Page 112 - Hong Kong Green School Guide

3. Green School Guide - 3.4 Water Use
Hong Kong Green School Guide 110
Benefits
• Reduce water usage;
• Reduce water discharge hence lessen impact on sewage treatment plants;
and
• Reduced water usage also means reduced energy use for pumping, treating,
delivering and heating the water.
Issues to Consider
a. Opportunities
• Schools can retrofit or select water efficient fixtures (i.e. low flow, infrared
sensor, spring type water tap, tap aerator, dual flush water closet, low flush
sensor controlled urinal, etc.) to reduce water consumption.
b. Constraints
• For existing schools, water fixtures can be difficult to be replaced due to
inconvenience to user and/or high costs.
c. Solutions
• For existing schools, to lower water consumption without retrofitting water
fixtures, the following measures can be implemented:
- - Install tap aerator to existing water tap. Many tap aerators available in the
market can reduce flow rate by 30% to 50%. (Please consult Licensed
Plumber to assess the adaptability of aerator to existing water tap); and
- - Fill water bottle with water and/or with some sand or some pebbles and
put it into water tank of water closet and, make sure not to affect the toilet’s
working parts. Many toilets flush well with a submerged 2-liter soda bottle,
but experiment is needed to find out what size best fits and produces the
best flush. This should reduce 15% to 30% of flushing water.
• For new developments, low flow, sensor control and low flush water fixtures
should be selected. Water efficient fixtures include water tap with low flow
and infrared sensor control / spring type, tap aerator, dual flush water closet,
low flush sensor controlled urinal, etc.;
• Water Supplies Department’s Voluntary Water Efficiency Labelling Scheme
can help schools select water efficient fixtures (such as that with Grade 1
water efficiency rating) for water tap, shower head and urinal equipment. See
Useful Reference (1) for more information;
3.4.1 Water Efficient Fixtures Applies to NS & ES