Tisbury establishes denitrification regulations

Tisbury has established denitrification regulations effective Feb. 1, 2022. — courtesy Town of Tisbury

The Tisbury board of health has established enhanced denitrification regulations for the Lake Tashmoo and Lagoon Pond nitrogen watershed overlay districts, an area that covers much of the town. 

“The regulation requires the installation of onsite denitrification wastewater disposal technology that meets a nitrogen groundwater discharge standard of not more than 13 mg/liter of nitrogen from septage waste, or removes 75 percent of septic nitrogen waste,” a release states, “and is approved by the Massachusetts Department of Environmental Protection for general use, provisional use, or piloting use for nitrogen reduction …”

The regulations encompass properties or properties with the following conditions:

a) a new wastewater treatment system is required to serve a property (i.e., new construction).

b) a property’s existing wastewater treatment system fails, and replacement is necessary, as determined by the board of health.

c) additional development on the property or a change in use or in intensity of use (or potential use) which would increase wastewater nitrogen discharge beyond the board of health–approved system capacity, irrespective of whether the existing wastewater treatment system has excess sanitation capacity.

d) at the time that a property is transferred to another owner and based on a septic system inspection, the board of health determines that a new wastewater treatment system or system upgrade is necessary.

The regulations go into effect on Feb. 1.