The Binary Treatment of Aqueous Metribuzin Using Anodic Fenton Treatment and Biodegradation

Abstract

An advanced oxidation process, anodic Fenton treatment (AFT), and a mixed microbial culture were used to degrade metribuzin [4-amino-6-tert-butyl-3-methylthio-1,2,4- triazin-5(4H)-one], a broad-use triazinone herbicide. Complete and rapid removal of metribuzin was demonstrated. The appearance and subsequent degradation of metribuzin oxidation products--deaminated metribuzin (DA), diketo metribuzin (DK), as well as the production of deaminated diketo metribuzin (DADK)--were observed. To support the use of AFT as a chemical pretreatment, the ratio of 5-day biochemical oxygen demand (BOD5) as measured in the standard test to chemical oxygen demand (COD) was investigated, and an increase from 0.03, a nonbiodegradable solution, to 0.35, a biodegradable solution, was observed. This increase in biodegradability was associated with decreased metribuzin, DA, and DK concentrations and increased DADK concentration. AFT effluent was inoculated with either an enriched microbial culture or Polyseed, a commercially available inoculum. Although there was minimal biodegradation of the remaining metribuzin, there was a significant decrease in DA concentration in inoculated incubations compared with sterile controls after 5- and 10-minute AFT treatment. The enrichment inoculate appeared more adapted toward the less-oxidized, 5-minute-treated effluent, whereas the Polyseed culture, developed to degrade complex waste solutions, appeared to be more effective in a moreoxidized, 10-minute-treated, and potentially more complex effluent. This research supports the continued investigation of AFT and biodegradation as a binary treatment of aqueous pesticide wastes.

Titanium Dioxide-Mediated Photcatalysed Degradation of Two Herbicide Derivatives Chloridazon and Metribuzin in Aqueous Suspensions

“…CHL and MET possess high mobility in soil and thus have great potential to leach and pollute surface and groundwater [17]. Few studies relating to the degradation of chloridazon and metribuzin in UV and sunlight have been reported recently in the literature [18][19][20]. No major efforts have been made to study the detailed degradation kinetics of these two herbicide derivatives.…”

Combined photo-Fenton and biological treatment for Diuron and Linuron removal from water containing humic acid

“…EC 15 50 values for all the solutions after photo-Fenton process were higher than TOC effluent concentration. This means that none of the solutions (A, B or C) were toxic [14].…”

“…This means that none of the solutions (A, B or C) were toxic [14]. According to BOD 5 , COD and EC 15 50 data, it can be suggested that intermediates coming from Diuron and Linuron herbicide oxidation with or without the presence of HA are good candidates for a SBR treatment.…”

“…On the other hand, Fe(II) can be eliminated by raising the pH of the solution if its concentration exceeds the legal environmental disposal level. Recently, the coupling of an AOP and a biological treatment has been proposed as a new approach to regenerate polluted effluents [12][13][14][15]. The objective of this strategy is the use of an AOP to convert initial toxic and non-biodegradable compounds into by-products that can be assimilated by the biomass.…”

“…With this aim, COD, TOC, herbicide concentration, EC 15 50 and BOD 5 /COD of the intermediates generated at the end of the chemical step have been measured. Moreover, a SBR has been used to evaluate the feasibility of the coupled chemical-biological treatment for water containing those herbicides in the presence of high concentrations of HA.…”