Benefits of Biochar for Anaerobic Digester Plants

It has long been determined that activated carbon or biochar aids in the production of methane (CH4) and Hydrogen (H2) through the process of anaerobic digestion/degradation of organic matter.

This post covers just some of the benefits in layman’s terms to show the economic viability of using biochar as an additive.

Firstly, and most economically important is the fact that biochar, through scientific tests has been proven to increase production by 23,5 – 47.1%. It can also increase the quality of methane produced by up to 25%. It does this in various ways:

1) Boosts anaerobic digestion performance.

2) Biochar acts as a carrier to increase microbial abundance.

3) Maintains good viscosity.

4) Improves stability of the system. Biochar stabilises acidic inhibition on anaerobic digestion of digestate by reducing load shock.

5) Reduces lag phase of methanogenesis. Shortens the lag phase of H2 reactors and CH4 reactors by 21.4 – 35.7 and 41 – 45% respectively.

6) Absorbs toxicants like ammonia which inhibit anaerobic degradation by up to 10.5%.

7) Assists in the degradation of biomass.

8) Increases the value of digestate as a fertiliser. i) By stabilising the nitrogen: phosphorous ratio through mitigating nitrogen loss in the volatilisation of ammonia. ii) By increasing metallic elements in digestate such as potassium by up to 33 times. iii) By playing host to microorganisms and storing nutrients as a slow-release nutrient supply for plant use. iv) By closing the carbon cycle by putting carbon back into the soil.

9) Easier spreading and lengthened spreading window.

10) Reduces bad odor of degradation.

11) Mitigates Green House Gasses through its sorption qualities.

12) Assists in sanitising digestate by absorbing pathogens like E. coli.

References:
https://www.researchgate.net/publication/343397890_The_Role_of_Biochar_to_Enhance_Anaerobic_Digestion_A_Review
https://www.sciencedirect.com/science/article/abs/pii/S0959652623035114
https://www.sciencedirect.com/science/article/abs/pii/S1385894724007538

Photo Courtesy of Wikipedia Anaerobic Digester