environmental
clean
contaminated
dam
danger
dirty
discharge
ditch
drain
drainage
dump
eco
ecology
effluent
environment
filter
foam
garbage
industrial
industry
meltwater
metal
nature
oil
outflow
pipe
plant
pollution
polution
production
river
sanitary
sanitation
scum
sewage
sewer
sludge
smell
smelly
spring
stormwater
system
technology
toxic
treatment
tube
waste
wastewater
water
white