Biosolids alternative would use AWA equipment, land
Method could also generate revenue
Several months ago, a consulting engineer for the Altoona Water Authority spoke to the board about a new method of handling sewer sludge.
That method would require a $2.5 million investment in equipment to heat, then blow dry the sludge, so it could be sold as shrubbery mulch, according to the consultant.
The blow-dry method could replace the authority’s current system, which requires spreading centrifuge-dewatered — but still water-heavy — sludge on farm fields — a system that is problematic, because of a dearth of willing farmers and restrictions on application times because of concerns about possible ingestion of contaminants.
On Thursday, Environmental Services Manager Todd Musser outlined a third alternative that could generate revenue like the blow-dryer approach, eliminate the regulatory problems of farm application, remediate problematic watershed land and be done with equipment and expertise already in the authority’s possession.
It’s called “deep row hybrid poplar biosolids recycling” and calls for digging trenches 3 or 4 feet deep in forests or open land, filling them with sludge, covering over with soil, then planting hybrid poplar trees, which take up the nutrients in the sludge over several years.
Because the trees are not a potential food source, the trench method eliminates concerns connected with farmland application.
The authority has about 10,000 acres of watershed, including unreclaimed and poorly reclaimed strip-mine areas that the trench method could help restore, according to Musser.
There’s enough land that the authority might be able to take in sludge from other agencies to generate revenue, he said.
The reclamation could also help improve water quality in streams like Kittanning Run above the Horseshoe Curve, which is polluted with acid mine drainage, enabling the authority to divert it from a bypass channel into the Curve reservoir complex, Musser indicated.
“I’m really impressed,” said board member Marla Marcinko.
Musser also proposed that the authority consider alterations to its sewer treatment plants to enable them to earn revenue by generating electricity, then selling it to the “grid,” utilizing their excess capacity to process food waste from commercial enterprises like dairies and food processing plants.
He plans to visit a plant in Hermitage that uses the process.
That plant recently took in a load of rejected onions and soon would be processing a rejected shipment of adulterated honey, he said.
Revenue from such changes can help stabilize customer rates, he said.
Mirror Staff Writer William Kibler is at 949-7038.