John Worley

Anaerobic Digestion of Poultry Litter: A Review

Poultry litter is an excellent example of how a source of organic nutrients became an expensive problem in concentrated poultry producing areas due to nutrient imbalance at the farm and regional scale resulting in water quality impairment in some watersheds. Recently, anaerobic digestion technology, which is a proven solution for waste reduction and energy production for dairy, swine, and other organic wastes, has been proposed for poultry litter utilization. Although anaerobic digestion is widely studied for many organic and agricultural wastes, it is less understood for poultry litter (combination of manure, spilled feed, feathers, and bedding material). This review presents a detailed analysis of anaerobic digestion of poultry litter in terms of technology and optimization techniques, goals of poultry litter disposal, and economics. The review suggests that anaerobic process does not fulfill the goal of poultry litter nutrient disposal problems. While selecting any alternative option for a given region, one must consider the goals of poultry litter disposal for that area.

BEDDING FOR BROILER CHICKENS: TWO ALTERNATIVE SYSTEMS

Both alum and boric acid treated recycled paper were field tested and show promise as partial substitutes for pine shavings or sawdust as broiler bedding. In the area where it is available, recycled shredded paper with boric acid added is competitive with sawdust and has the advantage of darkling beetle suppression. This test did not demonstrate fuel savings for recycled paper. Alum applied at 0.976 kg/m 2 (0.20 lb/ft 2 ) reduced fuel usage by approximately 863 L (228 gallons) per 18,000-bird flock per house on winter flocks and was as effective at suppressing beetle populations as a commercial product costing

Reduced levels of alum to amend broiler litter.

100 per house per flock. Litter value was also increased because of increased retention of ammonium nitrogen.

Effect of fractionation on fuel properties of poultry litter.

Aluminum sulfate (alum) has been demonstrated to reduce ventilation and heating requirements by lowering pH and thus reducing ammonia release from broiler litter during brooding of broiler chickens raised on used litter. It also has been shown to reduce darkling beetle populations, reduce runoff of phosphorus from fields where litter is applied, and increase nitrogen levels in treated litter. Currently, however, no economic benefit exists for reducing phosphorus runoff in Georgia, and as a result, the economic benefits are approximately equal to the additional costs of adding alum in winter flocks in North Georgia, and represent a net loss on summer flocks. This research demonstrated that much of the economic benefit of adding alum can be achieved by adding only half the recommended rate. Heating costs and bird performance were the same for full and half-rate applications. Soluble phosphorus and ammonium nitrogen levels were adversely affected by reducing alum application rates. While the environmental benefit of phosphorus runoff reduction would be lessened by adding less alum, an advantage may be realized industry wide if reduced rates are used since more growers would be likely to use it due to economic benefits.

Effect of Fractionation and Pyrolysis on Fuel Properties of Poultry Litter

In raw form, poultry litter has certain drawbacks for both energy production and fertilizer. These include high ash content and moisture content, a corrosive nature, low heat content, and low nutrient content. Fractionation divides poultry litter into a fine, nutrient rich fraction and a coarse, energy rich fraction. In this research, poultry litter was divided into coarse and fine fractions using a #20 screen. The following analyses were performed on the raw poultry litter and its coarse and fine fractions: higher heating value, proximate, ultimate, compositional, mineral, thermogravimetric (TGA), and differential scanning calorimeter (DSC) analysis. Preliminary results show that the coarse fraction from screen #20 is potentially a much better feedstock for energy production than whole litter. The results of this study may be directly applied to the poultry industry to promote value added utilization of litter and to improve the efficiency of energy producing industries using poultry litter as feedstock.

Ammonia Emissions from a Commercial Broiler House

Abstract Raw poultry litter has certain drawbacks for energy production such as high ash and moisture content, a corrosive nature, and low heating values. A combined solution to utilization of raw poultry litter may involve fractionation and pyrolysis. Fractionation divides poultry litter into a fine, nutrient-rich fraction and a coarse, carbon-dense fraction. Pyrolysis of the coarse fraction would remove the corrosive volatiles as bio-oil, leaving clean char. This paper presents the effect of fractionation and pyrolysis process parameters on the calorific value of char and on the characterization of bio-oil. Poultry litter samples collected from three commercial poultry farms were divided into 10 treatments that included 2 controls (raw poultry litter and its coarse fraction having particle size greater than 0.85 mm) and 8 other treatments that were combinations of three factors: type (raw poultry litter or its coarse fraction), heating rate (30 or 10 °C/min), and pyrolysis temperature (300 or 500 °C). After the screening process, the poultry litter samples were dried and pyrolyzed in a batch reactor under nitrogen atmosphere and char and condensate yields were recorded. The condensate was separated into three fractions on the basis of their density: heavy, medium, and light phase. Calorific value and proximate and nutrient analysis were performed for char, condensate, and feedstock. Results show that the char with the highest calorific value (17.39 ± 1.37 MJ/kg) was made from the coarse fraction at 300 °C, which captured 68.71 ± 9.37% of the feedstock energy. The char produced at 300 °C had 42 ± 11 mg/kg arsenic content but no mercury. Almost all of the Al, Ca, Fe, K, Mg, Na, and P remained in the char. The pyrolysis process reduced ammoniacal-nitrogen (NH4-N) in char by 99.14 ± 0.47% and nitrate-nitrogen (NO3-N) by 95.79 ± 5.45% at 500 °C.

