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Use of Oxygen Uptake Rate to Determine the Toxicity of a Wastewater or Fracking Water Sample. Presenter : Dr. Edward F. Askew Askew Scientific Consulting. . Oxygen Uptake Rate.
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Use of Oxygen Uptake Rate to Determine the Toxicity of a Wastewater or Fracking Water Sample Presenter: Dr. Edward F. Askew Askew Scientific Consulting.
Oxygen Uptake Rate • Aerobic and Facultative Anaerobic bacteria metabolize carbon, nitrogen, and sulfur organic compounds and also perform redox on inorganic compounds utilizing oxygen.
What is Inhibition or Toxicity • Toxicity: The degree to which something is poisonous. • Inhibition: An inhibitor is a substance that delays or slows the bacteria metabolism. • Therefore: A chemical may slow down the biological treatment of a waste (inhibit) or stop it all together (toxic).
Types of Toxicity Tests • WET: Whole Effluent Toxicity (Indicating Organisms). • Microtox®: Bioluminescent Bacteria Vibrio fischeri. • ATP: Bioluminescence of Residual ATP. • OUR: Oxygen Uptake Rate of Bio-organisms.
OUR • Utilizes bio-organisms from the wastewater process of the receiving watershed. • Measures rates of metabolism of affected organisms. • Can be performed with simple BOD equipment or OUR rate monitoring instruments: GreenLight® 910 or 930
GreenLight • Utilizes a vial with an internal oxygen sensor and a thermostatic cell holder(s)
Setting Up the Toxicity Test • Select a growth matrix for the bacteria (i.e. Food Source) • Tryptic Soy Broth • Synthetic Wastewater • ISO 11733-2004 OECD Medium • ISO 11733-2004 Synthetic Sewage #2 • Marlene Mix (EPA)
Setup Your Baseline Sample • Mix together your: • Food • Bacteria • Dilution Water • Transfer to a GreenLight Vial • Run the Analyses • Determine the Time to Threshold
Set up Your Toxicity Test Samples • Mix together your: • Food • Bacteria • Dilution Water • Toxicity Samples • Transfer to a GreenLight Vial • Run the Analyses • Determine the Time to Threshold
