biochemical oxygen demand bod and dissolved oxygen do n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO) PowerPoint Presentation
Download Presentation
Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO)

Loading in 2 Seconds...

play fullscreen
1 / 11

Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO) - PowerPoint PPT Presentation


  • 350 Views
  • Uploaded on

Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO). 1. Background Information. Saturated Oxygen Levels in Fresh Water. Like all gases, O 2 is less soluble as temperature increases Saturated level of water exposed to the atmosphere is typically 8-14 mg/L. Effects of Oxygen Depletion.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Biochemical Oxygen Demand (BOD) and Dissolved Oxygen (DO)' - rooney-burt


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
saturated oxygen levels in fresh water
Saturated Oxygen Levels in Fresh Water
  • Like all gases, O2 is less soluble as temperature increases
  • Saturated level of water exposed to the atmosphere is typically 8-14 mg/L
effects of oxygen depletion
Effects of Oxygen Depletion
  • Effects of low DO on ecosystem communities and populations
    • How much DO is enough?
    • Rapid decrease in DO can cause massive fish kills
    • So-called dead zones form if DO level falls enough
  • Effects of low DO on chemical composition
    • Converts chemicals to different forms
      • carbon dioxide (CO2) to Methane (CH4),
      • sulfate (SO42-) to hydrogen sulfide (H2S),
    • Forms of metals frequently more soluble
      • Metals can become more mobile
      • Increases exposure of humans and animals to toxic metals
bod waste water
BOD Waste Water
  • Questions
    • What is “high-BOD” waste water?
    • What are the major sources of high-BOD waste water?
    • BOD = biochemical (or biological) oxygen demand
      • When organic material is decomposed (mostly microbial aerobic respiration) it “demands” oxygen
    • Oxygen demand represents a potential loss of DO in a water body
    • Oxygen demand can be quantified by measurement of BOD
      • BOD measurement: (i) collect a sample of known volume; (ii) measure the DO level; (iii) seal and incubate at constant temperature for 5 or 7 days; (iv) measure the DO level again.
      • The BOD is the difference between the two DO measurements.
oxygen sag curves
Oxygen-Sag Curves
  • Question
    • What is an oxygen sag curve?
    • An oxygen sag curve is the dip in dissolved oxygen observed when BOD waste water is discharged continuously into a river.
      • The extent of the sag is determined by BOD level in the wastewater stream, by the rate of discharge, and by other factors such as temperature and river characteristics (flow rate, turbulence, etc).
    • An oxygen sag curve is also observed due to a one-time discharge of BOD waste into a lake
      • In that case, the DO drop is with time instead of distance downriver.
methylene blue
Methylene Blue
  • What does it do?
  • Demo

http://www.csun.edu/scied/2-chem/redox_methylene_blue/index.htm

lab requirements
Lab Requirements
  • Answer pre-lab questions based upon information learned today.

(except for 2nd

bullet)