Flushing Out Facts

Earlier this month, Washington’s Department of Ecology and a coalition of industries and municipalities dumping large amounts of wastewater into the Spokane River announced a negotiated delay in the process to impose new, tougher limits on river pollution. The two factions — plus the federal Environmental Protection Agency and a whole slew of concerned citizens — are crunching the numbers to see how much they can limit pollution without hampering development — and how much they can develop without endangering the river. Meanwhile, we thought we’d cast some light on a couple of the stats that have come up so far.

This debate is more than academic, however, as keeping the Spokane River clean is job that belongs to everyone. In fact, you pay for it in your utility bills, which may go up in the future as some kind of new wastewater treatment capacity will be needed. Municipalities including Spokane, Spokane Valley and Liberty Lake are all seeking to treat more wastewater at an affordable price. Where the final levels of allowable pollution come in will determine how expensive that solution will be to local ratepayers.

55 million gallons

According to the Total Maximum Daily Load (TMDL) study, conducted by Ecology, that’s about how much effluent — tap water, crap water, industrial waste — that major dischargers pump into the Spokane River every day. To reach that same number yourself, try flushing your toilet about 16 million times in a row, and you’ll get the picture.

Both the TMDL and the Use Attainability Analysis, a similar study conducted by the dischargers, focus on the amount of dissolved oxygen in the river. Plenty of oxygen means a healthy environment for fish and native plants. But the more effluent that is dumped in the river, the more algae and other weedy water plants thrive, sucking up the oxygen the other river inhabitants need to survive. And with 55 million gallons entering the river daily, effluent is getting in. Limiting how much is the real challenge.

23 micrograms per liter

During an unusually dry summer, like the one we’re bound to have this year, that’s about the concentration of phosphorus the Spokane River dumps into Long Lake (or Lake Spokane), about five miles downriver from downtown Spokane. To compare, fill up an Olympic-sized swimming pool with clean water, then fill a shot glass with liquid phosphorus and pour it in. That doesn’t sound like much, but science tells us that it only takes a little phosphorus to upset nature’s balance.

Phosphorus is one of the most worrisome elements of all the effluent going into the river for a pretty good reason: It’s the main ingredient in fertilizer. And fertilizer doesn’t cease to be fertilizer when it enters a stream. It goes on fertilizing — in this case, whipping those algae and other water weeds into a frenzy and acutely diminishing dissolved oxygen levels.

These are hardly fightin’ words for most of us, we know, but it’s got Ecology plenty worried. They’d like to bring phosphorus concentrations down to around 6 micrograms per liter, or about a quarter of a shot glass in the swimming pool. And that idea, in turn, has dischargers worried. Because even if they can figure out a way to meet those limits — and some say it’s impossible — it’s not going to be cheap.

$600 million

That’s how much dischargers are saying it will cost to filter phosphorus out of the river using a technology called “reverse osmosis,” in which wastewater is essentially distilled by forcing it through a membrane and removing all the dissolved ions. It’s a good process, to be sure. Its proponents say it has the potential to remove 100 percent of all pollutants (not just phosphorus) from the wastewater.

But everyone involved admits that $600 million is a hefty price tag. The city of Spokane could live off that kind of money, Ken Lay-style, for about five years. It could build about 14 high-speed train refueling depots over the aquifer with that money. Or fix 500-some leaks from said depots.

Ecology’s Ken Merrill admits that reverse osmosis is “one of the most expensive alternatives you could think of,” and he thinks the same goal could be reached for less money.

$550 million

That, suggests Merrill, is the potential savings in ditching this reverse osmosis idea and going instead with dual-stage sand filtration, in which polymers are added to the wastewater, which is then sent up through columns of progressively finer sand to get the phosphorus out. He says that while such a treatment wouldn’t filter everything out, it could bring the above-mentioned level of phosphorus in the effluent dumping into the river and Long Lake down to around 10 micrograms per liter in the warm, dry summer months. Those levels don’t make for the healthiest drinking water — but that degree of filtration, says Merrill, would be plenty sufficient for piping the water back to farms for irrigation.

And besides, you could take that savings to the grocery store and buy yourself about 1.4 million pounds of trout, plucked fresh from a healthier Spokane River.