Ferric and Alum Storage: Challenges and Solutions

Commonly used to remove suspended solids in wastewater treatment, ferric and alum require specialized storage solutions. This article will examine the challenges of storing ferric and alums, and offer safe, practical storage solutions.  

Ferric and Alums: Storage Challenge

Ferric and alum are heavy chemicals. They can create sediment within the storage tank. Ferric are an acid. With ferric oxidation can corrode certain types of storage tanks and fittings. If the tank is not properly vented, surrounding property can be damaged. Outside storage without proper venting can damage trees and shrubbery.

Ferric and alum often are delivered at elevated temperatures during colder months, creating stress on the expansion and contraction of the storage tank.

Ferric and Alum: Storage Solutions

• Remove Tank Sediment Build-up: In the IMFO® system, the flange is integrally molded as one piece in the bottom of the tank. This permits easy tank draining of sediment and eliminates the need to enter the tank for cleaning.
• Tank Strength: High density cross-linked polyethylene, XLPE, handles the stress of the weight of these chemicals. In addition, the one piece IMFO® system provides the hoop stress required to withstand storing these chemicals. 
• Withstand Elevated Temperatures- High density cross-linked polyethylene is capable of handling the elevated temperatures of ferrics and alums with an increased factor of safety. Please refer to the ASTMD 1998 technical bulletin, page 6 for the specific technical data on temperature hoop stress safety margins.

Ferric and alum are key chemicals used in the removal of solid phosphates and nitrogen in wastewater treatment. These chemicals do present storage challenges and require specialized storage solutions.

For additional information, please download the Ferrics, Alums, and Polymers Guide.

For specific questions around storing ferric and alum, please contact a Poly Processing chemical storage tank expert.