Excreta Disposal Flashcards
basis for human activities
life support systems
Life support systems
energy, social, built environment and geophysical aspects
Composition of human excreta
nitrogen phosphorus potassium total NPK pathogen
*inorganic pollutants in excreta
What should be the pollutants present in excreta be?
Chemical/inorganic (nutrients in urine)
Biological (pathogens, in feces)
In constructing septic tank or pit latrine, if the site is quite right (water table is quite deep), the movement of the pollutants can only be?
3m vertically and 1m laterally
How do septic tanks limit contamination of groundwater esp in hilly and mountainous areas?
Septic tanks limit the movement of water
T or F: If the source of pollution is downstream in relation to the water source, it is more likely that the water source will be contaminated compared to a upstream source of pollution
false, converse is true
Bacterial pollutants can travel up to
11 meters
Chemical pollution can travel up to
115 meters
What is DOH standard for constructing water sources
25 m away from source of pollution
What happens if the soil is not water tight?
pollutants could leach in the soil and contaminate water source
How many years before septic tank must be dislodged to maintain its proper functioning?
every 3-5 years
Mode of transmission of excreta transmitted disease
disease individual + carriers excrete bacteria, viruses, and intestinal parasites which contaminate soil, water, hands, and arthropods such as flies and roaches which all could come in contact with food and infect susceptible individual
Where does transmission of an excreted infection depend on?
→ Excreted load → Latency persistence multiplication (How long will the organism be able to survive in the outside environment? Can it multiply in the outside environment? At what temperature do the pathogenic organisms multiply *ideal = btemp*?) → Infective dose → Susceptibility of host
category of diseases which are caused by organisms that are NON-LATENT, UNABLE to multiply in the outside environment, LOW infective dose
Category I
Viruses, protozoa, Enterobius, Hymenolepis
Transmission foci of category I and II ETD
Domestic, personal contamination
*Category II: + water and crop contamination
Mode of control for category I and II ETD
→ Improve domestic water supply
→ Health education
→ Improved housing
(Cat. 2: + effective treatment prior to discharge or reuse of excreta)
Diseases caused by organisms that are NON-LATENT, with MEDIUM TO HIGH infective dose, moderately persistent, ABLE to multiply in the outside environment
Category II
*all bacteria
Diseases caused by organisms that are LATENT, VERY PERSISTENT, no multiplication, no intermediate host, can thrive in the soil
Category III
*geohelminths: ascaris, trichuris, hookworm, strongyloides
Transmission foci for Category III
yard, field and crop contamination
Control for category III and IV
→ Avoid contamination of soil
→ Treatment before land application of excreta
→ Provision of toilets
(Cat IV: + thorough cooking and meat inspection)
Diseases caused by organisms that are LATENT persistent,NEED INTERMEDIATE HOST (pig or cow)
Category IV
→ Taenia solium, Taenia saginata