Officials at Denver International Airport and the city of Denver are completing negotiations on a $650-million-plus project to remake DIA’s terminal. The renovation, the largest public-private partnership in the city’s history, will be done by Great Hall Partners (GHP), a consortium led by Madrid-based Ferrovial Airports. DIA officials disclosed details about the proposed contract on June 2.

The project will increase the capacity of the 1.5-million-sq-ft terminal to serve 80 million passengers per year. When the airport opened 22 years ago, it was designed to handle 50 million passengers a year. In 2016, DIA traffic topped 58.3 million people, according to airport records.

Terminal upgrades aim to boost security-screening capacity by at least 50% and relocate TSA positions to the north end of the terminal, leaving room at the south end for an open meet-and-greet area near the train station and new airport hotel. Ticket counters will be consolidated, eliminating dozens of positions left empty by airline consolidations and online-ticketing technology. More food and retail concessions will be added.

The P3 contract, which could run as high as $775 million, will extend for 34 years, including four years of construction and 30 years of operations, airport officials said in a statement. GHP will build and pay for all of the improvements but manage only the terminal’s concessions after completion. Revenues from concessions will be split, with 20% going to GHP and 80% to DIA, officials said.

The Denver City Council will review the P3 contract in late July, and if it is approved, construction could begin as early as next summer and finish in 2021.