Assessing the Performance and the Microbial Dynamics of Co-composting System Using Recycled Cow Manure and Bedding Material Waste

Co-composting of recycled cow manure and waste bedding material has been used to convert both agricultural wastes to biofertilizers. This study explored the succession of microbial community, metabolic function and substances conversion capacities during 60 days’ co-composting using high throughput sequencing technology. The study revealed that co-composting of cow manure and bedding material waste at a ratio of 1.32 (CM+B) had the highest efficiency among four treatments. The bacterial and fungal community diversity changed significantly during the co-composting of CM+B group, and the major phyla included Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria and Ascomycota. PICRUSt and FUNGuild analysis showed that carbohydrate, lipid metabolism and especially nitrogen fixation were enhanced in the thermophilic phase, while animal and plant pathogens were not detected after the co-composting. Wood saprotrophs became the dominant fungal group (89.1%) in the maturation phase. Canonical correlation analysis (CCA) and redundancy analysis (RDA) confirmed that temperature influenced bacterial community succession more than it influenced fungal community succession. Ruminiclostridium had a significantly positive relationship with temperature (p_value < 0.05), while pH and C/N had significant effect on the fungal (p_value < 0.05), and Penicillium and Mortierella were significantly related to moisture (p_value < 0.05). This work describes an efficient methodology to deal with co-composting systems that had been successfully applied in agricultural wastes treatment, enabling further understanding in mechanisms underlying the substance conversion and the involved microbial community succession in sophisticated composting system.

Recycling Organic Materials to Improve Your Florida-Friendly Edible Landscape

This new 7-page publication of the UF/IFAS Environmental Horticulture Department is intended to educate homeowners on environmentally friendly ways to enhance soil fertility for vegetables, herbs, and fruits in the home landscape. It discusses strategies for recycling nutrients in place or via composting systems to create productive edible landscapes with less waste. Adopting these methods into your landscape maintenance routine will build organic matter and add nutrients to the soil naturally. Written by Terra Freeman, Tiare Silvasy, Lynn Barber, Tom Wichman, Esen Momol, Tina McIntyre, Jacqlyn Rivas, and Jen Marvin.https://edis.ifas.ufl.edu/ep599

Evaluation of Design Characteristics for Animal Mortality Composting Systems

HighlightsDesign characteristics for animal mortality compost cover materials were tested.Compressive stress was applied to simulate the effects of the mortalities on cover materials.The highest permeability was measured for sawdust at 25% moisture content.A linear relationship was found between the volumetric flow rate and the power required to aerate the piles.Abstract. Composting is an aerobic process that relies on natural aeration to maintain proper oxygen levels. Air-filled porosity, mechanical strength, and permeability are among the essential parameters used to optimize the process. This study’s objective was to measure the physical parameters and airflow characteristics of three commonly used cover materials at four moisture levels, which could be used in designing actively aerated swine mortality composting systems. A laboratory-scale experiment was conducted to measure pressure drops across the cover materials as a function of the airflow rate and the material’s moisture content. Compressive stress was applied for 48 h to simulate the impact of swine mortalities on the cover materials. The power required to aerate each material was determined as a function of volumetric flow rate and moisture content. As expected, air-filled porosity and permeability decreased with increasing bulk density and moisture content. The highest average permeability values were measured at 25% moisture content and ranged from 66 × 10-4 to 70 × 10-4 mm2, from 161 × 10-4 to 209 × 10-4 mm2, and from 481 × 10-4 to 586 × 10-4 mm2 for woodchips, ground cornstalks, and sawdust, respectively. For the range of airflow rates tested in this study (0.0025 to 0.0050 m3 s-1 m-2), a linear relationship (R2 = 0.975) was found between the volumetric flow rate (m3 s-1) and the power required to aerate the compost pile (W per 100 kg of swine mortality). Keywords: Airflow, Darcy’s law, Livestock, Modeling, Permeability, Pressure drop.

Assessment of Disintegration of Compostable Bioplastic Bags by Management of Electromechanical and Static Home Composters

Interest in small scale composting systems is currently growing, and this in turn raises the question of whether the compostable bags are as suitable as in industrial composting facilities. In this work the physical degradation percentage of compostable lightweight bioplastic bags in two types of composter was examined. The main goal was to understand whether the mild biodegrading conditions that occur in electromechanical or static home composters are sufficient to cause effective bag degradation in times consistent with the householders’ or operators’ expectations. Bags, which complied with standard EN 13432, were composted in a number of 600 L static home composters, which were run in different ways (e.g., fed only with vegetables and yard waste, optimizing the humid/bulking agent fraction, poorly managed) and a 1 m3 electromechanical composter. Six months of residence time in static home composters resulted in 90–96 wt% degradation depending on the management approach adopted, and two months in the electromechanical composter achieved 90 wt%. In the latter case, three additional months of curing treatment of the turned heaps ensured complete physical degradation. In conclusion, in terms of the level and times of physical degradation, the use of compostable bioplastic bags appeared promising and consistent with home composting practices.

EVALUATION OF NEW SMALL-SCALE COMPOSTING PRACTICES WITH ENERGY RECOVERY

This study involves the evaluation of new composting systems for the treatment of organic solid waste that has low environmental impact. Two composting devices were developed, with four types of management. Their behavior was analyzed regarding temperature, gas production, moisture, leachate and percolated water production, compost maturation, nutrient presence, pH and water heating, which can be seen as an energy gain in addition to the economic viability of the process. The proposed composting techniques kept the waste at thermophilic temperatures for more than 20 days, with no significant emission of CH4, under aerobic conditions by passive aeration, without leachate generation. These results can be partially attributed to the suspension of the compost on pallets, the residue composition chosen in the experiments and the boundary conditions of the compartments. The energy recovery test, through water recirculation inside the compost, presented temperatures that reached 51°C after 24 h of recirculation, and were maintained throughout the process, 20 days, demonstrating its effectiveness. The proposed models are environmentally viable, minimizing gas emissions and leachate generation compared to landfill or industrial composting plants. They can be used in industrial kitchens, residential complexes, shopping malls and other small and medium solid waste generators. In addition, the solution presented in this study avoids the transportation of waste over medium and long distances, which also brings a significant reduction in energy expenses, and in the case of landfills, it avoids occupation for long periods, thus reducing emissions of gases and leachate, whose control and treatment are expensive.

Effect of Double-T and V-shaped Pipe Configurations and Perforations on the Quality of Chicken Litter Compost

Livestock waste management has received much attention because of the huge volume and instability. One of the good management practices adopted to address this menace is composting. This study examined the effect of specialized passively aerated composters on some physicochemical properties of chicken litter. The composter is made up of six double T and V shaped pipe with three different perforation diameters of 15, 20 and 25 mm. Pile configuration of the developed composters had marked effect on total nitrogen content (p0.05) of the compost subjected to 90 days composting time. The composters had uniform air distribution as pile temperature was not significantly affected by pile configuration, perforation size, and their interactions. Furthermore, both T and V shaped pipe structures reached a thermophilic temperature of 49.0 and 67 oC respectively and the compost stabilized in the 12th week. From the agronomic point of view, V-shaped pipe outperformed double inverted T pipes with perforation sizes of 15 and 20 mm. Overall result from this study suggests that double-T and V-shaped composters are feasible composting systems that can enhance biodegradation, maturation, and stability of chicken litter.Keyword: compost, litter, composter, double-T, pile, perforation.