Posted: August 26th, 2021
Coliforms and UV Disinfection: CE 360 Laboratory Exercise 10
Name
Institutional Affiliation
Coliforms and UV Disinfection: CE 360 Laboratory Exercise 10
Data Analysis (20 Points)
The dilution with acceptable number of colonies within acceptable range is the Drinking Water 100 mL B.
The results are fairly reliable. However, sources of error may include poor lighting that affects distinguishing of colors and failure to obtain test within the standard time that affects ultimate results. It affects results with different water chemistry.
CFU/100 ml = (120*100)/25 = 480 units.
Ultra-violet radiation is suitable for inactivating sporous ad vegetative types of bacteria such as cysts, Cryptosporidium cysts and Giadia lambia, among other pathogens. However, it is not effective for water that has amounts of coliform, suspended solids or substantial color.
The use of coliform swabs offers the simplest approach to detect coliform pathogens in water.
Questions (30 Points)
Coliform bacteria are considered “indicator” organisms because they are tested using simple tests and they can be easily detected even in low forms. The coliform bacteria can survive for long in water, a property that makes them a good indicator for existence of other pathogens in water.
Coliforms and fecal coliforms sources differ in terms of temperature. Fecal coliforms can be found in poorly treated municipal sewerage and urban storm water while coliforms are found in common water sources. An example of fecal coliform is the E.Coli.
During the outbreak at Milwaukee, about 400,000 people were infected and an estimated 100 people died. The predominant symptoms for Cryptosporidium parvum were watery diarrhea, abdominal cramps and headache.
The outbreak was discovered following a widespread sickening among people with diarrhea. The immediate action was to evacuate people out of the area and stop use of water from the affected plants. Further, people were advised to boil or disinfect water before us.
Cryptosporidium is a protozoa. Some strains of Cryptosporidium are dangerous because they can cause serious illness and even death especially to people with low immunity.
Figure 1: Figure Seen on John’s Island
The contaminated must have originated from the north plant. The source of contamination was probably due to the counterclockwise current in Lake Michigan.
In order to prevent other outbreaks, Milwaukee drinking
water treatment should strengthen the protection of water sources using strong
barriers, ensure constant disinfection and proper filtration.
Appendix
Data Recording
# | Sample | Location Collected | Dish Label | Coliform Count | Observations |
1 | Drinking Water 100 mL A | Bathroom by Jobst 215 | DW-A | 0 | Completed |
2 | Drinking Water 100 mL B | Water Fountain by 208 | DW-B | 0 | Completed |
3 | Blank: Dilution water only | DI Faucet in Env. Eng. Lab | Blank | 2 | Completed |
4 | IL River Water 1 mL diluted in in 100 mL DI | River shore in downtown Peoria | ILR – 1 | 7 | Completed, low content |
5 | IL River Water 5 mL diluted in in 100 mL DI | River shore in downtown Peoria | ILR – 5 | 64 | Completed, with moderate content |
6 | IL River Water 25 mL diluted in in 100 mL DI | River shore in downtown Peoria | ILR – 25 | 120 | Completed, high content |
7 | IL River Water 1 mL diluted in in 100 mL DI Sample passed through UV | River shore in downtown Peoria | ILR – 1 UV | 0 | Completed |
8 | IL River Water 5 mL diluted in in 100 mL DI Sample passed through UV | River shore in downtown Peoria | ILR – 5 UV | 20 | Average content, completed |
9 | IL River Water 25 mL diluted in in 100 mL DI Sample passed through UV | River shore in downtown Peoria | ILR – 25 UV | 70 | |
10 | Swab 1 | Swab 1 | 0 | ||
11 | Swab 2 | Swab 2 | 0 | Damaged filter | |
12 | Swab 3 | Swab 3 | 0 | ||
13 | Swab 4 | Swab 4 | 0 |
Place an order in 3 easy steps. Takes less than 5 mins.