environmental
building
clean
dam
dirty
drop
effluent
environment
facility
factory
filter
filtration
flow
garbage
icon
illustration
industrial
industry
isolated
liquid
pipe
plant
plumbing
pollution
processing
pump
purification
purified
purity
recycle
reservoir
sedimentation
set
sewage
sign
sludge
station
steel
storage
strainer
symbol
system
tank
tap
trap
treatment
waste
wastewater
water