city

pour

river

environmental

problems

sanitary

sewer

rain

waste

roadway

manhole

ecology

garbage

pollution

environment

population

stormwater

sewage

industrial

pipe

liquid

removal

recycling

industry

green

sludge

flow

dirty

wastewater

water

sedimentation

smell

slimy

turbid

discharge

purified

stream

disaster

effluent

tube

engineering

drain

flowing

pump

chemical

dump

concrete

danger

drainage