Turbidity vs Suspended Solids

Turbidity is the lack of clarity in the sampled water caused by suspended insoluble particles interfering with light passing through. Despite a direct link with these two parameters, no co-relation exists between the results for turbidity and suspended solids. The values of both parameters are negligible as all are too low to demonstrate a clear co-relation.

TDS vs pH

There is no co-relation between total dissolved solids and pH in both theory and the results obtained. As pH is only affected by the concentration of hydrogen ions, total dissolved solids involves many different kinds of ions and molecules, but not hydrogen ions.

Nitrate vs Nitrite

The graph shows that there is a strong relation between the nitrates and nitrites concentration in the waters of the sites, Tank before Pond not included. This was mainly caused by the similar values of the nitrate and nitrites concentrations that remained mostly in the same range as shown by the table. Thus, the relation between these ions are insignificant.

The maximum acceptable concentration (MAC) for nitrate & nitrite in drinking water is 45 mg/L & 3.2mg/L respectively. Given that our average values for nitrate & nitrite is 0.0838mg/L & 0.0186mg/L respectively, this shows that the water is usable as potable water & for domestic purposes.

The nitrate value increases as its sources in water includes breeding of tadpoles and fishes, especially in the ponds. Their wastes (that contained organic-nitrogen) would have contributed to the increase in nitrate. The nitrite value is low as it is only formed by drinking water distribution systems that use chloramines, such as tap water. Only under anaerobic conditions, nitrate may be degraded to nitrite.

http://www.hc-sc.gc.ca/ewh-semt/pubs/water-eau/nitrate_nitrite/index-eng.php

DO vs BOD

The higher the BOD, the lower the DO present in the sample. This is caused by the organisms thriving in water, especially bacteria in polluted water such as the Grease Trap. And since the organisms in the waters require high amount of Oxygen for their activities, it results in the decrease of DO.

Given that the values of BOD are 4.75mg/L in average, it falls into the standard values of BOD of Raw Water source which is 3 to 15 mg/L.

DO vs TEMPERATURE

The higher the temperature of the sites, the lower the Dissolved Oxygen (DO). This is due to several reasons:

1. The solubility of oxygen varies with temperature. The concentration of Oxygen in the water is inversely proportionate to the temperature.
2. Due to high temperature (28 degrees Celcius), organisms such as tadpoles, planktons, plants and bacteria in the water require higher amount of DO to respire and carry out their activities as per normal.

Our results, however, shows a weak relation between these two parameters. This was probably due to experimental errors in measuring the temperature and DO values on site. Instead of dipping the DO cum Temperature probe into the water bodies, we collected samples from the sites into bottles before measuring them. The samples were left in the bottles for a length of time before they were measured for their temperature and DO values.

Hence, we can assume that some of the DO had escaped into the atmosphere and that the temperature had changed slightly when we tested them, causing varied or inaccurate values.

BOD vs COD

There is no correlation between the BOD and COD of the different water collection points. Theoretically, as BOD concentration increases, COD concentration should increase as well. However, our results showed otherwise. The reasons could be that:

1. The COD and BOD values were too low and insignificant to show a strong relation between them.

2. Apart from the grease tap, the other water collection points were relatively low in organic matter that can be chemically oxidized and organic matter decomposable by bacteria. The grease tap contained chemicals with nitrogen/phosphorus compounds in them. These chemicals were mainly soaps, detergents and grease that resulted in the high COD reading.
These nitrogen/phosphorus compounds were later on channeled to plants which absorbed them reducing their concentration greatly in the inlet, outlet and ponds.

3. There had been human error in carrying out the BOD test resulting in inaccurate final values.

Hence, the correlation between COD and BOD values is non-existent and can be ignored in this project.

Conductivity vs TDS

There is a strong and significant relationship between the conductivity and total dissolved solids content of the different sites.

Both of theses parameters are co-related as Conductivity measurement is able to conduct a quick estimation on the amount of the Dissolved Solids (DS).The TDS content of the waters had consisted of ions that contributed to the electrical conductivity of the waters. They mainly came from the various kinds of dissolved substances such as detergent, soap, oils and bacteria from hands and face.

Hence, from the graph, we find that as the content of total dissolved solids increases, the conductivity of the water increases as well.

http://www.britannica.com/EBchecked/topic/424285/ocean/67070/Dissolved-organic-substances#tab=active~checked%2Citems~checked&title=ocean%20%3A%3A%20Dissolved%20organic%20substances%20--%20Britannica%20Online%20Encyclopedia

Hardness vs TDS

There is no correlation between the hardness and total dissolved solids content of the different water collection points.

This would mean that the bulk of the total dissolved solids did not consist of hardness-causing cations and anions like Calcium, Magnesium, Carbonates and Bicarbonates.

To prove this further, the hardness of our control (Tank before Pond) was one of the higher ones despite having a TDS concentration of 0mg/L.