Authority authorizes nutrient credit sales

The Altoona Water Authority has given its general manager permission to sell nutrient credits, available because the authority’s sewer treatment plants remove more nitrogen and phosphorous than required by the


The authority projects that it will generate credits for 73,000 pounds of nitrogen and 2,000 pounds of phosphorous to sell to organizations that discharge more of those nutrients to streams than

permitted, said Mark Perry.

He’s already had inquiries from an authority in Blossburg interested in buying nitrogen credits, Perry said.

Phosphorous, however, is the “hot commodity,” he said.

While nitrogen currently fetches $3 a pound, phosphorous is bringing in $8, said Perry and Environmental Services Manager Todd Musser.

Phosphorous is more valuable because it’s harder to eliminate from effluent, said Musser and in-house engineer Mike Sinisi.

It’s harder to eliminate “organically” because it requires a tricky series of alterations in biological treatment, requiring workers to provide lots of food to the microorganisms that digest the nutrients, then to “starve” those microorganisms — along with providing those microorganisms lots of air at first, then no air, Sinisi said.

Such operations require a large investment and extra tanks, Musser indicated.

Phosphorous also can be eliminated chemically, adding alum to settle it out, but that too is expensive, he said.

It’s easier for smaller plants — with a capacity of fewer than 1 million gallons — to simply buy phosphorous credits, Musser said.

Because of the high value of phosphorous credits, the authority itself is considering adding alum to its sewer effluent to bring phosphorous levels down even further, providing more credits to sell, Musser said.

Whether it follows through on those plans depends on whether the gain from the additional nutrient sales is greater than the cost of adding alum, Musser said.

The nutrient credit exchange provides incentive for organizations to exceed minimum standards, coupled with incentive for organizations that can’t meet those standards to do better — without actually having to pay punitive fines.

Mirror Staff Writer William Kibler is at 949-7038.