Agriculture feedstocks

Crops

Large quantities of crop residues are derived from farms each year and often destroyed by burning or burial when they could alternatively be recycled to produce energy and fertiliser.  Most herbaceous crop residues are dry and thus most suited to combustion rather than anaerobic digestion.  However high moisture vegetables and fruit residues are ideal for recycling via anaerobic digestion.

Animal effluent

Animals produce excrement which can be recycled to produce energy and biofertiliser.  In the New Zealand context where farm animals are not contained the excrement is distributed directly onto the soil.  In this case the decomposition of the organic matter produces methane direct to atmosphere.  Where farm animals are contained for feeding or milking then the excrement can be easily collected for recycling into energy and high grade fertiliser.

Improving soil fertility

Soil management

Soil management can be improved when agriculture residues are collected and recycled into high grade fertiliser which can be used when and where it will give the most beneficial value to soils.

Biofertiliser

Processing of agricultural residual organic matter in an anaerobic digester produces biogas as well as the digestate. Digestate which meets specified criteria as to being safe to use as a biofertiliser on soils can be certified as a biofertiliser.

Producers of certified digestate biofertiliser can have their AD facilities accredited.

Farm scale AD plant

Guide for producing and using biogas and biofertiliser on farms

The Canadian Biogas Association has established a website for providing farmers with information that will help them to recycle their farm residues into biogas and biofertiliser. The website is the go-to source for agricultural biogas and biofertiliser information and connections in Canada - www.farmingbiogas.ca