FAQ
Welcome to our FAQ page. Here you’ll find answers to the most common questions about our products, applications, services and support.
If you can’t find what you’re looking for, feel free to contact our team directly.
General
Questions about BPC Instruments products and services in general, including how to access training and support.
Do you offer training for customers?
Yes! In addition to the online resources and training offered with our systems, we offer training and consultation packages.
What training resources are avaliable?
All our customers have access to BPC Academy, where they can find technical documentation including user manuals, video guides, training courses and more.
Visit BPC Academy to request access.
Do you offer service analysis?
Our laboratory is able to offer limited service analysis for both biogas na dbiodegradability applications.
Visit analysis service to learn more.
I am having problems with my instrument or experiment, how can I seek help?
Our customer support team is readily available to assist you with technical issues or questions. To seek support, check our customer resources, FAQs or visit our support page and fill out a form. Alternatively, contact your sales representative. We aim to get back to all our customers as quickly as possible.
Does the instrument require a continuous computer or internet connection?
No. A computer connection is only required for initial configuration and data retrieval. Once configured, the instrument operates stand‑alone and records data internally. Internet access is only required for remote instrument access.
Instruments
Questions about our instruments including general maintenance and common issues.
What is the maximum gas flow rate the instruments can measure accurately?
Our instrument’s maximum gas flow depends on the resolution. For 9 mL FCUs, the flow rate has a maximum of 6 L/h and for 2mL FCUs the maximum flow rate is 1.5 L/h.
Our BPC Titan instrument has a maximum flow rate of 360 L/h.
How can I clean inside Flow Cell Units? Should they be replaced regularly?
Flow Cell Units are considered consumable components. If cleaning is necessary:
Rinse the unit thoroughly with warm water.
Fill the flow cell with a 2–3% hydrogen peroxide solution and let it soak for; 1–3 hours; Rinse several times with clean water until no residue remains.
Be sure to empty FCUs if they will stand for long between uses to avoid build-up.
Why is my thermostatic water bath beeping?
Some of our older generation thermostatic water baths are fitted with a conductivity sensor to monitor water level. As this sensor does not recognise distilled/deionised water, it may be necessary to add a small amount of tap water to the water bath.
Do you recommend another fluid with a low evaporation rate, which can be used in the thermostatic water bath?
To eliminate the necessity for periodically examining the water level in the thermostatic water bath and to minimise water loss due to evaporation, some laboratories use silicone oil (e.g. LABOTHERMOL S from NeoLab) to replace water. While this is an option, water is more cost effective, cleaner and easier to work with and does not attach to objects it comes in contact with.
We also offer an alternative incubation unit, the BPC Air, which utilises air as an incubation medium and does not require refilling or maintenance.
How do I maintain the systems’s motors?
The motors in our agitation systems contain electronic components that are not waterproof. Exposure to liquids or high humidity can cause corrosion or electrical failures in the motor or its connectors, leading to malfunction. To protect motors, avoid spilling reactor contents or water on them and do not submerge them. Keep connectors and motor units dry during operation and storage.
Depending on usage and environmental conditions, a motor’s typical lifespan is around five years or more. Signs of aging may include decreased speed or torque, intermittent operation, or unusual noise.
Why is one of my motors not turning at all (while others work)?
Double-check that the motor’s connection cable is firmly attached at both ends, and that its power light (if present) is lit. If one motor still won’t start even though others do, that motor or its internal driver circuit has likely failed. To confirm, you can test the motor by connecting it directly to the motor controller. If it remains unresponsive (especially with no indicator light or a persistent red light), the motor unit likely needs replacement or servicing.
All my stirrer motors stopped or won’t start. What happened and what should I do?
If all motors stop at once or fail to start, the issue is typically central—such as a temporary MCU shutdown caused by load or overheating, a problem with the motor signal cable or instrument output, or sometimes a permanent malfunction of the MCU itself.
What to do
- Power down and cool: Turn off the motor controller and wait 10–15 minutes, then restart.
- Check power & settings: Confirm the MCU is powered (status LED on). Make sure stirring is enabled in the software and set to continuous mode (not paused). Use a moderate speed (e.g., ~20–40%) for testing; avoid maximum speed during troubleshooting.
- Reseat the signal cable: Unplug and firmly reconnect the main signal cable at both the instrument and the MCU. If possible, try a known‑good cable.
- AUX connector check: With stirring commanded “on,” gently wiggle the signal cable at the instrument port. If motors twitch or start briefly, the AUX connector is likely the issue. If there’s no response, the MCU is more likely affected.
To prevent issues, always power down before connecting or disconnecting motor or signal cables.
Is it safe to connect or disconnect stirrer motor cables while the system is powered on?
No – do not plug or unplug the motors while the motor controller is powered. Always turn off and unplug the motor controller (MCU) before adding, removing, or reconfiguring motor cables. Connecting or disconnecting motors while connected to power can cause electrical surges or short-circuits that may damage the motor controller or the motor’s driver electronics.
Is it possible to shut down the computer when the instrument is running and the data has to be registered?
