Miami-Dade Mayor Carlos Gimenez is appointing a special committee to rank which of two engineering companies should be awarded the bid to manage a $1.2 billion sewerage system overhaul.

Gimenez’s decision, announced late Friday by memo, means the bid process will not start from scratch despite ethical concerns raised about the process so far.

Colorado-based CH2M Hill Inc. and Los Angeles-based AECOM Corp. are the finalists for the $80 million project, which entails overseeing a complete overhaul of the county’s sewer system. CH2M Hill, which received the first-place ranking in the final tier selection, chastised Gimenez’s decision to “further delay the process.”

“If today’s decision moves forward, the losing team will have a fifth bite at the apple and the county will disregard the expert opinion of its selection committee, which chose CH2M Hill as the winner,” Al Dotson Jr., a partner at Bilzin Sumberg Baena Price & Axelrod, said in a statement. “Nothing could be less fair and less proper than changing the rules midstream, especially considering CH2M HILL has ten times more experience managing similar projects than its competitor.”

The county is under a consent decree with the federal government to replace its deteriorating sewer pipes and must award a preliminary contract by December.

After a complaint was raised by AECOM, Gimenez asked the county Ethics Commission to consider whether the so-called “cone of silence” on bidding or any other ethics rules were violated when CH2M Hill delivered 400 pages of supplemental documents to the project selection committee two days before a second-tier decision was made.

The head of the Ethics Commission concluded CH2M Hill did not break any rules or procedures but its actions raised doubts about the integrity of the bidding process.

The county’s interim inspector general, Patra Liu, made similar findings, saying a “troubling” loophole exists that allows vendors to communicate with members of a selection committee before a bid.

Gimenez said he would appoint an advisory committee composed of three external members and two county staff members “with knowledge and expertise in these types of services” to provide him with a final ranking and a consensus statement. He did not name the committee members in his memo.

AECOM and CH2M Hill will be allowed to submit supplemental information or a new proposal within two weeks. County staff will then schedule a final evaluation meeting with oral presentations. The mayor’s committee will then rank the two firms and send its recommendation to Gimenez.

“It is important that the selection of the program and construction management services related to the wastewater system priority projects be completed via a fair and equitable process,” Gimenez said. “My administration is committed to expediting all water and sewer infrastructure projects. In doing so, I want to ensure that the process we use to select firms and contractors is one that is fair, competitive and transparent.”

Dotson labeled Gimenez’s action unfair.

“CH2M Hill responded to the county’s request for qualifications, followed the rules of the process in good faith and was selected as the most qualified team to overhaul Miami-Dade’s aging sewer system,” he said in a statement. “The county attorney, Ethics Commission and inspector general have all vindicated CH2M Hill’s selection, and yet Mayor Gimenez has chosen to further delay the process.

However, Holland & Knight partner Miguel de Grandy, who represents AECOM, welcomed Gimenez’s decision, saying, “We feel our position was vindicated and believe the mayor has arrived at a just result, and we look forward to a fair and transparent competition.”