Even the best-run wastewater treatment plants can fall out of compliance for reasons beyond the operators’ control. Recently, one of our customers, a municipal wastewater treatment authority, encountered an unexpected phosphorus spike after a nearby food manufacturing plant closed its doors.
Workers at the plant dumped cleaning and sanitizing chemicals down the drain on their way out, and the chemicals introduced significant amounts of quaternary ammonium compounds (QAC), also known as quaternary amines or quats, into our customer’s treatment tanks. And it would be an understatement to say that QACs are not good for the phosphorus accumulating organisms (PAO) that normally kept the plant in compliance.
As biocides, QACs can bind to and destroy the cell walls of PAO and other bacteria, eventually causing cell death. These QACs took a toll on our customer’s phosphorus levels, which quickly surged higher than 2.5 mg/l from a typical value of below 1 mg/l.
Finding the Problem. At first the rising phosphorus levels were something of a mystery. Our customer’s plant was well-controlled and had recently been upgraded with our miGRATE and inDENSE solutions, which reduced the plant’s SVI by 25% and ammonia level by 13.4% comparing 6 months of data before and after the upgrade. Samples sent to the World Water Works lab, however, quickly identified troublesome QAC concentrations.
Bioaugmentation to the Rescue. QACs are a common problem in wastewater treatment, and we had a bioaugmentation treatment ready to go.
WWW ArxZyme QAA/PAA Oxidizer degrades and oxidizes QACs and does so in a hurry. This bioaugmentation treatment contains QAC-resilient strains of bacteria that work together synergistically to break down QACs. The different strains exhibit complementary mechanisms of action — producing an enzyme called amine oxidase that facilitates cleaving the carbon-nitrogen bond in the QACs into smaller compounds with a much lower level of toxicity.
We introduced our QAA/PAA oxidizers on a Friday. By Monday, our customer’s phosphorous levels dropped below their target value of 1 mg/l.
It Could Have Been Worse. In addition to PAOs, QACs also destroy nitrifying bacteria. In this case, however, our miGRATE solution was already in place, producing a biofilm that helped protect the nitrifying bacteria from the effects of the QACs and showing how migrating carriers and bioaugmentation can work together hand in hand.
Are you experiencing unexplained changes in your wastewater process? Get in touch. Our WWW Lab Services can diagnose problems in a flash, and our wide range of bioaugmentation products can quickly get you back in compliance.