All of our instruments with detection units have a built-in computer within the unit . An externally connected computer, tablet or smartphone is used for control and visualisation of the experimental data.
Unplugging the ethernet cable or shutting down / restarting a computer that is connected to the instrument has no effect on the data being registered and there is no risk that it will interrupt ongoing experiments. Data will not be recorded while the instrument is powered off.
Experimental set-up
Questions relating to the general set-up of instruments and experiments.
Do I need to submerge the tubing in the carbon dioxide (CO2) absorption unit?
For instruments with an ex-situ carbon dioxide (CO2), the unit is connected to the bioreactor and subsequent detection unit using a piece of tubing. The tubing does not need to be submerged in the alkaline solution and we recommend to not include tubing within the absorption unit bottles.
Do Flow Cell Units require regular calibration by the user?
No routine user calibration is required. Flow Cell Units are factory‑calibrated, and their exact volumes are provided with the system. These values should be entered into the software as specified. Gas volumes are automatically normalized by the software to standard temperature and pressure conditions.
How can the reactor headspace be flushed in order to create anaerobic conditions before starting batch tests?
A comprehensive guide to flushing, with pictures/videos, can be found in customer resources at BPC Academy
For flushing the reactor headspace prior to an anaerobic batch tests, each bioreactor bottle has to be flushed with a flush gas separately. There is no practical way to flush all of the reactors at the same time. The flush gas should contain an oxygen free gas (e.g. N2 or a mixed gas based on 60% CH4 and 40% CO2 or 60% N2 and 40% CO2).
Before flushing a reactor, the gas tubes from the CO2-absorption unit must be disconnected.
The gas source has to be connected to the gas tube with either the push-in valve or the tubing clamp by using a plastic tube connector / reduction adapter. The tubing clamp or push-in valve from the reactor should then be opened and the reactor can be flushed gently with a low gas flow for 30 to 60 seconds.
How can I prevent liquid or foam from entering the gas measuring system?
To prevent liquid backflow:
- Always use check valves in the correct orientation.
- Avoid overfilling reactors and absorption bottles.
- Route tubing with upward loops so gravity helps prevent liquid migration.
Why does my instrument show “Invalid cell volume” and not record gas?
This message indicates that the Flow Cell Unit volume has not yet been configured. On first use, the instrument must be connected to a computer so the correct cell volume can be entered. The cell volume is provided with the instrument or printed on the Flow Cell Unit.
Experiment results
Questions relating to observed experimental results.
Gas is bubbling in the reactor, but no gas volume is recorded. Why?
This usually indicates that gas is not reaching the measuring device. Common causes include leaks in tubing or connectors or improperly seated or malfunctioning Flow Cell Units.
Check all connections for tightness and ensure each flow cell is correctly installed. A brief removal and reinsertion of the flow cell during operation should create a small detectable signal if the unit is functioning correctly.
There is an accumulation of condensation water in the gas tubes between the bioreactor(s) and carbon dioxide absorption bottles(s). Is there any negative impact to the experiment result?
Condensation of water between the bioreactor and ex-situ carbon dioxide absorption unit is regularly seen during our anaerobic tests utilising ex-situ CO2-absorption units. This additional liquid does not affect the efficiency of the CO2-absorption step and gives no negative impact on the accuracy and precision.
The biogas produced during an AD process contains water vapour and the fractional volume of water vapour is a function of the AD process temperature.
The biogas produced in each bioreactor passes through individual CO2-absorption units containing an alkaline solution before reaching the detection unit. Due to temperature drops in the water saturated biogas exiting the bioreactor, condensation water can be formed in the gas tubes which connect to the CO2-absorption bottles.
This phenomenon cannot be avoided in our standard set-ups since biogas which is produced at a high temperature (e.g. 37 or 50 oC) is coming into contact with a gas tube kept at a lower temperature (i.e., room temperature). Part of the water accumulated in the gas tube is transferred by the gas produced in the bioreactor into the CO2-absorption bottles. The level of liquid in the bottles can increase around 25% during one batch test.
Where the ex-situ absorption units are kept at a similar temperature to the bioreactors (eg. using BPC Air), less condensation is expected.
Is there any reason for inconsistent gas production, which leads to a graph with multiple steady-states during a BMP test?
When cycles of high gas production followed by plateau levels are periodically observed, it is recommended to check the water level in the thermostatic water bath. When the amount of water falls below the recommended level, there is a risk of temperature drop in the incubated reactors. This can lead to less or no gas production and therefore appears as multiple steady-states. The user needs to check the water level of the thermostatic water bath regularly, e.g. twice per week. In cases of an experiment running under thermophilic conditions, more frequent checks are suggested. The level of water should reach the plastic glass lid of the thermostatic water bath.
Why is there no gas registration in one channel?
There may be various reasons for no gas registration. Some of them may relate to the experiment itself, others may concern instrument setup.
It is very important to isolate the issue before it is possible to find the right solution. Test if the flow cell is the problem by manually lifting the flow cell with your hand and seeing if the opening of the flow cell is registered by the software or not. If the software can register the opening of flow cell, the data acquisition of the instrument is intact.
