The city of Portsmouth will pay the state a fine of $6,825 to conclude an enforcement action arising from an accidental discharge of partially treated water into Suffolk’s Lake Meade.

The discharge, on June 26, 2012, tinted the water a pink hue because of an excess amount of sodium permanganate, a chemical used in the treatment process to remove impurities from the water.

The chemical is regulated by the U.S. Drug Enforcement Administration because it is useful in the production of cocaine. It also is considered a pollutant.

According to the consent order issued by the state Department of Environmental Quality, the mishap occurred when the source of raw water for the facility was being switched from the Pitchkettle Road pump station to the primary intake point on Lake Meade.

The facility had recently switched from a powdered form of the chemical to a liquid form, and operators “were not yet fully proficient in the operation” of the new system, according to the consent order.

As a result, the chemical had overfed and was being stored in a chamber in the pump station, according to Bryan Foster, Portsmouth’s director of public utilities. When workers attempted to divert the chemical-laden water to the wastewater stream, it overwhelmed the system and resulted in the overflow, Foster said.

“That’s why there was a violation of our permit,” he said, adding that there were no apparent adverse environmental effects in the lake kill. “It was certainly an unfortunate event.”

Foster said the city has taken steps to ensure it doesn’t happen again.

“We’ve done several things as far as our process and training and things we are doing to make sure we don’t have a reoccurrence of that type of event,” he said.

For example, according to the order, facility operators have been instructed to keep gate valves closed when not in use, flush the lines of the sodium permanganate feed pumps when they are taken offline, and notify a supervisor if a nightly inventory reveals an increase in the amount of sodium permanganate used during the previous day.

The city has also outlined new procedures to take in the event of a chemical or equipment failure, according to the consent order. In addition, liquid sodium permanganate will no longer be allowed to accumulate in the wells.