ArticleRound goby
(Neogobius melanostomus
) is an
invasive fish species in the Baltic Sea.
While meat can be used for human consumption, fish processing residues are considered as a
waste. Within circular economy and bio
-
economy perspectives fish waste could be used as a
valuable feedstock for biogas prod
uction. However, the research is mostly focused on evaluating
biogas yield at mesophilic conditions (i.e. 37
°C
). In this study the impact of low temperature on
Biochemical Methane Potential (BMP) tests has been investigated. Round goby’s processing
leftov
ers
-
heads, intestines and skin/bone mixture were tested in codigestion with sewage sludge.
Anaerobic digestion (AD) was carried out in 100
mL batch tests at low temperature 23
°C
and
37
°C
conditions, over an incubation period of 31 days. The results sho
w that AD at low
temperature occurs twice as slowly as under 37
°C
conditions. However, after 31 days the BMP
values for 23
°C
samples were only 2% lower than for high temperature samples. Heads and skins
showed similar BMP values
reaching on average 502
L
CH
4
kg
VS
-
1
and 556
L
CH
4
kg
VS
-
1
respectively. BMP for fish intestines was higher, reaching on average 870
L
CH
4
kg
VS
-
1
. Average
BMP for mixes of fish heads, skins, intestines and bones was 660
L
CH
4
kg
VS
-
1
. Acquired BMPs
were further compared with the theoretical BMPs from Buswell's formula. Research results
suggests that anaerobic digestion of fish waste under low temperature conditions could be feasible
as the process still efficiently occurs, in fact ope
ning a new opportunity to explore the overall
sustainability of technologies based on these conversion processes
