Wastewater101 not needed

Question 1

What is municipal wastewater?

Answer 1

Sewage

Question 2

Volume of wastewater per person per day?

Answer 2

225 to 450 L

Question 3

Whats ICI stand for?

Answer 3

Industrial, commercial, institutional flow

Question 4

What is the waste treatment plant at a low point?

Answer 4

Because pipes are often gravity fed. May be pumps to boost.

Question 5

What is infiltration?

Answer 5

When water seeps into cracks in the pipes.

Question 6

What are combined sewer systems?

Answer 6

Where wastewater is mixed with stormwater.

Question 7

What are common constituents in domestic wastewaters?

Answer 7

• Organics
• Solids
• Nutrients
• Pathogens

Question 8

What are the three means of removing wastewater contaminants?

Answer 8

Physical
Chemical
Biological

Question 9

What hours are peak for volume of wastewater?

Answer 9

Morning and night.

Question 10

What are tested parameters?

Answer 10

Total nitrogen
Total ammonia nitrogen
Total phosphorus
Total suspended solids
BOD - indicates organic material in wastewater
CBOD

Question 11

What does the clarifier do?

Answer 11

Removes some of the suspended solids and organic matter.

Question 12

What is the most widely used form of wastewater treatment?

Answer 12

Primary sedimentation. Particles settling at the bottom of the tank. Settled particles called primary sludge.

Question 13

What helps speed up sedimentation?

Answer 13

Chemicals called coagulants. They cause flocculation so they settle faster.

Question 14

What happens to the sludge?

Answer 14

Scraped from the bottom of the tank into a hopper. Then pumped from the tank for processing. Usually water is removed before further processing.

Question 15

How is biodegradable organic matter removed? (second treatment - secondary clarifier)

Answer 15

Microorganisms.

Question 16

Wastewater and biomass are mixed, what is this called?

Answer 16

Mixed liquor.

Question 17

What do microorganisms need to work?

Answer 17

DO. That is why there are aeration.

Question 18

What is secondary clarification for?

Answer 18

Separating the mixed liquor suspended solids. Similar process to the primary clarification.

Question 19

What happens to secondary sludge?

Answer 19

Called RAS, returned activated sludge. Contains many living things. Sent back to aeration basin to maintain high biomass. Rest of biomass is removed WAS so conc doesn’t get too high.

Question 20

Another reason coagulants are added?

Answer 20

To remove phosphorus.

Question 21

Another method for removing phosphorus?

Answer 21

Enhanced biological phosphorus removal. Phosphorus accumulating organisms (PAOs) grow more easily than others.

Question 22

Two processes that nitrogen can be removed?

Answer 22

Nitrification and denitrification. Only little by organic matter breakdown.

Question 23

What is the third stage of wastewater treatment?

Answer 23

Removal of the residual suspended solids following secondary treatment. This is done by filtration through granular media/material. Chemicals added prior to convert dissolved into particles.

Question 24

How is the third stage maintained?

Answer 24

Backwashing. This water go earlier in the cycle.

Question 25

When is disinfection involved?

Answer 25

Second or third part.

Question 26

How is chlorine disinfection applied? How does it work?

Answer 26

Gas or liquid.
Danages the cell and or DNA or organisms.
Chlorine removed by process called dechlorination.

Question 27

What are examples of advanced filtration?

Answer 27

Membrane filtration. Reverse osmosis. Also potentially the tertiary treatment.

Question 28

What is stabilisation in terms of sludge?

Answer 28

Reduces pathogens and sludge odours.

Question 29

What are biosolids?

Answer 29

Stabilised sludge.

Question 30

What is digestion?

Answer 30

Biological stabilisation.

Question 31

How much does dewatering remove the water content?

Answer 31

to the 20-30% tot water left