Co-composting rice hulls and/or sawdust with poultry manure in NE Argentina.

Rice hulls and sawdust are two common C-rich wastes derived from rice and timber agro-industries in subtropical NE Argentina. An alternative to the current management of these wastes (from bedding to uncontrolled burning) is composting. However, given their C-rich nature and high C/N ratio, adequate composting requires mixing with a N-rich waste, such as poultry manure. The effect of different proportions of poultry manure, rice hulls and/or sawdust on composting efficiency and final compost quality was studied. Five piles were prepared with a 2:1 and 1:1 ratio of sawdust or rice hulls to poultry manure, and 1:1:1 of all three materials (V/V). Different indicators of compost stability and quality were measured. Thermophilic phase was shorter for piles with rice hulls than for piles with sawdust (60 days vs. 105 days). Time required for stability was similar for both C-rich wastes (about 180 days). Characteristics of final composts were: pH 5.8-7.2, electrical conductivity 2.5-3.3 mS/cm, organic C 20-26%, total N 2.2-2.9%, lignin 19-22%, total Ca 18-24 g/kg, and extractable P 6-8 g/kg, the latter representing 60% of total P. Nitrogen conservation was high in all piles, especially in the one containing both C-rich wastes. Piles with sawdust were characterized by high total and available N, while piles with only rice hulls had higher Si, K and pH. Extractable P was higher in 1:1 piles, and organic C in 2:1 piles.

Composting of fish offal and biosolids in northwestern Patagonia.

Composting of fish processing wastes and biosolids with wood by-products and yard trimmings was conducted during the summer of 1996 and winter of 1997 in NW Patagonia using: (i) static piles for fish offal and (ii) turning piles for biosolids. Fish offal was mixed with sawdust + wood shavings (FOC) at 3:1 ratio by weight and biosolids with wood shavings (BCw) and yard trimmings (BCt) at 1:1 ratio by volume. Samples were taken at six dates during the composting period and analyzed to determine the factors that predict compost maturity. Composting of biosolids was affected by the type of bulking agent during winter. Thermophilic temperatures > or = 55 degrees C were sustained long enough to satisfy the USEPA requirements for processes to further reduce pathogens (PFRP) in FOC and BCt, and for processes to significantly reduce pathogens (PSRP) in summer BCw, while in winter BCw temperatures were lower than those recommended for effective pathogen reduction. However, coliform fecal content in all BC treatments was less than 10 most probable number (MPN) g(-1) dry sample at the end of the process. The ratio of water soluble carbon (WSC) to total nitrogen (TN) appeared to be a more adequate index to predict compost maturity than the ratio of total organic carbon to nitrogen.

Compostaje como alternativa de manejo de biosolidos: la experiencia de Bariloche

Por pedido de la empresa responsable de la Planta de Saneamiento de Bariloche (SURBASA) y mientras finalizaba su construccion, el Grupo de Suelos del CRUB inicio estudios de compostaje de biosolidos en 1995. Estas experiencias se realizaron en base a lodos provenientes de plantas de tratamiento de la region. En 1997 SURBASA construyo la Planta de Compostaje de Lodos de la Ciudad de Bariloche, la primera del pais con controles segun exigencias de organismos internacionales. La experiencia constituye un ejemplo de la posible colaboracion entre empresas privadas e instituciones publicas

Lodos cloacales en Bariloche: de residuos peligrosos a recurso agronómico

Se presenta este trabajo, donde se han utilizado materiales cloacales provenientes de distintas plantas de tratamiento de liquidos cloacales de Bariloche. Los estudios incluyen -analisis del contenido de nutrientes, de elementos pesados y de patogenos, -estudios de laboratorio e invernáculo, -estrategias de manejo. Los resultados preliminares obtenidos en base estas experiencias han permitido la elaboracion de un plan de manejo de lodos de la ciudad en un emprendimiento en comun entre SURBASA S.A. y un empresario local, que actualmente se encuentra en fase de evaluacion del impacto ambiental en la Municipalidad de S.C. de Bariloche

Lodos cloacales en Bariloche: de residuos peligrosos a recurso agronómico

Se presenta este trabajo, donde se han utilizado materiales cloacales provenientes de distintas plantas de tratamiento de liquidos cloacales de Bariloche. Los estudios incluyen -analisis del contenido de nutrientes, de elementos pesados y de patogenos, -estudios de laboratorio e invernáculo, -estrategias de manejo. Los resultados preliminares obtenidos en base estas experiencias han permitido la elaboracion de un plan de manejo de lodos de la ciudad en un emprendimiento en comun entre SURBASA S.A. y un empresario local, que actualmente se encuentra en fase de evaluacion del impacto ambiental en la Municipalidad de S.C. de Bariloche