Constructed wetlands for domestic wastewater treatment in a Mediterranean climate region in Chile

Background: Constructed wetlands are a promising, cheap and effective wastewater treatment in small communities. The studies on these systems have been reported mainly from cold, tropical or subtropical climate regions. In this work we constructed a pilot plant with six horizontal subsurface flow constructed wetlands (HSSF CWs) with a surface area of 2 m² and a depth of 0.6 m each, planted with Typha latifolia or Scirpus sp., and filled with gravel (G) or fine gravel (FG) of 2.8 and 1.2 cm of diameter respectively, continuously fed with raw domestic wastewater. This experimental setup was evaluated over 280 days for the removal of organic matter and nutrients in a Mediterranean climate, near Valparaíso, Chile. The removal of total COD, NH4+-N and PO4-3-P was calculated, in order to assess by analysis of variance the effect of initial pollutants concentration, air temperature (season) and plant/support combination on the wetlands performance. Results: The Scirpus/FG combination showed the highest average removal of total COD of about 59%, and Typha/FG shows the highest removal of NH4+-N and PO4-3-P (49 and 32%, respectively). Furthermore, the removal of organic matter was independent of influent concentration, while mildly dependent of the season, unlike nutrients removal that was dependent on these two parameters. Media, plant and the plant/media combination influenced positively organic matter, ammonia and phosphorous removal, respectively. Conclusions: Overall, the results demonstrate the potential of wetlands in treatment of wastewater in Mediterranean regions and show how these can help to improve the quality of water in domestic zones without high-throughput technologies.

Notas sobre la avifauna del humedal santa maría del lago, cordillera oriental de los andes Colombianos / Notes on he birdd species of the santa maria del lago wetand, cordilleraa oriental of the Colombian andes mountains

Se presentan los resultados del inventario de la macrofauna observada (desde febrero 23 hasta mayo 31 del 2001) en Santa María del Lago, humedal netamente urbano, de los trece presentes en la ciudad de Bogotá durante su rehabilitación paisajística (recuperación del espejo de agua, revegetalización y reforestación). Los resultados incluyen una lista con las observaciones sobre el hábitat, actividad y frecuencia de tres especies de peces, una de anfibios, treinta y una de aves y tres de mamíferos, registradas en los diferentes muestreos mensuales con una intensidad de uno por semana. Dentro de la fauna del citado humedal, se resalta la presencia de los mamíferos Cavia porcellus (Caviidae), Oeomys speciosus (Muridae) y Olygoryzomys fulvescens (Muridae), la rana Hyla labialis (Hylidae) y los peces Eremophilus mutissii (Trichomycteridae) y Grundulus bogotensis (Characidae), que se consideraban desaparecidos del humedal. También se registran por primera vez para el humedal, nueve especies de aves (Anas platyrhynchos, Carduelis psaltria, Anser anser, Diglossa humeralis, Piranga olivacea, P. rubra, Rhamphocelus dimidiatus, Stelgidopteryx ruficollis, Vireo olivaceus), al igual que el pez exótico (C. auratus).

This article presents the results of the inventory of the observed macrofauna (from February 23rd to May 31st 2001) in Santa María del Lago, one of the thirteen present wetlands in Bogotá during its landscape rehabilitation (recovery of the water mirror, revegetation and reforestation). The results include a list with observations regarding the habitat, activity and frequency of 3 fish species, 1 amphibian, 31 bird and 3 mammal species, registered in the different monthly samplings with a weekly intensity. The fauna of the previously-mentioned wetland, includes mammals such as Cavia anolaimae (Caviidae), Oeomys speciosus (Muridae), and Olygoryzomys fulvescens (Muridae), the frog Hyla labialis (Hylidae) and the fish Eremophilus mutissii (Trichomycteridae) and rundulus bogotensis (Characidae) considered missing from the wetland. New species are also reported for first time in the wetland, 9 species of birds (Anas platyrhynchos, Carduelis psaltria, Anser anser, Diglossa humeralis, Piranga olivacea, P. rubra, Rhamphocelus dimidiatus, Stelgidopteryx ruficollis, Vireo olivaceus), and the exotic fish (C. auratus).