Inventor pitches mobile dissolved-air flotation barge for pond algae; commissioners and residents raise feasibility, permitting and ecological concerns

Mark Bellora, founder of Clear Waterways Group, presented a prototype mobile dissolved-air flotation clarifier and described pilot tests the company conducted, including third-party laboratory measures the presenter cited for one earlier test.

Bellora said the prototype processes about 65 gallons per minute and that a planned version 2 would treat roughly 200 gallons per minute; he described the prototype as about 8 feet 5 inches wide and 18 feet long and said the wet weight is approximately 5,700 pounds. Bellora said a single day (eight hours) of treatment produced three loads of sludge totaling about 135 gallons and that third-party results showed average removals of about 74% of total suspended solids, 74% of total nitrogen associated with those solids and 69% of total phosphorus.

Commissioners and members of the public responded with technical and logistical questions. Multiple speakers raised the ponds’ shallow depths and limited access as obstacles: commissioners and residents reported that Duck Pond, Fountain Lake and other neighborhood ponds are very shallow (frequently less than a foot in many places) and in some locations have dense vegetation and obstructed shorelines that would prevent launching or maneuvering a heavy barge. One commissioner said portions of the system may be less than a foot deep and suggested the device would be unable to operate in many of the parks’ ponds.

Bellora responded that the unit can operate in water depths he said he has operated in previously (he said he had operated in 18–24 inches of water) and that the machine can be left in place and fed by a tow or hose. He also said the device can run in a non-chemical, air-only mode to treat active blooms and that a low-dose potable chemistry (used in drinking-water treatment) could be added to treat nutrient loads at tributary inflows.

On permitting, Bellora said he discussed a prior pilot with DEP staff (he named David Wong and cited “WMO4”) and that DEP told him air-only dissolved-air flotation testing did not require the same permitting as chemical treatments in that case; commission members and attendees said other permits could be required. Commissioners advised Bellora to consult the Natural Heritage & Endangered Species Program and other state permitting authorities and suggested that a formal filing or permit application would prompt the ecological and access questions to be addressed. A resident also noted prior chemical treatments (company name Solitude was mentioned) and asked how the DAF approach would compare to treatments already used.

Commissioners and residents also asked about invertebrates and other aquatic life living in the surface layer that is targeted by the device; Bellora said the suction is not so strong that fish would be taken and that invertebrates may be displaced but argued the goal is to treat the most contaminated top layer rather than every gallon of a pond.

No formal vote or permit decision was taken at the meeting. Commissioners suggested next steps: Bellora should confirm pond depths and access points, consult the Natural Heritage & Endangered Species Program, coordinate with local staff (Adam) on possible launch locations and prepare any permitting filings needed before operations could proceed. Several commissioners and residents said Duck Pond in particular appears too shallow and obstructed for the current prototype but suggested other sites or design changes (a lighter, smaller unit or trailer rollers) could be explored for future trials.

Bellora asked for collaborators and said the company is seeking additional non-dilutive funding (he referenced M2I2 and an application to MassVentures) to build a version 2 for 2026 and lighter materials to commercialize the device.