ISSN: 1659-2751

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Evaluation of a System for Treatment of Ordinary Domestic Wastewater in the Community of Suerre, Guápiles, Limón

Abstract

The present treatment system was implemented in 2012 by the Water and Sewer Association (Asociación de Acueductos y Alcantarillados, or ASADA, in Spanish). The system consists of an anaerobic reactor and a sub-surface flow artificial wetland. After a year of operation the biogas production capacity of the anaerobic reactor and the decontamination levels of the wetland were assessed. The previous experience of a family in the community of Suerre showed that the anaerobic reactor did not produce enough biogas for their own consumption. Therefore, biogas production from sewage was estimated and it was determined that it is a very poor substrate, i.e. sewage does not have a high potential for producing biogas; it only manages to supply a maximum of 12 % of the household biogas demand. In order to meet the family demand for biogas needs, the implementation of a new reactor to process substrates with high potential for biogas production was recommended, using substrates available in the area, such as cattle and swine manure. It was calculated that 39.32 kg of cattle manure or 30.25 kg swine manure would be needed to meet the remaining biogas demand. It was determined that the sub-surface artificial wetland successfully removed DBO5, DQO, NO3¯, y PO42¯ present in the ordinary domestic wastewater. However, with regards to ST, the reduction in levels was not sufficient to comply with the law.

Key words: water quality, sub-surface flow artificial wetland, biogas production, anaerobic reactor, wastewater treatment.

Artículo en español (pdf) (96)