THE POTENTIAL USAGE OF DUCKWEED BIOMASS (Lemna minor) FOR BIOGAS PRODUCTION

Vodena leća je sitna slobodno plivajuća vodena biljka koja nastanjuje mirne ribnjake bogate nutrijentima. Nagli reproduktivni kapacitet vodene leće može potpuno prekriti ribnjak u samo nekoliko tjedana a ta pojava ne predstavlja samo estetski problem već ljeti može izazvati i pomor riba u ribnjaku pa je stoga nužno redovito je uklanjati. U ovom radu cilj je bio utvrditi potencijal vodene leće za proizvodnju bioplina u usporedbi s kukuruznom silažom čija je uporaba u te svrhe vrlo često osporavana budući da kukuruz predstavlja jednu od glavnih žitarica u ljudskoj i prehrani životinja. Vodena leća se svrstava u drugu generaciju biogoriva te se stoga može smatrati vrlo poželjnom sirovinom za proizvodnju bioplina. Prinos bioplina kukuruzne silaže iznosi 180 m3/t dok su prinosi vodene leće neznatno manji, 176 m3/t. Sukladno prinosu bioplina vodene leće napravljeni su proračuni o isplativosti njezina uzgoja na ribnjacima u HR, troškovima izgradnje i proizvodnji energije u tri bioplinska postrojenja snage 1 MW pri čemu su uzeti u obzir troškovi prikupljanja, transporta i manipulacije tom sirovinom.Duckweed is a tiny free-floating aquatic plant which is typically found in quiet, nutrient rich ponds. The plants explosive reproductive capacity can make a pond completely covered in just a few weeks and this not only causes aesthetic problems, but summer fish kills are common too, so it is necessary to regularly remove it. The aim of this study was to determine the duckweed potential for biogas production compared to corn silage whose use for this purposes is often disputed because corn is one of the major cereals in human and animal nutrition. Duckweed is classified as a second generation of biofuels so it could be considered highly desirable feedstock for biogas production. The biogas yield of corn silage amounts to 180 m3/t while the yield of duckweed is slightly smaller, 176 m3/t. According to biogas yield of duckweed calculations of profitability of its cultivation on the fishponds in Croatia, construction costs and energy production in three biogas plants of 1 MW power were performed, also considering costs for collecting, transportation and manipulation of this feedstock