PRESQUE ISLE, Maine — The Presque Isle Utilities District has a two-part $15.6 million plan that will update its wastewater treatment plant to use a sludge dewatering system and to increase treatment capacity.
The changes will bring the city of Presque Isle into compliance with 2019 orders from the Maine Department of Environmental Protection.
In February 2019, the Maine DEP issued a consent order that all wastewater flows into the district’s Dyer Street plant receive secondary biological treatment. Currently, the plant’s capacity makes it unable to perform that treatment during heavy rain and rapid spring snow melts.
A month later, the DEP ordered the city to stop spreading wastewater sludge on fields until they tested the soil for PFAS chemicals, popularly known as “forever chemicals,” because they do not break down over time. The department later found that PFAS chemicals on nine out of Presque Isle’s 12 fields were higher than the state-mandated limit.
The Presque Isle facility was among the few statewide at the time to rely almost exclusively on sludge spreading, and had been planning to phase out the practice.
Heavy exposure to PFAS chemicals has consistently been linked to higher cholesterol rates in humans, according to the U.S. Department of Environmental Protection. More limited findings link them to cancer and low infant birth weights.
The city has chosen New Hampshire-based Apex Construction to update its wastewater dyeing and disposal system in a $2.3 million contract.The sludge will be dried to a lower moisture content than before and disposed of in a landfill. The district said it no longer applies biosolids containing PFAS chemicals to land.
Maine DEP spokesperson David Madore praised the utilities district for pursuing the sludge dewatering project. He said the new process would provide the district additional options for sludge disposal once it is operational.
The second phase of the project will see the plant receive extensive upgrades that will increase treatment capacity from 5.2 million gallons per day to 9.6 million per day. That project is scheduled for a bid in the fall of 2020 and to be completed by 2023.
The district also described some new changes they would like to bring to the city of Presque Isle’s wastewater systems in the future.
The district said it would be necessary to replace some of Presque Isle’s network of wastewater collection pipes, some of which were constructed in the 1920s using clay pipe. Many of those century-old pipes are cracked and deteriorated, causing groundwater to seep into them.
The district also said that a significant amount of building roof drains, basement drains and sump pumps were connected to wastewater pipes. These connections — which the district described as illicit — are estimated to make up 20-30 percent of flows during snow melts and rain.
Staff plan to ask homeowners and businesses who have those connections on their properties to seek alternative means of handling the water.
The total cost for both parts of the project is estimated to be $15.6 million. Funding will come from a $6 million grant and a $9.6 million loan, both from the U.S. Department of Agriculture.
The district’s efforts to address issues at the plant have received national acclaim. This year, the Environmental Protection Agency selected the district for a Regional Wastewater Treatment Plant Excellence Award, citing its efforts to improve water quality in Presque Isle.