Page 118 - Hong Kong Green School Guide

3. Green School Guide - 3.4 Water Use
Hong Kong Green School Guide 116
3.4.4 Rainwater Harvesting and Grey Water Recycling
Benefits
• Reduce potable water usage;
• Reduce water discharge and hence less impact on the sewage treatment
plants;
• Reduced water usage provides a good opportunity to reduce the use of
energy (less energy used to pump, treat and deliver the water); and
• Another source of water for irrigation and flooring cleaning.
Applies to NS & ES
Rainwater Recycling System
Issues to Consider
a. Opportunities
• Rainwater harvesting and/or grey water recycling system can be installed to
reduce reliance on potable water supply; and
• Harvested rainwater and treated grey water can be used for irrigation,
cleaning floor, toilet flushing, etc. that require only low grade water.
b. Constraints
• Selection between rainwater and grey water recycling systems;
• Operation and maintenance of rainwater / grey water treatment systems can
be complicated; and
• Space requirements for water treatment system.