5
Alternative Water
Supply Technologies
The New Green Building Hydrologic Cycle
Re-think use of potable water!
Water sources:
•Traditional Potable Water
•Harvested Water
•Treatable Wastewater
Pages 41-43
The New Green Building Hydrologic Cycle
New Ways of Supplying
and Reusing Water:
•Harvested Water
•Treatable Wastewater
Page 43
How Alternative Systems Work
Rainwater Harvesting Systems
Page 48
How Alternative Systems Work
Greywater Treatment and Reuse Systems
Pages 50-51
How Alternative Systems Work
Blackwater Treatment and Sewer Mining
Pages 52-54
Wastewater Treatment: Basic Biology
• Biological Materials:
Pathogens
• 3 Main types of
Biological Digestion
Aerobic
Processes
Anoxic
Processes
Anaerobic
Processes
Pages 46-47
Precautions with Reused Water
• Ensuring reclaimed water
is used safely and
appropriately is extremely
important
• Be aware of potential
cross-connections in
plumbing systems
• Install backflow prevention
from nonpotable to potable
systems
Pages 54-55
TEST YOURSELF:
1. What are the three sources of harvested water? Where
are they collected, and what can the water be used for?
2. Describe greywater systems, and how the greywater is
purified and used.
3. What is the primary public health issue related to
wastewater treatment?
4. Describe the three main types of biological digestion, and
what type of wastewater treatment they are appropriate
for.
5. What are the risks associated with reused water?
6. What are the recommendations of the American Water
Works Association (AWWA) in terms of backflow
prevention?
6
Energy Savings
Direct vs. Indirect Water Heating
• Direct: Self-contained unit and energy is
transmitted directly to heat the water
• Indirect: Uses heat from secondary source to
heat water
Potable Water Heating: Direct-energy
Direct Energy Heating Equipment
Primary source to heat water
• Storage water heaters
• Condensing water heaters
• Instantaneous water heaters
Page 58
Potable Water Heating: Indirect-energy
Indirect-energy Heating Equipment
Rely on external sources
• Coil-in-tank
• Shell-and-tube system
• Tube-in-tube system
Page 61
Solar Energy
Page 61
Potable Water Heating
Solar Thermal “Wet” Systems
Energy from the sun used to
heat a domestic water supply
• Flat plate collectors
• Evacuate tube collectors
(direct-flow and heat-pipe)
Page 64
Potable Water Heating
• Direct Circulation Systems
• Cannot tolerate freezing
temperatures
• Drain-Back Systems
• Must be sloped to ensure
water drains to reservoir
• Indirect Circulation Systems
• Pumps circulate through
a non-freezing heat
transfer liquid
Pages 66-67
Potable Water Heating
Ground-Source Energy
• Draw heat from the
ground during winter
• Deposit heat from indoor
air during the summer
• Primarily for homes
• “Desuperheater”
Page 67
Cogeneration (CHP) Systems
• Converts waste heat
that accompanies
electricity production
into usable thermal
energy
• Microturbines
Page 68
Energy Recovery
• Drain-Water Heat
Recovery
• Steam Condensate
Heat Recovery
• Condenser Heat
Recovery
Pages 70-72
Special Issues in Retrofitting DHW Systems
• Preheaters
• Condensing
Boilers/Water Heaters
• Instantaneous Water
Heaters
• Circulation Balancing
• Pipe Insulation
Page 72
TEST YOURSELF:
1. Explain the differences between direct and indirect
heating
2. What are the issues to be aware of with instantaneous
water heaters?
3. What are the benefits and drawbacks of indirect-energy
water heaters? Condensing boilers?
4. Describe and compare direct flow and heat-pipe
evacuated tube collectors.
5. What is cogeneration? What are the benefits?
6. What are the forms of energy recovery and how do they
work?
7
Managing Green
Projects
Contractor and Subcontractor Roles
• Many work practices, product
specifications, and technologies are unique
to a successful green building project
• Be aware of what is involved to ensure
conformance with the overall project
requirements
• Know how the building codes address
new technologies
Page 73
Work Practices: Indoor Air Quality
Work practices must be
followed to ensure
sustainability goals and/or
LEED certification
• Low-VOC materials
• Air sealing
• Moisture control
Page 74
Work Practices: Construction & Demolition
Construction & Demolition
Waste Management
Aim to recycle 50-95% of the
total waste-stream
• Sorting recyclable materials
on site
• Co-mingled waste sorted
off-site
Page 74
LEED Documentation
• LEED projects require
additional documentation
submitted to the
USGBC/GBCI
• Required LEED
documentation primarily
relates to IAQ and lowflow fixtures
Page 75
LEED Product Specifications
• All information for documentation is found on product
MSDS sheets
• Need to ensure LEED certification for the project
• Make sure new materials procured meet specified
standards
• Need to be reviewed by the sustainability coordinator
Page 75
Cost and Scheduling Issues
Work practices that may affect your schedule
• Commissioning/building flush-out
• Product documentation
• Value engineering
Page 76
Commissioning
Coordination with
commissioning agent (CxA)
• Pre-functional and start-up
testing of installed equipment
Building Flush-Out
• Measuring air quality
• Purge contaminants using a
high exchange of inside air with
fresh outside air
• Done prior to or just at
occupancy
Flush out
Page 76
Value Engineering
Value Engineering
• Generally occurs in the design phase before the
plumber has a bid on the job
• May be required to provide costing for proposed or
determined changes
High probability of green elements being eliminated if
the budget gets tight
• Newer technologies are more expensive to install
• Owners and engineers may see them as expendable
Page 76
Code Compliance
Needed changes to existing
building codes may not have been
made yet
Often no regulations regarding the
use of rainwater or reused
wastewater to supply bathrooms
Understand how new technologies
and installation practices are or are
not addressed by your local
jurisdiction
Page 77
TEST YOURSELF:
1. What are the indoor air quality work practices specific to
plumbers that need to be followed to ensure
sustainability?
2. What work practices should the plumbing contractor be
aware of in regards to commissioning?
3. Explain the two forms of construction and demolition
waste management: sorting and co-mingling.