Fast removal and detoxification of oxytetracycline, triazine and organophosphate pesticides in a biopurification system

Biopurification systems (BPS) are aimed at treating pesticide-containing wastewater. Since antibiotics employed in agriculture produce similar wastes, their treatment in BPS represents the logical disposal approach; nonetheless, antibiotics could hinder the biological removal of pesticides in BPS. This work aims at assessing the simultaneous removal of several pesticides (four organophosphates and four triazines) in a BPS biomixture during their co-disposal with the antibiotic oxytetracycline (OTC) at relevant concentrations (10 mg kg−1 and 50 mg kg−1). All pesticides were removed from the biomixture, regardless of the presence of OTC; among organophosphates, DT50 values were among the lowest reported in BPS or soil, ranging from 1.1 d to 9.31 d; only cadusafos showed a similar removal than in soil (DT50 56–61 d). Successful and fast removal was also achieved for triazines, with DT50 values ranging from 6.9 d to 11 d. Interestingly, co-application of OTC enhanced the removal of methamidophos; while in the case of triazines, OTC (at 50 mg L−1) produced a slight increase in the DT50 for every herbicide, an effect only evident for terbutryn at OTC 10 mg L−1. The system also proved to be efficient in removing OTC itself, achieving DT50 values from 8.0 to 12.3 d, the fastest so far reported in BPS. Important detoxification, over 90% towards D. magna and 26–37% on the germination index in L. sativa, provide additional support to suggest the co-disposal of OTC and the studied pesticides in the same BPS as a feasible agricultural practice at real on-farm conditions. [Display omitted] •Biopurification systems (BPS) employed for the removal of herbicides/organophosphates.•Successful and fast removal of most pesticides in the presence of oxytetracycline (OTC).•Fast removal of OTC regardless of the dose applied in the BPS.•Detoxification of the system according to tests in Daphnia magna and Lactuca sativa.•Use of the BPS for simultaneous elimination of pesticides and OTC is recommended.