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
- Nutrients released from wastewater and make it fertile
- Carries diseases
Oxygen demand
- 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
Nutrient Release
- 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
Disease causing organisms
- 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
Septic Tanks
- Relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas

We have technologies to treat wastewater