529 Research Article Received: 12 August 2009 Revised: 8 November 2009 Accepted: 10 November 2009 Published online in Wiley Interscience: 23 December 2009 (www.interscience.wiley.com) DOI 10.1002/jctb.2324 Comparison of different treatment alternatives for removal of pesticide from water solution Fares A. Al Momani, a* Ahmad T. Shawaqfeh a and Hani Al-Zoubi b Abstract BACKGROUND: Removal of recalcitrant chemicals is an essential step in conventional wastewater treatment plants. Among these, pesticides are of great environmental concern. Different treatment options were compared in this work: the combination of advanced oxidation processes (AOPs) with biological treatment, an aerobic process and anaerobic biological treatments. The role of chemical processes in improving solution biodegradability was verified. Oxidation by-products were identified and biological process kinetics are reported. The performance of biological processes and their kinetics were studied. RESULTS: Chemical oxidation increased the solution biodegradability index to 0.25. Oxidation by-products were identified as maleic acid, phenol and a mixture of catechol, resorcinol and hydroquinone. The combined processes resulted in 98% organic matter removal. Pesticide degradation followed pseudo-first-order kinetics with a rate constant in the range 0.5 – 1.2 L g -1 TVSS h -1 . An anaerobic process was found to be an attractive option with 92% removal efficiency. The aerobic process had a long adaptation time (>200 days), 80% removal efficiency and an average pseudo-first-order rate constant of 0.18 L g -1 TVSS h -1 . CONCLUSION: Comparison of the investigated processes favoured the use of combined AOPs and biological and/or aerobic biological treatment due to its practical operating conditions. c  2009 Society of Chemical Industry Keywords: bacterial culture; biodegradability; by-products; kinetic; oxidation INTRODUCTION In recent years there have been many reports of significant levels of contamination of water resources (underground and surface) by pesticides. 1–4 Pesticides are introduced into theses resources as a result of human activities such as disinfection processes and pesticide industry cleaning. Also, agricultural applications and precipitation runoff discharge high amounts of pesticide to the environment. Jordan has extensive agricultural activities that involve the use of pesticides. As a result, the presence of significant amounts of pesticide is frequently reported in different types of wastewater. 5 Due to the fact that Jordan has scarce resources of fresh water, great efforts were made by consecutive governments to maintain clean water resources. In addition, world legislation (e.g. world ISO 14 001 certification) has been an important motivator for these governments to sponsor different kinds of research into economical effluent treatment. 6 Initiatives implementing efficient, cheap and fast wastewater treatment are highly desirable. Biological treatment of wastewater was often considered the most economical option when compared with other treat- ment options. 7,8 The capability of wastewater to undergo bio- degradation is dependent on many factors, such as concentration of contaminants and their chemical structure, water matrix, pH, and substrate/co-substrate ratio. 9 Unfortunately, not all organic molecules are readily biodegradable, and these are referred to as biorecalcitrant. 10,11 On the other hand, chemical treatment processes have also been employed to mineralize many organic chemicals, but the costs associated with these processes have limited their use. To overcome the economic problems, two alternatives were proposed. The first was the integration of chemical and biological treatment steps in one process, and the second was the application of a special adaptive biological process. The first alternative suggested the use of a chemical process to increase the biodegradability of biorecalcitrant compounds when using the biological process in series. 12–14 In these combined processes, it was important to follow the biodegradability enhancement during the chemical reaction and the effect of different operational conditions on integrated process performance. The proposed methods for measuring biodegradability improvement are listed elsewhere. 7,15 – 17 The adaptive biological process was rarely used due to its long adaptation time, non-stoichiometry of the biological process and the limited applicability of the adaptive biomass to one kind of substrate. However, if the process was used for a specific pollutant and the bacteria were fully adaptive, the process would be considered feasible. Among all the chemical oxidation processes, advanced oxida- tion processes (AOPs) were those which resulted in inefficient oxidation of refractory contaminants. 7,18,19 The oxidation of ∗ Correspondence to: Fares A. Al Momani, Chemical Engineering Department, Mutah University, Karak, Jordan. E-mail: fares1233@mutah.edu.jo a Chemical Engineering Department, Mutah University, Karak, Jordan b Computer Engineering Department, Mutah University, Karak, Jordan J Chem Technol Biotechnol 2010; 85: 529–535 www.soci.org c  2009 Society of Chemical Industry