Reject water and liquid digestate can become a real operational burden for a biogas plant. They take time, create cost, and increase pressure around storage, hauling, spreading and disposal. NPHarvest helps reduce that burden by recovering nutrients – nitrogen and phosphorus – from these side streams as a service, giving plant personnel a practical solution to manage reject water and liquid digestate without pulling attention away from the core process.
For many biogas plants, reject water and liquid digestate are not just a technical challenge. They can become expensive and time-consuming to handle, while also increasing pressure around logistics, storage capacity, spreading windows and disposal routes. As volumes grow or restrictions tighten, digestate management can consume disproportionate time, attention and money relative to its role in the overall plant. In some cases, side-stream handling can also start to limit operational flexibility or future biogas production.
Key points:
• Expensive and time-consuming to handle
• Can increase pressure around hauling, storage, spreading and disposal
• Can pull time and attention away from core plant operations
• Can become a bottleneck as restrictions tighten or volumes grow
NPHarvest recovers nitrogen and phosphorus from reject water and liquid digestate to make nutrient-rich side streams easier to manage. Instead of adding another complex piece of equipment to the plant, the solution is delivered as a service designed to work alongside existing plant operations. Its modular fit helps biogas plants address digestate treatment and reject water treatment in a more manageable way while not demanding any additional work from the plant personnel.
Typical use case: Liquid digestate / sludge
Benefits:
• Lower handling burden
• Less pressure around disposal and logistics
• More focus on running the plant and producing biogas
• No disruption to existing infrastructure and operations
With NPHarvest’s solution, pH is raised in the incoming stream, phosphorus is recovered through precipitation and nitrogen is recovered through hydrophobic membrane stripping. The process produces reusable nutrient outputs, supporting nutrient recovery from digestate and reject water in a form that is more manageable for the plant. NPHarvest also handles the nutrient end-product management and offtake.
Important note: This is not pressure-driven membrane filtration. Nitrogen recovery is based on hydrophobic membrane stripping, which is a different principle. Unlike pressure-driven membrane filtration, the process does not force wastewater through the membrane, which helps reduce filtration-style clogging burden and supports easier operation.
Get in touch to discuss your plant. A next conversation typically looks at your sidestream type, current handling route, flow volume and variability, nutrient concentrations if known, and where cost, process or compliance pressure shows up most clearly in your plant. If the stream is a fit, NPHarvest can assess how nutrient recovery could work alongside your existing operations.
He’s the brain behind the tech and the right person for deep dives.
+358 40 861 1915
juho@npharvest.fi
He’ll show you how to get started.
+358 40 707 2462
sales@npharvest.fi