black
canal
chemical
concrete
dirty
drain
drainage
dump
ecology
environment
environmental
flow
flowing
fluid
garbage
generation
gushing
industrial
liquid
mud
old
pipe
pipeline
polluted
polluter
pollution
pouring
residential
ripple
river
rust
rusty
sea
sewage
sewer
sewerage
sluice
stagnant
station
stream
substance
toxic
treatment
tube
unclean
waste
wastewater
water
water pipe
wave