Waterborne Diseases & Treatment Flashcards
Describe the problems of E. coli contamination of drinking water and beaches (Walkerton, Ontario).
Caused poor chlorination; 7 direct deaths, 14 with “E. coli” complications, 2300 people sick (over 40% of population)
Describe the problems of cryptosporidium contamination of drinking water in the Great Lakes ecosystem (Milwaukee, WI).
403,000 of 1.6 million residents sick; more than 100 deaths, mostly among immuno-compromised.
Why are waterborne diseases still occurring, and to some extent re-emerging, in the Great Lakes region?
Human and Animal Waste being deposited in the great lakes: (Human - Sewer overflows and septic systems; Animal - Livestock and wildlife feces)
Describe the differences in access to safe drinking water and sanitation in the developed and developing regions of the world.
In developing regions, there is very little access to safe sanitation. While safe drinking water is becoming a little better, there is still much contamination. - 2.5 billion people lack adequate sanitation - 1.25 billion people lack safe drinking water - Sub-Saharan Africa is the region of greatest concern (30% & 23% relatively)
Define the following types of diseases: Waterborne, Water-Scarce, Water-Based, and Water-Related Insect Vector. Give 2 examples of each
Waterborne: Pathogen is in water that is ingested; ex Diarheas, dysenteries, typhoid fever Water-Washed: Person-to-person transmission because of lack of water for hygiene; ex. Scabies, trachoma Water-Based: Transmission via an aquatic intermediate host; ex. Schistosomiasis, guinea worm Water-Related Insect Vector: Transmission by insects that breed in water or bite near water; ex. Dengue, malaria, trypanosomiasis
How can a scarce water supply contribute to the spread of infectious diseases?
- Lack of water for washing can increase the prevalence of other infectious diseases. - The need to walk great distances to obtain safe water increases spread.
Describe the major steps in the treatment of sewage in modern wastewater treatment plants.
How do septic systems process domestic sewage waste?
Describe the major steps in the treatment of water in modern drinking water treatment plants.
Why do wells (ex. groundwater) generally supply water that is free of waterborne diseases? How can waterborne diseases enter groundwater supplies?
Water is taken below impervious rock layers. Can be contaminated by industrial waste runoff, leaking of underground gasoline storage tanks, agricultural spraying and leaking septic tanks.
Describe the major goals and challenges for meeting the millennium Development Goals for drinking water and sanitation during the ‘Decade for Water for Life’?
Drinking Water: By 2015, all of world would have adequate drinking water. Would require the provision of services to an additional 300,000 people a day Sanitation: Would require providing services to an additional 450,000 people of day between 2005 and 2015. We are way behind.
Why is the proximity of clean water source so important?
If drinking water source is more than 5 minutes away, people usually do not use more than the very basic quantities required for hygiene , drinking, and cooking
Describe household and community-level water treatment devices employed in developing countries that parallel important treatment steps in modern drinking water treatment plants (#8).
- Boiling - Solar Disinfection by UV - Solar Disinfection by Heat - UV Disinfection with lamps - Chlorination plus Storage - Combined Systems of Chemical Coagulation, Filtration, and Chlorine Disinfection.
Describe drinking water technologies that are unique to developing countries.
- Settling or plain sedimentation - Fiber, cloth or membrane filters - Granular media filters - Slow sand filter
Why is treating water turbidity so important?
Turbidity, or “haziness” in the water supply”, can cause gastrointestinal diseases and many viruses and bacteria can become attached to the suspended solids.
