SBR Technology for Biological Process Control

In 2005, Key Largo Wastewater Treatment District (WWTD) in Key Largo, Fla., utilized a small alternative sequencing batch reactor (SBR) for treating the district’s wastewater.

After five years, the plant was in need of an upgrade to address increasing flow rates from the population it serves and future stringent effluent limits. The district began exploring options for the upgrade, including oxidation ditch and SBR technology. In addition, the planning staff visited nearby installations to see the potential technologies in operation.

Finding a Solution

Following the selection research, Key Largo WWTD ultimately chose a three-basin AquaSBR followed by two AquaDisk cloth media filters (12-disk units) for its expansion.

The plant currently utilizes two of the SBR basins for its biological process and the other basin as an aerobic digester until it is needed for future treatment capacity as a third SBR basin. To enhance its process control capabilities, the plant also incorporated an IntelliPro process monitoring and control system. 

These Aqua-Aerobic Systems technologies were chosen because of their reputation for meeting performance objectives, dependability and process control flexibility. The plant’s new treatment scheme went into operation in August 2010.
    
The AquaSBR system features time-managed operation and control of aerobic, anoxic and anaerobic processes within each reactor as well as equalization and clarification. The system provides advanced nutrient and biological phosphorus removal.

Clarified effluent flows by gravity from the SBR to the AquaDisk cloth media filters. The pile cloth filtration media, uniquely designed for wastewater applications, produces filtrate containing low total suspended solids and phosphorous.

The state-of-the-art IntelliPro process monitoring and control system actively controls the SBR process parameters with the added capability of monitoring and controlling biological and chemical nutrient removal. It also offers process notifications with recommended corrective action for current and future process concerns.  

Seeing Results
    
In order to achieve the average effluent limits shown, the operators are dosing aluminum sulfate for phosphorus precipitation, sodium hydroxide for pH adjustment and glycerin as a carbon source during denitrification.

“This system is very dependable," Key Largo’s Lead Operator Jered Primicierio said. "Tech support is second to none and preventative maintenance is minimal yet very necessary.”

Primicierio also noticed a drastic improvement in monitoring and controlling the biological process. His opinion is due to the IntelliPro process monitoring and controls installed with the AquaSBR system.

The plant feels that the most beneficial aspect of the IntelliPro system is its ability to fully monitor the process, including real-time ORP, pH, TSS and DO concentrations in each SBR basin.

Key Largo operators also make use of the majority of the system’s additional features, including active mass control and trending capabilities. The plant has been very satisfied with its new treatment scheme and looks forward to meeting its future permitted effluent in 2015.

Tamera Knapp can be reached at [email protected] or 815.654.2501.