SESSION V: P130
ORGANIC POLYMERS FOR THE REDUCTION OF ATRAZINE CONCENTRATION IN WATER
M.F.Mohd Amin1,2,*, , S.M. Scherrenberg1, L.C. Rietveld1
1
Department of Sanitary Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600 GA Delft, the Netherlands
2
Faculty of Earth Science, UMK Kampus Jeli, Universiti Malaysia Kelantan, 17600 Jeli, Kelantan, Malaysia.
* Corresponding author email: M.F.Mohdamin@tudelft.nl Summary
This study aims to investigate the ability of organic polymers of reducing atrazine concentration in water and the mechanism involved. Experimental studies carried out with two pre-selected cationic polymers to study the removal of atrazine from demin water. Preliminary results indicate that a reduction of the atrazine concentration expected to reach up to 40%.
Introduction
Micropollutants have become one of the main concerns in environmental pollution nowadays, especially when it comes to water treatment. These pollutants are not sufficiently removed in conventional sewage treatment plants. In order to prevent the spreading of contamination to groundwater and soils, the emission of these priority compounds, is regulated through the European Water Framework Directive (2000/60/EC). The availability of advanced treatment methods has optimised the removal of these pollutants from the wastewater, however such treatment is often costly. The development of organic polyelectrolytes as coagulant and/or flocculant, help reducing the quantities of these pollutants in a more cost effective way (Virkutyte et al.,2010). The process is based on the addition of organic polymers during the primary sedimentation process of wastewater treatment plants. This paper provides a study on direct interaction of polyelectrolytes and atrazine in demin water. Atrazine is selected as model compound based on its properties that represent other pollutants in wastewater.
Materials and methods
Experimental studies were carried out with two pre-selected cationic polymers (Flocculant Nalco 71350 (N7), Nalco starch (NS)) to study the removal of atrazine from demin water. The differences between this two polymers is their functional group and molecular weight. It is expected that N7 will outperform N8 in atrazine reduction rate due to the higher charge. All samples were spiked with 20 ± 3 μg/L of atrazine before addition of polymer. For the polymer dosage a concentration range varying between 1ppm to 500 ppm was used. In order to determine the reduction of atrazine concentration, all samples were analysed using gas chromatography (GC) (Agilent’s 7890A) based on U.S Environmental Protection Agency (EPA) 551.1 (1995) method.
Results and Discussion
Both selected polymers were able to reduce the atrazine concentration in the water. Based on selected polymer dosing concentrations from 1ppm to 500 ppm, the reduction percentage was in the range of 11-40% for both polymers. The reduction assumed to be caused by adsorption of the atrazine to the polymer. According to Ternes et al., (2004); Bolto and Gregory (2007) adsorption mainly caused by electrostatic interactions of positively charged groups of chemicals with the negatively charged surfaces of the compound. In this case, for dosage from 20-100ppm, the adsorption of atrazine is a possible mechanism. The dosage of higher polymer concentration did not improve the atrazine removal. Various factor can indirect or directly influence polymer-atrazine association such as temperature, polymer chain length, polymer molecular weight and polymer concentration.
Conclusions
This experimental study highlighted the polymer’s ability to reduce the atrazine concentration in demin water. The Nalco starch could be one of the potential polymer flocculants for pollutant removal in wastewater due to its better adsorption properties than the Nalco 71305.
Acknowledgments
Authors thank Nalco (Netherlands), Waterboard Rijnland (Netherlands) and Aquasetup (Netherlands) for research grant (Optimix– Project). The scholarship given by the Malaysian Ministry of Higher Learning (KPT, Malaysia), and Universiti Malaysia Kelantan (UMK, Malaysia) which provided financial support for the Ph.D. students Mohamad Faiz Mohd Amin is gratefully acknowledged.
References
Bolto, B., Gregory, J., (2007). Organic polyelectrolytes in water treatment. Wat. Res.;41:2301–24.
Carballa, M., Omil, F., Lema, J. M (2005) Removal of cosmetic ingredients and pharmaceuticals in sewage primary treatment. Wat. Res. 39; 4790-4796
Ternes T A, Herrmann N, Bonerz M, et al.(2004) A rapid method to measure the solid-water distribution coefficient (Kd) for pharmaceuticals and musk fragrances in sewage sludge. Wat. Res. 38(19):4075-84]
Virkutyte, J., Varma, R.S. & Jegatheesan, V., (2010). Treatment of Micropollutants in Water and Wastewater Treatment of Micropollutants in Water and Wastewater IWA Publishing, London, UK.
