Monitoring and Assessing Drinking Water Quality

Overview

• Municipal water supply testing the effecitveness of a water treatment

• Water samples were taken before treatment and post treatment.

Question

What is the effect of the water treatment on the microbial biomass and community structure?

 
Analyses Requested:
           
            PLFA

Results:

• PLFA analysis showed that biomass content was two orders of magnitude greater prior to treatment.  The treatment was effective in reducing the microbial biomass in the water supply.

• PLFA profiles showed that prior to treatment, the microbial community in the water supply was quite diverse and included a large proportion of eukaryotes ( likely algae, protozoa or diatoms). "Anaerobic" community members, including Firmicutes, anaerobic metal reducers and sulfate-reducing bacteria were also seen.

• After treatment, the microbial community was much less diverse, with eukaryotes, anaerobic metal reducers and SRBs no longer detected in appreciable proportions. This suggests that the treatment was effective at reducing eukaryotes and some types of anaerobes.

• Metabolic status ratios showed that the growth rate of Gram negative Proteobacteria was cosiderably slower after treatment. Even though Proteobacteria were not eliminated, the water treatment appeared to be effective at reducing the growth rate of Proteobacteria

Answer:

PLFA results showed that the water treatment reduced overall biomass, with a notable loss of eukaryotes and certain anaerobic members of the community. PLFA results also suggested that even though the treatment did not eliminate Proteobacteria, it did slow their growth rate.