety of xenobi- otics and micropollutants [13–15]. An immense body of lit- erature has been already devoted to the applications of AOPs to industrial effluents of diverse nature. The most widely known and effective AOPs include ozonation combined with UV-light and/or H 2 O 2 , Fenton, photo-Fenton reagents (ho- mogenous AOPs) and heterogeneous, mainly TiO 2 -mediated photocatalysis, all of which have specific advantages and drawbacks [14–16]. Either generation of ozone or production 0304-3894/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jhazmat.2004.04.009