Post by jeff on Jan 6, 2018 17:54:37 GMT
SUMMARY
Nowadays, with the rapid development of aquaculture and fishery, amount disposals
of fish waste and by-catch are causing pollution and negative impact on the marine
environment, such as the Baltic Sea.
As to handle this serious problem, the anaerobic digestion of fish waste and by-catch
were proposed. It could not only reduce the pollution by discard of fish waste and bycatch,
but also reproduce valuable substances such as CH4 used as alternative energy
or fuels for vehicles, and the rest digested substrates and liquid used as fertilizer.
Those products could be obtained by digested a large amount of organic compounds
in the oxygen free condition.
The purpose of this project is to optimize biogas production based on adjusting the
proportion among fish waste, by-catch and sludge. By the commission of the fishery
industry in Simrishamn, the project was carried out at the Swedish Environmental
Research Institute (IVL) in Hammarby Sjöstadsverk by thesis worker at the Royal
Institute of Technology (KTH).
There were two test series based on the proportion of sludge wet weight, i.e. 33 % and
50 %. In each, five experiments were made based on the ratio between by-catch and
fish waste wet weight, i.e. 1:0, 2:1, 1:1, 1:2 and 0:1. The sludge was the secondary
sludge from Simrishamn WWTP, and the cod intestine and meat from Simrishamn
were used to represent fish waste and by-catch respectively. All the bacteria or cells
used for decomposition of organic substance were incubated from the previous
studies. The ratio between inoculums and substrates was 3:2.
The project was conducted in the laboratory scale by using Automated Methane
Potential Test System (AMPTS II) from the Bioprocess Control Sweden Company,
which was followed the principle of conventional Biochemical Methane Potential test
but stripping the CO2 and H2S gases out before measuring the produced methane
volume. The substrates and inoculums were poured into reactors which were put in
the thermal water basin at 37 ± 0.5 ºC and stirred by rotating agitator every one
minute. The produced gas would flow through connected tubes into corresponding
vials, which contained NaOH solutions to eliminate the effect of CO2 and H2S. The
final pure CH4 was measured based on the liquid displacement by flow cells inside the
water basin. The defined gas volume was recorded as a digital pulse. It was produced
by clicked back down the lifted flow cell. Finally, the data was collected automatically
by the pre-set program. When the computer was connected with the equipment, the
treated data was displayed as figures.
The optimal methane potential obtained after an experiment with 13 days digestion
was 0.533 Nm3 CH4/kg VS, produced from the composition of sludge, by-catch and
fish waste as 33 %, 45 % and 22 %. It was improved by 6 % and 25.6 %, to compare
with the previous studies by Almkvist (2012) and Tomczak-Wandzel (personal
communication, February 2012) respectively. In addition, less sludge was suggested to
be mixed with fish waste and by-catch but no less than the needed quantity.
Moreover, the cod intestine had an advantage in promoting the hydrolysis of
substrate, because it included a large number of enzymes promoting. Therefore, it was
the necessary substrates that should be added. Furthermore, the inoculums were used
from the previous studies which could improve the adaptability of microorganism in
such tough circumstances.
However, some errors existed during the operation of the experiment such as weight
errors and the inoculums used in different times of incubating. Those should be
avoided or reduced by some ways. Besides, the volatile solid removal could not be
used alone for evaluating the biodegradability of substrate due to its overestimation
and inaccuracy when make the analysis of few digestate.
www.facebook.com/download/preview/141556483225154
Nowadays, with the rapid development of aquaculture and fishery, amount disposals
of fish waste and by-catch are causing pollution and negative impact on the marine
environment, such as the Baltic Sea.
As to handle this serious problem, the anaerobic digestion of fish waste and by-catch
were proposed. It could not only reduce the pollution by discard of fish waste and bycatch,
but also reproduce valuable substances such as CH4 used as alternative energy
or fuels for vehicles, and the rest digested substrates and liquid used as fertilizer.
Those products could be obtained by digested a large amount of organic compounds
in the oxygen free condition.
The purpose of this project is to optimize biogas production based on adjusting the
proportion among fish waste, by-catch and sludge. By the commission of the fishery
industry in Simrishamn, the project was carried out at the Swedish Environmental
Research Institute (IVL) in Hammarby Sjöstadsverk by thesis worker at the Royal
Institute of Technology (KTH).
There were two test series based on the proportion of sludge wet weight, i.e. 33 % and
50 %. In each, five experiments were made based on the ratio between by-catch and
fish waste wet weight, i.e. 1:0, 2:1, 1:1, 1:2 and 0:1. The sludge was the secondary
sludge from Simrishamn WWTP, and the cod intestine and meat from Simrishamn
were used to represent fish waste and by-catch respectively. All the bacteria or cells
used for decomposition of organic substance were incubated from the previous
studies. The ratio between inoculums and substrates was 3:2.
The project was conducted in the laboratory scale by using Automated Methane
Potential Test System (AMPTS II) from the Bioprocess Control Sweden Company,
which was followed the principle of conventional Biochemical Methane Potential test
but stripping the CO2 and H2S gases out before measuring the produced methane
volume. The substrates and inoculums were poured into reactors which were put in
the thermal water basin at 37 ± 0.5 ºC and stirred by rotating agitator every one
minute. The produced gas would flow through connected tubes into corresponding
vials, which contained NaOH solutions to eliminate the effect of CO2 and H2S. The
final pure CH4 was measured based on the liquid displacement by flow cells inside the
water basin. The defined gas volume was recorded as a digital pulse. It was produced
by clicked back down the lifted flow cell. Finally, the data was collected automatically
by the pre-set program. When the computer was connected with the equipment, the
treated data was displayed as figures.
The optimal methane potential obtained after an experiment with 13 days digestion
was 0.533 Nm3 CH4/kg VS, produced from the composition of sludge, by-catch and
fish waste as 33 %, 45 % and 22 %. It was improved by 6 % and 25.6 %, to compare
with the previous studies by Almkvist (2012) and Tomczak-Wandzel (personal
communication, February 2012) respectively. In addition, less sludge was suggested to
be mixed with fish waste and by-catch but no less than the needed quantity.
Moreover, the cod intestine had an advantage in promoting the hydrolysis of
substrate, because it included a large number of enzymes promoting. Therefore, it was
the necessary substrates that should be added. Furthermore, the inoculums were used
from the previous studies which could improve the adaptability of microorganism in
such tough circumstances.
However, some errors existed during the operation of the experiment such as weight
errors and the inoculums used in different times of incubating. Those should be
avoided or reduced by some ways. Besides, the volatile solid removal could not be
used alone for evaluating the biodegradability of substrate due to its overestimation
and inaccuracy when make the analysis of few digestate.
www.facebook.com/download/preview/141556483225154