英文關鍵字
aeration
bacterium
basin
biological
bioreactor
brown
clarifier
cleaning
contamination
dirty
environment
excrement
factory
filter
foam
industrial
industry
pipe
plant
pollution
pool
processing
purification
purify
reactor
recycling
sanitary
sanitation
secondary
sediment
sedimentation
seethe
seething
sewage
sewer
sludge
stir
tank
toxic
treatment
urban
waste
wastewater
water