Abstract

In Ecuador, many communities depend on untreated surface water as the primary source of drinking water and are contaminated with fecal coliforms and Escherichia coli. The objective of the present study was to find aquatic plants with remove of contaminated water with E. coli and total coliforms. For this purpose, the following species were sampled: Azolla caroliniana Willd., Eichhornia crassipes, Pistia stratiotes, Salvinia auriculata, Ceratopteris thalictroides and Lemna sp. (Positive control). The plants were reproduced in vitro and bioassays were performed to verify their ability to remove E. coli. Assays were run by triplicate in 0.5 L of water with fertilizer and an E. coli ATCC25922 reference strain was inoculated. As negative control the bacteria without plants and positive control were inoculated with the plant L. minor. After 7 days, the remaining bacterial load was determined. To analyze E. coli, the technique ISO 9308-1 was used. A percentage of 99% E. coli removal was found for A. caroliniana, E. crassipes, C. thalictroides (L.) Brongn and Lemna minor. And 100% for P. stratiotes and S. auriculata. Subsequent waste water tests were performed in which S. auriculate and A. caroliniana achieved 100% removal of the coliforms and the remaining lower efficiency. The use of these species is proposed for the treatment of wastewaters.