Treatment of trace organics in membrane concentrates I: pesticide elimination

Abstract

The objective of this study was to eliminate organic micropollutants in the membrane system concentrates, which is produced by drinking water production plants, in order to protect existing water resources. This work is divided into two parts, pesticide elimination (I) and natural organic matter removal (II) in membrane system concentrates. Seven commonly detected pesticides in French surface waters, i.e. atrazine, sulcotrione, bentazone, isoproturon, diuron, glyphosate and acetochlore, were selected as the model micropollutants. Removal/degradation of these pesticides was studied by testing conventional processes employed for potable water production, i.e. adsorption, oxidation by ozone and clarification. Only partial removal of these pesticides was achieved with conventional processes. Removal of nonpolar pesticides was obtained by adsorption and rapid degradation of most of the pesticides was observed with low ozone dosages, except for atrazine and its metabolites. On the other hand, only the phosphonate-based pesticides were removed by clarification. By combining these processes, however, almost complete removal of the selected pesticides was achieved. Simultaneous ozonation and adsorption in the same reactor seems to be the most promising option for this study.

Pesticides in water sources used for human consumption in the semiarid region of Argentina

“…Several methods can be used to remove pesticides from water but their efficiency depends on the characteristics of the pesticides and they are not always applicable at household level. Compounds like atrazine and its metabolites (molecules with low solubility in water) are easily adsorbed by the powdered activated carbon (PAC), while glyphosate and AMPA show low adsorption onto PAC due to their high polarity [81,82]. On the other hand, ozone oxidation produces complete degradation of glyphosate and AMPA, but not for atrazine, HOA, DIA or DEA [81,83].…”

“…Compounds like atrazine and its metabolites (molecules with low solubility in water) are easily adsorbed by the powdered activated carbon (PAC), while glyphosate and AMPA show low adsorption onto PAC due to their high polarity [81,82]. On the other hand, ozone oxidation produces complete degradation of glyphosate and AMPA, but not for atrazine, HOA, DIA or DEA [81,83]. Therefore, total elimination would be achieved with a combination of both methods [81].…”

Detoxification of Pesticide-Containing Wastewater with FeIII, Activated Carbon and Fenton Reagent and Its Control Using Three Standardized Bacterial Inhibition Tests

“…For all samples, with EC 50 values between 3.9 and 17.7 mL/L, the luminescent bacteria were found to be the most sensitive. The EC 50 values for nitrificants were between 17.3 and 480 mL/L. The heterotrophic organisms, on the other hand, proved to be very resistant, but not to the extent that they could process the raw samples as a nutrient (no significant negative values).…”

“…The parameters m 1 (location parameter), m 2 (slope parameter), m 3 (saturation value, usually 100%) and m 4 (baseline parameter) were determined using the least squares method. The effective concentration EC x (EC 20 , EC 50 or EC 80 ) at the inhibition I x (=20, 50 or 80%) was then calculated using Equation ( …”

“…For this, however, the PAC concentrations tested were also not high enough. For example, with a complex matrix as found in raw sample A, it is possible that some organic compounds such as glyphosate have such a strong polarity that an affinity to PAC is not present [50]. For the larger scale experiment (Section 3.5), a dosage concentration of 1125 mg/L PAC was chosen because higher concentrations caused too low loadings and lower concentrations caused too little COD removal.…”