Re: Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar

Frank Strie

Scientists like to have lab test scale projects to discover and debate for years on end, farmers and practicing industries move forward when it is clear what works.

Switzerland, Germany:

Treating liquid manure with biochar,
the Biochar Journal 2014, Arbaz, Switzerland.
ISSN 2297-1114
Version of
01 th September 2014

Treating liquid manure with biochar

by Hans-Peter Schmidt

One of our oldest preconceptions is that a cowshed inevitably stinks. But the pungent odour of liquid manure is first and foremost the sign of a microbial decomposition process that has gone out of control. That which stinks to high heaven is not only an offence to delicate citizens’ noses but above all a source of disease for the animals living there. Thanks to biochar and to the control of the microbial environment in the shed and in the manure pit, materials cycles can be closed. Liquid manure in this way becomes a highly efficient, sustainable and odourless fertilizer.

In spring and autumn, when farmers spray their fields with liquid manure, an acrid stench spreads across the countryside. This pungent smell comes especially from ammonia, a volatile nitrogen compound formed from the urea contained in the manure. Large portions of the ammonia, which is corrosive to soil organisms and fine roots, escape into the atmosphere, where it binds to dust particles and returns in the form of acid rain onto fields, forests, cities and water systems, causing major environmental damage. …




Liquid Manure Treatment

Biochar adsorbs efficiently Ammonia, Ammonium and other odorous organic substances. While in non-treated liquid manure lagoons more than 30% of Nitrate is lost to the atmosphere, the treatment of liquid manure with biochar, lactobacilli and rock powder nearly all Nitrogen can be stored in a plant available form. As the fertilizing efficiency further increase, the fertilizer capacity of the manure nearly doubles. 

Using biochar for the liquid manure treatment reduces leaching of the manure treatment to the subsoil, which protects the groundwater and avoids soil acidification. The biochar treated liquid manure enhances biological soil activity and helps for the build-up of soil organic mater. 

Recommended Quantities: 

0,6% - 1% (vol) Biochar based on the total volume of the liquid manure (if biochar is milled, the application quantities can be reduced)

Add the biochar regularly to the manure lagoon. 

Even more important than the application of biochar is the guidance of the microbial milieu in the manure. Bad smelling rotting has to be avoided. Putrid smells are an unmistakable sign of bad manure quality. To guide the microbial milieu, we recommend to use the commercial product EM-A or self produced IMO (indigenous microorganisms). Adding rock powder further helps:

0,1 % (vol) EM-active or up to  0,5% (vol) IMO2-3 % (m/m) rock powder

Only a few days after the treatment, the lagoon will not smell bad anymore. However, soil application of the treated manure should be done only 20 days or more after the treatment to allow the microorganisms to finish their job. 

We suggest to start the liquid manure treatment when the lagoon is still rather empty. You can thus avoid nutrient losses and climate gas emissions. We further recommend to use biochar already in the bedding and to spray regularly EM-A and IMO in the barn. 

ithaka institute for carbon strategies


Austria available and used :

In Germany 2015:






From: <> On Behalf Of Tom Miles
Sent: Sunday, July 4, 2021 2:25 AM
Subject: [Biochar] Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar

Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar

Abstract: The risk of inhalation exposure to elevated concentrations of hydrogen sulfide (H2S) and ammonia (NH3) during the agitation of stored swine manure is high. Once or twice a year, farmers agitate manure before pump-out and application to fields. Agitation of the swine manure causes the short-term releases of highly toxic levels of H2S and NH3. In our previous pilot-scale studies, the biochar powder showed significant mitigation of H2S and NH3 emissions when it was surficially applied to manure immediately before agitation. However, fine biochar powder application poses hazards by itself and may not be practical to apply on a farm scale, especially when livestock and workers are present. We hypothesized that applying pelletized biochar to manure surfaces is just as effective as applying powder to protect farmers and animals from excessive exposure to H2S and NH3. This work reports on the lab-scale proof-of-the-concept trials with biochar pellets on the lab scale. The objective was to compare the biochar pellets and biochar powder on their effectiveness of mitigation on H2S and NH3 gases during 3-h-long swine manure agitation. Three[...]

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