While chemical water treatment methods are a common choice, there also are nonchemical ways to treat process water. Here are three common methods.

Ozone Generation.Ozone is a commonly occurring compound that develops when lightning passes through the atmosphere or when an electrical discharge creates a spark. The benefits of using ozone to treat water include the near instantaneous oxidation of any organic materials and microbial growth. However, ozone has a very short half-life, especially when in contact with water, which means it must be constantly applied if used for water treatment. Ozone generator prices have decreased but they are still relatively expensive compared to other technologies.

Reverse Osmosis.Reverse osmosis uses a semi-permeable membrane that allows water to pass through it while rejecting contaminants. These contaminants can include bacteria, sugars, salts, particles, dyes and miscellaneous substances that have an atomic mass unit greater than 150 to 250 daltons and carry a particle charge. This means that many organic materials would not be rejected. In my opinion, this technology makes economic sense only when extreme amounts of water are consumed each day.

Mechanical Filtration.Methods of mechanical filtration include sand filters, strainers and centri-separators.

Sand filters may be better know for their extensive use in clearing swimming pools of large debris, but industrial-grade units with the correct media can remove debris down to 5 µm dia. for process applications. One drawback to sand filters is that the media first must become fouled with larger particles to capture the micron-level ones.

Strainers are typically rated in mesh sizes and can be as small as 55 µm. This helps with large particles but will not remove calcium carbonate that flows with the water.

Centri-separators use centrifugal force to remove particles but are limited to heavy particles.