There are approximately 170,000 public water systems in the U.S. Roughly 97% of these systems serve communities of less than 10,000 people, and although revenues generated by large systems dwarf that of small systems, analytical parameters required for compliance and performance purposes are basically the same for both. Due to manpower and fiscal pressures, smaller water facilities often face an endless struggle to keep up with the workload while also keeping pace with developing technology.
Operators at the Kahoka, Mo., water treatment plant are not immune to such challenges. The 0.5-mgd facility supplies water to the city of Kahoka and the city of Wayland, Mo. The groundwater plant treats an average of 280,000 gpd, serves approximately 1,200 service connections and provides a backup water supply for the Clark County Rural Water District.
Multitasking challenges
With no dedicated lab technicians on staff, the plant supervisor and an operator are responsible for sampling and analysis at the water treatment facility, as well as sampling and analysis duties at the city’s wastewater treatment facility, located 9 miles away. This demands tight scheduling, according to Plant Supervisor Kevin Eagle, who was named 2006 Operator of the Year, Northeast Section by the Missouri Water & Wastewater Conference.
“We wear a lot of hats around here,” Eagle said. “There are four full-time water department people—two are responsible for our distribution system, and the other two, including me, are in charge of plant operations and maintenance. But besides that, we’re responsible for maintaining our four lift stations, as well as for carrying out numerous other duties. We even mow the grounds at both locations.”
To meet the daily workload requirements for both treatment facilities, speed and accuracy in water analysis are high priorities. Until recently, however, plant personnel struggled with worn and outdated instrumentation that created inefficiencies and increased the testing load at the water treatment plant. This made the staff’s many responsibilities at both facilities much more difficult to carry out.
“The water lab’s spectrophotometer had been going downhill for a long time,” Eagle said. “It was an old unit that had been here for many years. It had been a good, durable instrument in its day, but we had been operating it long after its intended life and it became unreliable. Sometimes it wouldn’t even come on, and we had to unplug it and plug it back in the AC outlet before it would come on.”
Operating the old instrument long past its useful life not only made carrying out laboratory duties inefficient at the water treatment facility, but plant personnel increasingly began to lose confidence in its data. In January 2006, the plant replaced it with a Hach DR 2800 portable spectrophotometer. The switch has brought time savings, accuracy and confidence in water quality analysis at the plant.
Expanded capabilities
The portable spectrophotometer includes preprogrammed software and stored calibrations for more than 200 colorimetric methods using prepackaged chemistries. Each of these methods had previously involved the determination of percent transmittance at numerous wavelengths, followed by cumbersome calculations. The stored procedures in the lab’s new spectrophotometer allow personnel at the Kahoka plant to simply prepare and insert the samples; the instrument performs the measurements and calculates the appropriate concentration values. Eagle said the new spectrophotometer has many sophisticated new features and functions, compared to the plant’s previous instrument.
“We’ve found the new unit to be very user-friendly and very easy to understand,” Eagle said. “With its touchscreen and memory function, there’s less chance for error, and we can save and date the test data.”
Eagle and his crew use the spectrophotometer to test for free and total chlorine, fluoride and phosphate (added for iron sequestering). Testing is performed at four points: ground storage, the water wells, the treatment plant and the distribution system.
The new spectrophotometer can be used for more than 240 analytical methods and stores up to 50 user programs and 500 data points, including sample and operator ID.
“We like the memory storage and operator ID feature,” Eagle said. “It tells us which one of us did the testing, the date and the results. There’s also a ‘favorites’ feature where you can go to the touchscreen and select the test you want, eliminating the need to enter your test number. This saves us a lot of time. For example, we perform a dilution test on our phosphate, and now we can just enter the dilution factor and the unit automatically performs the math.”
The modified procedure with the dilution factor can then be stored as a user program, eliminating the need to re-enter the dilution factor on subsequent start-ups by other operators or analysts.
Most importantly, the Kahoka treatment plant has gained speed and accuracy in water analysis. Less time is spent testing, and potential errors are reduced, resulting in increased productivity and confidence in the results.
“We get an almost instant read and go on to the next test right away,” Eagle said. “It really has streamlined the process considerably.”
Although the Kahoka facility does not currently use the feature, adopting the spectrophotometer’s bar code reading feature may eventually further enhance efficiencies in the Kahoka water plant lab. Hach currently provides more than 20 TNTplus reagent vial tests that provide bar code labeling for reliable, automatic method detection. The unit automatically reads the bar codes to select the correct test procedure. The prepared vials are inserted into the cell holder. The spectrophotometer automatically rotates the vials, taking 10 measurements in less than five seconds. The average of the 10 values is used to calculate the results. In addition, measurement data can be quickly transferred with a USB memory stick and downloaded to a computer or transferred directly using Hach’s DataTrans Software.
Keeping it in the lab
Although designed to be both a laboratory and a portable instrument, the Kahoka plant’s new spectrophotometer is used strictly in the lab, according to Eagle.
“We didn’t even purchase the battery for it. We figured if we did, someone would be tempted to take it out of the lab, and we want to keep it just for the lab,” he said.
In addition to adding the new spectrophotometer, the water plant also recently upgraded its pH meter, according to Eagle.
“Our unit was getting pretty old and going through batteries very fast. And, like our former spectrophotometer, we were starting to question its accuracy,” he said.
The plant replaced the unit with a Hach Sension 3 benchtop pH meter. Eagle said the meter responds quickly to the electrode signal and stabilizes in a matter of seconds.
“It’s much faster than our old unit and saves us a lot of time. It’s also easy to calibrate,” Eagle said.
In a fast-paced, small water treatment facility where only a few people must juggle numerous duties and responsibilities, updating laboratory instrumentation can provide numerous benefits. The Kahoka water treatment plant has now gained new efficiencies and better confidence in water analysis procedures, thereby providing personnel more time to accomplish other important duties.
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