осадок, образующийся при аэрации сточных вод и используемый для их биологической очистки.
"A penny saved is a penny earned." Benjamin Franklin
"The mystery of government is not how Washington works but how to make it stop." P. J. O'Rourke
"Never retreat. Never explain. Get it done and let them howl." Benjamin Jowett
"We have a system that increasingly taxes work and subsidizes nonwork." Milton Friedman
