Anaerobic digestion is often used at wastewater treatment plants to break down organic waste. Indirectly, it produces digester gas. This biogas is a methane-rich byproduct and is often used to create energy. Thermal mass flow meters are utilized in the modern wastewater treatment process to measure digester gas flow or flare gas flow.
In large contemporary wastewater treatment plants, anaerobic digestion breaks down organic waste, which produces digester gas from sewage sludge decomposition. The wastewater biogas is methane-rich and can be an energy source. The thermal mass flow meter monitors digester gas applications.
Wastewater Digester Gas Composition
Digester gas is a form of biogas. The wastewater digester gas composition varies though the main components are methane (CH4) and carbon dioxide (CO2). Oxygen gas (O2), nitrogen gas (N2), and hydrogen sulfide (H2S) may also be present in trace amounts. While the compensation will fluctuate depending on the process and temperatures, the methane-rich gas (~60-70% CH4) becomes an appealing energy source. The biogas may be burned to create electricity or heat the digester tank to advance the decomposition. Additionally, the biogas, at times, may be supplemented with natural gas to heat the facility. Digester gas is dirty and wet and condenses, which causes build up in the pipe and probes within the piping.
For suggestions on where to use thermal mass flow meters within the waste-to-energy (WtE) or energy-from-waste (EfW) process, along with the considerations and recommendations for flowmeter selection, visit our Wastewater Digester Gas at Wastewater Treatment Plant. Alternatively, download our new application brief.