McDonald Group International, Inc

Water, Wastewater, Environmental Engineering 


Advanced Wastewater Treatment Plant, Florida Keys



This privately owned facility  in the Florida Keys was converted over to meet the requirements of what had known as the 2010 environmental protection standards for the Florida Keys,   which required that effluent discharge standards for facilities this size meet a 10 mg/L BOD, TSS and Total Nitrogen limit, as well as a 1 mg/L Total Phosphorus limit .

The original treatment plant seems to have been constructed in the early 1970s as a conventional extended aeration facility with a capacity of 60,000 gallons per day. Site specific challenges included extremely limited land area which required custom design tankage,  failing injection wells which had to be replaced, high levels of groundwater inflow from deteriorating sewer collection mains, not to mention the need to maintain service while the work was going on.  A further design challenge was the plant had to be expanded in order take in service from surrounding properties.

The completed facility has two flow trains, the process used includes flow equalization,  anoxic, aeration, post anoxic and rearation tankage, along with chemical reduction of phosphorus