circular
clean
cleaner
dirty
ecology
ecosystem
effluent
environment
environmental
factory
filtering
flowing
full
green
industrial
industry
liquid
nobody
overflow
plant
pollution
process
purification
purified
purifying
purity
recycle
recycled
recycling
reduce
round
sedimentation
separation
separator
settle
settler
settling
sewage
sewer
sewerage
sludge
station
storage
system
tank
technology
treatment
waste
wastewater
water