A nine-story affordable housing project will break ground at 810 Arch St. in September, thanks to an innovative partnership among nonprofit developers and the city to improve the blighted block.

Sister Mary Scullion's Project HOME and the Philadelphia Chinatown Development Corp. (PCDC) will build the $23.5 million apartment complex on an empty lot on the south side of Arch Street.

Expected to be completed by late 2015, the complex will provide 94 efficiency apartments for lower-income rental tenants ranging in age from seniors to children aging out of foster care.

"This is a partnership with the Philadelphia Housing Authority, the Pennsylvania Housing Finance Agency, the James and Frances Maguire Foundation, and Leigh and John Middleton, and many other donors," said Sister Mary.

The Philadelphia Redevelopment Authority donated land for the public-private partnership, said John Chin, executive director of the PCDC.

"It's going to fill in what looks like a missing tooth in the block," said Chin. "Within 15 months, we'll see positive changes."

There is some affordable housing in Chinatown, including Dynasty Courts and On Lok House, Chin said. But the neighborhood needs more.

"The partnership between Project HOME and PCDC is special because we serve distinct populations and we found a way," Chin added. This neighborhood was especially strategic for "the elderly, homeless, and those on the verge of homelessness," Sister Mary said.

The goal is for the 78,000-square foot building to be LEED Silver certified by MaGrann Associates, and offer an underground rainwater collection system to deal with runoff, said Christopher Bombardier, with architects Kramer + Marks, based in Ambler.

For units with project-based vouchers through Philadelphia Housing Authority, tenants will pay 30 percent of income.

An additional 57 units will be affordable to those at or below 50 percent of income, and 15 units will be affordable to those at or below 20 percent.

Rents are projected to be between $690 to $799 per month.

Between 2006 and 2010, the median rent in Chinatown was $931, compared with $683 citywide, according to a report in 2013 by the Asian American Legal Defense and Education Fund (AALDEF).