Effects of quebracho on nitrification in a pilot scale extended aeration unit / J. David Eye in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXVI (Année 1981)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXVI (Année 1981) . - p 424-435 Titre : Effects of quebracho on nitrification in a pilot scale extended aeration unit Type de document : texte imprimé Auteurs : J. David Eye, Auteur ; Kenneth E. Kruse, Auteur Année de publication : 1981 Article en page(s) : p 424-435 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675.2 Préparation du cuir naturel. Tannage Résumé : Tannery wastes contain high concentrations of ammonia and organic nitrogen which constitute a significant oxygen demand on receiving waters. Also, ammonia in the un-ionized form is extremely toxic to fish and other aquatic organisms. By converting the ammonia and organic nitrogen to nitrates through biological oxidation ( nitrification ) the oxygen demand and the toxicity can be reduced significantly or eliminated completely. The nitrifying bacteria are extremely sensitive to environmental conditions and careful control of nitrification systems is required. The wastes from tanneries employing the vegetable tanning process normally contain high concentrations of tannins as well as ammonia and organic nitrogen. This study was conducted for the purpose of determining if quebracho inhibits nitrification and at what concentration inhibition becomes significant. The results obtained showed that the efficienty of nitrification was reduced at all concentrations of quebracho in the influent above 100 mg/l ( quebracho in the influent ). The maximum reduction in nitrification efficiency was observed to be about 30 percent. The quebracho concentrations investigated ranged from zero to 500mg/l. At 500mg/l the observed reduction of ammonia was 93 percent. The authors believe that the reduction in nitrification was caused largely by the adverse effect of the quebracho on the clarification efficiency rather than by a direct toxic effect on the nitrifying organisms. En ligne : https://drive.google.com/file/d/1lptZFKcsC71UfqA9QuGWJmYefyMCIxIR/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17679 [article]

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Laboratory evaluation of the biological degradation of para-nitrophenol / Daniel L. Perrin in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXX (Année 1985)

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXX (Année 1985) . - p. 81-93 Titre : Laboratory evaluation of the biological degradation of para-nitrophenol Type de document : texte imprimé Auteurs : Daniel L. Perrin, Auteur ; J. David Eye, Auteur Année de publication : 1985 Article en page(s) : p. 81-93 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : The purposes of this study were to determine the ability of an activated sludge system to treat wastewater containing Para-Nitrophenol, (PNP), and to evaluate the effect of a commercially available “bioaugmentation product” on the performance of an activated sludge unit treating wastewater containing PNP. The activated sludge system was simulated using two-liter operated reactors seeded from a municipal wastewater treatment plant. Various experimental comparisons were made on units exposed to PNP, not exposed to PNP, and units exposed to PNP while undergoing bioaugmentation. Results show that the batch activated sludge units were able to adapt to and degrade PNP up to concentrations of 113 mg/l in the mixed liquor. The presence of PNP interfered slightly with the performance of the batch units in terms of solids production, effluent suspended solids, and sludge volume index. The results of this study also indicate that the addition of the bioaugmentation product improved batch activated sludge operation in terms of PNP degradation, COD reduction, effluent suspended solids, and solids production. A similar improvement in PNP degradation was obtained by the addition of small amounts of fresh activated sludge microorganisms from a municipal wastewater treatment plant. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9249 [article]

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Laboratory techniques for estimating the design and performance characteristics of pressure filters / Christian Davies-Venn in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. LXXX (Année 1985)

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. LXXX (Année 1985) . - p. 63-80 Titre : Laboratory techniques for estimating the design and performance characteristics of pressure filters Type de document : texte imprimé Auteurs : Christian Davies-Venn, Auteur ; J. David Eye, Auteur Année de publication : 1985 Article en page(s) : p. 63-80 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Laboratory procedures and mathematical models routinely used for sizing vacuum filters were evaluated and modified to permit their use in sizing pressure filters for sludge dewatering. The results obtained on a tannery sludge gave a linear relationship between predicted and observed filter yields for a bench-scale pressure filter. A modified mathematical model was developed for calculating the filter yield and for sizing full-scale pressure filters based on laboratory studies. These same laboratory procedures can also be used determining the optimum chemical conditioning required for obtaining the maximum sludge dewatering capability from an operating pressure filter. Some of the more important filtration variables which affect the performance of pressure filters were investigated statistically. It was found that the specific resistance and the suspended solids content of the sludge were the most significant. The pressure filter cake solids content (dryness) varied directly with the pressing time per unit of cake thickness while the filter yield in pounds of dry solids per hour per square foot of filter area was inversely proportional to the dryness (cake solid content) of the filter cake. These observations stem from the fact that increased pressing time removed additional water from the weight of sludge solids in the filter chamber. Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=9248 [article]

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A pilot plant study of the effects of quebracho and wattle on anaerobic digestion / J. David Eye in JOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA), Vol. XXVII (Année 1982)  

[article]  inJOURNAL OF THE AMERICAN LEATHER CHEMISTS ASSOCIATION (JALCA) > Vol. XXVII (Année 1982) . - p. 137-148 Titre : A pilot plant study of the effects of quebracho and wattle on anaerobic digestion Type de document : texte imprimé Auteurs : J. David Eye, Auteur ; Charles F. Ficker, Auteur Année de publication : 1982 Article en page(s) : p. 137-148 Note générale : Bibliogr. Langues : Américain (ame) Index. décimale : 675 Technologie du cuir et de la fourrure Résumé : Anaerobing digestion has been used extensively fot the biological stabilization of hight-strengh organic wastes and sludges. In a properly operating anaerobic system, methane gas which has considerable fuel value is produced as the organics are decomposed. The anaerobic process occurs in three simultaneous reaction steps : - 1) The complex organics are hydrolyzed to simpler compounds - 2) These compounds are then converted to a variety of organic acids and carbon dioxide by "acid" forming bacteria - 3) The organic acids from the second reaction are converted to methane gas by the methane-producing bacteria. The methane producers are extremely sensitive and require a carefully-controled environment. Since tannins have been shown to be toxic to selected strains of bacteria, this study was conducted to determine if quebracho and watlle would inhibit the anaerobic digestion process. The results of the study showed that both quebracho and wattle tannin adversely affected the operational controle required for the systems as well as methane production. The anaerobic organisms however were able to degrade the tannins so that the characteristic red color was effectively removed from the supernatant (liquid phase of digested sludge) during digestion. Note de contenu : - EChemical oxygen demand (C.O.D.) - Volatile suspended solids (V.S.S.) - Volatile acids (V.A.) - Gas volume and composition - Tannin mass balance En ligne : https://drive.google.com/file/d/1wVb27Um7ikYkeAQscQFxyCACCw7AlOAC/view?usp=share [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=17434 [article]

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