Thermal mass flow meters provide accurate gas flow measurement and monitoring of air, oxygen, ozone, and digester gas in various applications at water and wastewater treatment plants.
- Dissolved Oxygen Feedback Loop Control
- Air to Primary Treatment Basin
- Air to Secondary Treatment Basin
- Digester Gas
- Oxygen and Ozone Monitoring
Air to Basins and Dissolved Oxygen (DO)
In wastewater treatment, the introduction of air oxygenates the mixture to help grow beneficial aerobic bacteria, which breaks down waste. Older treatment systems manually inject air through drop lines into the basins. Unfortunately, in most instances, no measurement or control or airflow rate is determined, and there are massive inefficiencies. Current aeration systems use air diffusers, and flow meters can balance the flow to different aeration basin sections.
By measuring the air flow rates with a thermal mass flow meter and outputting the results to the dissolved oxygen (DO) feedback control loop, the entire process can be automated, potentially saving substantial energy.
The digesters further break down waste and release digester gas downstream of the aeration basins. The digester gas is typically 65% methane and 35% carbon dioxide. At many plants, digester gas is conditioned for use in internal combustion engines to produce electricity for on-site service. In other situations, the digester gas is sold to an outside company for cogeneration production. When the digester gas does not sustain the engines’ BTU levels, natural gas blending may occur.
Thermal mass flow meters monitor flow rates to digester gas conditioning, compressor, and fueling stations. If the digester gas is not used for power production flares, flow meters can measure the flow of digester gas to the flare.
Oxygen and Ozone Monitoring
Some facilities use oxygen or ozone and chlorine in the purification of water. Thermal mass flow meters can measure oxygen and ozone in systems that do not use chlorine. Additionally, Sage Metering supplies flow metering to ozone-generating manufacturers, and they use the meters in water purification systems.
For more information, visit Wastewater Treatment Plants – An Industry Guide for Thermal Flow Meters for more insight into the applications for wastewater treatment plants.