Module 1: Wastewater from Humans and Livestock

Wastewater from humans

A major type of water pollution is wastewater
- Water produced by livestock operations and human activities, including human sewage from toilets and gray water from bathing and washing of clothes and dishes
Pollution comes from two sources
- Point
  - Distinct location from which pollution is directly produ5ced
  - A particular factory
- Non-point
  - A “general” area from which pollution is produced
  - Can be an entire farming section
  - Suburban community
Wastewater is of concern b/c
- Wastewater undergoes decomposition by bacteria
  - increased BOD
- Nutrients released from wastewater and make it fertile
- Carries diseases

Microbes are decomposers
- Microbes require oxygen to decompose
  - As they increase in population, increase BOD
BOD:
- Amount of oxygen a quantity of water uses over a period of time at a temperature
- Lower BOD = less polluted
When there is high BOD for long time, oxygen in a lake can decrease, causing hypoxic water, and maybe even dead zones
- Lethal

Wastewater decomposition releases nitrogen and phosphorous
- Important nutrients for aquatic organisms
Eutrophication
- Phenomenon where body of water becomes rich in nutrients
- Cultural eutrophication
  - increase in fertility in a body of water, the result of anthropogenic inputs of nutrients

Contaminated wastewater = bad
Wastewater can carry a variety of pathogens
- Viruses
- Bacteria
- Protists
- Can cause diseases
It is important to be able to test for pathogens
- Done by testing for indicator species
  - Species that indicate whiter or not disease causing pathogens are likely to be present
  - An example is Fecal Coliform Bacteria
    - Group of generally harmless microorganisms in human intestines that can serve as an indicator species for potentially harmful pathogens associated with sewage water
    - E. coli

Relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas

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