environmental
black
clean
construction
dirty
drainage
drop
effluent
environment
factory
filter
filtration
flow
flowing
icon
industrial
industry
isolated
line
liquid
nature
outline
pipe
pipeline
piping
pollution
processing
purification
purity
recycle
recycling
river
sedimentation
sewage
sewer
sludge
station
steel
strainer
tank
tap
thin
trap
treatment
tube
waste
wastewater
water