William C. Merka

Fate of Selected Bacterial Pathogens and Indicators in Fractionated Poultry Litter During Storage

Abstract A study of broiler litter re-utilization potential was conducted with the goal of determining if storage of litter significantly reduced potential pathogens to levels safe for re-utilization. Litter from four broiler houses was separated into a fine fraction for fertilizer use and a coarse fraction for use as a supplement to wood shavings in growing subsequent flocks of birds. Fractions and whole litter were stored in indoor piles for four months with periodic analysis for culturable pathogenic and indicator bacteria. Significant reductions in microbial concentrations occurred in a majority of samples tested during four months of storage (in most cases to below detection limits of approximately 30 CFU/g dry weight). Poultry feed was found to be one possible source of litter contamination.

Nitrous oxide and carbon dioxide emissions from pelletized and nonpelletized poultry litter incorporated into soil

While several studies have shown that the addition of animal manures to soil can increase N2O and CO2 emissions, limited information is available on the effect that manure physical characteristics can have on these emissions. This study compared N2O and CO2 emissions from poultry litter incorporated as pellets (5.5 mm OD, 7 mm long) or fine particles (<0.83 mm) into Cecil soil samples. The soil-litter mixture was packed in acrylic plastic cylinders and adjusted to 55 or 90 % water-filled porosity (WFP). The cylinders were placed inside jars that were sealed and placed in an incubator at 25°C for 35 d, with periodic air samplings conducted for N2O and CO2 analyses. At 55% WFP, cumulative emission of CO2 was similar for both litter types, but cumulative emission of N2O was slightly higher for pelletized (6.8 % of applied N) than for fine-particle litter (5.5 %). In contrast, at 90 % WFP, cumulative emission of N2O was larger for fine-particle litter (3.4 % of applied N) than for pelletized litter (1.5 %). These results indicate that the effect of poultry litter physical characteristics on N2O emissions from incorporated applications can be expected to vary depending on the soil water regime.

FRACTIONATION OF POULTRY LITTER FOR ENHANCED UTILIZATION

ABSTRACT A potential waste management system for the use of poultry litter was studied based upon the fractionation of litter. It was determined that the compositions of the litter by particle size varied both with the number of flocks that had been raised on the litter and the type of house. As the number of flocks raised on the litter increased from one to three flocks, the amount of fine material increased from 23 to 41%, while the concentration of the middle fraction decreased from 47 to 40%, and the coarse fraction decreased from 26 to 16%. The efficiency of retrieval of the fine fraction from the raw litter by either a vibrating screen separator or a rotary drum separator were found not to be significantly different. It was determined by chemical analysis that the P and K concentrations appeared to be distributed uniformly throughout the litter in each fraction while the N was non-uniformly distributed. The concentration of N was greatest in the fine fraction.

Proximate Composition of Poultry Processing Wastewater Particulate Matter from Broiler Slaughter Plants

An experiment was conducted to compare the proximate composition of particulate matter recovered from poultry processing wastewater (PPW) generated by broiler slaughter plants. Poultry processing wastewater is the cumulative wastewater stream generated during the processing of poultry following primary and secondary physical screening (typically to 500 mum) that removes gross offal. Composite samples of PPW from 3 broiler slaughter plants (southeast United States) were collected over 8 consecutive weeks. All 3 broiler slaughter plants process young chickens with an average live weight of 2.0 kg. At each plant, a single 72-L composite sample was collected using an automatic sampler programmed to collect 1 L of wastewater every 20 min for 24 h during one normal processing day each week. Each composite sample was thoroughly mixed, and 60 L was passed through a series of sieves (2.0 mm, 1.0 mm, 500 mum, and 53 mum). The amount of particulate solids collected on the 2.0 mm, 1.0 mm, and 500 mum sieves was insignificant. The solids recovered from the 53-mum sieve were subjected to proximate analysis to determine percent moisture, fat, protein, ash, and fiber. The average percentages of fat, protein, ash, and fiber for all samples on a dry-weight basis were 55.3, 27.1, 6.1, and 4.1, respectively. Fat made up over half of the dry-weight matter recovered, representing PPW particulate matter between 500 and 53 mum. Despite the variation in number of birds processed daily, further processing operations, and number and type of wastewater screens utilized, there were no significance differences in percentage of fat and fiber between the slaughter plants. There were significant differences in percent protein and ash between the slaughter plants.

