Wastewater Flows

Question 1

What is the equation for Mass Loading?

Answer 1

• Concentration * flowrate
• ML (kg/day) =(concentration, g/m^3)(flowrate, m^3/d)/ (10^3g/kg)
• ML, lbs/d = (Concentrationmg/L)(flowrate, Mgal/d)(8.34lbs/Mgal * (mg/L)

Question 2

What is infiltration?

Answer 2

-groundwater thats seeps into a collection system from different points

Question 3

What is inflow?

Answer 3

-Rain water that enters publicly owned sewers and manholes

Question 4

What is Flow Equalization?

Answer 4

-Allows for constant to prevent overflow or suspended particles from settling.

Question 5

When is flow equalization used in wastewater treatment facilities?

Answer 5

-During peak times of the day of water usage

Question 6

What is Hydraulic Retention Time?

Answer 6

Volume per Flow rate

Question 7

What is a gravity sewer slope?

Answer 7

-2ft/sec

Question 8

What is mass loading used for?

Answer 8

• important is in the design/ sizing of the wastewater units
• mass of BOD that must be processed

Question 9

How are wastewater flow rates obtained for newly sewered areas?

Answer 9

• analysis of the population

- est. per capita

Question 10

What is the weight of 1 gallon of water?

Answer 10

-8.34 lb

Question 11

What is the effect of infiltration& inflow?

Answer 11

• Causes:
• -> dilution in sewage
• -> sewage volumes to exceed design capacity
• -> decreases efficiency of sewers

Question 12

What is Manning equation?

Answer 12

-gives the velocity if flow in feet per second

Question 13

What are the types of wastewater collection system?

Answer 13

• Sanitary
• Storm
• Combined

Question 14

What are the sources of waste water flow?

Answer 14

• Domestic
• Industrial
• Infiltration/Inflow

Question 15

Average, Maximum, and minimum daily flow all account for what type of weather conditions?

Answer 15

-Dry weather