Information

Biochemical Oxygen Demand

The BOD analysis is one of the most common applications for water laboratories. The test is used as an indication of the organic quality of water. All Skalar Robotic Analyzers can provide the automation for BOD according to EPA 405.1/ISO 5815-1. Various possibilities are available based on the sample load, budget and the level of automation. From 32 up to 120 BOD bottles can be set as uninterrupted sample batches. Sample trays can be added during analysis runs to handle any required sample load.

The analyzers can hold all available standard BOD bottles, and a wide range of sample trays are provided for various incubators. The automation of the labor-intensive BOD application can save up to 85% of operator time and provides the required consistency for the application.

A typical BOD analysis sequence:

Samples are pipetted, either manual or automatically (option), into the BOD bottles and the identity and the dilutions are entered or downloaded from LIMS into the sample table. Bottles are placed in the racks and placed on the Robotic Analyzer. Analyzer is started by operator. The manipulator sets the Oxygen probe in position, bottle is capped and filled with Nitrification inhibitor (ATU) and/or seed (option) and dilution water. Sample is then stirred and the initial Oxygen value is measured. The bottle is capped and the Oxygen probe and stirrer are rinsed before going to the next sample. The same procedure is followed until a value is recorded for all samples. The sample racks are placed in a 20°C incubator for 5 days. After incubation the racks are placed on the Robotic analyzer. The operator starts the analyzer. The bottle is decapped. The sample is stirred and the final Oxygen value is measured. The BOD value is calculated. The bottle is capped or the cap is discarded in a collector (SP100 only). This procedure is repeated until all samples are measured. The data can be presented on screen, printed or converted to a file compatible with other software and LIMS's.

If there is a requirement for other analyses such as pH, conductivity, alkalinity and turbidity then these methods can be combined with BOD on the same robot.

Steps of Automation

  • Pippetting of the sample (option)
  • Addition of Nitrification inhibitor (ATU) and/or Seed
  • Addition of dilution water
  • Sample homogenization
  • Measurement of initial Dissolved Oxygen value (DO1)
  • Probe/stirrer rinsing between each measurement
  • Bottle capping/decapping (option)
  • Measurement of final DO2 value
  • Calculation of BOD according required regulations
Comparison Skalar analyzers alt
SP10
alt
SP50
alt
SP1000
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SP100
Sample capacity

32 bottles

 (2x16)

54 bottles

 (3x18)

90 bottles

 (5x18)

120 bottles

 (6x20)

Probes 1 Up to 2 Up to 6 Up to 5
Auto capping/decapping - - Dual Single
Sample pipetting station Option Option Option Option
Multiple parameters analysis Yes Yes Yes Yes
Barcode reader Option Option Option Option
Typical throughput 40-50 bottles/hr 80-100 bottles/hr 160-200 bottles/hr 200-250 bottles/hr

 

 

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