The Chisago Lakes Joint Sewage Treatment Commission heard a couple of good news items at the meeting Monday this week.
The state is allowing landspread sites to be utilized again, after field study of a non-native invasive plant, Phragmites, thought to be proliferating through land spreading of wastewater treatment plant sludge.
There was a theory that spreading the sludge from treatment plants which have phragmites on the edges of the ponding areas where the sludge is dredged out of-- spreads the seeds/fragments to the countryside. Land spreading sites are dotted all over the rural landscape.
The Chisago Lakes Joint Sewage Treatment Commission members were informed this week that state research teams have not found any evidence that the invasive phragmites were springing up on any haul roads between sewer treatment sites and land spreading locations. The state has authorized land spreading to be used again.
CLJSTC Plant Supervisor Mark Nelson commented that without the ability to be spreading again, the sludge from the CLJSTC facility would have to be hauled to Mora to a lined and regulated landfill. The commission only spreads every few years or so.
The second positive announced at the meeting is that the commission doesn’t have to do eradication of its non-native invasive phragmites growth. For now. Engineer Ron LaFond stated, “long term” the state doesn’t condone non-natives being used as a biological tool for taking up nutrients at wastewater facilities, adding, “At this point the Chisago Lakes commission is not affected,” he told the commissioners.
State regulators are looking into options which would be less of a biologic and environmental nuisance than phragmites are. There are 15 other wastewater facilities in Minnesota that have incorporated the tall reed-like plant into the ponding systems used at sites. But, there is “no funding” at the state level now to research suitable replacements, LaFond added.
Years ago the phragmites were thought to be a natural response to the need to reduce nutrients in treatment plant waters because Minnesota winters would curtail the growth cycle, and not allow the species to spread. That line of thinking has been shown to be incorrect as phragmites has become the number one nuisance on lakeshores and low lying wet areas in general.
Minnesota may elevate phragmites to a status that would mandate its removal and then the commission will have to act.
At this point the non-native invasive is no longer sold or used in plantings and there is some research being done into eradication. Local lake associations and the Lake Improvement District for the Chisago Chain and its watershed have been acting on their own to identify stands and remove the invasive phragmites. Theirs is a multi-year plan of hand removal methods at opportune times and custom targeted chemical use.
The alternative to wastewater treatment sites’ use of plants for taking up excess phosphorous and nitrogen would be a mechanical process to remove the final nutrients from wastewater and that’s very costly, Nelson remarked.