KINGSPORT — Domtar’s Kingsport mill told the Tennessee Department of Environment and Conservation that it will try a method to improve wastewater quality at its wastewater lagoon this week. The mill said it will add an oxidant near the outlet of the lagoon’s settling zone for about 30 days to see if it would improve the effluent water quality. “It will be fed at a low rate of approximately 1 [part per million] with monitoring and testing being done at our effluent sample point before the discharge to the river,” the letter states. The mill has also tried chemical treatments and injecting liquid oxygen to address sulfuric odors attributed to the 25-acre wastewater lagoon.It is currently constructing a new wastewater treatment system, an anaerobic digester, to address wastewater odors attributed to the mill. Construction is expected to complete near the end of 2026.