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Legacy Farms wastewater treatment plant addresses high nitrogen levels

by | Dec 5, 2023 | Featured: News, News

The state’s Department of Environmental Protection in early November cited the private wastewater treatment plant at Legacy Farms for having a higher than permitted level of nitrogen discharge in the groundwater. The problem has been corrected and nitrogen levels are within regulatory limits, according to a Nov. 30 letter from the water engineering consultant working with Legacy Farms.

Health Department Director Shaun McAuliffe explained at the Nov. 27 Board of Health meeting that he received a notification from MassDEP about the situation at the plant, located at 29 Clinton Street. He expressed concern that, left unresolved, the high nitrogen levels could lead to cases of methemoglobinemia, a rare blood disorder also referred to as “blue baby syndrome.”

“It’s probably going to require some plant modifications,” McAuliffe said at the meeting. He noted then that the plant had a week to get a corrective action plan to MassDEP.

The Independent obtained a letter from MassDEP to Legacy Farms developer Roy MacDowell Jr. dated Nov. 3. The letter stated that it “observed or determined, that on October 10, 2023, activity occurred at Legacy Farms wastewater treatment facility … in noncompliance with one or more laws, regulations, orders, licenses, permits, or approvals enforced by MassDEP.”

According to the letter, monthly discharge reports indicated that the plant “exceeded its groundwater discharge permit effluent limits for nitrate nitrogen and total nitrogen” on 20 occasions between March 14 and June 1.

The letter stated that MacDowell, the permittee, needed to submit to MassDEP a written description of each of the actions taken to correct the violations noted above within 30 calendar days of the citation. A status report of any corrective actions planned or being taken to achieve or maintain compliance “shall be included with the response to MassDEP.”

MassDEP stated that the permit limits the effluent nitrate nitrogen and total nitrogen from exceeding 10 milligrams per liter. The amounts detailed in the letter ranged from 10.8-21 milligrams per liter.

This is not the first time that the facility has experienced this problem. The wastewater treatment plant was cited on Aug. 31, 2021, according to a MassDEP letter. There were four violations indicated in that letter, with effluent nitrogen levels ranging from 25-39 milligrams per liter — close to four times the allowable amount at its highest point on April 6, 2021.

At that time, MacDowell responded with a letter dated Oct. 4, 2021, submitted by Onsite Engineering, Inc. on his behalf that addressed the noncompliance issues. No further action was taken by MassDEP, and the facility returned to being in compliance.

The Independent emailed MacDowell seeking comment and a corrective action plan. He did not respond by press time.

On Nov. 30, Onsite Engineering, Inc. responded to MassDEP in a letter on behalf of MacDowell. The letter explained what occurred at the facility that led to the issuance of the notice of noncompliance.

“Based on a review of the operations records, it appears that these effluent violations were attributed to work that took place at the facility during that time frame,” the letter stated.

Repair and replacement of “several motorized control valves associated with the process aeration system” had been performed. Dissolved oxygen probes within the aerobic reactors were relocated “in an effort to improve process control and to allow for better long-term operator maintenance.”

The relocation of the dissolved oxygen probes prompted adjustments to be made to the return activated sludge cycle. The operations staff “also performed the intermittent removal/transferring of mixed liquor from/between reactors to facilitate the replacement of aeration bladders in Aerobic Reactor #1.”

“While temporary in nature, these efforts made it more difficult to consistently operate the facility as the process reactors were in a state of flux at that time,” the letter continued. The repairs were “directly attributable” to the violations cited and had to be made while the plant was “actively in use” processing incoming wastewater.

The letter noted that since the repairs were completed in June, “the facility quickly returned to full compliance with all groundwater discharge permit effluent limits, including nitrate/nitrogen and total nitrogen, through the most recent reporting period” in October.