英文關鍵字
sewage
water
treatment
stage
filtration
sedimentation
flow
grid
closeup
concrete
technology
basin
circle
clean
ecology
environment
industrial
industry
plant
pollution
purification
recycling
reservoir
settle
storage
waste
clear
detail
clarification
big
drinkable
drinking
treated
motion
primary
fly
dirty
liquid
close
move
chemical
recycled
recycle
engineering
fresh
cleaner
last
facility