Tahoe's Sewage Water Fit to Drink

At an environmental conference in Washington last spring, I was given a glass of water to drink. I sipped with some misgiving, for it was the end product of a sewage plant.

There was an amused glint in the eyes of Frank Sebastian as he watched how slowly I tilted the glass. Mr. Sebastian is Senior Vice President of Envirotech, a California corporation that makes, among other things, tertiary sewage-plant equipment.

"It's purer than the water that comes from your faucets at home," he said comfortingly.

The water—which tasted like any other water—came from the sewage plant at South Lake Tahoe, California.

Beautiful Lake Tahoe has long been known as one of the purest lakes in the world, but the number of tourists and residents on its shores has skyrocketed in the past two decades. Increasingly, Lake Tahoe was losing the purity that made it so attractive. But for once something was done in time.

"Even secondary sewage treatment wasn't enough," Mr. Sebastian said, "so more modern tertiary equipment was installed."

Although the nutrient content of the output water is low, it is not discharged into Lake Tahoe, instead, it is pumped 27 miles into another drainage basin. Dr. Charles R. Goldman, of the University of California, explained why. He is one of the Nation's leading limnologists—lake experts.

"Lake Tahoe has very little flushing action," he told me. "Its 37 ½ cubic miles of water are nearly permanent. We just can't add any nitrates and phosphates unnecessarily—even that sewage water. It would aggravate the lake's algal problem."

Algal problem? To me, Lake Tahoe looked as clear as blue crystal. Where were the algae getting their nutrient?

Dr. Goldman reminded me of construction I had seen around the lake. "If all that bulldozing isn't done very carefully—and often it isn't—topsoil washes into the lake during rains. Nutrients wash in with the soil."

We walked down to the shore. Dr. Goldman felt down between underwater rocks and came up with a handful of green strands.

"There is a lot more of this than there used to be," he said. "The lake is still clear enough for sunlight to penetrate about 300 feet and sustain plants down there. If it clouds over with algae or silt, its life-sustaining ability will be greatly reduced."

When residents of Seattle, Washington, head for the water—and most of them do at every opportunity—they have a choice. Puget Sound stretches along the city's western edge, 20-mile-long Lake Washington on the east.

That lake is important to the people. Ten years ago it was on its way to Lake Erie's fate. Inadequately treated sewage gushed in. A green scum could be seen on the lake's cloudy surface, and the unpleasant stench of dead lake life was hard to ignore on a hot summer day.

Puget Sound was in trouble, too, for seventy million gallons of raw sewage from the Seattle area poured in daily.

In September 1958 the citizens voted Metro into existence—the Municipality of Metropolitan Seattle—to solve the problem. Four up-to-date sewage plants were built, replacing 28 old ones. It was expensive but worthwhile. Discharge of treated wastes into Lake Washington has ended entirely. Output of raw sewage into Puget Sound has virtually stopped.…