Resource Recovery

Turn digestate and manure into clean water and recover valuable nutrients

Digestate is solid material that remains after the anaerobic digestion of a biodegradable feedstock. Nijhuis developed various options for treating digestate. Under anaerobic circumstances organic waste material is transformed into biogas which can be used to produce heat, electricity and concentrated fertilizer.

Pre-treatment of raw materials:
To optimize the biogas quality and amount some feedstock materials require a pre-treatment step, like macerating, sterilization or pasteurization processes.

Digester, type AECOMIXTM-Taurus:
Under anaerobic conditions the feed materials are digested / fermentated to create biogas with around 50-60% methane and 30-40% carbondioxide. The digester tank is equipped with a mixing and heating system.

Biogas treatment & utilization:
Biogas can be used to feed boilers and Combined Heat & Power (CHP) installations or can be upgraded to green or natural gas and supplied to the (natural) gas grid.

Solid / liquid separation:
The solid fraction from the digestate can be separated from the liquid fraction by mechanical separation systems, like screw press, decanter centrifuge or dewatering drum.

Manure treatment, type GENIAAL system:
A revolutionary and cost-effective solution to turn manure into a bio-based fertilizer and clean water. An innovative solution based on a smart combination of proven decanting, flocculation-flotation and membrane solutions and application know-how.


AECO-RECOVERY solutions

Advanced resource recovery solutions towards a circular ECOnomy


Ammonia Recovery, type AECO-NAR:

Another award winning solution to recover ammonia from digestate or substrates from digestion. Instead of biological oxidation the recovered ammonia is turned into a bio-based fertilizer turning waste into value. The Nijhuis mission with this next level of ammonia recovery is ‘doing more with less’. The AECO-NAR has a proven ammonia removal efficiency of 80-90%, with the lowest energy consumption. Dilution of the substrate creates a higher biogas production by minimizing toxicity. Less additional co-substrates are required to mix the high ammonia substrates.

Fat Recovery, type AECO-FAT:
Maximize the value of flotation sludge, turning flotation sludge into biofuel based on the water, solids and fat concentration in the sludge. It is a true ROI based system as the biofuel can be used as energy production on site and flotation sludge disposal cost are dramatically being lowered. Fat recovery can be obtained by heating the dissolved air flotation sludge, followed by separation into a liquid fat, a water and a solids fraction.

CIP Recovery, type AECO-CIP
In process recovery solutions are crucial to achieve the increasingly demanding environmental requirements to create a more sustainable way of operating beverage plants. The Nijhuis CIP recovery unit is a plug & play packaged recovery system to treat spent CIP solutions (i.e. hot soda based). While the CIP agents and heat remains in the recovered stream, the organic fouling, solids and part of the inorganic soluble content will be captured by special membranes and concentrated prior to disposal.





  • CHP
  • Ammonia-recovery
  • AECO-FAT
  • membranes-AECO-CIP