In this paper, a laboratory-scale experimentation allowed comparing the performances of two upflow anaerobic packed-bed filters filled with different packing materials and operating at mesophilic conditions (30 degreeC) for treating slaughterhouse wastewaters. Methane production was experimentally evaluated considering different volumetric organic loading rates as well as feeding overloading conditions. Although filter performances declined with loading rates higher than 6 kg CODin m-3 d-1 , the chemical oxygen demand (COD) removal efficiency remained always above 60%. The experimental results allowed for determining kinetic parameters for bacterial growth rate and methane production, following Monod and Chen-Hashimoto models, respectively. Results demonstrated that the reactors reached a cellular retention time significantly greater than the hydraulic retention time. The kinetic parameter values (Ks, l/max) revealed the low microorganisms' affinity for the substrate and confirmed the moderate biodegradability of slaughterhouse wastewater. The kinetic analysis also allowed the comparison of the filters performances with another anaerobic system and the assessment of the parameters useful for real-scale plant design. The system design, applied to a medium-sized Argentinean slaughterhouse, demonstrated to (i) be energetically self-sufficient and (ii) contribute to the plant's water heating requirements.

Using a factorial design: two full floor types, concrete vs. concrete waterproofed with resin (resin floor) and two slat types, concrete vs. metal, were used to house 72 pigs in four rooms (18 pigs room -1 ). During the experimental period which lasted from 22.9 kg to 112.7 kg live weight the four groups of pigs received the same feed. Growth, water consumption and health status of the pigs as well as subjective odour level inside the rooms were studied. The resin floor with metal slats tended (P < 0.1) to improve feed conversion efficiency and positively affected (P < 0.03) pig health. In the room with the resin floor and metal slats odour level was significantly lower than in the other three rooms. The potential predictive function for the relationship between average daily water consumption (WC, in L) and feed average daily intake (FADI, in kg) is WC = 2.692 x FADI 1.265 . Odour level increased with pig live weight. The use of resin as an impermeable floor material is promising for housing growing, finishing pigs. Additional key words: odour level, production results, resin floor, sanitary status, water consumption. ResumenEfecto del tipo de suelo sobre los resultados productivos y estado sanitario de cerdos en crecimiento y acabado Bajo un tratamiento factorial: dos tipos de suelo, hormigón vs hormigón impermeabilizado con resina (suelo de resina) y dos tipos de rejilla, hormigón vs metálica, 72 cerdos fueron alojados en cuatro salas (18 cerdos por sala). Durante el periodo experimental, comprendido entre 22,9 y 112,7 kg de peso vivo los cuatro grupos de cerdos recibieron el mismo tipo de pienso. Se estudió el crecimiento, el consumo de agua y el estado sanitario de los cerdos, así como el nivel subjetivo de olor en el interior de las salas. El suelo de resina y la rejilla metálica tendieron (P < 0,1) a mejorar el índice de transformación del alimento y afectaron positivamente, a un nivel significativo (P < 0,03), al estado sanitario de los cerdos. En la sala de suelo de resina y rejilla metálica el nivel de olor fue significativamente más bajo que en las restantes. La relación entre el consumo de agua y de pienso se ajustó a una función potencial. El nivel de olor aumentó con el peso vivo de los cerdos. La utilización de resina como material impermeabilizante del suelo es prometedora para los alojamientos de cerdos de cebo.Palabras clave adicionales: consumo de agua, nivel de olor, resultados productivos, sanidad, suelo de resina.Abbreviations used: ADG (average daily gain), FADI (feed average daily intake), FCE (feed conversion efficiency), ME (metabolizable energy), SEM (standard error of mean), WC (water consumption).