Increased production of biogas in Sweden has led to adjustments and increased use of biofertilisers. RISE and Avfall Sverige have established certification to ensure that the biofertilisers are of good quality.
Waste streams from households, food industries and slaughterhouses have been mainly processed through composting. Two products are now being produced – biogas and biofertilisers. The process involves anaerobic digestion and has the advantage of both providing plant nutrients for agriculture as well as energy.
Furthermore, biofertilisers are used as substitutes for mineral fertilisers, which are energy-intensive to produce, that may contain high levels of cadmium and that contain phosphorus, which is a finite resource. But there is no legislation regulating the content of biofertilisers, which has created a lack of clarity for users.¨
Certification guarantees quality
To clarify quality for farmers using biofertilisers, a certification system was established in 1999. The system, which is voluntary, is used by biogas plants producing biofertilisers. Certification guarantees, among other things, that biofertilisers do not contain infectious agents such as E. coli bacteria and salmonella, and is within the limit values for heavy metals such as lead, cadmium and mercury.
Avfall Sverige, the municipal branch organisation for waste management and recycling, and RISE have established certification. RISE serves as an independent certification body, which means that we carry out annual monitoring and also issue and administer the certificates.
“This is a continuous task,” says Caroline Steinwig, advisor for biological recycling at Avfall Sverige. “RISE has broad expertise and is also involved in individual projects that we conduct in biogas and recycling. Thus far, 23 plants have been certified of a total of about 30 in Sweden.”