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The Activated Sludge Plant Controller (ASP-CON)

Multi-parameter Probe Optimizes Activated Sludge Plant performance

Since the discovery of the activated sludge process, analytical instruments have been applied to optimize sludge plant performance. Conventional analytical measurements report the conditions in the lanes, but they don't provide data regarding the health of the plant's biomass or toxicity. Poor sludge health can result in clarifier bulking, poor ammonia removal, solids carry-over, poor energy performance, over-aeration, excessive wasting, or non-compliant discharge.

Continuous Sludge Health Monitoring Without the Lab

Continuous sludge health monitoring is now possible thanks to the development of the ASP-CON, the world's only in-situ respirometer. Only the ASP-CON provides continuous monitoring of Oxygen Uptake Rate - as well as many other parameters - yielding trended data previously only possible through extensive laboratory analysis (and yielding only a single data-point). Never-before available, continuous, trended OUR can now be reported directly to your SCADA system for unprecedented sludge plant control.

The ASP-CON also monitors suspended solids, enabling it to calculate and report Specific Oxygen Uptake Rate (SOUR), as well as Sludge Volume Index (SVI) and Stirred Sludge Volume Index (sSVI).

Extensive software enables the ASP-CON to perform settlement tests directly in the basin, yielding MLSS data as well as predicting the TSS value of the secondary clarifier's final supernatant. All these measurements are provided from the aeration lane, before the flow enters the secondary clarifier, and hours before clarifier discharge.

Monitoring Against Toxic Influent

Since the ASP-CON aerates it's own sample, it can monitor OUR upstream of the aeration lane in the anoxic zone for early detection of toxic influent. Detecting a single toxic event up-stream may save a plant from weeks of re-seeding operations.

Multiple Measurements from a Single Device

The ASP-CON provides many of the conventional measurements needed for efficient plant control, including: Dissolved Oxygen, pH, Ammonium, potassium, Nitrate, Chloride and temperature. The ASP-CON calculates the critical oxygen points for both heterotrophs and nitrifiers, as well as F:M ratio.

Self-cleaning and Self-Calibrating

The ASP-CON is designed for minimal maintenance and is provided as a complete system, including an electric winch, a rail-mounted industrial PC, auto-clean and auto-calibration. The PC provides connectivity to SCADA through Modbus as well as complete remote monitoring and control of the system. The calibration system automatically performs scheduled calibrations in-situ and holds enough solution for over a month of hands-free operation. With every measurement cycle, the ASP-CON automatically cleans all sensor heads.

Breakthrough Technology

The ASP-CON is the only device available that provides continuous, trended respiration data. By combining this data with other key process-control parameters in a single instrument the ASP-CON represents a breakthrough in sludge plant control technology, performing in-situ "laboratory" measurements, reducing labor-intensive tasks and providing reliable and consistent data that results in improved automatic control of aerobic wastewater treatment plants.



 Self-Cleaning / Self Calibrating Multi-Sensor


 Stand-alone apparatus  ~30 lbs
 Mounting bracket  ~35 lbs


 Voltage Supply  120 VAC (Internal 24VDC)

Operating Temp range

 Low  -13°F
 High  104°F

Dissolved Oxygen - LDO

Two sensors for simultaneous respirometry and D.O.
 Range:  0 - 100% Saturation
 Response, Respirometer  T90 = 15 seconds
 Response, In-Basin  T90 = 120 seconds

Ammonium (Single ISE electrode)

 Range:  0 - 100mg/L
 Response:  T90 = 50 seconds

Potassium (Single ISE electrode)

 Range:  0 - 50mg/L
 Response:  T90 = 50 seconds

Nitrate (alternative to ammonium)

 Range  0 to 10,000 mg/L
 Response  100ppm change in 60 sec.

Solids Measurement Sensor

Transmitted and Reflected light sensor
   Range:  0 - 24,000 mg/L
   Response: T90 = 0.2 seconds

pH Measurement (Single Glass)

   Range:  0 - 14
   Response:  T95 = 30 seconds
   Reference Electrode:  Teflon single junction

ORP (alternative to pH electrode)

   Range:    -500 to +500
   Response:  T90 60 seconds External communications

External communications

   ▲ Dual PID loop controller in Display unit with two 4-20mA outputs  
   ▲ RS485  
   ▲ Zigbee wireless  
   ▲ Modbus protocol  

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Related Links

Activated Sludge Plant Controller

The multiparameter ASP-Con provides your control system with continuous data on the health of your biomass for unprecedented process optimizaion and control. A YouTube video tour is viewable here:
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Laboratory Respirometer

The StrathTox provides precision respirometry to rapidly measure actual Activated Sludge bacterial performance.
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Portable Respirometer

Real-time results show the health of your sludge plant. - more -