Section 8: Environmental Health Flashcards
What are fecal coliforms
Gram negative, lactose fermenting, facultative microbes that produce gas
What does BOD stand for and what is it
Biochemical oxygen demand
- assesses the quantity of oxygen needed by microbes in water
- high BOD results in the aging of a body of water, called eutrophication
What is the goal of coliform testing
number of zero in drinking water
-water treatment systems are tested between 1-480 times a month
What is the goal of water treatment
reduce the levels of BOD
What is primary sewage treatment
- physical process
- removal of about 50% of solids in sedimentation tanks
- remaining is effluent, reduced BOD by 25%
What is secondary sewage treatment
- Biological process
- Trickling filter
- Activated sludge process
How does a trickling filter work
- effluent sprayed over rocks. Organic materials adheres to stone and is digested by microbes present in tank
- often used in smaller treatment plants
What is an activated sludge process
- slime forming bacteria added to effluent and stirred in aeration tank. Bacteria digest remaining organic materia forming flotsam, significant reduction in BOD (95%)
- following aeration, water is treated chemically or with UV light and release
What is tertiary sewage treatment
- expensive
- add lime or alum to remove nitrates and phosphates
- may also involve filtration
- tertiary effluent is then dechlorinated by aeration as it flows down a series of steps
What are septic tanks
- Individual sewage treatment systems
- anaerobic digestion of organic material
- effluent overflows into drain field of soil or gravel and further digestion by aerobic microbes
- only effective for small amounts of sewage
Who assigns letter grades to milk and who did previously
Previously graded by USPHS now done by the USDA
What is pasteurization
originally 30 minutes at 62 degrees, now 72degrees for 15secs.
What is a phosphatase test
enzyme should be destroyed by pasteurization treatment.
What does chiropractic involvement in public health allow chiropractors to do
- promote preventative health care
- participate in public health effort
- interact with a variety of other healthcare professions
- work within health care system used evidence based approach
- evaluate and design clinical trials
- recognize individuals at risk