Sludge Measurement Using Global Positioning System (GPS) Enabled Sonar Equipped Airboat in a Lagoon

Emission of ammonia gas from broiler houses has become an issue of concern. Yet most of the research that has been done on ammonia in poultry houses is more concerned with in-house air quality than with emissions, and most of the research has occurred in northern Europe where climatic conditions and perhaps management are different from that in the southeastern United States which is the area that produces the largest amount of poultry in the US. This research monitored ventilation rates and ammonia levels in a commercial broiler house in the southeastern United States to determine the approximate emission rates under hot and cool climatic conditions. In hot conditions, although ammonia concentrations were only in the 3 to 5 ppm range, extremely high ventilation rates resulted in estimated emissions of approximately 35 lb (16 kg) /day/house on some days. The instrument used to measure ammonia levels was not reliably accurate at concentrations below 5 ppm, however, and an error of 1 ppm at these high ventilation rates would result in an error of 20 lb (9 kg)/day/house. In cooler conditions, ammonia concentrations were higher, and ventilation rates were lower resulting in daily emissions similar to summer conditions. However, when the sensor was exposed to constant high levels of ammonia, the output became unstable, rendering these results questionable as well.

Determination of Composition of Cellulose and Lignin Mixtures Using Thermo Gravimetric Analysis (TGA)

Proper management of animal waste treatment lagoons requires regular sludge surveys of the lagoons. The traditional manual method of sludge survey is unsafe and time consuming. This article presents the effect of sonar unit variables (sensitivity, noise rejection, and surface clarity) on measurements of top and bottom depth of sludge layer in a lagoon using a GPS enabled sonar equipped (model LCX-15M, Lowrance Electronics, Inc, Tulsa, Okla.) remote controlled airboat. Comparisons between airboat measurements and sludge meter readings and the discrepancy between the measurements from the airboat and an instrument from Remediation Resources, Inc. are also discussed. To study the variables, the top and bottom depth of a sludge layer, position and speed of the air boat were measured using a GPS sensor and an ultrasonic sonar in three situations: 1) Statically at single point; 2) Dynamically along two lines; and 3) Dynamically on a lagoon water surface on a random grid. The top and bottom depth of the sludge layer was also measured using a sludge meter method at several points within the cone area for the static location of the transducer. This preliminary study suggested the use of 25% sensitivity level, an inclusion of a correction factor accounting for speed of sound in lagoon water, the steady movement of the boat and the use of a more accurate GPS system (accuracy within inches with DGPS) for future research to measure sludge within acceptable limits.

Electrostatic Space Charge System for Air Quality Improvement in Broiler Production Houses

The proportional composition of cellulose, hemicellulose, lignin and minerals in a biomass plays a significant role in the proportion of pyrolysis products (bio-oil, char, and gases). Traditionally, the composition of biomass is chemically determined, which is a time consuming process. This paper presents the results of a preliminary investigation of a method using thermo-gravimetric analysis for predicting the fraction of cellulose and lignin in lignin-cellulose mixtures. The concept is based on a newly developed theory of Pyrolytic Unit Thermographs (PUT). The Pyrolytic Unit Thermograph (PUT) is a thermograph showing rate of change of biomass weight with respect to temperature for a unit weight loss. These PUTs were used as input for two predictive mathematical procedures that minimize noise to predict the fractional composition in unknown lignin-cellulose mixtures. The first model used linear correlations between cellulose/lignin content and peak decomposition rate while the second method used a system of linear equations. Results showed that both models predicted the composition of lignin-cellulose mixture within 7 to 18% of measured value. The promising results of this preliminary study will certainly motivate further refinement of this method through advanced research.Copyright

Ammonia and Fine Particulates Inside and Outside Tunnel Ventilated Broiler Houses – A First Look

Reducing airborne dust in enclosed animal housing has been shown to result in corresponding reductions in airborne bacteria, ammonia and odor. Technologies that have been shown to be effective for reducing airborne dust in animal areas include misting with an oil spray, water mists, extra ventilation, and electrostatic space charge systems. Increasing pressure from environmental groups to reduce PM-10 and ammonia emissions from animal housing has led to considerable interest by the poultry and swine industries for practical systems to reduce these air pollutants. This presentation will describe an electrostatic space charge system (ESCS) that was designed to reduce airborne dust and ammonia emissions from a commercial broiler production house. The ESCS for this application was based on patented technology that was developed over a period of several years to reduce airborne dust and pathogens and proven in numerous research trials in poultry hatchers and growout areas. A recently completed study in a small broiler breeder house showed the ESCS reduced airborne dust by an average of 60%, ammonia by 56%, total bacteria by 76%, and it reduced the number of Salmonella infected broilers produced from eggs gathered in the study. Preliminary results of the present study in a broiler production house during the cool months of November through April indicate the ESCS reduced airborne dust by an average of 55% and ammonia by an average of 8% in a house with built-up litter. Later studies will include litter that is fresh or not over a few months old which is expected to improve the effectiveness of the ESCS for ammonia removal since a higher percentage of the ammonia produced would be on the dust that is removed.