Spontaneous light emission applied to microbiological wastewater monitoring

Author(s)

Samuel Ricardo dos Santos

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Engenharia Agrícola
• Defense date: 2010-05-02

Examining board members

José Euclides Stipp Paterniani; Cassiana Maria Reganhan Coneglian; Marco Roberto Pires

• Advisor: Cristiano de Mello Gallep; José Euclides Stipp Paterniani

Abstract

The coliform bacteria have been widely used in water quality monitoring, using Escherichia coli as indicator of faecal contamination. Current standard methods for of coliforms and Escherichia coli detection take 18-h minimum and the complete testing process, including confirmatory biochemical tests, may require at least 48 hours. The importance of rapid detection of coliforms and Escherichia coli, regarding to the quality and safety of water, is obvious and necessary. The spontaneous light emission of living systems emerge as a promising methodology that applied to microbiological in monitoring water can lead to shortterm analysis. The present study evaluated the potential of biophoton measurements applied to wastewater monitoring by using ultraweak light emission in coliform tests. The procedure is based on photon-counting measurements inside a dark-chamber, of wastewater samples, before and after treatment, inoculated in nutrient medium. Strain of Escherichia coli (ATCC 25922) was used in control tests by monitoring the light emission in nutrient medium. The results for strain and wastewater incubated in chromogenic substrate show better correlation between microbial growth and light emission, in contrast to experiments with EC Broth and Presence/Absence nutritive medium. The data show that microbiological monitoring can be done by photon-counting with at least three hours in chromogenic substrate and at least twelve hours with EC and Presence/Absence Broth. (AU)