Mayor Nutter celebrated the long-awaited replacement for the Youth Study Center on Thursday with the hope that as few children as possible would need it.

"We've been talking about this for 20-plus years," Nutter said Wednesday at a dedication for the Philadelphia Juvenile Justice Services Center, the city's detention facility for youngsters and young people. "I don't want to have children here, but some children need to be here."

The $110 million center, at 48th Street and Haverford Avenue, is the permanent successor to the Youth Study Center, removed from its Parkway site in 2008 to make way for the Barnes Foundation. The former Eastern Pennsylvania Psychiatric Institute (EPPI) in East Falls has served as an interim detention facility.

Officials from the Department of Human Services, which oversees the facility, expect the moving of children from East Falls to West Philadelphia to begin in January.

The center is a short-term stop for those 13 through 20 who are awaiting legal proceedings or transfer to long-term placement.

Speaking at the dedication, DHS Commissioner Anne Marie Ambrose recalled working in the "dark and dreary" Youth Study Center. Around 1998, she said, the center was so far above its 105-person capacity that "kids were sleeping in boats in the gym."

The new, environmentally friendly facility can hold 150 residents and has 10 classrooms - classes are run by the School District - a medical-care area, a gymnasium, an outdoor exercise field, and a garden.

Throughout much of the ceremony, about 14 protesters carrying signs that read "Schools not jails! Free the Streets!" could be heard chanting. They were from the group Free the Streets, which opposes the juvenile center in its community and a proposal to move Police Headquarters to 48th and Market Streets.

Marq F. Temple, executive director of the old and new juvenile facilities, said someone splashed a can of green paint over the new center's front doors Thursday morning, forcing the city to send out a cleanup crew at 5 a.m. Cardboard covered the ground in front of the entrance where the paint could not be removed.

Neighborhood concern about the center delayed construction as Councilwoman Jannie L. Blackwell brokered a deal with city officials to create a community advisory board and build a community room in the center.

Blackwell said city officials have learned from the bumpy road to building the juvenile center. She predicted fewer obstacles if Police Headquarters should come to West Philly.

"I think they'll have their ducks in a row," she said.

Contact Carolyn Davis at 610-313-8109, cdavis@phillynews.com, or @carolyntweets on Twitter.