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Biochemical Oxygen Demand Presentation
Transcript of Biochemical Oxygen Demand Presentation
1. "Biochemical Oxygen Demand ." Polyseed . N.p., n.d. Web. 23 May 2013. <www.polyseed.com/misc/BODforwebsite.
2. "Anacostia Park - Anacostia Park." U.S. National Park Service - Experience Your America. N.p., n.d. Web. 23 May 2013. <http://www.nps.gov/anac/index.htm>. In conclusion, further study would have illustrated that while the biochemical oxygen demand is decreasing over time, BOD is still substandard to the healthy drinking water standard. We decided that in order to improve the porduction of quality effluent water, and decrease the BOD there needs to be suitable levels of nitrates and phosphates present in the wastewater, and a constant temperature. Biochemical Oxygen Demand By Shonali and Alexandra In this lab, our hypotheses were supported. According to our results, we found that over the course of one year (2011-2012), the average of the BOD's in the Anacostia went from 4.4 to 2.7. The line graph showed us that the BOD decreased in the Anacostia. It turns out, the data from the water quality over time helped us proove our hypothesis. Because of the decrease in BOD, we can see that the water quality got better. We can see that the averages of the WQIs changed from 54.97 to 73.33, which meant while the BOD deacreased, the water quality went from moderate to good. While we did not have an error a hypothetical one would be that we did not let the first sample of water sit long enough for the aeorbic bacteria fully oxidize the organic material.This would alter our data because the water would not be able to go through the full process of oxidization, and and the bacteria may not have been able to use up as much of the oxygen as it should have. BOD is a measure of how much oxygen the bacteria uses in the aerobic oxidation of organic matter, so if the bacteria does not use up as much oxygen as it should, we will get a lower BOD rate than we should have. This could have altered our conclusion because we may not have been able to prove the hypothesis if the BOD was lower than it was supposed to be, and therefore not seen a significant enough decrease in the BOD to prove that the decrease in BOD improves the water quality. #1 Over the course of three years, if the BOD decreases, then the water quality will get better
#2 If you examine the water quality as it moves downstream, then their should be little change in the BOD Basic Information: Results Bar Graph Hypotheses: Greenbelt = Upstream - against flow of current
Anacostia = Downstream
Kenilworth = Middle region
BOD is a measure of how much oxygen the bacteria uses in the aerobic oxidation of organic matter – standard method for indirect measurement of the amount of organic pollution that can be oxidized biologically in a sample of water
Measure BOD by comparing the amount of dissolved oxygen present in a freshly collected water sample with the amount of dissolved oxygen in a second collected under the same circumstances – but allowed to “sit” for five days so that the bacteria in the sample has time to work (Biochemical.)
The difference between the two samples is how much oxygen the decomposing bacteria used to oxidize the organic material in water during the 5-day incubation period Natural Sources: Organic matter include plant decay and leaf fall, Urban runoff carries pet wastes from streets and sidewalks; nutrients from lawn fertilizers; leaves, grass clippings, and paper from residential areas, which increase oxygen demand. Sources Bacteria decompose the organic compounds and release into the water inorganic nutrients such as nitrate and calcium Under normal conditions, dissolved oxygen exists in very low concentrations. Thanks Influences The BOD of natural waters is 5 mg/L, and there is plenty to available for aquatic organisms
If a lot of organic material is added to water, BOD increases
When aerobic bacteria uses up a lot of dissolved
oxygen, little is left for other aquatic organisms
Over 30 mg/L of BOD: aquatic life threatened with suffocation Line Graph Based of the results of BOD, our second hypothesis was correct. We came to this conclusion by analyzing the data in each location. The data proved that the average BOD per specific location's were all very siliar. Greebelt had a BOD of 3.5 mg/L which is similar to the BOD of Kenilworth Aqatic Gardens of 2.7 mg/L. Borth of those BOD's are similar to the Anacostia Park's BOD of 2 mg/L. Therefore, BOD levels (increasing or decreasing) do not depend on the location. Error Analysis LOW BOD BETTER WATER QUALITY HAPPY PEOPLE mg/L locations