英文關鍵字
aerated
aeration
air
bacterium
basin
blow
brown
bubbling
chamber
circle
cleaning
dirty
drinkable
ecology
environment
facility
factory
filter
garbage
grit
industrial
industry
liquid
modern
muddy
outdoor
oxygen
pipe
plant
pollution
pool
processing
purification
purified
recycling
reservoir
sanitary
sedimentation
sewage
sludge
stage
tank
technology
toxic
treatment
waste
wastewater
water