By Robert Smith
In early 2012, the wastewater treatment plant (WWTP) serving the town of Millersburg, Ohio, noticed that its discharge into the Killbuck River watershed was borderline compliant with Ohio Environmental Protection Agency (EPA) regulations.
"We were getting readings from our monitoring process that some of our ammonia levels were out of whack, causing a real challenge with our nitrification across the plant," said Kevin Vaughn, plant manager. "As a result, our effluent was creeping into troublesome areas of compliance."
Luckily for the facility, the team at the Ohio EPA Compliance Assistance Unit (CAU) was recently on site conducting stress tests, so they ended up carrying out additional evaluation to try and determine the problem with the ammonia levels.
There to Help
The government-funded CAU was established by the Ohio EPA to act as a resource to WWTPs across the state to help with compliance issues. If a plant is determined to be out of compliance or is having difficulty monitoring and maintaining regulations, CAU can provide an assessment and diagnosis of its systems and processes to get them back on track.
Many Tools in the Toolbox
When CAU first arrives at a facility, the immediate action is to determine what compliance challenges might exist. This initial assessment is based on what data the treatment plant has available from the measurement and monitoring equipment in place. Based on the initial assessment, CAU then sets up its own measurement and monitoring equipment to monitor the plant's biological activity, as well as conduct its own analysis.
This CAU assessment can be as quick as one day, or it can take place over several months and can utilize multiple tools in a toolbox of testing and monitoring equipment. The toolbox can contain a range of technologies, including traditional, low-tech settleometer and core samplers; mid-tech microscopy and multiparameter wet-chemistry applications using grab samples; or sondes and dataloggers as part of the latest cutting-edge, high-tech solutions available. One such solution in the CAU toolbox is the IQ SensorNet continuous monitoring system from YSI, a Xylem brand.
The Latest and Greatest
At Millersburg, there were nine different locations within the plant -- from intake through effluent -- that were being sampled via a traditional analyzer system. When CAU set up their assessment at Millersburg, YSI provided a loaner IQ SensorNet unit to augment the CAU toolbox. To help assess the collected data of the required parameters, CAU installed the SensorNet alongside the traditional analyzer already in place and ran them contiguously.
Early on in the assessment, both CAU and the team at Millersburg realized the benefits of the IQ SensorNet online technology versus the capabilities of the existing unit -- the latter being cutting-edge technology 10 years ago; the former, a sophisticated, state-of-the-art system for monitoring and control of a wastewater treatment process.
"To get that comprehensive perspective of what's happening in the process, there's no substitute for 24/7 datalogging," said Jon van Dommelen of the Ohio EPA CAU unit. "That is what gives us the true picture of a complete system, from beginning to end, and it provides the critical pieces of data that tend to be missing."
Putting it to the Test
CAU couldn't tie the IQ SensorNet into the plant's SCADA system due to upgrades required to the SCADA, but they were still able to optimize the IQ SensorNet capabilities. With the many man-hours saved with the new system -- eliminating time-consuming grab samples and the corresponding lab work -- the plant staff was able to partake in other important duties crucial for a small team with limited resources.
When it came time to conclude the CAU assessment, the Millersburg team came to realize how often they walked by the IQ SensorNet interface and observed the output readings, providing an immediate view of the parameters being measured -- the current plant status at-a-glance.
"It was something we didn't realize until CAU finished up their assignment and pulled out the IQ SensorNet system," said Vaughn. "We had gotten so used to the real-time status the unit provided -- from both a monitoring and a control perspective. The peace-of-mind was an extra benefit we hadn't expected until those real-time readings were gone. Having that information at our fingertips was a real convenience."
Once CAU packed up their toolbox, the Millersburg team had to address the long-term diagnosis and action plan of the CAU assessment and determine how to facilitate compliance based on that assessment. Further, Millersburg had to consider the YSI IQ SensorNet as a long-term solution. Their immediate concern with the unit was the higher initial cost. But some quick math addressed those concerns, and the team quickly realized that, amortized against necessary maintenance and reagent costs of the existing analyzer system, the YSI solution provided long-term value, considerable peace-of-mind and lower total cost, in addition to the data they needed.
As WWTPs struggle with compliance, CAU will continue to provide a critical assessment service, applying their expertise and assortment of technologies to help solve the different challenges plants might face. Be it low- or high-tech solutions, the various tools in the toolbox are the lifeblood of CAU, providing the ultimate assessment for WWTPs and furnishing the data necessary for diagnosis of non-compliance issues.
About the Author: Robert Smith is the applications engineer - wastewater at YSI, a Xylem brand, based in Yellow Springs, Ohio. He can be reached at [email protected] or at 937-767-7241, x461.
