17 companies had tendered for the project by the October 12 deadline.
The 2,000-km pipeline will be built at a cost of US$3 billion.
Installation of the security system is set for completion in March next year.
Centurion Symbio-City is expected to be the 14th tallest free-standing structure in the world.
The building features 80 pre-fabricated apartments spinning a full 360 degrees.
The highway was split into three sections for construction works.
The resort will comprise an 18-hole golf course, a lodge, 80 cottages and an airstrip.
The project begins with building the first three of 32 planned berths at Manda Bay.
Solarcentury will install a 500kW solar photovoltaic (PV) system at Moi International Airport.
The architectural design of the resort was done by Matteo Fantoni Studio of Milan, Italy.
Developers will be allowed to build up to 75 floors in high-density areas.
The much-awaited summit will take place on June 12-13, 2025.
All development applications will now require residents' approval.