B4: Green Water Supply Systems

Question 1

What is Rain Water Harvesting?

Answer 1

is the practice of collecting / storing rainwater for future use

Question 2

Where does the water collect from?

Answer 2

roofs

Question 3

Harvested rain water can be used for what?

Answer 3

toilet flushing and lawn irrigation (also urinals)

Question 4

Other uses of rain water are not allowed unless.

Answer 4

Treated, inspected / certified

Question 5

Harvested or recovered rainwater commonly refers to?

Answer 5

A type of auxiliary water supply that is collected from external surfaces of buildings or other hard-surfaced areas not exposed to vehicular or pedestrian traffic

Question 6

What is water quality determined by?

Answer 6

Its microbiological, chemical
physical properties

Question 7

What does physical properties include?

Answer 7

pH, colour, odour, turbidity and bacteria

Question 8

Rainwater has the potential to harbour what types of organisms?

Answer 8

pathogenic

Question 9

Who should you check with prior to installation / enquire about permits?

Answer 9

AHJ

Question 10

What are the 3 benefits of RWH?

Answer 10

1) protecting / conserving water
2) reducing amount of storm water runoff
3) Reducing homeowners’ potable water use

Question 11

True or False: roofs are the only surface permitted for residential rainwater collection

Answer 11

True

Question 12

Why is collection from asphalt roofs not great?

Answer 12

dt its rough surfaces, tendency to slow down / evaporate surface water, particulates / other contaminates can dislodge

Question 13

Are green roofs recommended for rainwater harvesting?

Answer 13

no

Question 14

What style are most gutters?

Answer 14

5” K style aluminum or galvanized steel

Question 15

What size are typical leaders?

Answer 15

2x3” or 3x3”

Question 16

Where shouldn’t leaders be located?

Answer 16

Inside corners of walls or inside the building envelope (unless absolutley necessary)

Question 17

What is a conveyance pipe?

Answer 17

a pipe that transports rainwater from leader to storage tank

Question 18

What must be taken into consideration when conveyance pipe is located above ground?

Answer 18

above grade / sun exposure

Question 19

What needs to be considered when designing / installing a conveyance network?

Answer 19

Sizing / placement
site conditions / location / placement of storage tank

Question 20

What type of material is not recommended for gutters/leaders?

Answer 20

copper, wood, vinyl plastic
(rainwater can be acidic which can affect copper)

Question 21

True or False: the greater the slope the better

Answer 21

true

Question 22

What materials are used for storage tanks?

Answer 22

high-density polyethylene
fibreglass, steel, concrete / crate and bag

Question 23

What are the benefits of the different storage tank materials?

Answer 23

Concrete = longevity / strength
Plastic / fibreglass = lightweight / strong
Steel = corrosion / aesthetics
crate - and-bag = light / strong (not normally used)

Question 24

Tank sizing includes what?

Answer 24

rainwater load, number of toilets, irrigation, roof catchment area, local rainfall, potential growth, number of people in the house

Question 25

What is collection effeiciency?

Answer 25

the % of rainfall landing on the roof that will find its way to the storage tank

Question 26

What is the average collection effeciency?

Answer 26

75%

Question 27

What are reasons for lost effeciency?

Answer 27

1) roof material, overhanging branches 2) collection system (overflow / spillage) 3) Seasonal factors

Question 28

1 metre squared of catchment area x 1mm = how many L?

Answer 28

1L

Question 29

What size of access hatch is needed?

Answer 29

24" or larger -- allows entry

Question 30

Does an overflow pipe need to be larger, smaller or the same size as inlet pipe?

Answer 30

Same size or larger

Question 31

What is a calmed inlet?

Answer 31

conveyance pipe is brought near to the bottom w/o disturbing the sediment (is 90 degrees or U shaped)

Question 32

What is dead space?

Answer 32

the 4-6" unused portion of rainwater at the bottom of the storage tank

Question 33

What is the dead space's job?

Answer 33

to ensure the submersible pump or suction line does not run dry

Question 34

How often should rainwater tanks be inspected?

Answer 34

at least once a year

Question 35

What are 2 ways treatment can be applied to improve rainwater quality?

Answer 35

Pre-storage tx Post-storage tx

Question 36

What are 3 methods of Pre-storage tx? (For fuck sakes)

Answer 36

1) First flush diversion 2) Filtration 3) Settling

Question 37

What is the First Flush diversion?

Answer 37

diverting the first portion of runoff away from the storage tank

Question 38

What does filtration include?

Answer 38

Involves screening out leaves / large debris from runoff

Question 39

Settling chamber, what is it?

Answer 39

A rainwater tank that has a separate chamber for debris to settle and water to con't to the storage tank

Question 40

What is Post-storage tx include? (DTF)

Answer 40

1) filtration 2) disinfection 3) tx of aesthetic issues - colour, taste, odour

Question 41

What is commonly used for disinfection?

Answer 41

UV and chlorine

Question 42

Pre-storage tx devices should be inspected how often?

Answer 42

at least twice a year (or as per manufactures instructions)

Question 43

How often should post-storage tx devices be inspected?

Answer 43

at least quarterly

Question 44

What is the primary concern w/ a make up system?

Answer 44

requires a potable water source to be brought in close proximity w/ rainwater which creates a CC

Question 45

What are 2 types of Make-up water systems?

Answer 45

1) top up - uses potable water to fill storage tank when needed 2) bypass

Question 46

What are 2 areas of protection that the installation of backflow preventers address?

Answer 46

1) zone isolation 2) premise protection

Question 47

What is a zone isolation?

Answer 47

backflow preventer is installed at the point of use protects occupants in building

Question 48

A zone isolation backflow preventer uses what for a rainwater storage system

Answer 48

air gap

Question 49

Premises protection

Answer 49

uses an air gap?

Question 50

What is the point of a pressure tank?

Answer 50

To prolong pump life

Question 51

Pump selection involves what?

Answer 51

Pump location, controller, voltage pump flow rate (l/sec or GPM) pump system head (pressure)

Question 52

What are the 3 components of total dynamic head (FDS)

Answer 52

1) suction head 2) Discharge head 3) friction head

Question 53

What is suction head?

Answer 53

the vertical distance or height that water must be lifted (pulled) before arriving at the pump. only applies to Jet pump

Question 54

What is Discharge head?

Answer 54

the vertical height from the pump --> the highest fixture

Question 55

What is Friction head?

Answer 55

the loss in pressure resulting from water traveling through pipes / fittings