Evaluación de la biodegradabilidad de detergentes comerciales con el método de prueba presuntiva mediante la norma ASTM D2667, en el laboratorio AQLAB, en la ciudad Francisco de Orellana.

Abstract

The objective of this work was to evaluate the biodegradability of commercial detergents with the presumptive test method by the ASTM D2667 standard, in the AqLab laboratory, in the Francisco de Orellana city. A bibliographic review was carried out of the ASTM D2667 and ASTM D2330 methods of the INEN specification. By using the method ASTM D2667 the presumptive test was selected, the biodegradation efficiency was compared of commercial detergents applying strain ATCC 25922 (Escherichia coli), active sludges and river water, in solutions of commercial solid and liquid detergents tested, which were maintained during eight days of incubation with the continuous shaking of the flasks. Then proceeded to apply the method ASTM D2330, this method was used on the initial day and on the eighth day of incubation, which determined the reduction in the content of surfactant in mg / l in the tested detergents, it was expressed in fraction mass in a minimum percentage of 90% biodegradability, complying with the requirement of the INEN standard. A procedure manual was elaborated for the study of biodegradability of detergents. Three tests were performed by repetitions of each inoculum used: ATCC25922 strain (E. coli), active sludges and river water, the microbial culture medium and surfactants. It is concluded through the comparison of the biodegradation efficiency of the inoculums, which ATCC 25922 strain (E. coli) is the most efficient with results from 86 to 99% biodegradability, which ATCC 25922 strain (E. coli) is the most efficient with results from 86 to 99% biodegradability. Of the three surfactant solids and tensoactivos liquids tested, the detergent C in solid that is commercialized on the market as a biodegradable product had a biodegradability of 98%. It is recommended to prepare the reagents for incubation and extraction on the same day of the trial, to ensure the quality of results since these solutions are not very stable.