Our last blog introduced the three different type of flocculants. In this blog, we will go deeper into discussion about each type.
- "Dry" flocculants are very concentrated and extremely hydroscopic so they need to be kept away from water and moisture. If this type of flocculant is kept dry, it can last more than a year. Dry flocculants always require efficient pre-wetting of each particle to properly prepare solutions and prevent the formation of “fish eyes” - a gelatinous water/polymer mass. Their dissolution time in water is usually between 30 and 90 minutes with good agitation but can be dissolved faster in warm water (80 -110°F). Aging the flocculant solution for 30-60 minutes after make-down usually helps allows for more efficient use. Typical use solution strengths for dry flocculants range from 0.20-0.50% by weight.
- “Emulsion” flocculants have a shelf life of between 6 and 18 months and should be stored between 50°F and 90°F in a tightly sealed container. Emulsion flocculants require short duration, high sheer mixing to disperse the oil or water phase and free the polymer molecules, a process called inversion. For this polymer, aging may be beneficial. The maximum use concentration of this polymer is 0.5-2% by weight.
- “Solution” flocculants are typically very dilute but go into solution fairly quickly and easily. However their shelf life is only about 3-6 months. These flocculants can be very vicious, and can be hard to handle if not set up properly. Typically solution flocculants are used in smaller, low volume wastewater systems where volume of polymer use is not an issue.
When handling these flocculants, there are a few safety tips to keep in mind:
- Use gloves and safety glasses
- Use a dust mask for dry flocculants
- Work in a well-ventilated area
- Wetted flocculants are slippery and should be cleaned up immediately
- Read the Material Safety Data Sheets for detailed instructions on handling.
Proper selection, preparation and feeding of polymer flocculants is critical for their efficient use in treating wastewater. Your water treatment provider can be an invaluable resource when working with polymers.