Water Reuse Handbook - the Public Building Commission of Chicago

Water Reuse Handbook
42 : Public Building Commission of Chicago
Learning curve: The Illinois Department of Public Health (IDPH),
the City of Chicago Department of Buildings, and the Committee on
Standards & Tests (CST) reviewed the system. IDPH required changes
including modifying the disinfection and filtration components, the
incorporation of backflow prevention, and signage to indicate that
the system’s water is non-potable (including signage with yellow
lettering on all fixtures flushed with Harvested Rainwater). IDPH
required the plumbing contractor to repipe the UV sterilizer to ensure
that UV sterilization would occur prior to rainwater entering the day
tank. In addition, CST required a custom-fabricated air gap fitting
to meet the City requirements to keep harvested water out of the
municipal supply.
Post-Installation Maintenance: Staff will need to change UV bulbs about once every
three seasons or after 10,000 hours of use; the UV system has an
hours-run meter to indicate when the bulb needs to be changed.
Due to the fact that the building is not heated (it is shut down during
the winter months), winterization is necessary at the end of the
summer and includes draining the day tank, both UVs , and the pump
inside the building.
Monitoring: Remote panel will display: (1) volume of rainwater
harvested; (2) volume of municipal water used as backup; (3) volume
of water in underground storage; and (4) indicator light for when the
UV bulb needs replacing or if there is a problem with the UV system.
Water quality monitoring is not being performed.
Lessons learned: The team learned that they should allow additional
time to get the rainwater harvesting system through the nonstandard
review process involving the State and CST. Until water reuse
standards are codified, future projects should budget additional time
and expect some level of design changes to the system.
The solenoid valves initially did not work at the beach houses, which
shut down the rainwater harvesting systems.
Local Case Studies: Beach Houses
August 2011