Transcript slides

WASTEWATER TREATMENT
NOTES
TYPES OF POLLUTION
• Vegetable oil, salt, vinegar, food, dirt,
soap, bacteria, nitrates, phosphates,
heavy metals, human waste, litter, E. coli,
chemicals, suspended solids
TREATMENT PROCESS
PRIMARY TREATMENT: 1st Stage: Gets out the big stuff.
filtering and settling. Solids settle out and scum rises.
Skimming the top of the tank removes the scum. Uses a
screen, pools/ponds, settling tank.
STEPS:
1. Goes through a screen to filter out big stuff
2. Settling tank – heavy stuff sinks down, lighter stuff
floats.
3. Sludge (stuff at bottom of settling tank) goes to ocean,
farm, is buried, or burned.
4. Slow process
TREATMENT PROCESS
SECONDARY TREATMENT: 2nd Stage: Biological
Process -- gets little stuff. Uses an aeration tank.
Uses chlorine. Solids and microorganisms are
separated.
STEPS:
• Bacteria eat the waste in the Aeration tank.
• Oxygen is supplied to bacteria so they have
plenty of DO.
• Settling tank is used for dead bacteria to settle
out.
Wastewater treatment plant
Wastewater treatment plant
• Filtration – removing large particles
• Sedimentation – sinking of the solid
material to the bottom of a tank.
• Aeration – adding air to push out foul
smelling gases.
• Disinfection – adding chlorine to kill
disease-causing organisms.
• Distribution – releasing the treated water
into a stream.
WHY IS TREATMENT
NECESSARY?
• Toxic to organisms, poisonous to
organisms, smelly water, makes water
easier to turn into drinkable water.
Wastewater would increase turbidity, mess
up pH, mess up DO, contains bacteria,
contains heavy metals.