NON CONVENTIONAL WASTEWATER TREATMENT TECHNOLOGIES (INFILTRACIÓN PERCOLATION AND CONSTRUCTED WETLANDS)

Abstract

The use of non-conventional technologies for treating wastewater in small communities is in a stabilisation step at the autonoums region of Catalonia (Spain). This fact is a consequence of the advantages associated to this type of treatments (low building costs, low energetic requirements, easy to manage, etc.). This study presents the experience carried out at a Catalan municipality which treats its wastewater through two different types of natural systems (modified infiltration-percolation and constructed wetlands). During the research period, the population has grown up from 1,200 inhab-eq to 2,000 inhab-eq at the end of the study, consequently hydraulic load has increased and changes on the influent quality were observed. Results associated to modified infiltration-percolation show that the increment of hydraulic load influence on ammonia removal, nitrification percentage and disinfection capacity. In relation with constructed wetlands, organic matter removal is bigger when the system doesn’t work in a continuum way (the bed is emptied after 5 days of functioning).

The aim of this work is, first of all, to determine the viability of natural treatments, specifically related to modified infiltration-percolation and constructed wetlands, in a small community which has increased its number of inhabitants and has produced a wastewater with different qualities. Besides, the influence of hydraulic and contaminant load are studied in order to find out their impact on treatment capacity of both natural systems.

Keywords: aguas residuales, infiltración percolación modificada, zonas húmedas construidas.