Anaerobic digestion of vegetables processing wastes with catalyst metaferm
Latvia University of Agriculture, Faculty of Engineering, Institute of Agriculture Energetics, 5, Cakstesblvd, LV3001 Jelgava, Latvia *Correspondence: vilisd@inbox.lv
Abstract:
There are 54 active biogas plants in Latvia today. It is necessary to investigate the suitability of various biomasses for energy production. Maize is the dominating crop for biogas production in Latvia. The cultivation of more varied crops with good economical characteristics and a low environmental impact is thus desirable. One of the ways for improving biogas yield in Latvian conditions is using biological catalysts. This paper explores the results of the anaerobic digestion of vegetables’ processing wastes using the new biological catalyst Metaferm. The digestion process was investigated in view of biogas production in sixteen 0.7 l digesters operated in batch mode at the temperature of 38 ± 1.0 °C. The average methane yield per unit of dry organic matter added (DOM) from the digestion of onions was 0.433 l g–1DOM; with 1 ml ofMetaferm: 0.396 l g–1–1DOM, and with 2 ml of Metaferm: 0.394 l gDOM . The average methane yieldfrom the digestion of carrots was 0.325 l g–1–1DOM; with 1 ml of Metaferm: 0.498 l gDOM , and with2 ml of Metaferm: 0.426 l g–1DOM. The average additional methane yield per unit of dry organicmatter from the digestion of 50%:50% mixed onions and carrots was 0.382 l g–1DOMwith 2 mlof Metaferm. The average additional methane yield per unit of dry organic matter from the digestion of cabbage leftovers was 0.325 l g–1–1DOM; with 1 ml of Metaferm: 0.375 l gDOM , andwith 2 ml of Metaferm: 0.415 l g–1DOM. The average additional methane yield per unit of dryorganic matter from the digestion of potato cuttings was 0.570 l g–1DOM; with 1 ml ofMetaferm: 0.551 l g–1–1DOM, and with 2 ml of Metaferm:0.667 l gDOM . The average additionalmethane yield per unit of dry organic matter from the digestion of 50%:50% mixed cabbages and potatoes was 0.613 l g–1DOMwith 2 ml of Metaferm. All investigated vegetable wastes canbe successfully cultivated for energy production under agro-ecological conditions in Latvia. Adding the catalyst Metaferm increased methane yield, except for onions.
Key words:
anaerobic digestion, biogas, biological catalyst., cabbage, carrot, methane, onion, potato