General Wastewater Treatment Flashcards
Why is grit/debris removed?
- aesthetics
- pathogen carrier
- can ruin pumps
What contaminant causes eutrophication?
COD/BOD
What is NPDES?
National Pollutant Discharge Elimination System
What are the three parts of preliminary treatment?
- bar rack
- grit chamber
- equalization basin
What is the function of preliminary treatment?
Get rid of “stuff” that you don’t want to go into the plant
What is the most expensive thing at a plant?
Electricity
Why is primary treatment called “primary”?
A long time ago, that’a the only treatment they did
What percent of BOD does primary settling remove?
1/3
What is the purpose for bar racks?
Removes larger objects
What is the purpose of grit chambers?
Remove inert dense material, such as sand, broken glass, silt, and pebbles; Avoids abrasion of pumps
What are the two types of grit chamber?
Aerated grit chamber, vortex grit chamber
What is the purpose of primary settling?
Settle organic particulate matter and thus remove BOD
How is sludge removed in primary settling?
Settled sludge is removed mechanically. Raw sludge is stabilized and dewatered before disposal
What is the purpose of secondary treatment?
Provide BOD removal beyond what is achieved in primary treatment. Has a goal to stabilze the water adn get rid of oxygen demanding waste
What are the three parts of dispersed growth? What is dispersed growth?
- oxidation ponds
- activation sludge
- membrane bioreactors
Dispersed growth is when organisms float in a tank of water
