Effects of Sewage Run off on River Water Quality John Peilert Central Catholic High school grade 9 2nd year of PJAS
Problem The sewage system in Pittsburgh is one of the oldest in the country. Whenever it rains the water treatment plant diverts the sewage directly into the river. As a city that relies heavily on its rivers, this could be devastating.
Storm Water Runoff Runoff is part of the water cycle. It is water that flows over a land surface. Precipitation causes substances to enter bodies of water unchecked.
Sewer Runoff Combined Sewer System collects both waste and rain water. This allows for both storm water and waste water to enter the sanitation plant. Overflow causes waste water to enter water bodies. Pittsburgh s municipalities mainly have combined
Nitrate Nitrates are used as components in fertilizers. Nitrates can also be used as a salt.
Ammonia Ammonia is used in the home as a cleaner. Also a component in fertilizer.
Phosphate Used is an ingredient in soap It is also used as a component of fertilizer.
E. coli Gram negative Rod-shaped Intestinal mammalian symbiont Widely studied Easy to maintain, high growth rate, simple nutritional requirements
Enterobactor aerogenes Gram negative Rod shaped Found in human intestinal tract Is an opportunistic infector
Purpose The purpose of this experiment is to determine whether or not sewage will significantly affect the levels of chemicals and fecal matter in the river water.
Hypothesis Null: The river water affected by the sewer runoff will not vary significantly from the normal river water. Alternative: The Coliscans that test the water collected after the precipitation will contain significantly more fecal and non-fecal coliforms.
Materials Carolina spectrophotometer nitrate solution 10mg/1L(stock) phosphate solution 10mg/1L(stock) ammonia solution 10mg/1L(stock) nitrate testing kit phosphate testing kit ammonia testing kit Incubator 10ml sterile test tubes 10 & 5 ml pipette 1000μL micropipette water test tube rack river water samples river water samples with sewer runoff Coliscan easy gel Coliscan easy gel plates
Procedure Two samples of river water were collected. The first was collected on January 4. The sample was collected then because there was almost no precipitation. The second was collected on the 12 a day after four straight days of precipitation. A 3mL sample was added to the Coliscan fluid and then immediately poured into a sterile Coliscan plate After an hour of hardening the plates were then incubated over night at 37C. The resulting colonies were identified and counted. Three standard curves were then established using the following solutions (The stock is the amount of either nitrate, phosphate, or ammonia in solution. All were used.)
Procedure 0% 20% 40% 60% 80% 100% Pure water 5ml 4ml 3ml 2ml 1ml 0ml Stock 0ml 1ml 2ml 3ml 4ml 5ml total 5ml 5ml 5ml 5ml 5ml 5ml After the solutions were made, a reporter molecule packet was added to each of the corresponding test tubes. The samples were allowed to sit for 10 minutes, to promote the colorimetric reaction. Absorbance readings at 400 nm were recorded for all samples.
absorbance Standard Curve Ammonia 0.14 0.12 0.1 0.08 0.06 Series1 Poly. (Series1) 0.04 0.02 0 0% 50% 100% 150% [Concentration] mg/l
Absorbance Standard Curve 0.2 Phosphate 0.15 0.1 0.05 Series1 Poly. (Series1) -0.05 0 0% 50% 100% 150% [Concentration] mg/l
absorbance Standard Curve 0.9 Nitrate 0.8 0.7 0.6 0.5 0.4 0.3 Series1 Poly. (Series1) 0.2 0.1 0 0% 50% 100% 150% [concentration] mg/l
mg/l Runoff chemical results 3.5 3 2.5 2 1.5 1 0.5 0 Phosphate nitrate ammonia River water without sewage River water with sewage
Results Standard Curve 0% 20% 40% 60% 80% 100% Phosphate average 0 0.049 0.118 0.163 0.177 0.186 Nitrate average 0 0.257 0.390 0.579 0.737 0.805 Ammonia average 0 0.050 0.065 0.089 0.089 0.129 Absorbance of river water samples River water without sewage mg/l River water with sewage mg/l Phosphate average 3.04 3.05 Nitrate average.145.189 Ammonia average.5.525
Phosphate Anova Anova: Single Factor Phosphates SUMMARY Groups Count Sum Average Variance River water without runoff 4 121.817 30.45425 0.129732 River water with runoff 4 122.3 30.575 0.154433 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.029161 1 0.029161 0.20524 0.666445 5.987378 Within Groups 0.852497 6 0.142083 Total 0.881658 7
Ammonia Anova Anova: Single Factor Ammonia SUMMARY Groups Count Sum Average Variance River water without runoff 4 2.13 0.5325 0.000158 River water with runoff 4 2.1 0.525 0.000167 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.000113 1 0.000113 0.692308 0.437237 5.987378 Within Groups 0.000975 6 0.000163 Total 0.001088 7
Nitrate Anova Anova: Single Factor Nitrate SUMMARY Groups Count Sum Average Variance River water without runoff 4 58.17 14.5425 1.405225 River water with runoff 4 75.94 18.985 10.0409 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 39.47161 1 39.47161 6.896939 0.039259 5.987378 Within Groups 34.33838 6 5.723063 Total 73.80999 7
Coliscan Results Three types of colonies were identified. E. coli (fecal) Enterobacter Aerogenes (non-fecal) Unidentified coliforms (other) Average number of coliforms E. coli Enterobacter aerogenes Other River water without sewage 4.25.25 River Water with sewage 22.75.75 1
Number of colonies Coliscan Results 25 20 15 River water with sewage 10 5 0 Fecal coliforms non fecal coliforms other river water without sewage sewage
E. Coli Anova Anova: Single Factor E. coli SUMMARY Groups Count Sum Average Variance River water without runoff 4 1 0.25 0.25 River water with runoff 4 3 0.75 0.916667 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 0.5 1 0.5 0.857143 0.390259 5.987378 Within Groups 3.5 6 0.583333 Total 4 7
Enterobactor aerogenes Anova Anova: Single Factor Enterobacter aerogenes SUMMARY Groups Count Sum Average Variance River water without runoff 4 16 4 4.666667 River water with runoff 4 91 22.75 195.5833 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 703.125 1 703.125 7.022472 0.038029 5.987378 Within Groups 600.75 6 100.125 Total 1303.875 7
Unidentified coliforms Anova Anova: Single Factor Other SUMMARY Groups Count Sum Average Variance River water without runoff 4 1 0.25 0.25 River water with runoff 4 4 1 1.333333 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 1.125 1 1.125 1.421053 0.278236 5.987378 Within Groups 4.75 6 0.791667 Total 5.875 7
Conclusion Nitrate was significant. Phosphate and Ammonia were not significant The count of non-fecal coliform colonies changed significantly. The count of unidentified coliforms and E. coli coliforms were not changed significantly. The majority of tests did not change significantly.
Limitations and extensions Only one wavelength of light was used during the tests. The samples for the standard curve should have sterile filtered. There should have been more replicates to receive more accurate results on the Coliscan. The test tubes were not polished before having the absorbance measured. More samples should have been taken when more or less rain had fallen. Algae growth should be tested with each sample. Multiple rivers should be tested in multiple places.