A $65 million project to renovate the Lincoln Mill into market-rate apartments will move forward after the Biddeford Planning Board approved changes to the proposal.

The Planning Board on Wednesday approved an amended site plan and granted LHL Holdings LLC and developer Tim Harrington a waiver allowing an additional 79 parking spaces. Harrington plans to transform the former textile mill into 181 apartments, a fitness club and restaurant.

Harrington originally proposed a $50 million hotel with apartments and two restaurants, but announced in February that the first phase of development would instead double the number of apartments. He plans to build a stand-alone hotel during the second phase and will increase his total investment in the project from $62 million to $65 million.

The project has been heralded by city officials as a sign of economic development in the downtown and mill district after the departure of the former Maine Energy Recovery Co. trash incinerator. Since the City Council voted in 2012 to buy the riverfront property that housed MERC, more than $100 million in new investment has been announced for the downtown, according to city officials.

The Planning Board approved plans for the mill in January, but had to consider an amended site plan when Harrington announced the changes. City Planner Greg Tansley said the board only had to decide whether to grant a waiver for 79 parking spaces.

Mark Robinson, a spokesman for the project, said the board’s decision on the waiver means construction will begin as early as spring. The developer is obtaining bids from contractors, he said. Construction is expected to take 18 to 24 months.

“(The developers) are very glad the Planning Board approved the parking waiver,” Robinson said. “It’s onwards and upwards.”

The Lincoln Mill project now includes 181 market-rate apartments, a 10,000-square-foot fitness club, a rooftop pool, a 107-seat restaurant and an 18,000-square-foot commercial space on the first floor.