英文關鍵字
sewer
garbage
drain
pipe
waste
water
sewage
dirty
environment
hole
drainage
ecology
tube
cleaning
industry
pollution
industrial
flow
house
trash
urban
home
system
environmental
metal
maintenance
plumbing
chemical
food
recycling
flood
street
plumber
kitchen
old
storm
background
vector
liquid
treatment
worker
lid
manhole
sewerage
nature
river
factory
disposal
wet