|Emulsion polymers are used extensively in dairy wastewater applications.
Most commonly they are used to pretreat waste before a biological system as a
means of solid-liquid separation in a biological system, or to assist with
tertiary nutrient removal such as phosphorus. These products can provide very
effective results, however makedown, feed and control have a large impact on
the effectiveness, and ultimately, the cost of using emulsion polymers.
factors to consider when feeding an emulsion polymer.
Emulsion polymers need to be “made down” with water in a special
feeder in order to be activated. For maximum effectiveness it is important to
use potable water for dilution because it offers consistent quality. Reusing
water from another process can lead to problems if the upstream process has an
upset. In addition to consistent quality, a consistent flow rate is also
important. Inconsistencies in the dilution water and flow rate, result in
inconsistencies in the quality of the activated polymer, which leads to
inconsistencies in performance.
This term refers to the ratio of “neat” polymer to the dilution
water into which it is fed. Typically emulsion polymers work best at a final
concentration of 0.25% – 0.5%. Higher
final concentrations do not allow the polymer to activate as efficiently which
has a significant impact on their performance and cost. In addition, some
mechanical polymer feeders are designed to only work at final concentrations
below 1.0%. Running higher final
concentrations in these systems can actually lead to failure and/or excessive
maintenance requirements. We have seen many applications where simply adjusting
the final concentration will reduce polymer usage by 25-50%.
The process of activating polymer with dilution water and a
polymer feeder is intended to allow the polymer molecule to “unwind”. When the
polymer molecule is fully unwound it maximizes the number of charge locations
that solids in the water can attach to. While proper dilution water and a good
polymer feeder are critical to this activation process, often additional time between
the activation stage and injection into the process will allow the polymer to
fully unwind. This time period is called aging. Typically an aging period of
10-30 minutes is enough time to allow a properly made down polymer solution to
fully activate. As with a proper final concentration, we have seen reductions
in polymer usage by 25-50% simply by adding as little as 10 minutes of aging
between makedown and feed of a polymer.
While there are many factors that affect the
overall effectiveness and cost of feeding emulsion polymers, proper dilution
water, final concentration
and aging are the first to consider when optimizing their use.
learn more about emulsion polymers or to request a free site assessment contact us today. We will analyze your system and share recommendations to improve performance and reduce operating costs to help achieve your goals.