Utilization of by products of the tequila industry. Part 11. Raw agave bagasse and biosolids composting from a tequila vinasses treatment plant [Utilizaci�n de subproductos de la industria tequilera. Parte 11. compostaje de bagazo de agave crudo y bios�lidos provenientes de una planta de tratamiento de vinazas tequileras]

Abstract

A field study was conducted for composting raw agave bagasse using water or biosolids to maintain the process's moisture. Eight 30-ton piles of bagasse were composted. Piles 1-4 were moved once a week for aeration and addition of water or biosolids. Pile 1 was added with 1560 L of tap water and piles 2-4 with 1560, 3120 and 4680 L of biosolids, respectively. Piles 5-8 were added with the same amount of water or biosolids quantity, but were moved every two weeks. The piles' temperature was measured every third day and the average of six sensors was plotted according to the composting time. Every seven or 14 days, depending on the turning time, samples from four points of each pile were taken for moisture, pH and electric conductivity analyses. At the end of the composting period, the color, smell and texture of the composts from the piles became similar to gardening soil. At this point composite samples were taken for microbiological, granulometric and chemical analysis. The ratio of raw agave bagasse (kg) / water or biosolids (L) added to the piles of each treatment (1-8) was 1/0.728, 1/0.676, 1/1.04, 1/1.56, 1/0.52, 1/0.364, 1/0.572 and 1/0.858, respectively. If the latter ratio is considered to add vinasses (as currently practiced in the tequila industry) instead of biosolids, and the 2011 CRT statistic with regards to bagasse and vinasse production is considered, it is concluded that only 59.6 % of vinasses produced could be disposed in the composting of bagasse, while the remaining 40.4 % would require a different kind of disposal.