Jesús M. Martín-Marroquín

Livestock Waste: Fears and Opportunities

One of the common tendencies of livestock activities in developed countries is to intensify the animal production and to increase the size of the production units. High animal density is always accompanied by production of a surplus of manure, representing a considerable pollution threat for the environment in these areas. Intensive animal production needs therefore suitable manure management, aiming to optimise their recycling. Treatment technologies can play an important role in the management of livestock manure by providing a more flexible approach to land application and acreage limitations, and by solving specific problems such as odours, pathogens, water pollution, ammonia emissions, greenhouse gas emissions, and phosphorus and heavy metal contamination of soils. Treatment can be enhanced with the use of biological, chemical, and physical methodologies, especially in combination as part of holistic systems. This chapter discusses sustainable treatment practices, emerging technologies, and holistic systems to solve related problems and to provide direction on animal waste treatment systems of the future.

Anaerobic co-digestion of agro-food waste mixtures in a fed-batch basis

ABSTRACT The agro-food industry (including livestock) generates millions of tonnes of waste products. A solution to this sectors waste disposal challenges was explored by a joint treatment model of organic waste products from several industries. An inventory of agro-food industry organic waste streams with high potential for biogas production was carried out in a logistically viable area (Cider Region, Asturias, Spain). Three industries were selected as those with the higher potential for this study: livestock, dairy and beverage. The kinetics of anaerobic degradation and methane production of four mixtures of selected waste streams were investigated. The specific methane production at five different substrate-to-inoculum ratios (0.50, 0.75, 1.00, 1.50 and 2.00) showed a slightly decreasing trend at the higher ratios. Some hints of a synergistic effect have been observed in mixtures with higher content in milled apple waste, while antagonistic symptoms were noted in mixtures mainly composed of dairy wastes. The estimation of fluxes of waste and methane potentials in the Cider Region suggests centralised anaerobic digestion as a sustainable solution for the valorisation of livestock and agro-food wastes generated in this area. Sector-specific waste streams (livestock and agro-food industry) could cover up to 12% of regional total energy demand.