The Board of Directors for Pennvest Wednesday awarded the Altoona Water Authority a $6.75 million low-interest loan to replace the four trash screens at the entrances to each of the authority’s two Combined Sewer Overflow tanks.

The 30-year-old screens have reached the end of their usefulness, with key components no longer being manufactured, so when those need replaced, the parts must be custom-made, officials have said.

The screens protect the tanks from debris that washes off the streets during storms and into sewer inlets in areas of the city where storm and sanitary flows are combined.

Excess water is diverted into the approximately 1-million-gallon tanks by authority operators when the combined sewer pipes that take the flow to the authority’s two sewer plants reach capacity.

When the tanks fill up with that “first flush,” the remaining flow from the streets that cannot be handled by the pipes that connect with the plants overflows channel curbs near each tank, flowing into Mill Run at the Tuckahoe Park CSO and into the Little Juniata River at the Bellwood Avenue CSO.

The water entering those streams at such times contains highly diluted sanitary effluent from the homes and businesses in the combined sewer areas of the city.

When a storm abates, the authority pumps out the tanks, so the water from the tanks flows to the treatment plants — and so the tanks are empty for the next storm.

One CSO serves the Westerly treatment plant and one serves the Easterly plant.

Authority officials had hoped that some of the funding for the screens would be in the form of a grant, due to Pennvest having adjusted its affordability index to take advantage of money made available by the Bipartisan Infrastructure Law of 2021.

In doing so, Pennvest lowered the target range of annual utility costs for average customers that it hopes to help its client utilities to maintain.

Prior to the BIL, Pennvest’s target range for those annual utility rates was between 1% and 2% of the average median household income for each utility’s full customer base, a Pennvest official told the Mirror last year.

After the BIL, Pennvest’s target range for annual utility rates went down to between 0.5% and 1.25% of median household income for the average customers of each utility.

“We lowered the bar,” the Pennvest official said at the time.

The city census tracts served by the authority’s combined storm and sanitary sewer system are at least close to the affordability range that could have made the project grant-eligible, an authority consulting engineer has said.

The authority had no comment Wednesday about all the funding for the screens being in the form of a loan.

Work on the screens should begin in September, according to authority spokesman Daniel Ramsey.

The contractor chosen for the project will not be able to work on more than two of the four screens at each of the CSO locations at the same time, to ensure that each facility remains functional in case of a rainstorm.

The screens are about five feet wide and 14 feet high.

While the current screens are largely cast iron, parts of the new ones will be made of stainless steel.

Mechanized rakes moved by chains comb the surface of the screens to keep larger debris from clogging the openings.

The screens are about six feet below grade, with the tanks farther down.

“We are pleased to have been approved for the funding,” Ramsey said.

State Sen. Judy Ward, R-Blair, and State Rep. Lou Schmitt, R-Altoona, announced the awarding of the loan in a joint news release.

Mirror Staff Writer William Kibler is at 814-949-7038.