fibres to retailers such as Walmart, as well as produced nitrogen and phosphorus to
offset commercial fertilisers. Carbon reductions can be also sold as offsetting
credits. In this business model, dairy farms and food companies achieved GHG
reduction targets and investors profit by converting waste into product, which meet
green supplier criteria. Target incentives, collaboration along supply chain, and a
business model that balances business risk and opportunities largely contributed to
the success. The AgSTAR project of the U.S. EPA [3] analysed the possibility of
installing anaerobic digesters with energy generation and nutrient capture in confined animal feeding operations with 500+ cows in the US, suggesting 2647
digesters to be installed nationwide. By implementing the proposed business model
to dairy operations and 3rd party digester companies, it could potentially generate
12 Mio MWh of electricity, and also 42 Mio metric tons of CO 2 offsetting credits
annually, mainly driven by reducing methane emissions from landfilling food waste
and manure lagoons, and also avoiding grid electricity production.
4 The Role of Composting in a Circular Economy
A decline in soil organic matter (SOM) can be observed in Europe. It is one of the
most important indicators for soil quality which hugely affects the agricultural sector
and bio-economy. The sustainable management of SOM is an explicit requirement
of several international standards and programmes e.g. the EC 16752 Bio-based
product sustainability criteria. Food waste and garden waste are common feedstocks
for the production of compost. The waste material is collected and biologically
treated. The produced compost contains nutrients and humic substances which
directly contribute to increase the SOM pool in the soil. Applying compost to
agricultural land contributes to improved soil quality and thus bio-economy.
Compost use also affects the GHG balance of crops since 58% of SOM is carbon.
Francesco Razza reported on a case study where compost is applied in a cardoon
cropping system in North-East Sardinia. The crop system consists of a rotation of
6 years of cardoon, 1 year of durum wheat and 1 year of field bean, analysed over a
time frame of 22 years. One ‘compost’ scenario, where compost is applied during
the 1st and the 4th year of cardoon is compared to a ‘no compost’ scenario, where the
only organic matter contribution was from above-ground biomass left in the soil after
harvest. The trials showed clearly higher levels in SOM increasing steadily over the
time frame of 22 years (carbon stock changes are generally calculated over a time
frame of 20 years). A GHG balance of the above crop system also showed benefits
for the application of compost: CO 2 uptakes linked to the increase of SOM in soil
have the same order of magnitude as the overall cardoon “Cradle to gate” GHG
emissions. Consequently, taking into account SOM dynamics compost scenario
shows a reduction of its carbon footprint of 70% compared to ‘no compost’ scenario.
Putting this research into the bigger European context shows that only about 1/3
of municipal bio-waste is collected and recycled into high quality compost and
digestate while demand for compost clearly outstrips availability. A better
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N. Unger and F. Razza
offset commercial fertilisers. Carbon reductions can be also sold as offsetting
credits. In this business model, dairy farms and food companies achieved GHG
reduction targets and investors profit by converting waste into product, which meet
green supplier criteria. Target incentives, collaboration along supply chain, and a
business model that balances business risk and opportunities largely contributed to
the success. The AgSTAR project of the U.S. EPA [3] analysed the possibility of
installing anaerobic digesters with energy generation and nutrient capture in confined animal feeding operations with 500+ cows in the US, suggesting 2647
digesters to be installed nationwide. By implementing the proposed business model
to dairy operations and 3rd party digester companies, it could potentially generate
12 Mio MWh of electricity, and also 42 Mio metric tons of CO 2 offsetting credits
annually, mainly driven by reducing methane emissions from landfilling food waste
and manure lagoons, and also avoiding grid electricity production.
4 The Role of Composting in a Circular Economy
A decline in soil organic matter (SOM) can be observed in Europe. It is one of the
most important indicators for soil quality which hugely affects the agricultural sector
and bio-economy. The sustainable management of SOM is an explicit requirement
of several international standards and programmes e.g. the EC 16752 Bio-based
product sustainability criteria. Food waste and garden waste are common feedstocks
for the production of compost. The waste material is collected and biologically
treated. The produced compost contains nutrients and humic substances which
directly contribute to increase the SOM pool in the soil. Applying compost to
agricultural land contributes to improved soil quality and thus bio-economy.
Compost use also affects the GHG balance of crops since 58% of SOM is carbon.
Francesco Razza reported on a case study where compost is applied in a cardoon
cropping system in North-East Sardinia. The crop system consists of a rotation of
6 years of cardoon, 1 year of durum wheat and 1 year of field bean, analysed over a
time frame of 22 years. One ‘compost’ scenario, where compost is applied during
the 1st and the 4th year of cardoon is compared to a ‘no compost’ scenario, where the
only organic matter contribution was from above-ground biomass left in the soil after
harvest. The trials showed clearly higher levels in SOM increasing steadily over the
time frame of 22 years (carbon stock changes are generally calculated over a time
frame of 20 years). A GHG balance of the above crop system also showed benefits
for the application of compost: CO 2 uptakes linked to the increase of SOM in soil
have the same order of magnitude as the overall cardoon “Cradle to gate” GHG
emissions. Consequently, taking into account SOM dynamics compost scenario
shows a reduction of its carbon footprint of 70% compared to ‘no compost’ scenario.
Putting this research into the bigger European context shows that only about 1/3
of municipal bio-waste is collected and recycled into high quality compost and
digestate while demand for compost clearly outstrips availability. A better
130
N. Unger and F. Razza