RESUMEN
The negative environmental impacts associated with home composting may be due to the absence of a defined operation criteria for the degradation process. In addition to the potentially low environmental impact in terms of energy and water usage, which is minimal to the manufacture of the composting unit and avoiding the processing and transportation of waste or byproduct, composting at home can also promote a reduction in the emission of unpleasant gases. The proportion of the food waste and bulking agents in the composting mixture may be decisive to fulfill good practices of waste stabilization. The aim of this study was to investigate how different ratios of bulking agent and organic household waste can affect the progress and outcome of the composting process. Three treatments, varying in the ratio of rice husk: raw fruit and vegetable leftovers (70:30, 50:50, 30:70; v:v) were used in a home composting system on a pilot scale. Results show that the proportion of starting materials used in the composting mixture influenced the degradation of organic matter, nitrogen dynamics of the process and its toxicity on germinating plants. The proportions with greater amounts of food waste had higher concentrations of mineral matter, higher peak temperature, and a better initial carbon-to-nitrogen ratio, while the proportion containing 70% of bulking agent lacked odors and leachate generation and showed a low nitrogen loss. A higher proportion of food waste presented better conditions for microbiological development and less time to obtain characteristics of matured composts. A higher proportion of bulking agents resulted in favorable conditions for household handling and less potential for environmental impacts.
Asunto(s)
Compostaje , Alimentos , Eliminación de Residuos , Carbono , Nitrógeno , Suelo , TemperaturaRESUMEN
Pig farming is one of the human activities carried out to meet the increasing food demand by the increasing population. South Brazil is the region with most intensive pig farming in the country, exerting pressure on the water and soil environments by the relevant pollutant emissions. Therefore, the main objective of this work was to assess pig farming pollution by monitoring superficial water qualities of the Taquari-Antas Watershed in South Brazil. The study area is about 8062 km2 (south latitude 292,614, 282,624 and west longitude 520,802, 504,554). In 2014, there were 861 pig farmers and 739,858 animals were slaughtered. Samples were collected bimonthly from 13 spots during 2 years of monitoring. The main analysis included the determination of the water quality index (WQI)-a nine physicochemical and microbiological parameter index-and the trophic state index (TSI), which gives a trophic degree based on phosphorous and chlorophyll-α concentration to assess the impacts of the pig farming on superficial water of the region. The results suggest that the regions with high concentration of finishing stage farms present a higher risk to water quality. A distance of 4 km between different spots was enough to detect a significant decrease in the WQI. The WQI was found ranging from "regular" to "good" (62.77 and 78.95). The TSI were found to be mesotrophic at every spot during the entire period of the study.
Asunto(s)
Crianza de Animales Domésticos , Ríos/química , Calidad del Agua , Animales , Brasil , Monitoreo del Ambiente , Sus scrofaRESUMEN
ABSTRACT The need for cleaner sources of energy has stirred research into utilising alternate fuel sources with favourable emission and sustainability such as biodiesel. However, there are technical constraints that hinder the widespread use of some of the low cost raw materials such as pork fatty wastes. Currently available technology permits the use of lipolytic microorganisms to sustainably produce energy from fat sources; and several microorganisms and their metabolites are being investigated as potential energy sources. Thus, the aim of this study was to characterise the process of Staphylococcus xylosus mediated fermentation of pork fatty waste. We also wanted to explore the possibility of fermentation effecting a modification in the lipid carbon chain to reduce its melting point and thereby act directly on one of the main technical barriers to obtaining biodiesel from this abundant source of lipids. Pork fatty waste was obtained from slaughterhouses in southern Brazil during evisceration of the carcasses and the kidney casing of slaughtered animals was used as feedstock. Fermentation was performed in BHI broth with different concentrations of fatty waste and for different time periods which enabled evaluation of the effect of fermentation time on the melting point of swine fat. The lowest melting point was observed around 46 °C, indicating that these chemical and biological reactions can occur under milder conditions, and that such pre-treatment may further facilitate production of biodiesel from fatty animal waste.
Asunto(s)
Animales , Staphylococcus/metabolismo , Biocombustibles , Fermentación , Residuos Industriales , Biotransformación , Industria de Alimentos , Carne RojaRESUMEN
The need for cleaner sources of energy has stirred research into utilising alternate fuel sources with favourable emission and sustainability such as biodiesel. However, there are technical constraints that hinder the widespread use of some of the low cost raw materials such as pork fatty wastes. Currently available technology permits the use of lipolytic microorganisms to sustainably produce energy from fat sources; and several microorganisms and their metabolites are being investigated as potential energy sources. Thus, the aim of this study was to characterise the process of Staphylococcus xylosus mediated fermentation of pork fatty waste. We also wanted to explore the possibility of fermentation effecting a modification in the lipid carbon chain to reduce its melting point and thereby act directly on one of the main technical barriers to obtaining biodiesel from this abundant source of lipids. Pork fatty waste was obtained from slaughterhouses in southern Brazil during evisceration of the carcasses and the kidney casing of slaughtered animals was used as feedstock. Fermentation was performed in BHI broth with different concentrations of fatty waste and for different time periods which enabled evaluation of the effect of fermentation time on the melting point of swine fat. The lowest melting point was observed around 46°C, indicating that these chemical and biological reactions can occur under milder conditions, and that such pre-treatment may further facilitate production of biodiesel from fatty animal waste.