For Florida Power & Light, and environmentalists fighting the utility’s plans to expand the Turkey Point nuclear power plant, the stakes of a zoning hearing on Thursday before the Miami-Dade County Commission were high.

FPL was seeking final county approval on “unusual use” permits for two key projects: a plant to treat up to 90 million gallons a day of wastewater it intends to use to cool two proposed new reactors and a network of coastal wells designed to tap groundwater under Biscayne Bay as a back-up cooling system.

Environmentalists were there to argue the treatment plant would destroy some 40 acres of wetlands and warn that the shallow wells, capable of drawing up to 125 million gallons a day, could compromise efforts to restore freshwater flows to Biscayne Bay and worsen the inland march of salt water that threatens the county’s drinking water supply.

Both sides turned out in force.

County commissioners, however, did not.

After a 40-minute delay for lack of enough bodies to do official business on the 13-member board, a seventh commissioner moseyed in. But commissioners began drifting on and off the dais after FPL’s team of experts and attorneys made its presentation.

After hearing from just one opponent, Pinecrest Mayor Cindy Lerner, Commissioner Barbara Jordan urged a time constraint on speakers, saying she feared the board would lose its quorum — as it quickly did, after hearing from just a handful of the 15 critics signed up to speak.

Now, a decision — if enough commissioners manage to show up — will be pushed to the next scheduled zoning hearing on Jan. 10.

“Let me first and foremost apologize for wasting everybody’s time,’’ said Commissioner Esteban “Steve” Bovo, who chaired the hearing and had pressed opponents of the projects to keep their comments brief. “I guess circumstances were beyond everyone’s control up here.”

Afterward, Steven Scroggs, FPL’s senior director of project development, echoed the reaction from both sides: “disappointing.’’

The zoning decision represents one of the last significant county hurdles in FPL’s plan to add two more nuclear reactors to its complex on south Biscayne Bay. Environmentalists will be allowed to continue making their case at the next meeting.

In addition to Bovo and Jordan, other commissioners in attendance were Audrey Edmonson, Jean Monestime, Lynda Bell, Juan Zapata, Bruno Barreiro and Dennis Moss.

Edmonson left the dais, followed later by Jordan, leaving the commission short of a quorum.

Absent were Sally Heyman, Rebeca Sosa, Xavier Suarez, Javier Souto and Jose “Pepe” Diaz, who did show up but too late to take part in the quasi-judicial hearing. Diaz issued an apology during the hearing.