Melvin T. Yokoyama

Ozonation of swine manure wastes to control odors and reduce the concentrations of pathogens and toxic fermentation metabolites

Abstract The use of ozone for the remediation of nuisance odorous chemicals in liquid swine manure slurry was investigated. Gaseous ozone was bubbled directly into stored swine manure slurry in a continuously stirred batch reactor. One‐liter samples of swine slurry were ozonated to achieve ozone dosages of 1.0, 2.0 and 3.0 g ozone/liter of waste. Olfactometric determinations demonstrated a significant reduction in odors in ozonated samples as compared to raw and oxygenated samples. Volatile fatty acids, nitrate, phosphate and ammonia concentrations were unchanged by ozonation. The biochemical oxygen demand (BOD) and the chemical oxygen demand (COD) were essentially unaffected by ozonation. The concentrations of odorous phenolic microbial metabolites (e.g., phenol, p‐cresol and p‐ethylphenol) and odorous indolic microbial metabolites (e.g., 3‐methylindole and indole) were reduced to non‐detectable levels by ozonation. Hydrogen sulfide concentrations were reduced slightly by the process, with a concurrent i...

The effect of storage and ozonation on the physical, chemical, and biological characteristics of swine manure slurries

Abstract The reduction of odor emanating from wasted swine manure is a very challenging environmental engineering problem. In an earlier work (Watkins et al., 1997), we showed the effect of ozone in reducing the odor and concentration of phenolic compounds in swine manure obtained from the pits under the slotted floors where the swine were housed. In this paper, we have expanded significantly upon the work of Watkins et al. by determining the effect of storage on the physical, chemical and biological characteristics of the swine manure slurry and whether the efficacy of ozonation is dependent upon storage time.

Some aspects of cellobiose effect on bacterial cell surface structures involved in lucerne cell walls utilization by fresh isolates of rumen bacteria

Abstract The effect of the inclusion of cellobiose or lucerne cell solubles on the pattern of lucerne cell walls (CW) digestion by a mixed rumen population in vitro was followed. Inclusion of soluble sugars reduced the rate of lucerne CW degradation by a mixed rumen population without reducing the extent of overall CW digestion (59.8%). The predominant ruminal bacteria utilizing lucerne hay or lucerne CW as the sole added carbohydrate substrate were isolated, enumerated and identified. Fresh isolates of the predominant cellulolytic bacteria ( Ruminococcus flavefaciens 7a3, Ruminococcus albus 7a6 and Bacteroides succinogenes 7a8 or 7a14) were then grown on lucerne CW or cellobiose as the sole added carbohydrate substrate. The effect of substrate on bacterial cell surface topology was investigated by scanning electron microscopy (SEM) visualization using cationized ferritin pretreatment and the ability of the isolates to adhere to cellulose was determined. Lucerne CW degradability by each of these bacterial isolates was also determined. The surface topology of B. succinogenes 7a14 and 7a8, R. albus 7a6 and R. flavefaciens 7a3 cells grown on and attached to CW particles was specified by a dense layer of characteristic protuberant structures. In contrast, when grown on cellobiose the surface topology of these bacterial strains (excluding isolate 7a8 of B. succinogenes ) was smoother and contained less protuberant structures. The ability to attach to cellulose of these bacterial strains was higher when adapted to lucerne CW vs. cellobiose, indicating possible involvement of these organelles in the attachment mechanism of the bacteria. A possible explanation for the inhibitory effect of cellobiose on CW digestion in this study is discussed.

Ozone-treated lucerne hay as a model to study lucerne degradation and utilization by rumen bacteria☆

Abstract The effect of ozone treatment on the composition of lucerne hay and on the digestion of total and cell-wall (CW) monosaccharides was examined in vitro, and the changes in the occurrence of the predominant rumen bacterial species involved in whole hays and their CW utilization were determined. The effect of ozone treatment was expressed in a reduction of lucerne CW concentration from 51.5% to 35.6%, destroying 65% of the lignin and solubilizing 53% of CW non-glucose polysaccharides (NGP). Ozone treatment improved the in vitro digestion of dry matter and total monosaccharide components significantly by 15.3 and 21.0% up to 79.5 and 87.6%, respectively. This improvement by ozonation originated from both solubilization of CW monosaccharides and improvement in the digestion of residual CW glucose and CW NGP by 15.5 and 14.9% up to 81.7 and 72.5%, respectively. The changes in the occurrence of the predominant rumen bacterial species grown for 48 h on untreated or ozonated lucerne hays or their CW preparations as the sole substrates were determined using the agar roll-tubes technique. Ozonation increased the total viable count of rumen bacteria by 30% from 1.0 × 10 9 in untreated hay up to 1.3 × 10 9 in the ozonated hay. The proportion of the Ruminococci species comprising 70% of the population utilizing untreated hay was reduced to 46% in the ozonated material, while that of Bacteroides ruminicola and Butyrivibrio fibrosolvens increased from 6.66 to 30.7%. When grown on untreated CW preparations, the Ruminococci species and Bacteroides succinogenes were identified in equal proportions (18.2% each), but on the ozonated CW preparations B. succinogenes and B. fibrosolvens were the predominant rumen bacteria, comprising 36.4 and 22.7%, respectively, while proportions of the Ruminococci species and of B. ruminicola were reduced. The feasibility of ozone treatment of lucerne hay, and some of the rumen bacterial mechanisms involved in CW degradation and utilization, are discussed.

Action of High Dietary Copper in Promoting Growth of Pigs

High levels of dietary copper (125 to 250 ppm) are used routinely in Europe (Braude, 1967) and the USA (Wallace, 1967) to promote weight gain of growing pigs. The growth response of pigs to high copper feeding is similar to that of subtherapeutic levels of antibiotics and is a consistent and inexpensive positive response.

Sodium Tetraborate Decahydrate Treatment Reduces Hydrogen Sulfide and the Sulfate-Reducing Bacteria Population of Swine Manure

Emission of odorous and toxic gases from stored livestock manure is well documented and poses a serious health risk to farmers and livestock. Hydrogen sulfide emissions have been sharply rising with increasingly intensive livestock production and are of particular concern because of the acute toxicity of this gas. Numerous strategies, technologies, and chemical treatments have been used to control hydrogen sulfide emissions, but none have worked particularly well because they are neither cost-effective nor environmentally sustainable, or they are too toxic for animals. The inhibitory effect of the sodium tetraborate decahydrate (i.e., borax) treatment to reduce hydrogen sulfide production using sulfate-reducing bacteria was examined in shallow manure pits in a starter-grower swine facility. Monitoring of air emissions and DNA analysis revealed that treatment of stored swine manure effectively reduced hydrogen sulfide production, and the reduction correlated to a decrease in the sulfate-reducing bacteria population in the stored swine manure.