Fate of the herbicide 14C-atrazine during sewage treatment on a lab-scale bioreactor

Jaime L. M. Oliveira, Edir M. Ferreira, Denise da P. Silva, Márcia Dezotti, Tomaz Langenbach

Abstract


Atrazine (2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine) is a persistent herbicide used on some crops and it has been found both in ground and surface water and drainage systems. This work studied the behaviour of atrazine during a sewage treatment process by activated sludge. The process was conducted on a laboratory scale using an under fed-batch system with a hydraulic retention time of 24 hours. After this period, the raw sewage (with atrazine) was changed and another batch was begun (the sludge age was 7 days old). Radiolabel molecules (14C-atrazine) were used for to trace their fate and to measure to the 14C-CO2 and the residues of atrazine were analysed by HPLC/UV. Initially about 50% of radioactivity was sorbed by the settled sludge but it was desorbed with successive additions of raw sewage without atrazine. The final balance of radioactivity showed that 98% of the atrazine was released into the treated effluent, probably without any biodegradation. Therefore, other organic micropollutants with similar characteristics to atrazine may behave a similar way.

Keywords


atrazine, activated sludge, persistent organic pollutants



Revista Ambiente & Água. ISSN:1980-993X  DOI:10.4136/1980-993X

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