More Floc
Question: Steve, in your March 2003 “Increased Floc” article, you responded to a reader’s question regarding increasing amount of floc in the wastewater pretreatment clarifier even though “nothing in our operations or chemistries has changed...” Chances are that something did indeed change, and detective work is needed to find the culprit.
Question:
Steve, in your March 2003 “Increased Floc” article, you responded to a reader’s question regarding increasing amount of floc in the wastewater pretreatment clarifier even though “nothing in our operations or chemistries has changed...” Chances are that something did indeed change, and detective work is needed to find the culprit. Let me tell you about an experience several years ago. Just like S.T., we were seeing higher solids in our clarifier, sometimes causing non-compliance. Of course, initially the process line and wastewater operators responded, “nothing has changed.”
We did not accept these responses at face value. After much detective work, we found the culprit, excessive dosage of anionic polymer. Due to equipment failure, the anionic polymer was continuing to be fed into the system even when no wastewater was being fed to the system. Once this was corrected and the polymer dosage returned to its target value, the amount of floc and metals in the clarifier’s effluent dropped back to historical levels. D.E.
Answer:
Thanks D.E. This is another example that with many wastewater pretreatment chemistries “more is NOT necessarily better,” in fact, “more is bad.” I am sure your experience will help others.
Related Content
-
NASF/AESF Foundation Research Project #120: Electrochemical Destruction of Perfluorooctanesulfonate in Electroplating Wastewaters – 7th & 8th Quarter Report
This NASF-AESF Foundation research project report covers the seventh and eighth quarters of project work (October 2021-March 2022) at the University of Illinois at Chicago. The major activities reported are: (1) to investigate 6:2 FTS oxidation, a common replacement compound for PFOS in the electroplating industry, and (2) PFAS oxidation in both a wastewater sample procured from an electroplating facility and in synthetic solutions.
-
NASF/AESF Foundation Research Project #122: Electrochemical Approaches to Treatment of PFAS in Plating Wastewater - 6th Quarterly Report
The NASF-AESF Foundation Research Board has selected a project on addressing the problem of PFAS and related chemicals in plating wastewater streams, studying PFAS destruction via electrooxidation and electrocoagulation. This sixth quarter report covers the continued assessment of eight perfluoroalkyl acids PFAAs most commonly found in wastewaters, by electro-oxidation with a Magnéli phase Ti4O7 anode across a range of anodic potentials in solutions, exploring the reaction mechanisms. To summarize, the PFAAs start to exhibit degradation behavior when the anodic potential reaches a level where water oxidation occurs, suggesting that the hydroxyl free radicals generated via water oxidation play a role in PFAA degradation.
-
Ultrafiltration Membranes, Filter Elements for Improved Industrial Water Reuse
Ultrafiltration membranes help with water reuse in a variety of applications.