Effect of turning frequency and season on composting materials from swine high-rise facilities

Abstract

a b s t r a c tComposting swine slurries has several advantages, liquid slurries are converted to solids at lower moisture, the total volume and weight of material is reduced and the stabilized product is more easily transported off-site. Despite this, swine waste is generally stored, treated and applied in its liquid form. High-rise finishing facilities (HRFF) permit liquid slurries to be converted to solids which are partially decomposed underneath the HRFF and then finished in compost windrows. The purpose of this study was to evaluate the effect of turning frequency and ambient weather conditions on biological, physical and chemical properties of composted slurry-woodchip mixtures from HRFF. Compost trials were conducted in either fall (FT) or spring (ST) and piles were turned once or three times per week or upon compost temperature reaching 65°C. Physical, chemical and microbiological characteristics were measured over the course of 112 (FT) or 143 (ST) days of composting. Total carbon, total nitrogen (N) and inorganic N decreased in all piles. Ammonium decreased while nitrate increased in all piles (including unturned), but total N losses were greatest in piles turned more frequently during the ST. Microbial populations of nitrifiers were dominated by ammonia-oxidizing archaea (3.0 Â 10 3 -4.2 Â 10 6 cells g À1 compost) but ammonia oxidizing bacteria (below detection to 6.0 Â 10 5 cells g À1 compost) varied in response to turning and compost temperature; denitrifiers were present in high concentrations throughout the process. Swine HRFF materials composted well in windrows regardless of turning frequency and despite significant differences in starting materials and low initial C/N. Volume reduction, low moisture and low readily degradable organic matter suggest that the finished compost would have lower transportation costs and should provide value as a soil conditioner. Published by Elsevier Ltd.

Seafood-Processing Sludge Composting: Changes to Microbial Communities and Physico-Chemical Parameters of Static Treatment versus for Turning during the Maturation Stage

“…Nikaeen et al [33] have also pointed out that the time needed to stabilize organic compounds in static piles is greater due to the lack of heat exchange. Furthermore, it has been stated that turning and how often it occurs affects the EC, pH, TC, TN, C/N ratio, GI, and temperature during the composting of different types of waste products [9–12,34]. Similar results have been obtained from this study, showing that turning pre-composted waste in line with temperature criteria following static-reactor composting affected the pH, electrical conductivity, ammoniacal nitrogen, dissolved organic nitrogen, organic matter, enzymatic activities, total nitrogen and total carbon; this led to the compost becoming stable in less time than through static conditions for the maturation stage.…”

Composting Time Reduction of Agro-Industrial Wastes

“…Although the isolated effects of turning frequency (GETAHUN et al, 2012;COOK et al, 2015), environmental conditions concerning the presence or absence of cover (MAREŠOVÁ & KOLLÁROVÁ, 2010) and use of inoculum (XI et al, 2012;JIANG et al, 2015a) are known in the composting process, the integrated effect of these factors in the composting time of the agroindustrial wastes become an important information, mainly to composting plants.…”

“…Composting piles submitted to high frequency of turnings get ready in a shorter time when compared to static piles (CÁCERES et al, 2006;GUO et al, 2012). However, the loss of N is strengthened (CARNEIRO et al, 2013;COOK et al, 2015). Greater aeration rates offered by turnings modify the thermodynamic factors that affect the generation and transference of the heat in the composting system, such as moisture and water vapor transport, natural aeration, volatilization, oxygen status and patterns of temperature distribution (MASON & MILKE, 2005).…”

Closing the nutrient loops in (peri-)urban farming systems through composting

“…Studies have shown that the total N loss can increase by over 88% during excessive aeration compared to optimal aeration (Chowdhury et al, 2014;Jiang et al, 2011). Similarly, Cook et al (2015) observed that frequent turning of the compost pile (i.e., three times per week) more than doubled the total N losses compared with less frequent turning (i.e., once a week). Aeration reduces CH4 emissions from composting (Chowdhury et al, 2014;Jiang et al, 2011), but its effect on N2O emissions remains controversial.…”

“…Excessive aeration, however, increases N loss via ammonia volatilisation (Chowdhury et al, 2014;Cook et al, 2015). Studies have shown that the total N loss can increase by over 88% during excessive aeration compared to optimal aeration (Chowdhury et al, 2014;Jiang et al, 2011).…”