英文關鍵字
dirty
water
recycling
liquid
squirt
flow
pipe
sewage
treatment
cleaning
technology
waterworks
plant
industry
environment
aeration
pollution
factory
tank
waste
pool
purification
ecology
industrial
sludge
bacterium
wastewater
basin
processing
sanitary
nature
outdoor
circle
brown
purity
equipment
activated
sediment
faeces
excrement
biomass
energy
stir
stream
effluent
sewer
quality
secondary