Welcome to the Key Largo Wastewater Treatment Plant

The Key Largo Wastewater Treatment Plant Overseas Highway Key Largo, FL 33070

The Key Largo Wastewater Treatment District was commissioned by the State of Florida in June 2002.

Plant Purpose Cesspits and septic tanks in the Keys provide little treatment of domestic wastewater in porous limestone and cause untreated, nutrient-rich wastewater to be discharged into our waters. The untreated water from these cesspits and septic tanks is a main source of nutrients and human pathogens in our ground and surface waters. Without reform of our wastewater discharge, the Keys' ecosystem may be destroyed. The plant will work towards restoring the ecological balance of the Keys' ecosystem and maintaining the Keys' economy by controlling the nutrient levels of our waters.

Sources of Key Largo Wastewater

What Happens at the Plant? Mechanical treatment removes inorganics. Biological treatment reduces organics and converts ammonia to nitrate (nitrification), and nitrates are then converted to a harmless nitrogen gas (denitrification). Chemical treatment removes phosphorus using alum, and chlorine is used to disinfect the final effluent. Mechanical filtering polishes effluent.

Headworks The headworks separates solids from the influent (incoming wastewater).

Sequencing Batch Reactors Sequencing Batch Reactor are industrial processing tanks used for the treatment of wastewater. KLWTD has constructed three Sequencing Batch Reactors (SBRs) to increase the amount of wastewater that can be treated. The operation of an SBR consists of five steps— fill, react, settle, decant/draw, and idle.

Fill- During the fill phase, the basin receives influent wastewater. The influent brings food to the microbes in the activated sludge, creating an environment for biochemical reactions to take place. React- During this phase, no wastewater enters the basin and the mechanical mixing and blower units are on. Because there are no additional volume and organic loadings, the rate of organic removal increases dramatically. Most of the nitrogen and phosphorus are removed during this phase. Settle- During this phase, activated sludge is allowed to settle-no flow enters the basin and no aeration and mixing takes place. Decant/Draw-During this phase, a decanter is used to remove the clear effluent located in the middle of the tank. Idle-This step occurs between the decant and the fill phases. During this phase, a small amount of activated sludge at the bottom of the SBR basin is pumped out—a process called wasting.

Our Sequencing Batch Reactors

Biological Treatment Activated sludge- microorganisms are enticed to remove nutrients (nitrogen and phosphorus) from the influent through manipulation of their environment, especially oxygen levels. Bacteria=Bugs BOD/COD=concentration of organic material (food for “bugs”)

Blower and Blower Motor The blowers and diffusers are used to provide oxygen for the “bugs” during the reaction phase. Diffuser

Equalization Tank

Microfiltration

Chlorination to Eliminate Pathogens Chlorine Contact Chamber

The Deep Injection Well

Advanced wastewater treatment is used for: – Additional organic and suspended solids removal – Removal of nitrogenous oxygen demand (NOD) – Nutrient removal – Removal of toxic materials

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