WILLIAMSBURG — Different wastewater test readings have become a topic of discussion between the town Water and Sewer Commission and the Northampton Department of Public Works.
The wastewater issue is not an esoteric one. Northampton treats Williamsburg’s wastewater and since it began testing the town’s wastewater daily in 2017 or 2018, Cerreta said the town has paid Northampton more than $100,000 in surcharges.
The readings from Northampton’s daily tests prompted Williamsburg to start having its own tests done, which have almost all shown better readings for Williamsburg.
“We’re at an impasse in figuring out why it’s so different,” said Eric Cerreta, the commission’s chair.
Northampton DPW Director Donna LaScaleia said, however, that most of Williamsburg’s samples were not collected and prepared in the same manner as Northampton’s, making comparisons problematic.
“We have full confidence in our test results,” LaScaleia said.
Northampton tests for total suspended solids (TSS) and biochemical oxygen demand (BOD), and charges Williamsburg additional money when levels of either of these are too high.
Williamsburg started collecting samples for its own tests, Cerreta said, first in the last manhole before the metering station where the Northampton DPW collects its samples, then from the manhole after and finally from within the metering station itself.
“We were narrowing it down,” Cerreta said.
These samples were sent to a lab by Williamsburg, and a number of them had strikingly lower TSS and BOD numbers than ones collected by the DPW on the same days — sometimes on the order of hundreds of percents.
The commissioners presented this information to LaScaleia at a March 8 meeting, which Cerreta described as productive.
Speaking to the Gazette, LaScaleia said that she has full confidence in Northampton’s lab and processes. She also said that it’s important to pull samples from the same location, that the same type of sampling device is used and that samples are taken in a consistent manner by licensed operators.
“If all those conditions are not met, that can cause discrepancies,” she said.
She also said that preparing the sample in a consistent manner is also important.
The director said that she is willing to send the DPW’s samples to a lab of Williamsburg’s choice in addition to the city lab, but that Williamsburg would have to pay for it.
“We want the sample to be both collected and prepared in a consistent way,” she said.
Williamsburg already has data from having Northampton samples tested at its lab. However, in those three instances the BOD and TSS numbers recorded by the Northampton lab were actually less than what the town’s lab recorded, or only slightly higher.
Cerreta said that Williamsburg will continue to test samples and that the town is confident in its procedures. He also said that they want to see how Northampton digests the information presented to it.
“We want to get to the bottom of it,” he said.
Additionally, Cerreta wrote in an email that he didn’t feel that the communities using different kinds of sampling devices could produce the discrepancies found between the samples. He also wrote that where Northampton is collecting its samples could be in an area of turbulence where solids are trapped in a whirlpool or eddy.
Bera Dunau can be reached at bdunau@gazettenet.com.