英文關鍵字
concrete
dirty
domestic
drain
drainage
drainpipe
duct
ecology
effluent
environment
environmental
flow
flowing
fragrance
gutter
heal
hole
human
industrial
industry
infrastructure
liquid
municipal
nature
outdoor
pipe
polluting
pollution
rainwater
river
sewage
sewer
sewerage
smell
stream
technology
treatment
tube
tubing
ulcerated
untethered
waste
wastewater
water