Municipal Water Treatment Pilot
Subject: KL-AOP-Pilot Study at City of Claremore Water Treatment Plant
On April 24, 2017, we began a study using KL-AOP as a pre-oxidant at the surface water treatment plant. The goal of this study was to reduce the formation potential of the raw water, thus reducing the DBP’ s (disinfection-b y products) and increasing the overall TOC removal as our alkalinity is rather lo w. We started at 15 mg/I of KL-AOP prior to the flash mixer and began to monitor water quality (raw water, settled water, and finished) by measuring ORP, UVA254, TOC,DPBs.
From doing Jar Testing in the lab, we knew that we would need to reduce the primary & secondary coagulant dosages as the oxidation process was removing that chemical interaction, thus improving our overall coagulation. Within hours after injecting KL-AOP into the raw water line, we began to see an improvement in our processes at lower coagulant dosages. Over the first couple of days of using KL-AOP algae removal from the weirs of the clarifiers was substantial, and easily removed in our filter backwashes. During the next week, the watershed received 8 inches of rain during the weekend which caused the raw water turbidity to go from 15 NTU to 66 NTU. We didn’t change the dosage of the Keylate product and only increased the coagulant by 5 ppm, managing to still maintain 65% TOC removal and settled water turbidities less than 2.0 NTU.
Prior to using KL-AOP, the NOM removal was around 50% to 60%, using an ACH blend coagulant and polydadmac coagulant aid. With the addition of KL-AOP, the NOM removal has been greater than 85% removal, with a peak of91%. The TOC removal went from an average of 45% to an average of 64% in less than two weeks of being online with KL-AOP. Our clarifier effluent is non-detect for E. coli & coliform and we noticed a significant reduction in chlorine demand. The Oxidation Reduction Potential, ORP, has gone from – 290 mV to – 640 mV in the finished water, meaning that we are seeing a removal of the biofilm in the system.
Based on the results so far, we have observed the following:
- The primary and secondary coagulant are working better resulting in lowering chemical dosages;
- Increase in TOC removal
- Absolutely no algae throughout flash mix/clarifiers
- A reduction in chlorine for disinfection
- Oxidation of all iron & manganese
- No bromate!
Moving forward, our next goals will be to increase the ORP in the distribution system and monitor TTHM and HAAs in the trouble areas of our system. The operators seem to like the ease of application, safety, and monitoring of KL-AOP, as it can easily be measured with an ORP meter, and they are definitely enjoying not having to perform the tedious titrations necessary for chlorine dioxide/chlorite monitoring as previously used. The overall operation of the plant seems to be smoother and less problematic.