The Technology, Design and Utility of Rainwater Catchment Systems : A Literature Review

1
The Technology, Design and Utility of Rainwater
Catchment Systems A Literature Review

• Alan Fewkes
• School of Property and Construction
• Nottingham Trent University

2
The Technology, Design and Utility of Rainwater
Catchment Systems A Literature Review

• Background and application of rainwater catchment
  systems
• Rainwater catchment system categories and
  components
• Storage capacity of rainwater collectors
• Rainwater quality

3
Background and application of rainwater catchment
systems

• Background and History
• Simple concept
• System Scale
• Israel, Africa, India, 2000BC
• Mediterranean area, 1700BC
• Decline of systems
• Uses of collected rainwater

4
Background and application of rainwater catchment
systems

• Application in Developing countries
• Application in Developed countries
• Potable water systems
• Australia
• Canada
• USA
• Bermuda

5
Background and application of rainwater catchment
systems

• Application in Developed countries (cont.)
• Non potable water systems
• Increased use/awareness
• Traditional solutions
• Alternative strategies
• German experience
• Problems with existing systems
• Promotion
• Economics

6
Background and application of rainwater catchment
systems

• Application in Developed countries (cont.)
• Non potable water systems
• UK experience
• Application
• Economics
• Sustainability issues

7
Rainwater catchment system categories and
components

• System categories (Non Potable)
• Categorised by distribution characteristics
• Directly pumped
• Indirectly pumped
• Gravity feed systems

8
Directly Pumped
9
Indirectly Pumped
10
Gravity Feed Systems
11
System categories (non-potable applications)(cont.
)

• Categorised by hydraulic properties
• Total flow
• Diverter
• Retention Throttle
• Infiltration

12
Total Flow
13
Diverter Type
14
Retention Throttle
15
Infiltration Type
16
Rainwater catchment system categories and
components

• System Components
• Catchment areas
• First flush diverters
• Treatment
• Storage

17
Storage capacity of rainwater collectors

• General
• Importance of store capacity
• McMahon Mein (1978)

18
Storage capacity of rainwater collectors

• Moran related methods
• Queuing theory
• Gould matrix method (1961)
• Piggot et al (1982)

19
Storage capacity of rainwater collectors

• Critical period methods
• Mass Curve
• Rippl (1883)
• Limitations

20
Storage capacity of rainwater collectors

• Critical period methods (cont.)
• Behavioural analysis simulation)
• Mass storage equation
• Vt Vt-1 Qt Dt
• YAS operating Rule
• YBS Operating Rule
• Storage Operating Parameter

21
Storage capacity of rainwater collectors

• Critical period methods (cont.)
• Application of behavioural models in the UK
• Generic performance curves
• Input ratio (AR/D)
• Storage Period (S/d)
• Curve fitting

22
Performance Curves
23
Rainwater Quality

• Sources of contamination
• Wet deposition
• Dry deposition
• Reaction with system materials
• Bird/animal faeces

24
Rainwater Quality

• Chemical and physical contaminants
• Wet dry deposition
• Roofing materials (Metallic ions, turbidity, pH)
• Length of dry periods
• Location
• Component selection

25
Rainwater Quality

• Microbiological contamination
• Pathogenic organisms / risk
• Failure to meet WHO Drinking Water standards
• Pathogenic groups
• Legionella (chlorination, aquatic biofilms,growth
  temperature)
• Growth of pathogenic bacteria
• Survive but do not grow
• Cleaning of cisterns