title: A comparative study of different tests for biodegradability enhancement determination during AOP treatment of recalcitrant toxic aqueous solutions.
abstract: Four biodegradability tests (Pseudomonas putida bioassay, Zahn-Wellens test, BOD5/COD ratio and respirometry assay) have been used to determine the biodegradability enhancement during the treatment of wastewater containing 200 mg L(-1) of dissolved organic carbon (DOC) of a five commercial pesticides mixture (Vydate, Metomur, Couraze, Ditumur and Scala) by an advanced oxidation process (AOP). A comparative study was carried out taking into account repeatability and precision of each biodegradability test. Solar photo-Fenton was the AOP selected for pesticide degradation up to three levels of mineralization: 20%, 40% and 60% of initial DOC. Intra- and interday precisions were evaluated conducting each biodegradability test by triplicate and they were applied three times on different dates over a period of three months. Fisher's least significant difference method was applied to the means, P. putida and Zahn-Wellens tests giving higher repeatability and precision. The P. putida test requires a shorter time to obtain reliable results using a standardized inoculum and constitutes a worthwhile alternative to estimate biodegradability in contrast to other less accurate or more time consuming methods.
authors.affiliation: Department of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors.forename: M M
authors.initials: MM
authors.lastname: Ballesteros Martín
authors.forename: J L
authors.initials: JL
authors.lastname: Casas López
authors.forename: I
authors.initials: I
authors.lastname: Oller
authors.forename: S
authors.initials: S
authors.lastname: Malato
authors.forename: J A
authors.initials: JA
authors.lastname: Sánchez Pérez
mesh_terms: D000332:Aerobiosis; D001673:Biodegradation, Environmental; D001681:Biological Assay; D057919:Biological Oxygen Demand Analysis; D006861:Hydrogen Peroxide / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D010083:Oxidants, Photochemical / Q000737:chemistry; D010084:Oxidation-Reduction; D010575:Pesticides / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D016958:Pseudomonas putida / Q000187:drug effects; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D012996:Solutions; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D018508:Water Purification / Q000379:methods*
chemical_list: C045076:Fenton's reagent; D010083:Oxidants, Photochemical; D010575:Pesticides; D012722:Sewage; D012996:Solutions; D014874:Water Pollutants, Chemical; D006861:Hydrogen Peroxide; D007501:Iron