Storskarven Phalacrocorax carbo sinensis vid den österbottniska kusten

Den snabba tillväxten av häckande storskarv (underarten Phalacrocorax carbo sinensis) i Finland och även i Österbotten har orsakat konflikter för fiske och rekreation, speciellt i de områden där skarven häckar. År 2014 häckade drygt 20 000 par Storskarvar i Finland och knappt 10 % av dessa, eller 1 980 par i Österbotten. Storskarven hör till de fredade fågelarterna. Det är möjligt att ansöka om undantag från fredningen, om den fredade arten anses orsaka allvarlig skada. Regler som styr förvaltningen av skarv bygger på EU:s fågeldirektiv och nationell lagstiftning samt vägledningsdokument för hur dessa bör tolkas vid handläggning om undantag från fred-ning. I områden där skarvkolonierna vuxit sig stora har lokala intressenter för fiske och markägo ansökt om undantag från fridlysning enligt NvL 39 §. Enligt besvär som inlämnats mot besluten om undantag från fridlysning samt prövning i högre rättsinstans, har sådan allvarlig skada, som enligt fågeldirektivet möjliggör undantag, inte kunnat påvisas. ERUF-projektet ”Storskarven vid den österbottniska kusten” möjliggjorde en omfattande inventering av skarvbeståndet och dess ungpro-duktion, samt en utredning om skarvens inverkan på fisket med hjälp av enkäter och fångststatistik. För att komplettera utredningarna och kunskapsunderlaget inbjöds även sakkunniga att föreläsa för styrgruppen för projektet. En bättre växelverkan och kommunikation mellan olika intressegrupper har uppnåtts i och med projektet. Projektet har medgett en öppen dialog mellan representanter för lokala intresseföreningar och tjänstemän för myndigheterna. Trots olika värderingar och åsikter har de olika intressenterna en gemensam kunskapsbas att utgå ifrån. I rapporten konstateras att det i nuläget saknas sådana kriterier som enligt nuvarande lagstiftning skulle medge en reglering av skarvbeståndet vid den Österbottniska kusten. De skador som rapporterats på fisket skulle kräva bättre dokumentation och tilläggsutredningar, alternativt borde kriterierna i lagstiftningen omformuleras. Under projektets gång har det också framkommit att skarven inte enbart anses påverka fisket utan att acceptansen av skarvens närvaro också har en social di-mension. I rapporten har sammanställts en vision om ett skarvbestånd med möjligast små skade-effekter. Biologiska faktorer som styr beståndets tillväxt samt metoder för att förhindra skador på fisket presenteras. Styrgruppen har även sammanställt förslag på åtgärder på regional, nationell och EU nivå.

Chemical changes in biomass during torrefaction

Torrefaction is moderate thermal treatment (~200-300 °C) of biomass in an inert atmosphere. The torrefied fuel offers advantages to traditional biomass, such as higher heating value, reduced hydrophilic nature, increased its resistance to biological decay, and improved grindability. These factors could, for instance, lead to better handling and storage of biomass and increased use of biomass in pulverized combustors. In this work, we look at several aspects of changes in the biomass during torrefaction. We investigate the fate of carboxylic groups during torrefaction and its dependency to equilibrium moisture content. The changes in the wood components including carbohydrates, lignin, extractable materials and ashforming matters are also studied. And at last, the effect of K on torrefaction is investigated and then modeled. In biomass, carboxylic sites are partially responsible for its hydrophilic characteristic. These sites are degraded to varying extents during torrefaction. In this work, methylene blue sorption and potentiometric titration were applied to measure the concentration of carboxylic groups in torrefied spruce wood. The results from both methods were applicable and the values agreed well. A decrease in the equilibrium moisture content at different humidity was also measured for the torrefied wood samples, which is in good agreement with the decrease in carboxylic group contents. Thus, both methods offer a means of directly measuring the decomposition of carboxylic groups in biomass during torrefaction as a valuable parameter in evaluating the extent of torrefaction. This provides new information to the chemical changes occurring during torrefaction. The effect of torrefaction temperature on the chemistry of birch wood was investigated. The samples were from a pilot plant at Energy research Center of the Netherlands (ECN). And in that way they were representative of industrially produced samples. Sugar analysis was applied to analyze the hemicellulose and cellulose content during torrefaction. The results show a significant degradation of hemicellulose already at 240 °C, while cellulose degradation becomes significant above 270 °C torrefaction. Several methods including Klason lignin method, solid state NMR and Py-GC-MS analyses were applied to measure the changes in lignin during torrefaction. The changes in the ratio of phenyl, guaiacyl and syringyl units show that lignin degrades already at 240 °C to a small extent. To investigate the changes in the extractives from acetone extraction during torrefaction, gravimetric method, HP-SEC and GC-FID followed by GC-MS analysis were performed. The content of acetone-extractable material increases already at 240 °C torrefaction through the degradation of carbohydrate and lignin. The molecular weight of the acetone-extractable material decreases with increasing the torrefaction temperature. The formation of some valuable materials like syringaresinol or vanillin is also observed which is important from biorefinery perspective. To investigate the change in the chemical association of ash-forming elements in birch wood during torrefaction, chemical fractionation was performed on the original and torrefied birch samples. These results give a first understanding of the changes in the association of ashforming elements during torrefaction. The most significant changes can be seen in the distribution of calcium, magnesium and manganese, with some change in water solubility seen in potassium. These changes may in part be due to the destruction of carboxylic groups. In addition to some changes in water and acid solubility of phosphorous, a clear decrease in the concentration of both chlorine and sulfur was observed. This would be a significant additional benefit for the combustion of torrefied biomass. Another objective of this work is studying the impact of organically bound K, Na, Ca and Mn on mass loss of biomass during torrefaction. These elements were of interest because they have been shown to be catalytically active in solid fuels during pyrolysis and/or gasification. The biomasses were first acid washed to remove the ash-forming matters and then organic sites were doped with K, Na, Ca or Mn. The results show that K and Na bound to organic sites can significantly increase the mass loss during torrefaction. It is also seen that Mn bound to organic sites increases the mass loss and Ca addition does not influence the mass loss rate on torrefaction. This increase in mass loss during torrefaction with alkali addition is unlike what has been found in the case of pyrolysis where alkali addition resulted in a reduced mass loss. These results are important for the future operation of torrefaction plants, which will likely be designed to handle various biomasses with significantly different contents of K. The results imply that shorter retention times are possible for high K-containing biomasses. The mass loss of spruce wood with different content of K was modeled using a two-step reaction model based on four kinetic rate constants. The results show that it is possible to model the mass loss of spruce wood doped with different levels of K using the same activation energies but different pre-exponential factors for the rate constants. Three of the pre-exponential factors increased linearly with increasing K content, while one of the preexponential factors decreased with increasing K content. Therefore, a new torrefaction model was formulated using the hemicellulose and cellulose content and K content. The new torrefaction model was validated against the mass loss during the torrefaction of aspen, miscanthus, straw and bark. There is good agreement between the model and the experimental data for the other biomasses, except bark. For bark, the mass loss of acetone extractable material is also needed to be taken into account. The new model can describe the kinetics of mass loss during torrefaction of different types of biomass. This is important for considering fuel flexibility in torrefaction plants.