A Dynamic Simulation Model of in-situ Composting Of Caged Layer Manure

A dynamic simulation model for in-situ composting of caged layer manure in-house, was developed and implemented on STELLA® modeling environment. The model formulation was based on solids mass balances, water balances and energy balances. The model was validated with the following parameters from pilot studies: temperature profiles, bulk wet weights, dry weights, and moisture contents. Approximately all the simulated values of bulk wet weights, dry weights and moisture contents fell within one standard deviation of the measured values over four different samplings within the year the experiment was conducted. Similarly the simulated cyclic-temperature profiles predicted the measured temperature profiles fairly accurately, except at points immediately after the weighing sessions.

Stabilization of poultry processing by-products and poultry carcasses through direct chemical acidification

Abstract Laboratory and field experiments were conducted to test the feasibility of using chemical acidification for stabilizing poultry-processing offal and blood and poultry carcasses. Acidification of the ground poultry materials with 2% (w/w) of 90% formic acid was the most economical method for preventing putrefactive changes and did not adversely affect crude protein and fat content. The acid-preserved offal and carcasses were stable semi-liquid/solid products with pHs of 4.0–4.2. When stored for 28 days at 30°C, the acidified offal and carcass products had approximately 67 and 62% moisture, 12 and 14% protein, 17 and 15% fat, and 0.16 and 0.23% ammonia, respectively. Several problems were identified, however, when the acid-treated offal was heat-processed to produce a dry feed meal.

Ammonia volatilization and carbon dioxide emission from poultry litter: Effects of fractionation and storage time

Abstract In many poultry producing areas, the amounts of poultry litter generated exceeds the amounts needed for application to soil, as fertilizer, at environmentally safe rates. To reduce the amounts of litter produced, Ndegwa et al. (1991) proposed fractionating the litter to generate a fine fraction that could be used as fertilizer, and a coarser fraction that could be recycled into poultry houses as bedding material. Because the fine fraction may need to be stored for several months before land application, knowledge of the changes that occur during storage would be important from the point of view of litter utilization. The objective of this study was to monitor water and inorganic nitrogen (N) contents, as well as potential ammonia (NH3) volatilization and carbon dioxide (CO2) emission in samples of whole litter and fine fraction stored in an unheated building for 16 weeks. Potential NH3 volatilization and CO2 emission were measured at unamended water contents and at a water content of 0.5 kg kg‐1....

Effects of vibratory microscreening on proximate composition and recovery of poultry processing wastewater particulate matter

Experiments were conducted to compare the effects of tertiary microscreen gap size on the proximate composition and rate of recovery of particulate matter from poultry processing wastewater (PPW). A high-speed vibratory screen was installed within the wastewater treatment area of a southeast US broiler slaughter plant after the existing primary and secondary mechanical rotary screens. Microscreen panels with nominal gap size openings of 212, 106 and 45mum were investigated. The particulate matter samples recovered were subjected to proximate analysis to determine percent moisture, fat, protein, crude fiber and ash. The average percent wet weight moisture (%WW) content for all samples was 79.1. The average percent dry matter (%DM) fat, protein, crude fiber and ash were 63.5, 17.5, 4.8 and 1.5, respectively. The mean concentration of total solids (TS) recovered from all microscreen runs was 668mg/L, which represents a potential additional daily offal recovery rate of 12.1metric tons (MT) per 3.78 million L (1.0 million gallons US) of PPW. There was no significant difference in the performance of the three microscreen gap sizes with regard to proximate composition or mass of particulate matter recovered.