Portsmouth is on track for a waiver from the Environmental Protection Agency that would allow the city to continue the minimum level of water treatment at its Pierce Island water treatment plant and discharge effluent into the Piscataqua River, much to the dismay of opponents.

The EPA held a public meeting last week at Portsmouth City Hall about the waiver. Officials with the city's Public Works Department testified to the need for the waiver while opponents urged Portsmouth to upgrade the plant.

A higher level of treatment for the water, normally required by the federal Clean Water Act, is not necessary for the Pierce Island discharge location because the river's strong currents can dilute the effluent, according to Peter Rice, an engineer with the city's Public Works Department.

"The Piscataqua, at the existing location of the discharge, has 82 feet of water and particularly strong currents, which sets it apart from nearly all other discharges in the country," Rice said.

Portsmouth originally received the waiver, which Rice called a 301(h) exemption, in 1982. The waiver must be renewed every five years, he said.

Doug Bogen, state program director for Clean Water Action, said the city should directly address the problem and upgrade the plant.

"Portsmouth is one of the few remaining cities in the country that hasn't gotten up to speed in what's required of them," he said. "It's way past time to bite the bullet and deal with it. There are real impacts and we've got impaired waters."

The effluent discharge has "no discernible impact" on the river, Rice said. Other pollution sources, such as illegal discharges, rainwater and sewer overflows, are primary sources for pollution in the river, he said.

Even if the plant's impact on the river is small, it still needs to be addressed, according to Bogen.

"If you have waterways stressed by various pollutants...you don't add more to it. The city's trying to argue 'we're not the major source, we're not the only source,' but they are a source. They can't argue (they) have zero impact," he said.

It's not known when the EPA will make a final decision on the waiver. It would cost roughly $30 million in capital costs to upgrade the plant to handle secondary treatment, as well as an additional $1 million for operational costs, according to Rice. This is in addition to the $30 million the city is spending to upgrade its sewer system, he said. Also, the island may not be big enough for an expanded plant with additional tanks and treatment systems.

"Given the science, given the competing needs, we are targeting what we feel is the most effective use of our limited resources towards improving the environment," Rice said.