Title: Field Test Methods For Bulk Water Bacteria Counts: Does It Matter Which Test You Use?
Learner Objectives:
The objective of this presentation is to present the results of a research project to evaluate the differences between commonly used field test methods for microbial counts in water so that water treatment professionals can make more informed decisions for routine monitoring.
Content/Topic Outline:
Presenter:
Angela Delegard, Senior Research Scientist, Chem-Aqua, Inc.
Presentation Description:
A wide array of test methods have been developed and marketed for the onsite monitoring of microbial activity in water systems. The number and variety of tests that are available can make it difficult for water treaters to select the best method for monitoring microbiological control or to compare the results from different field methods and laboratory results.
Due to their simplicity, field tests for bulk water bacteria and fungi counts are commonly used as an indicator of microbiological control in cooling water treatment programs. The most widely used field test methods can vary considerably in terms of cost, time requirements, and ease of use and interpretation. The differences between these test methods along with the dynamic nature of real world microbial populations can make it difficult for water treatment professionals to select the best method for routine use.
A research project was initiated to compare commonly used field tests for bacteria and fungi counts for precision, accuracy, ease of use, time requirements, and cost. The study compares the results from different dip slide manufacturers as well as from test strips, serial dilution bottles, and floating ball testers. Validation for these tests used representative microbial species for total aerobic bacteria, sulfate reducing bacteria, iron reducing bacteria, iron oxidizing bacteria, mold, and yeast. The study approach provided useful insight into the types of bacteria and fungi that can be detected with different media and methodologies, and explanations for differences in each tests performance. Based on the study results, objective criteria is provided to help water treaters select the most appropriate field test method(s) for monitoring bacteria and fungi counts.
Presenter Bio:
Angela Delegard is a Senior Research Scientist for Chem-Aqua at NCH Corporation. She graduated from the University of North Texas with a Bachelors and Masters of Science in Biology. Within the Water Treatment department, she evaluates novel methods to treat microorganisms in cooling systems. She serves as lead scientist for the biomonitoring research program at the company by using a suite of techniques to characterize microbial populations and implement optimal treatment.