Manure treatment to recover nutrients presents a great
challenge
to delocalize nutrients from overloaded areas to those needing such
nutrients. To do this, approaches for the treatment of manure have
been proposed, and currently, they are mostly under investigation
before being upgraded to full scale. There are very few fully operating
plants recovering nutrients and, therefore, very few data on which
to base environmental and economic studies. In this work, a treatment
plant carrying out full-scale membrane technology to treat manure
to reduce its total volume and produce a nutrient-rich fraction, i.e.,
the concentrate, was studied. The concentrate fraction allowed the
recovery of 46% of total N and 43% of total P. The high mineral N
content, i.e., N-NH4/total-N > 91%, allowed matching
the
REcovered Nitrogen from manURE (RENURE) criteria proposed by the European
Commission to allow the potential substitution of synthetic chemical
fertilizers in vulnerable areas characterized by nutrient overloading.
Life cycle assessment (LCA) performed by using full-scale data indicated
that nutrient recovery by the process studied, when compared with
the production of synthetic mineral fertilizers, had a lower impact
for the 12 categories studied. LCA also suggested precautions which
might reduce environmental impacts even more, i.e., covering the slurry
to reduce NH3, N2O, and CH4emissions
and reducing energy consumption by promoting renewable production.
The system studied presented a total cost of 4.3 € tons–1of slurry treated, which is relatively low compared
to other similar technologies.