Search

The study investigated the effects of ensiling and brown juice-assisted ensiling of wheat straw and press cake from a green biorefinery plant prior to anaerobic co-digestion (Aco-D) with cattle manure on methane yield and nutrient availability in the digestates. Straw was ensiled with and without brown juice at field-scale and lab-scale levels, followed by Aco-D with manure using continuous stirred-tank reactors (CSTR) and batch tests. The digestates from CSTR were incorporated into the soil to study nitrogen and sulphur dynamics and availability over 80 days. Results show that ensiling of straw increased net inorganic nitrogen release in soil and reduced net inorganic sulphur immobilisation compared to the non-ensiled straw. Brown juice-assisted ensiling of straw at the lab-scale level significantly increased methane production by 14 % and increased hydrolysis and methane production rates compared to non-ensiled straw. These results demonstrate that ensiling of straw has the potential as a pre-treatment technique for enhanced biogas production and higher nutrient availability in digestates for crop production and provides an opportunity to valorise brown juice as an ensiling additive.

During the last years the application of biochar to arable land has been suggested as a method to improve soil fertility and plant growth, reduce greenhouse gas emissions and sequester carbon for centuries. The rapid increase in the interest in biochar means that empirical documentation and mechanistic understanding need to be assessed continuously. In the present report, background and current knowledge have been synthesized in relation to the use of biochar in agricultural soils primarily under Danish conditions and based on major streams of available feedstock. The report also features an economical assessment and points to areas with knowledge gaps where better documentation and research is needed in relation to the pyrogenic carbon capture and storage as well as the persistent effects of biochar on soil ecosystem services

Biogas er vedvarende energiproduceret ved at fordøje biomasse under anaerobe forhold. Husdyrgødning, spildevand og vådt organisk affald fra industrien og husholdningerne kan anvendes i produktionen, som så også fungerer som affaldsbehandling.Når husdyrgødning leveres til biogasproduktion, reduceres udledningen af drivhusgasser fra husdyr. Processen gør også næringsstofferne i gylle mere tilgængelige for planter. Omfanget af biogassens drivhusgas- og miljøpåvirkning afhænger af produktionskarakteristikaene, herunder navnlig de anvendte biomasseer. Desuden er faktorer som transport, procesenergiforbrug og eventuelt metanetab fra anlægget inkluderet. Kvantificeringen af biogasproduktionens drivhusgas- og miljøvirkninger udgør et vigtigt grundlag for at udforme og målrette fremtidig biogasfinansiering for at optimere de klima- og miljømæssige fordele ved produktionen. Rapporten præsenterer en analyse af biogasproduktionens virkninger baseret på husdyrgødning og forskellige relevante typer biomasse fra affaldshåndtering og landbrug. Virkningerne er beskrevet for fem model biogasanlæg med forskellige biomassesammensætninger.