英文關鍵字
canal
chemical
clean
concrete
conduit
contamination
dirty
drain
drainage
dump
ecology
environment
environmental
facilities
flow
flowing
flows
garbage
industrial
industry
infrastructure
liquid
nature
outdoor
pipe
pipeline
plant
polluting
pollution
pouring
river
sewage
sewer
sewerage
shore
smell
smelly
splash
stream
toxic
treatment
tube
waste
wastewater
water