CONICET | Buscador de Institutos y Recursos Humanos

There are different physicochemical and biological methods totreat effluents. However, their efficiency is not enough to meet theeffluents discharge limits. For this reason, it could be possible toemploy a polished treatment. A suitable alternative for this goal couldbe constructed wetlands (CWs). The aim of the present research was toevaluate contaminants removal efficiency of a pilot scale horizontalsubsurface flow constructed wetland (HSSFW) for tertiary treatment ofdairy wastewater. A vegetation study was also conducted in order todetermine the role of plants on nutrient removal. A pilot scale HSSFWplanted with Typha domingensis was built in a dairy factory, after thebiological treatment. The substrate used was river gravel. During aseven-month research period, thirty-two samples (influent and effluent)were taken and analyzed to determine physicochemical and microbiologicalparameters as well as removal efficiencies. Biomass, TP, TKN and organicmatter content in plants was determined at the beginning and end of themonitoring period. Suspended solids showed significant differencesbetween inlet and outlet, with a mean removal efficiency of 78.4%. ForBOD and COD, mean removal efficiencies were respectively 57.9 and 68.7%.Removal percentages for TKN, Nitrates and TP were lower than otherparameters (25.7%, 47.8% and 29.9%, respectively). Fecal Coliformbacteria decreased one order of magnitude in final effluent. In the caseof Escherichia coli and Pseudomona aeruginosa results were variable.Total biomass increased 4.6 times at the end of the monitoring period.The study of plants indicated its important contribution in terms ofcontaminant uptake and retention. HSSFW would be an advisable alternativeas a tertiary treatment of dairy wastewater.

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