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All Digestate Solutions


BKT's technologies are developed in-house and provide various digestate solutions, from treatment to resource recovery.

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Organic waste, including livestock waste, causes two major environmental problems: water contamination and air pollution. We need to treat wastewater and reduce greenhouse gas emissions, specifically methane, to prevent harmful environmental and public health impacts.

BKT has devoted years to developing proprietary solutions for digestate treatment or resource recovery and reuse. The following process flow diagram illustrates physical and biological treatment for solid and liquid separation of organic waste streams.


As shown above, our unit technology can be integrated with other solution partners such as anaerobic digester providers to deliver total digestate solutions. 

Our FMX technology is a unique anti-fouling membrane filtration system that effectively separates solids and liquids from high solid, high density and and high viscosity waste streams to produce clean water or to concentrate and recover nutrients.

Key benefits of FMX:

  • Small footprint
  • High recovery rates
  • Clean, quiet operation


Resource Recovery & Reuse

Biogas is produced when organic materials are decomposed by bacteria without the presence of oxygen - a process known as anaerobic digestion. This natural process has been a longtime popular practice for creating renewable energy simply by burning biomass as an organic heat source.

The leftover digestate consists of high solids and high viscosity streams with very high total nitrogen and phosphorus - valuable natural resources. In the past, a popular use of anaerobic digestate was to spray it on farmland as fertilizer. After years of doing this, however, many U.S. states have banned such practices due to pervasive soil saturation resulting in groundwater contamination from excess nutrients.

Want to increase your digester's profitability? Turn your waste into liquid fertilizer!

A nutrient recovery project is under way to recover and sell valuable nutrients to increase the revenue of the biogas plant. The project goal is to remove 100% of suspended solids prior to downstream Reverse Osmosis (RO) to further concentrate and recover the valuable dissolved nutrients from the digestate.

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Anaerobic digestion of manure, food processing byproducts, and other waste streams provides a source of low-cost, renewable energy but also generates a high-strength waste stream that contains high concentrations of nutrients, biomass, and organic matter. Processing this waste stream is so costly that it has prevented wider adoption of anaerobic digestion. However, BKT's solution allows the digestate to become a revenue stream by enabling the recovery of nutrients in the digestate as a marketable organic fertilizer. It also concentrates the solids in the digestate, reducing hauling costs for disposal.

BKT employs its anti-fouling FMX membrane filtration system as the basis of a treatment train for the recovery of nitrogen from anaerobic digester effluent (digestate) as a profitable liquid fertilizer. A sample process train is shown below.

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 T’Haantje BGP | Netherland

A 6 megawatt anaerobic digester in the Netherlands installed 3 FMX units for the treatment of digestate. Prior to FMX, the facility had a tubular membrane system installed, but due to the difficult characteristics of the digestate, the tubular system was fouled beyond recovery within 3 months.
The first full scale industrial installation of its kind, the FMX has been proven to effectively and reliably treat digestate. At this installation the FMX is used as a pretreatment to remove suspended solids prior to a spiral RO system. The RO can then be used to provide clean water for reuse onsite, while concentrating the nutrients for sale as a fertilizer.

Not only does the FMX provide a reliable and consistent RO pretreatment, but the concentrated biomass from the FMX can be returned to the digester. By returning the FMX concentrate, the biogas facility has reported up to a 20% increase in biogas production. In addition, the returned biomass helps maintain a more stable digester, decreasing operational downtime of the whole operation.

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Full Scale Digestate Treatment with Nutrient Recovery

Full Scale Digestate Treatment with Nutrient Recovery


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