Nutrient Deactivation (Alum)

ALUM APPLICATIONS

Aquatic Analysts, Inc. owns and operates a work barge used to apply aluminum sulfate (alum) to large waterbodies as a management and restoration tool.

Alum has successfully been used in lakes and reservoirs by:

1. Stripping the water column of sediments and particulate material.
2. Binding reactive, available phosphorus for the purpose of reducing the growth of algae.

When applied to water, it forms aluminum hydroxide, the major ingredient in Maalox. Alum precipitates  phosphorus out of the water column making it unavailable as a nutrient for algae growth.  In addition, when applied in high concentrations, alum can clarify the water column by concentrating and subsequently settling particulate material.

However, alum is not an algaecide and does not directly inhibit algal growth. Alum dosing for the purpose of stripping the water column or creating a sediment “blanket” involves the introduction of large quantities of alum, or an alum surrogate, over a short period of time.