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Low-cost approaches for the removal of terbuthylazine from agricultural wastewater: constructed wetlands and biopurification system (Journal article)

Vryzas, Zisis

Constructed wetlands (CWs) and biopurification systems (BPS) present two low-cost approaches for the removal of pesticides from waters of agricultural origin. Both strategies were tested in the treatment of the herbicide terbuthylazine, a triazine of worldwide use. Three horizontal subsurface flow (HSF) CW systems were operated continuously for one year; the planted CWs (containing either Phragmites australis or Typha latifolia) were able to remove up to 73.7% and 58.4% of the pesticide, respectively, and exhibited a markedly superior performance compared to the unplanted CW. However, by the end of the treatment period, some symptoms of phytotoxicity were observed in the plants of the CWs, which are related to high terbuthylazine concentrations in plant material. A coconut fiber-containing biomixture was used in BPS which was able to rapidly remove terbuthylazine, with an estimated half-life of 8.1 d, the fastest so far reported in these systems. However, the biomixture failed to detoxify the matrix, according to ecotoxicological tests of seed germination. The current data suggests that coupled/hybrid configurations comprising CWs and BPS in series could provide increased effectiveness and a low-cost technology to remove terbuthylazine from highly contaminated water.