Sewage gas/biogas flow measurement in wastewater treatment

The biological treatment process in wastewater treatment plants produces biogas, also known as sewage gas or fermentation gas, which consists mainly of methane and carbon dioxide. Measuring the amount of biogas is one of the most challenging applications in this process. Due to its humid nature, tendency to condensation and the potential to carry particulate matter, its composition can also vary and it can be somewhat corrosive. Therefore, safety and explosion protection need to be considered when using measuring instruments, and appropriate certification of measuring instruments is required.

The fermentation gas flow rate is measured directly at the digester outlet and before the combined power plant and flare. Flows measured before digesters and co-generators help regulate the output of generators, while at many plants the flow to the flares is also partially measured. Since flow meter need to meet requirements such as safety, economy, and durability, it is very important to choose the appropriate measuring instrument.

The DOWESTON Vortex sensor is an instrument particularly suitable for measuring fermentation gases containing water vapor. Its design with no moving parts makes it unaffected by condensation and particulate matter. Once installed, virtually no maintenance is required, providing a reliable solution for biogas measurement. The sensor is used in certified explosion-proof areas, ensuring safety while also providing an economical and durable solution.

Wastewater treatment is an energy-intensive process, especially in biological treatment processes where extensive ventilation is required. According to statistics, the energy consumed by municipal sewage treatment plants accounts for about 20% of the entire municipal use, so saving energy is very important. The biogas generated during sewage treatment can increase energy self-sufficiency by producing electricity, thereby achieving energy conservation.

Process data

Measuring task: Measure the flow velocity to determine the flow rate

Measuring point: Directly at the digester outlet, on the other side before the combined power plant and the open flame

Measuring range: up to 40 m/s

Process pressure: atmospheric pressure

Process environment: ATEX Zone 1

Process: ATEX Zone 0

Applications

During sewage treatment, anaerobic degradation processes occur in digestion towers, resulting in the production of biogas (also known as sewage or fermentation gas), which mainly includes methane and carbon dioxide.

Exactly measuring the amount of biogas is one of the most challenging applications in flow measurement technology. Biogas is very moist, prone to condensation, and contains particles. Its composition is unstable and quite corrosive. When mixed with air, it may become an explosive mixture, so appropriate safety measures need to be taken. The instruments used must be certified for the defined explosion protection areas.

The fermentation gas is measured directly at the outlet of the digestion tower and on the other side of the combined power plant. Part of the measurement goes to the open flame.

Your advantages:

Safe

Safe measurements even in hazardous areas

Economy

Once installed, the sensor requires little maintenance

Solid

Our Vortex sensors are particularly suitable for fermentation gases containing condensation and particles

Recommended products

insertion type vortex flow meter FTV-1600T

Standard compact device for hazardous applications with variable insertion depth

Measuring flow rates before digestion towers and combined power plants

Wastewater treatment plants are a key part of our wastewater treatment. The treatment process requires a lot of energy, mainly for biological treatment processes (ventilation). Municipal wastewater treatment plants are the largest consumer of energy, accounting for approximately 20% of total municipal use. There is great potential for energy savings. The sewage gas generated during the sewage treatment process can be used to generate energy in the sewage treatment plant.

The sludge is collected in a digestion tower, where bacteria break down the sludge through a process of anaerobic degradation (without oxygen), producing varying amounts of different gases.

Biogas, sludge gas, fermentation gas are gases with different names produced in digestion towers. Each gas has a different density and viscosity depending on the composition of the sludge and environmental conditions. The main components are methane, carbon dioxide and hydrocarbons.

Methane is flammable, making it ideal for energy production. It is fed into a combustion engine, which generates electricity and heat. Thermal energy can be further used for energy utilization.

How do we measure the flow of biogas?

Due to their variable composition, possible condensation and other contaminants, many measuring instruments are not suitable or require extensive cleaning and maintenance.

DOWESTON Vortex flow sensors can measure flow regardless of the density of the gas. Since there are no moving parts, it is not affected by condensation and other possible particles in the gas. It requires virtually no maintenance - "fit it and forget it".

Continue to measure the flow before the digester and combined power plant

Wastewater treatment plants are a key part of our wastewater treatment. The treatment process requires a lot of energy, mainly for biological treatment processes (ventilation). Municipal wastewater treatment plants are the largest consumer of energy, accounting for approximately 20% of total municipal use. There is great potential for energy savings. The sewage gas generated during the sewage treatment process can be used to generate energy in the sewage treatment plant.

The sludge is collected in a digestion tower, where bacteria break down the sludge through a process of anaerobic degradation (without oxygen), producing varying amounts of different gases.

Biogas, sludge gas, fermentation gas are gases with different names produced in digestion towers. Each gas has a different density and viscosity depending on the composition of the sludge and environmental conditions. The main components are methane, carbon dioxide and hydrocarbons.

Methane is flammable, making it ideal for energy production. It is fed into a combustion engine, which generates electricity and heat. Thermal energy can be further used for energy utilization.

How do we measure the flow of biogas?

Due to their variable composition, possible contamination and the presence of other contaminants, many measuring instruments are unsuitable or require extensive cleaning and maintenance. DOWESTON Vortex flow sensors can measure flow rates regardless of gas density. It has no moving parts and is therefore less susceptible to partial condensation and other particles that may be present in the gas. There is little maintenance required, just "install and forget".

Continue operation in sewage treatment plants

The amount of sewage gas produced in the digestion tower varies. Therefore, the gas is temporarily stored in storage facilities and then transported to the combined power plant.

The sewage gas produced is measured directly at the source, i.e. before the digester and combined power plant, to regulate the production of electricity. In many plants, the flow towards the flare is also measured.

Many operators add natural gas to biogas to ensure continued power generation. DOWESTON also supplies suitable measuring equipment.

The flow measurement task in sewage treatment plants is very challenging, and the Vortex flow sensor provided by DOWESTON is the best choice for measuring biogas in sewage treatment plants, with the advantages of accuracy, safety and economy.