The BioMonitor® from LAR Process Analysers AG is suitable for many different applications:
- for fast and reliable load ratio documentation of the influent and effluent of any plant with the aid of either the BOD concentration or the BOD load,
- for controlling the denitrification at the effluent of any plant by exact dosing of the waste water as carbon source,
- for adjustment of a constant sludge load by calculating the amount of return sludge with help of the known concentration of biological degradable substances, present at the influent,
- for water monitoring at water quality monitoring stations.
The patented measuring method of the BioMonitor® works just like a miniature treatment plant. The activated sludge, either supplied direct from the plant or circulating with the sludge recycling system, degrades the substances present in the waste water. The oxygen required for this process is measured. This process takes place in the waste water cascade of the BioMonitor® which works exactly like an aeration tank.
Since the microorganisms which are contained in the activated sludge do also breathe oxygen, the self-respiration has to be subtracted from the total oxygen consumption for the exact BOD determination. This self respiration is measured in the reference cascade of the BioMonitor®. Finally, the BOD is calculated from the difference between the values measured in both cascades.
Compared with Systems with just one reaction vessel the degradation happens not only faster, but through the multi-step construction. Additionally, hard degradable substances are determined in the rear waste water cascade.
The result for the user of this unique measuring principle is the precise and fully continuous determination of the BOD in three to four minutes. The sample gets degraded without any extra dilution exactly like in the particular treatment plant.
The measurement of the self-respiration of the activated sludge (ASR) serves not only the exact calculation of the BOD, but also the ASR provides important information on the condition of the plant's own biomass which is especially of importance for control and supervision. If the ASR, for example, is falling slowly it could be an indication of a steady poisioning of the activated sludge by toxic substances, which could easily be detected by the BioMonitor®.
The BioMonitor® is equipped with a good readable display which depicts clear graphical surveys of measured values. In addition to graphics, the actual measuring values can also be displayed in large digits.
The complete operation manual is integrated into the self-explanatory software. Thereby the user may look up even infrequently required information directly at the instrument at anytime. The BioMonitor® resumes normal operation after a power loss and stores all previous data in memory. This ensures optimum operation.
All graphics and results may be printed out through the printer interface. An uncomplicated data-transfer to disk or directly through serial or parallel interfaces to a measuring station is a matter of course, just as the preparation for teleprocessing and remote control.
The BioMonitor® detects even rapid BOD changes and shows accurate measuring results.
Accompanying illustration shows the BOD value after 5 days in comparison to the values measured with the BioMonitor® at the influent of a beverage company.
Noteworthy is the outstanding and most consistent correlation (r > 0,95) to the standard methods (DIN 38409-H51, APHA-AWWA-WPCF 5210 B, EPA - approval, etc. ).
The patented sample preparation system 
FlowSampler works filtration-free as the sample is taken in the center of the sample stream against the direction of the main stream. Thereby, all large particles are reliably removed. Smaller solid matter particles are also sampled, ensuring that a representative sample reaches the analyser.
FlowSampler masters even the most difficult tasks, for example; sampling at sewage work influents before the coarse screen.
| Type of measurement |
Continous measurement of BOD and sludge activity using activated sludge |
| Measurement Range |
user adjustable between 1 - 50 and 1 - 200,000 mg/ BOD |
| Actual Value |
every 3 - 4 minutes |
| Sample preparation |
maintenance-free particle separator |
| Graphic-LCD-screen, high resolution, back-lit |
| Autostart-Function |
| Self-explanatory Software including maintenance checklists and support |
| Industry-standard data interface |
| Waste water, drain |
tube 30 mm ID or threaded 32 mm OD or as specified |
| Electrical Power |
230 / 115 V ~, 50 / 60 Hz, 150 VA |
| Analog Output |
0/4 - 20 mA (BOD)
0/4 - 20 mA (sludge activity) |
| Serial Interface |
RS 232 for data transfer and remote control
Malfunction alarm
Life-Zero
connection for printer |
| Cabinet |
steel IP 54 |
| Dimensions |
720 x 600 x 420 mm (H x W x D)
28.4 x 23.6 x 16.5 inches (H x W x D) |
| Weight |
70 kg (154 lbs) |
