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PhosRID Lombardo Associates

Description of Technology

Descriptions for proprietary technologies are from the Massachusetts DEP Approval Letters for the technology.

The PhosRID TM System uses a reductive iron dissolution (RID) media anaerobic upflow filter to reduce total phosphorous. The System consists of two treatment units: the initial unit with RID media and a second unit, which operates as an oxygenation filter.

The RID media tank is designed for a hydraulic residence time of 6 to 24 hours. Within this tank, PhosRIDTM iron is biologically converted to ferrous-iron which combines with dissolved phosphorus to precipitate in the form of the mineral vivianite. This precipitation process removes a portion of the wastewater phosphorus from solution.

The oxygenation filter may consist of any sand, textile or foam media filter approved by the local Approving Authority or Lombardo Associates, Inc. (the ‘Company’). The hydraulic application rate for the down flow sand filter is 2 gallons per day per square foot. In the media filter the unreacted ferrous is converted to ferric and mineralizes the remaining dissolved phosphorus to stringite, which becomes entrained in the sand filter, resulting in a further reduction in wastewater phosphorus.

The process flow for the PhosRIDTM system is as follows. Wastewater effluent from a Title 5 compliant septic tank or alternative treatment system is discharged to the PhosRIDTM upflow filter. The RID treated wastewater then passes through the media filter and then either flows by gravity or is pumped to a soil absorption system (SAS) constructed in accordance with Title 5, 310 CMR 15.100 – 15.279.

The PhosRIDTM reactive media is eventually consumed and must be replaced, with media life estimated to be approximately 5 years of operation.

The Company specifies routine service inspections, primarily for performance verification and monitoring. The MassDEP requires Systems receive monthly inspections during the initial few months of operation followed by regular quarterly inspections and monitoring as part of this alternative technology’s piloting evaluation (see O&M requirements, section IV). Local Approving Authorities may require additional monitoring requirements.

Massachusetts Technology Approvals

Approval Type General Remedial Provisional Pilot
Secondary Treatment
Nitrogen Removal Credit
Phosphorus Removal Credit

Please check the Title 5 Innovative/Alternative Technology Approval Letters webpage at Massachusetts DEP for the most up-to-date information.

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