Integrated Engineers, Inc. tested the wastewater and found that adding caustic to a pH of 10.0 and Floccin D worked as well as the current chemistry. The Floccin D dosage was 0.35 grams in 800 ml (280 ppm). The third sample shown below is with 160 ppm of IE-061.
In addition, by switching from lime to caustic the reduction in solids generation would be a significant cost reduction. At peak flow the amount of lime required (17.3 lbs./1,000 gallons) generates 7,450 pounds of 100% dry solids. In a normally dry cake the solids are 30%, therefore they were generating nearly 25,000 lbs. of sludge per day that was hazardous and expensive to dispose of in a landfill. Based on a disposal cost of $35/ton, the cost reduction due to the lime addition to the sludge would be $450 per day ($160,000/year).