Next, test the gas tightness of the test line from the bioreactor to the inlet of the gas detection unit. If there are no symptoms of gas leakage for the entire test line, you need to figure out if there are any biological issues (e.g. very low activity of inoculum, substrate inhibition, etc).
BMP tests & biogas
Questions relating to BMP, biomethane and biogas tests, or utilising AMPTS III.
What is the impact of VS (volatile solids) calculations on the experiment conditions in setting up a BMP test?
The VS parameter provides an estimation of the organic material content in a sample. It is expressed either i) relative to the total amount of wet sample VS% (w/w) or ii) relative to the total solids VS% (VS/TS).
The VS parameter should be defined when a BMP test is performed with the help of the AMPTS III or other instruments. This means that the entered data for the inoculum and substrate concentration should be based on the organic material content relative to the initial weight of wet sample.
The user has to enter the VS values (VS%, w/w) for the inoculum and substrate together with inoculum to substrate ratio (ISR), as well as the total amount of mixture in the Experiment page of our instrument software. The software will automatically calculate and present the values for the weight of the substrate and inoculum which needs to be added to each test flask.
What are the recommended experiment conditions for achieving high quality test results with high precision and accuracy with a BMP test?
For high precision and accurate test data, the experiment should be set-up correctly: high amount of inoculum-substrate mixture (e.g. 400 g in 500 ml bottles), low bioreactor headspace volume, sufficient substrate quantity and suitable inoculum to substrate ratio (in the range of 2 to 4). This will lead to a high volume of gas production at a high flow rate and will allow for a high signal to background noise ratio.
Which substrates can be used as positive controls in a BMP test?
Control experiments are usually performed for testing the quality and activity of inoculum using a standard substrate (e.g. cellulose, starch or gelatin). Cellulose is most commonly used as a reference substrate for energy crops or waste from agriculture, starch for food residue, whereas gelatin is used for household waste rich in meat products.
The average methane yields for cellulose, starch and gelatin are reported in the literature as 350±29, 350±33, and 380±2 NmL CH4/g VSadded at an ISR of 2 (Raposo et al 2011). However, according to more recent publications, the methane yield for cellulose and starch should be within 85-90% of the theoretical value (i.e., 415 Nml/gVS), which means above 350 NmL/gVS (Holliger et al 2016).
Can the AMPTS be used for monitoring the accumulated biogas?
AMPTS III can be utilised to measure accumulated biomethane (CH4), with the ex-situ carbon dioxide (CO2) absorption unit in place. By removing the CO2 absorption unit, total biogas can be measured.
For enquiries about specific applications, older instrument versions or use cases, please contact us and speak to one of our expert team.
Do you have any recommendation for grinding or homogenisation units for preparation of samples such as silage, corn, grass and other large size particles?
In order to investigate the biomethane potential or biodegradability of substrates with a large particle size, you may need to homogenise your sample using a grinding machine.
The simplest solution is to use a regular household/kitchen blender. There are also mill homogenisers for laboratory and industrial applications. According to the literature, samples such as corn silage can be ground through a Wiley mill followed by grinding with a Udy mill.
Biodegradability testing
Questions relating to both aerobic and anaerobic biodegradability testing and usage of the BPC Blue
What biodegradability protocols can be performed using BPC Blue?
Many biodegradability standards and protocols can be performed using BPC Blue. For more information about specific protocols, visit our Protocols page or get in touch with our expert team.
Can BPC Blue be utilised to measure evolved carbon dioxide for aerobic biodegradability tests?
The BPC Blue cannot be used to directly measure carbon dioxide production. Our detection unit can be used to measure anaerobic gas production (biogas or biomethane) or oxygen consumption in aerobic tests. Oxygen consumption can be used to determine aerobic biodegradability
Why does water in the Flow Cell Unit flow back to the gas bag during an aerobic biodegradation test?
Backflow occurs because a relatively higher pressure builds up inside the reactor compared to atmospheric pressure (i.e., the gas bag). The following are the main factors that can contribute to this elevated relative pressure.
1) Anaerobic bioprocess occurring during an aerobic biodegradation test
When an anaerobic bioprocess develops during an aerobic biodegradation test, gases such as CH₄, H₂, and NH₃ are produced. These gases are poorly absorbed by alkaline solution, so their accumulation increases the pressure inside the reactor and pushes water in the FCU back toward the gas bag.
2) Atmospheric pressure drop
A drop in atmospheric pressure creates a relatively higher pressure inside the reactor, which can trigger backflow. A pressure drop of up to 5 kPa has been observed in past tests. At this magnitude, the water is only pushed back slightly — approximately 5 cm above the FCU inlet port — and will return to the FCU once atmospheric pressure recovers.
3) Water bath temperature increase
A rise in water bath temperature contributes to pressure buildup inside the reactor. To prevent this, keep the reactor open until a stable temperature is reached when the water bath begins heating. Additionally, when refilling water during a test, use water at a temperature similar to that of the water bath. Cold water can cause a pressure drop in the reactor and lead to reduced flow cell openings, while hot water can increase pressure and push water in the FCU back toward the gas bag.
Talk to a Specialist
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.