Philip R. Goodrich

Rheological properties of Moroccan dairy cattle manure

Abstract The rheological properties such as the consistency coefficient, the flow behavior index and the apparent viscosity of Moroccan dairy cattle manure of various total solids concentrations were studied. In the range of 2·5–12% total solids and at temperatures between 20 and 60°C, cattle manure behaves as a pseudoplastic suspension fluid. Two equations were established to relate the consistency coefficient and the flow behavior index of the manure to temperature and total solids concentration.

The effect of preparation temperature on some properties of a temperature-sensitive hydrogel

Abstract The physical and chemical characteristics of temperature-sensitive hydrogel, poly(N-isopropylacrylamide), were strongly dependent upon the preparation temperature and the kind of accelerator used for free radical polymerization. N, N,N′,N′-tetramethyl-ethylenediamine (TEMED) was a better accelerator for consistent gelation near room temperatures (17–24 °C) compared with sodium metabisulfite. Using TEMED, gelation time was 3.6 min at 18 °C, but decreased to 1.8 min at 23 °C. When the gel was prepared in a glass cylinder of 37 mm ID and 191 mm height at temperatures of 18 °C and below, it was completely transparent. The gel became more opaque starting from the core part of the gel cylinder, when prepared at higher temperatures. The gel became totally opaque at preparation temperatures of 23 °C and above. The transparent gel had better physical strength as determined by Instron, and higher transition temperature for volume change (lower critical solution temperature) as determined by differential scanning calorimetry. The transparent gel also had a better volume change capacity when the gel underwent temperature swings between 28 °C and 37 °C.

Dynamic olfactometry variability in determining odor dilutions-to-threshold

When conducting research on odor abatement technologies, a weak link has been the inability to place a precise quantifying number on odor strength that can be accurately reproduced within the same laboratory and between laboratories. Olfactometry is one of the most accepted means for evaluating odor samples. However, insufficient effort has been made to determine variation between or among individual panelists. This study was designed to analyze three odor sample strengths over a three-day period by two odor panels, each composed of eight panelists. Three sample strengths were presented randomly to each panelist three times within each session. Whole-panel variation ranged from a 22% to 50% difference in reported odor units for the same sample, depending on sample strength. Using two different airflow rate calibrations resulted in a 9% to 28% difference in odor units for the same sample, depending on sample strength. Panelist variation ranged from 4.3- to 7.1-fold, depending on sample strength, although panelist standardization slightly reduced this variation. Sample order had no effect on odor strength determination. A learning curve for individual panelists appeared to exist, as odor unit evaluation for later observations were 3.8 and 4.1 times greater than similar evaluations for the first samples. Variation between panelists is approximately the same as variation among evaluations done by the same individual; efforts should be made to reduce both these variations. To be able to detect differences in odor concentrations between control and treatment samples, large reductions in odor concentrations with several air samples are needed to accurately detect a significant reduction in odor.

Swine manure storage covers for odor control

Twenty-one, 750-L (200 gal) polyethylene tanks were filled with swine manure. Air samples were collected 24 and 48 h after each manure addition. The samples were tested for odor strength using a dynamic olfactometer and for hydrogen sulfide concentration using a Jerome® meter. The experimental design consisted of a randomized block design containing three blocks (replications) of seven treatments. The seven treatments included no cover (control), straw mat, vegetable oil mat, straw/oil mat, clay ball mat, PVC/rubber membrane, and geotextile membrane. Statistical analysis indicated that all three main effects—cover treatment, collection period, and time after manure addition—significantly (5% level) affected odor units and hydrogen sulfide concentration. Considering all air collections, the six covers reduced odor units and hydrogen sulfide concentration at various points in the study, but not in a consistent manner. The straw mat and PVC/rubber membrane significantly reduced both odors units and hydrogen sulfide concentration consistently 24 h after manure addition during the first three collection periods. Mixing vegetable oil with straw appears to increase longevity of the cover as compared to straw only. The vegetable oil layer, when mixed with the manure, produced a distinctively offensive non-swine odor. The clay ball mat reduced emissions, although not as well as other covers. A geotextile membrane may be a possible cover choice, since the fabric is self-floating and the biofilm that grew on the mat could self-seal the cover. A straw mat (possibly including vegetable oil) and PVC/rubber membrane appear to be the most effective covers in reducing both odors and hydrogen sulfide. Oil alone should not be used as a cover.

Poly(hydroxybutyrate-co-hydroxy-valerate) from swine waste liquor by Azotobacter vinelandii UWD

Azotobacter vinelandii UWD produced 2.0g/L of cell dry weight including 34.0 wt% of poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV) with 7.9mol% of hydroxyvalerate (HV) from two-fold diluted swine waste liquor. Supplementation of 30 g glucose/L increased cell dry weight to 9.4 g/L with 58.3 wt% of PHBV and 4.3 mol% of HV at a PHBV production rate of 0.11g PHBV/L-h.

Carbon-to-Nitrogen Ratio and Hydraulic Retention Time Effect on the Anaerobic Digestion of Cheese Whey

ABSTRACT SIXTEEN 1-L digesters were used to test four carbon-to-nitrogen ratios of 8.4, 13.9, 22.2 and 27.6 and four hydraulic retention times of 12, 18, 24 and 30 days on the efficiency of digester operation. Percent methane in the biogas and methane production were dependent on both carbon-to-nitrogen ratio and hydraulic retention times. Percent chemical oxygen demand reduction, volatile solids removal, total volatile acids concentrations, digester pH and amount of sodium hydroxide solution needed to control digester pH were dependent on hydraulic retention time only.

Bulk density and thermal properties of Moroccan dairy cattle manure

Abstract The bulk density, specific heat and thermal conductivity of Moroccan dairy cattle manure were studied with respect to total solids concentration. In the range of total solids studied regression equations were established relating each of these parameters to the percentage of total solids in cattle manure.

Real-Time Ventilation Measurements from Mechanically Ventilated Livestock Buildings for Emission Rate Estimations

A six-state USDA-IFAFS funded research project (Aerial Pollutant Emissions from Confined Animal Buildings, APECAB) was conducted with the purpose of determining hydrogen sulfide, ammonia, PM10, and odor emission rates from selected swine and poultry housing systems. An important aspect of emission studies is to be able to measure the mass flow rate of air through the housing system. For this research project, the decision was made to study only fan ventilated buildings due to the difficulty in estimated mass flow rates through naturally ventilated buildings. This paper highlights the various techniques used throughout the study to determine mass flow rate through fan ventilated swine and poultry housing systems.

EFFECTS OF DESIGN PARAMETERS OF PLANAR, SILENT DISCHARGE, PLASMA REACTORS ON GASEOUS AMMONIA REDUCTION

Odor control is a challenging issue for both animal producers and researchers due to the complexity of the odor components. Previous studies have demonstrated that non-thermal plasma is capable of decomposing dilute, complex polluting gases, and has the potential for animal house and waste odor reduction. In this study, we developed planar, silent discharge, non-thermal plasma reactors for decomposition of ammonia. Both the ammonia reduction efficiency and energy efficiency of the reactors were evaluated under different reactor configurations and operational conditions. Results showed that planar, silent discharge, reactors could achieve a wide range of ammonia reduction efficiencies depending on the operational conditions.

Farm-scale generation of bio-gas

A farm-scale research and demonstration digester has been constructed, operated and monitored on a private medium-sized swine farm. Materials handling problems have been studied. Bio-gas from the digester is used in a motor generator set to be integrated into the farmstead energy system. The digester has been monitored to determine operational characteristics, amount of energy produced and efficiency of energy production.