Play Misty for me: Gas Stripping and Gas Contacting
Muddy River employs water spray systems for two general applications: (1) Gas stripping that removes dissolved constituents as a gas, or (2) Gas contacting that dissolves gas constituents into water. Here is how to achieve optimal performance of gas stripping and gas contacting:
- Maintain a maximum difference in concentration of the constituent between gas phase and water
- Maximize the surface area of water or wastewater in air or other gas by forming tiny droplets
- Prolong the contact time of droplets in air or other gas via a long hold up time
- Provide ideal chemical and physical conditions such as pH and temperature to promote a shift of the constituent from water to air for stripping or visa versa for gas contact. As the Figures below indicate, strip un-ionized ammonia at pH greater than 9.3, and strip un-ionized hydrogen sulphide at pH less than neutral. The greater the un-ionized portion, the faster and more complete the performance.
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Ammonia Ionization vs. pH |
Sulphide Ionization vs. pH |
Gas Stripping exploits the gas: liquid equilibrium of dissolved constituents such as ammonia or hydrogen sulphide to remove them from water. Gas stripping applications include:
- Remove ammonia from manure, landfill leachate, or other municipal and industrial wastewaters
- Remove dissolved sulphide from oil and gas processing wastewater, or anaerobic digester effluent
Gas Contacting exploits the gas: liquid equilibrium of gaseous constituents such as carbon dioxide, oxygen, ozone, or hydrogen sulphide for mass transfer from the gas phase to water. Applications include:
- Neutralization of alkaline or acidic water using carbon dioxide gas, including CO2 in air
- Oxidation of wastewater constituents using oxygen or ozone
- Scrubbing of air borne constituents such as hydrogen sulphide or odours