ISSN: 1659-2751



Microorganisms as Bioindicators of Water Quality


Water quality routinely is determined using chemical analysis; however, the analysis of microbial populations is an additional tool that has been developed to determine the condition of aquatic environments. Microbiological analyses of the effluents of the water treatment systems of EARTH University were conducted to determine the communities of microorganisms present. The wastewater treatment systems studied were the Food Processing Laboratory and Dairy Products Plant, the biodigesters at the cafeteria and the dairy and swine facilities; the Banana Packing Plant and the wetlands of Las Mercedes. Effluent samples were collected at the discharge site of each system and microbial communities in each sample were identified and quantified. Photographs also were taken for microbial identification under the German Saprobic System and the Salvadorian IBG-SV-2010 System. The samples were then analyzed for physical and chemical characteristics including pH, total solids (suspended solids and settable solids), BOD5 (biochemical oxygen demand), COD (chemical oxygen demand) PO43–, NO3 and NH4+. The microbiological results were compared to the physical and chemical results, and both indicated that the effluents of the wastewater treatment systems still contained elevated levels of contaminants. This evaluation proved that microorganisms are effective bioindicators of water quality. It is possible to use microorganisms as bioindicators due to the extensive biodiversity of this group of organisms.

Key words: chemical analysis, water quality, microbiological analysis, bioindicators, German Saprobic System, Salvadorian IBG-SV-2010 System.

Artículo en español (pdf) (920)