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Yong-Woo Lee Qing Tian Say Kee Ong Chikashi Sato Jinwook Chung 《Water, air, and soil pollution》2009,203(1-4):17-27
Municipal wastewaters with industrial discharges typically contain heavy metals which may inhibit the biological processes in wastewater treatment plants. In this study, copper inhibition on strict nitrifiers in a suspended growth (SG) reactor and a combined attached and suspended growth (A&SG) reactor was compared. Both reactors were subjected to a continuous copper input of 5 mg/L. When the accumulated total copper concentration in the reactor were approximately 25 mg/L (due to sorption to the biomass), a sharp decrease in nitrification (increase in inhibition) were observed in the SG reactor while nitrification remained the same for the A&SG reactor indicating that attached growth systems were more robust against copper toxicity than suspended growth systems. Using MINTEQA2, the concentrations of various chemical species were estimated and, of the different species present, adsorbed copper in the biomass and aqueous Cu(NH3)4 +2 were found to positively correlate with percent inhibition of nitrification. Based on the changes in the concentrations of the two species, Cu(NH3)4 +2 was probably the main chemical species responsible for inhibition of nitrification. This study has implications for wastewater treatment plants treating wastewaters with high ammonia and copper present. 相似文献
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Tetsuo Tamura Kazunori Inoue Hideto Nishiki Masafumi Sakata Makoto Seki Teruaki Koga Yoshihiro Ookubo Kazuhiro Akutsu Say Sato Kouichi Saitou Hikari Shinohara Terumi Kuraisi Hiroshi Kajikawa Mitsunori Kurihara 《Animal Science Journal》2019,90(1):62-70
We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (n = 20) or Treatment (n = 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (p < 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged. 相似文献
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Studies on the decomposition/oxidation of nitrite at differentpH values and aeration flow rates were investigated using abench-scale batch reactor. The conditions were pH 2.85, 3.50,5.80, 7.0, and 11.6, and with or without aeration at airflowrates of 1.50, 2.25, and 3.25 L min-1.Decomposition/oxidation of nitrite may be described by apseudo-first order expression, and the rate constants fornitrite decomposition/oxidation ranged from 1.2 ×10-6 s-1 to 1.12 × 10-4 s-1 depending on the experimental conditions. The rate ofdecomposition/oxidation of nitrite was found to increase for lowpH conditions and for high airflow rates. The experimentalresults showed that the dominant reaction in thedecomposition/oxidation of nitrite in low pH solutions and inthe presence of some aeration was most probably thedecomposition of nitrous acid to NO and NO2. Oxidation ofnitrite to nitrate appeared to proceed in a smaller proportionin comparison to the breakdown of nitrous acid to nitrogen oxidecompounds. Results from this study showed that emissions ofnitrogen oxides from nitrite-containing solutions are possible ifthe solutions were agitated and the pHs of the solutions wereless than 6. 相似文献
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In situ denitrification walls and biofilters made of wood chips are being implemented as innovative technologies for the removal of nitrates in tile drainage water from farms to reduce pollution of surface waters and the hypoxia problem in the Gulf of Mexico. Although fairly effective in removing nitrates, not much is known about the effectiveness of the biofilters in removal of herbicides, pesticides, and antibiotics in the drainage water. Using weathered wood chips obtained from an in situ denitrification wall, four common pollutants tested sorbed strongly to wood chips in the following order: enrofloxacin > monensin A > atrazine > sulfamethazine. Of the four chemicals tested, enrofloxacin was found to desorb the least by water extraction. The apparent hysteresis index for atrazine was found to be lower than that for enrofloxacin and sulfamethazine indicating greater sorption?Cdesorption hysteresis for atrazine than enrofloxacin and sulfamethazine. Consecutive steps of water desorption and organic solvent extraction indicated that more than 65% of the sorbed atrazine, 70% of sulfamethazine, 90% of enrofloxacin, and 80% of monensin A were retained in wood chips. Results of this study showed that wood chip denitrification walls or biofilters have an added benefit in retaining herbicides and antibiotics and therefore can act as a barrier to reduce pollution of surface water and groundwater. 相似文献
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Waleeittikul Athiya Chotpantarat Srilert Ong Say Kee 《Journal of Soils and Sediments》2019,19(5):2357-2373
Journal of Soils and Sediments - The objective of this research was to investigate the effects of salinity levels and pore water velocity (PV) on the sorption, fate, and transport of Cd through... 相似文献
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Pharmacokinetics of cefquinome in red‐eared slider turtles (Trachemys scripta elegans) after single intravenous and intramuscular injections
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K. Uney F. Altan G. Cetin M. Aboubakr B. Dik Z. Sayın A. Er M. Elmas 《Journal of veterinary pharmacology and therapeutics》2018,41(1):e40-e44
The purpose of this study was to evaluate the pharmacokinetics of cefquinome (CFQ ) following single intravenous (IV ) or intramuscular (IM ) injections of 2 mg/kg body weight in red‐eared slider turtles. Plasma concentrations of CFQ were determined by high‐performance liquid chromatography and analyzed using noncompartmental methods. The pharmacokinetic parameters following IV injection were as follows: elimination half‐life (t 1/2λz) 21.73 ± 4.95 hr, volume of distribution at steady‐state (V dss) 0.37 ± 0.11 L/kg, area under the plasma concentration–time curve (AUC 0–∞) 163 ± 32 μg hr?1 ml?1, and total body clearance (ClT) 12.66 ± 2.51 ml hr?1 kg?1. The pharmacokinetic parameters after IM injection were as follows: peak plasma concentration (C max) 3.94 ± 0.84 μg/ml, time to peak concentration (T max) 3 hr, t 1/2λz 26.90 ± 4.33 hr, and AUC 0–∞ 145 ± 48 μg hr?1 ml?1. The bioavailability after IM injection was 88%. Data suggest that CFQ has a favorable pharmacokinetic profile with a long half‐life and a high bioavailability in red‐eared slider turtles. Further studies are needed to establish a multiple dosage regimen and evaluate clinical efficacy. 相似文献