1.0 PURPOSE
In the City of Flagstaff, there exists the Cheshire Pond and the Francis Short Pond. The Francis Short Pond is located south of the Cheshire Pond and is constantly being supplied with reclaimed water to maintain the water level while in the Cheshire has a constant supply of rainfall, snowmelt and is constantly being supplied by water from the Rio Del Flag. What raise many issues in the Francis Short Pond are the potential effects of the reclaimed water on the ecosystem around Francis Short Pond. Thus, to establish the differences between reclaimed water and as a source of water for ponds and natural water, a discussion of the different issues is provided in the discussion that follows below. To establish this differences water samples will have to be obtained from the two ponds and several tests including turbidity, dissolved oxygen levels and alkalinity performed.
2.0 METHODLDOGY
2.1 SAMPLE COLLECTION
Between 11:00 am and 2:00 pm, on 23 April 2013, water samples were collected. There was no recent event of rainfall, which would have an influence on the water quality. The weather during the day was windy (winds speeds recorded were between 6-10mph), sunny, with ambient temperatures reaching 55℉.
Three Nalgene sample bottles were utilized to collect three different samples at each sample site. The selection of the site depended on the ease of accessibility and the likelihood of it being a representative location for the whole pond. The sampling locations for the Francis Short Pond and the Cheshire Pond were indicated in the site maps as attached in the Appendix A.
Preservation of the samples was done using a refrigerator at a temperature of 4.4℃ for a duration of a maximum 48 hours before testing began.
2.2 DISSOLVED OXYGEN (DO)
Measurement of dissolved oxygen was done in-situ while using a transportable DO/Temp/pH/conductivity meter. At each sampling location, the different values of DO were recorded and reported immediately after the collection of the samples from those specific locations.
2.3 TURBIDITY
The SM 2130 B: Nephelometric Method standards were used to establish the turbidity of the samples. To do this, the samples were kept at a temperature of 10℃ for a period of 24 hours prior to performing the test. The sample was shaken before being transferred to 5ml glass vials and the turbidity recorded in NTUs.
2.4 VOLATILE SUSPENDED SOLIDS
The gravimetric method as stipulated in SM 2540 was used to establish the volatile suspended solids (VSS). A portion of the total amount of the sample was obtained after the sample was shaken for a while. Secondly, vacuum filtration of the sample was done through a preconditioned standard glass fiber. The mass of the filter prior to use but after pre-conditioning was recorded as M1. After drying for 24 hours at 103℃ , the mass of the filter was recorded as M2. The filter was then dried for 20 minutes at 550℃ and then cooled to room temperature and the mass recorded as M3. Calculations were done for the total suspended solids, the fixed suspended solids and volatile suspended solids
Calculations
TSS=M2-M1
FSS=M3-M1
VSS=TSS-FSS
2.5 STATISTICAL ASSESSMENT OF RESULTS
3.0 RESULTS
3.1 DISSOLVED OXYGEN
Analysis from the Francis Short Pond established that the dissolved oxygen levels were almost similar to those obtained from the Cheshire Pond. For the Francis Short Pond, the mean dissolved oxygen was 4.3 and the standard deviation was 0.25.
High temperature recorded for the site number 2 in the Cheshire pond was attributed to the low depth of the sample collection location. Most of the pond area was less than a foot deep and sloped gradually from a collection of reeds on the northwestern shore side of the pond. Sample number tow was collected near the red bed as indicated in Appendix A.
pH levels for both ponds were almost similar and no major differences were established. However, temperatures for the two ponds differed greatly and this was because of the depth of difference in depths of the ponds. The shallow Cheshire pond had a temperature higher than that of the Francis Short Pond.
3.2 TURBIDITY
3.3 VOLATILE SUSPENDED SOILDS
4.0 CONCLUSIONS
The quality of water in both ponds is almost similar. This was based mainly on the dissolved oxygen test. The Cheshire pond dissolved oxygen levels was 0.21 mg/l higher than that of the Francis Short Pond. Thus, based on this, the reclaimed water seemed to have no effect on the ecosystem of the pond. For aquatic organism to survive there is need to have sufficient levels of dissolved oxygen in the water.
