CONICET | Buscador de Institutos y Recursos Humanos

In Argentina, drinking water for c.a. 10% of the population has arsenic (As) concentrations higher than those rec-ommended by WHO (10 μg L−1). Reverse osmosis (RO) appears as an immediate and effective solution for As re-mediation. However, this process has a residual flow known as ?rejection? or ?concentrate? where dissolvedspecies are more concentrated than in the feed flow. In this study, phytoremediation with subsurfacehorizontal-flow constructed wetlands (CW) was proposed to reduce As concentration in the RO residues. Exper-iments were carried out during 419 days at room temperature and using a continuous regime (flow of 36 L d−1,As concentration around 85 μg L−1) of RO rejection from a water treatment plant located in Buenos Aires prov-ince, Argentina. The study was performed using prototypes planted with Cyperus haspan (PA), Juncus effusus (PB)and a mix of inert gravel and laterite (substrate) that was used as a control (PC). Results showed that after a sta-bilization time, As removal (%) was between 30% and 80% in the CW planted with J. effusus and between 10 and40% with C. haspan. As concentration along CW showed similarities between the prototypes PC and PA. The cu-mulative mass of As was 62%, 34% and 27% for PA, PB and PC, respectively. The contribution of C. haspan andJ. effusus during the experimental time was between 12 and 67% and 22 to 87%, respectively. The bioaccumulationand translocation factors indicated that for J. effusus the accumulation is more important than the translocationprocess (1.6 and 0.2, respectively), while for C. haspan both factors were similar (1.1 and 1.0, respectively). Re-sults suggested that this technology has the potential for an efficient and environmentally sustainable alternativeto RO rejection treatment and disposal regarding As concentration.

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