After the characterizaton of different byproducts from the production of wine and beer, three by-products were choosen for being composted: pure beer bagasse, residual beer bagasse (with some plastics) and dry grape pomace. Three mixtures were composted at intermediate scale (5 m3) using two by-products, being always one of them (dry grape pomace) a product rich in carbon and low in moisture. The composting has been monitored during six months to check if the ammonium N of the mixtures of such vegetable products (particulary beer bagasse) can be nitrified within the composting process; this fact has previouslly been tested in other by-products like manure.
The results confirm the hypothesis and three nitrified compost, with different nitrate levels, have been obtained. The intense nitrification in one of the composting piles has led to the slight acidification of this compost, which can be a consequence of the mentioned process.
