NEBRA Members Team Up on Phosphorus Innovation Challenge

The Village of Essex Junction Water Resource Recovery Facility in Vermont has teamed up with Chittenden Solid Waste District (also a NEBRA member) and the University of Vermont, Efficiency VT and James Morris Associates to test an innovative combination of technologies to remove phosphorus from wastewater. In 2018, the team received a $45,000 grant from the State of Vermont’s Phosphorus Innovation Challenge program being run by the Agency of Agriculture, Food and Markets. The goal of the Challenge is to find market-based innovative technologies to remove phosphorus from manure and other waste streams and make the recovered phosphorus available for beneficial reuse, for example, as a fertilizer.

The Essex/CSWD/UVM project proposes to employ a proprietary pipe descaling technology (PDT) which uses an induced electric field to precipitate crystalline phosphorus minerals, more commonly known as struvite. The struvite would then be collected using a custom-built “electric field-assisted” filtration device. The project was one of twelve in the first stage of Vermont’s Challenge, which began in 2018. In the second stage of the Challenge, the project was selected as one of six to receive initial funding to start testing their phosphorus-recovering proposal.

The project started because Essex was looking for a process to remove internally recycled nutrients, especially phosphorus, from its wastewater stream. Typically, struvite is a bane for wastewater operators due to the enormous amount of maintenance-related issues caused by its build-up in pipes and process equipment at the treatment facility. Essex’s proposal will generate struvite in a controlled manner and then capture and remove it, which could prevent build up elsewhere in the process. There are other benefits that may come from this project including potential energy savings, less chemical use for phosphorus removal, decreased phosphorus in land applied biosolids and reduced volume of biosolids.

Essex Junction’s treatment facility is where the experiments are taking place. The preliminary bench-scale work was concluded over the summer and the results show potential. The PDT process successfully creates soft crystals containing phosphorus. The next round of grants are coming up soon and the Essex team will be applying to pilot test the process. The project team thinks that by generating struvite from a specific waste stream (like supernatant from their digesters), it could be cost-effectively captured and filtered out. The struvite could then be processed into an agricultural fertilizer.

Essex found that there are commercially-available technologies to recycle phosphorus as struvite but, at the time, only at very large-scale treatment facilities. Essex, like the rest of the facilities in Vermont, is a relatively small facility where this commercially available technology would not be cost-effective. NEBRA applauds Essex for searching out their own solution as well as their partners for their willingness to innovate and take the next steps with the project.

The third phase of Vermont’s Phosphorus Innovation Challenge begins soon. NEBRAMail will highlight other projects and provide updates on this one in upcoming issues.