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.
Raw material preparations & storage:
Storage and preparation of the raw materials is required to maintain a frequent and high quality feed to the digester.
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.
Ammonia Recovery, type 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 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.
Treatment of solid fraction:
The solid fraction from the separation stage can be used as a fertilizer, depending on the market requirements, drying and pelletizer steps can be integrated.
