As all water operators know, the use of coagulants is the first step of water treatment, and among chemicals used is ferric chloride (Iron III). It’s the coagulant of choice used in many sanitary wastewater treatment programs, industrial applications, and drinking water production. It’s quite effective – in the right place. In the wrong place, the chemical can be detrimental. Read about how using the wrong wastewater treatment chemical results in problems you should avoid at all costs.


Disadvantages to Ferric Chloride

As with any chemical, there are advantages and disadvantages. Here are some other disadvantages to using ferric chloride:


  • Removes alkalinity
  • Extremely hazardous
  • Stains, therefore, can’t be used directly before UV disinfection
  • Poor dewatering
  • Narrow effective pH band
  • Requires pH adjustment or alkalinity addition to make it work effectively, and suppresses alkalinity requiring post-treatment adjustment.

Ferric Chloride Advantages

Even with the disadvantages, ferric chloride still has its place as a wastewater treatment chemical with approximately 60% usage in wastewater facilities. Its application in industrial water makes up about 8% and 20% in drinking water treatment, as well. Ferric is absolutely the right chemical to use in certain situations, but not all situations, and only in concentrations that make sense. Here are some benefits to using chlorine, which include:


  • Odor control
  • Aggressive Coagulant
  • Efficient for phosphorus removal (limited)
  • Improved settling
  • Struvite mitigation
  • No pH requirement
  • Working over a broad pH range
  • Fairly easy to use

The Key is Balance

Up until now, we’ve been discussing the problems with using the wrong chemicals in the wrong place but haven’t touched on the real problem: chemicals in general. It’s not enough to just throw in a bunch of chemicals and hope they treat sewage and drinking water.

Wastewater chemical treatment includes striking a balance; and at ATS Innova, our treatment program involves using precise ingredients in a delicately-balanced formula. Our products step in where ferric doesn’t make sense and will discuss that with you when you contact us to schedule a FREE plant walkthrough. Our goal is to identify any problems with ferric chloride or other wastewater treatment chemical you use. If you need help with compliance and/or want to try a different, but proven effective approach, reach out at 855.215.4600.

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