Water Treatment Processes - Mathematics and Statistics for the Environment - page 663

Section XI
Math Concepts: Wastewater
In the glory days of Empire Textiles, the solvents and dyes used on the fabrics were dumped directly
into the river, staining the banks below the falls red and green and yellow, according to the day of the
week and the size of the batch. The sloping banks contained rings, like those in a tree trunk, except
these were in rainbow colors, they recorded not the years but the rise and fall of the river. Even now,
fifty years later, only the hardiest weeds and scrub trees grew south of the pavement on Front Street,
and when the brush was periodically cleared, surprising patches of fading chartreuse and magenta were
revealed.
—Richard Russo ( Empire Falls , 2001)
Whenever in Peru, an important rule of thumb to keep in mind is do not flush your toilet paper.
—Frank R. Spellman