An Alternative Water Treatment
Alice Cai
Sir Winston Churchill Secondary
Floor Location : M 015 V

Did you know that over 844 million people don't have access to clean water? While many methods of processing water are available, a lot of those methods require elements and circumstances of which may not be possible to attain for many. But that doesn't mean that there isn't a way for them to treat water. Through solar disinfection, also know as SODIS, water can be treated for drinking, while at the same time staying budget friendly. So dos SODIS work? What percentage of bacteria would SODIS eliminate? My prediction is that SODIS method will eliminate bacterias in the water, and grow fewer colonies of bacteria compared to the untreated samples. 

To test my hypothesis, I collected water from three different bodies of water (Beaver Lake, Rice Lake, and Whyte Lake). Then, samples of the water were treated using the methods of boiling, and SODIS. After, swatches of both treated water and untreated water are smeared onto agar plates. The agar plates are then placed in a room at a controlled 25 degrees Celsius. After 48 hours of incubation, I made observations of the bacterial colonies growing. From the number of colonies grown in the plates of untreated water is divided by the number of colonies found in the treated samples, thus finding the percentage of bacteria that each method is capital of killing. 

By looking at my data, the number of colonies grown in the SODIS samples was higher in number compared to the samples of boiled water. But compared to the untreated samples, the samples that have been through the SODIS process had much fewer colonies of bacteria. From my data, I found that on average, the method of SODIS kills 45% of the bacteria, and the boiling process kills 94%.
While my experiment may have been factored by uncertain factors, the data collected indicates that while SODIS has proven to be a good alternative method of water treatment for areas where other methods of water treatments are not available, the method still doesn't have the efficiency of other methods like boiling water.