My visit to the sludge factory

Fifteen years ago, two investigative reporters published an exposè about the public relations industry.  They called it "Toxic Sludge is Good For You!"  The name, of course, was facetious.  But now, as it turns out, there's some truth to the ironic title of their book. 

Since 1993, an Ohio-based company called N-Viro International has been quietly making a livelihood collecting the evil-smelling residue from municipal wastewater treatment plants and transforming it into a nearly odor-free gravelly mix that's sold as an agricultural soil enrichment product.  They've been doing it in Canada, Michigan, and Florida as well as in Ohio. Up next are plans to open a plant in Israel. 

Despite their successes, the owners found there are limits to the market, at least for domestic agriculture.   So now they're moving in a new direction -- using the stuff as fuel for power plants that currently burn coal. In principle, it has the potential to generate steam as it holds about 6,000 BTU per pound. That's roughly half as much as coal, but it's more than enough to heat a plant's boilers. 

In 2009, the company ran a pilot program at Michigan State University to test the feasibility of using the transformed sludge as fuel.  They mixed it into the coal that a plant normally burns and found not only that it burned well, but it also reduced the harmful air emissions associated with coal. 

So now they're ramping up for a sustained run. 

A coal-fired power plant in Venango County has become serious about using the company's transformed sludge as a steady source of fuel, so N-Viro moved a small-scale mobile plant into nearby Emlenton to demonstrate its system.  And they've been scouting for raw material.  , along with Slippery Rock, Franklin and , have been happy to oblige.  So last week they invited all of us up to see how it works.

Even though it wasn't in production at the time of our visit, the technology is promising. For years, Cranberry's old municipal sewer and water authority operated a farm near its Brush Creek sewage treatment plant where it buried the plant's residual sludge.  Eventually, the property reached the limit of its EPA permit.  Ever since, the plant has been paying to have the stuff hauled away to a landfill.  Right now, the plant generates about 2,500 tons of sludge a year and the township pays more than $7,000 a month to have it taken away. 

If the N-Viro project works out on a commercial scale, the situation may greatly benefit Cranberry and its neighbors.  Instead of having to deal with an unpleasant residue, the township and its residents may be creating the fuel of the future. 

And, instead of paying to have it taken away, a market may someday emerge for selling the material – now delicately referred to as 'biosolids' – reducing the cost of treating sewage and returning clean water to the local environment.