Montville — The State Bond Commission is expected to approve a $5 million grant for upgrades to the wastewater treatment plant at its meeting Friday, state Sen. Andrea Stillman, D-Waterford, and state Reps. Kevin Ryan, D-Montville, and Betsy Ritter, D-Waterford, announced Tuesday.

The grant would be used toward a new $6.5 million plant on the grounds of the Rand-Whitney Containerboard plant on Route 163. The improvements are necessary because of wastewater that originates from the plant. The grant will be administered by the state Department of Energy and Environmental Protection.

“Effective and efficient wastewater treatment is essential to protect the integrity of groundwater supplies and local streams and rivers, and is particularly important given our proximity to Long Island Sound,” Stillman said in a news release. “I’m pleased by the prospects for this state investment in our local infrastructure because it supports additional economic development going forward.”

The company, which manufactures flexible packaging materials and is also known for its dry laminate and film lamination products, is expected to cover the remaining $1.5 million of the construction costs. The new wastewater plant would be an anaerobic digestion system that would help the town reduce what it pays for sludge treatment and removal, and would produce gas that would be burned by Rand-Whitney.

“It is right that Montville’s taxpayers will get some help with the economic burden of this upgrade,” Ryan said. “It will help with the future expansion of businesses and homes in Montville allowing the town to grow.”

The town and Rand-Whitney signed an agreement in 2011 that requires the town to seek ways to improve the wastewater treatment system at the plant. The new system would be owned by the town, but it would be the company’s responsibility to run and maintain it.

“The upgrading of Montville’s wastewater treatment plant is critically important, and the cost of it would be extremely burdensome, if not impossible, for town taxpayers alone to bear,” Ritter said. “I’m very grateful that we’ve been able to secure state funding for this vital project.”