Week 4- Offsite Servicing 1

Question 1

What are some design key refs for offsite servicing?

Answer 1

-subdivision control bylaws (muni design criteria)
-master mini const docs (MMCD)

Question 2

Hydraulic Principle

Answer 2

Pressure + velocity head + elevation (1) = Pressure + velocity head +elevation (2)

Question 3

Water Distribution Big picture

Answer 3

Natural reservoir -> dam and raw water main -> water treatment and pump stations -> city reservoir -> city water main -> member pump station, water main, distribution main -> plumbing in home

Question 4

Water distribution system key design parameters

Answer 4

-population (density)
-land use type (fire flow)
-minimum and maximum residential pressures

Question 5

Sanitary sewer system hydraulic principle

Answer 5

Manning formula Q= (A*R^0.667 *S^0.5)/n

Gravity sewer design should not allow flow depth to exceed 75% of full pipe depth

Question 6

Sewer system primary treatment stage

Answer 6

-screen large solids
-settling of solids over time
-grease, oil, fat are skimmed off

Question 7

Sewer system secondary treatment

Answer 7

-biological treatment bacteria
-some reduction in pharmaceuticals and chemicals

Question 8

Sewer system tertiary treatment

Answer 8

-improves quality of treated water using steps such as nutrient removal, membrane filtration and ultraviolet disinfection.

Resulting water can be used for irrigation, industry, drinking

Question 9

Sanitary sewer system key design parameters

Answer 9

-population
-land use
-peaking factor

Question 10

Storm sewer key design parameters

Answer 10

-catchment area
-area of previous and imperviousness (land use)
-rainfall return frequency & intensity

Question 11

Design flow calc methods

Answer 11

-rational method (RAIN)
-runoff hydrograph method
-minor systems (1:2 year to 1:10 year)
Major systems (1:100 year)