• Journal of Environmental Impact Assessment
• /
• v.15 no.6
• /
• pp.407-415
• /
• 2006

This study carried out submerged area due to Dam construction in the near future. It includes species classification of plant, survey of community structure, examination of pollutant load and assessment of water quality impact. The vascular plants of this area are listed 224 taxa; 64 families, 168 genera, 193 species, 30 varieties and 1 form. This study area is classified into total 21 communities, most community was consist of grass vegetation. Among the communities, Erigeron annuus ($869,286m^2$, 22%) community was dominant and Erigeron annuus-Avena fatua comminity (16%) was subdominant until May, and then Erigeron canadensis community occupied most area to $1,774,985m^2$ (32%) from May to July. For the evaluation of water quality impact due to submerged macrophyte, nutrient release test was conducted both dead body macrophyte and living body macrophyte. The results of release test show that T-N is not released at dead body macrophyte, but it is released at living body macrophyte, especially living body Artemisia priceps var. orientalis shows 1.436mgN/g. At release test of dead body macrophyte, T-P release rate of Erigeron annuus shows 0.500mgP/g at the top of them and it also shows 0.436mgP/g at Erigeron annuus of living body macrophyte. T-N load of submerged macrophyte shows 0.76% by comparison of total load on watershed and T-P load of that shows 3.61%. In case of removal macrophyte for reduction of pollutant load in submerged area, T-N load of submerged macrophyte changes from 0.76% to 0.15% by comparison of total load on watershed and T-P load of that changes from 3.61% to 0.72%.

• Asian-Australasian Journal of Animal Sciences
• /
• v.13 no.5
• /
• pp.711-719
• /
• 2000

The characteristics of the exocrine pancreatic secretions in pigs and its hormonal regulation as influenced by dietary lipids are reviewed. There is clear evidence that the secretion of lipolytic enzymes is positively correlated with the amount of fat consumed by the pig. For example, there was an increase in the specific lipase activity by 83% after the dietary fat content was increased from 5% to 25%. Moreover, it was shown that also the quality of fat has an influence on exocrine pancreatic secretions. Peroxidized canola oil stimulated total lipase secretion much more than non-peroxidized oil. The influence of fatty acid composition on exocrine pancreatic secretions is discussed equivocally. Some authors showed that saturated fats stimulated the exocrine pancreatic secretions more than unsaturated. Others showed that the chain length of fatty acids had a strong influence on pancreatic secretions as well. Due to the different surgical methods used for sampling of pancreatic juice and wide variety of fats and oils used in these studies, direct comparisons between studies are extremely difficult to make. Plasma levels of hormones such as cholecystokinin (CCK), neurotensin (NT) and peptide YY (PYY) are influenced by the nutrient composition of the diet. With increasing amounts of fat present in the small intestine, the release of these hormones was stimulated. There is evidence that CCK release is dependent on the chain length of the fatty acids. Medium chain triglycerides stimulated the CCK release more than long chain triglycerides. Neurotensin was released more by unsaturated than by saturated fatty acids; similar results were observed for the PYY release. However, results are contradictory and further investigations are warranted that focus on the underlying mechanisms involved in the regulatory response of the exocrine pancreas to lipids of different origin.

• International Journal of Aeronautical and Space Sciences
• /
• v.13 no.1
• /
• pp.14-26
• /
• 2012

The only extraterrestrial life detection experiments ever conducted were the three which were components of the 1976 Viking Mission to Mars. Of these, only the Labeled Release experiment obtained a clearly positive response. In this experiment $^{14}C$ radiolabeled nutrient was added to the Mars soil samples. Active soils exhibited rapid, substantial gas release. The gas was probably $CO_2$ and, possibly, other radiocarbon-containing gases. We have applied complexity analysis to the Viking LR data. Measures of mathematical complexity permit deep analysis of data structure along continua including signal vs. noise, entropy vs.negentropy, periodicity vs. aperiodicity, order vs. disorder etc. We have employed seven complexity variables, all derived from LR data, to show that Viking LR active responses can be distinguished from controls via cluster analysis and other multivariate techniques. Furthermore, Martian LR active response data cluster with known biological time series while the control data cluster with purely physical measures. We conclude that the complexity pattern seen in active experiments strongly suggests biology while the different pattern in the control responses is more likely to be non-biological. Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly. This suggests a robust biological response. These analyses support the interpretation that the Viking LR experiment did detect extant microbial life on Mars.

• Journal of Environmental Science International
• /
• v.28 no.10
• /
• pp.851-861
• /
• 2019

In this study, we performed a sediment elution experiment to evaluate water quality in terms of phosphorus, as influenced by the dissolved oxygen consumed by sediments. Three separate model column treatments, namely, raw, calcined, and sonicated oyster shell powders, were used in this experiment. Essential phosphorus fractions were examined to verify their roles in nutrient release from sediment based on correlation analyses. When treated with calcined or sonicated oyster shell powder, the sediment-water interface became "less anaerobic," thereby producing conditions conducive to partial oxidation and activities of aerobic bacteria. Sediment Oxygen Demand (SOD) was found to be closely correlated with the growth of algae, which confirmed an intermittent input of organic biomass at the sediment surface. SOD was positively correlated with exchangeable and loosely adsorbed phosphorus and organic phosphorus, owing to the accumulation of unbound algal biomass-derived phosphates in sediment, whereas it was negatively correlated with ferric iron-bound phosphorus or calcium fluorapatite-bound phosphorus, which were present in the form of "insoluble" complexes, thereby facilitating the free migration of sulfate-reducing bacteria or limiting the release from complexes, depending on applied local conditions. PCR-denaturing gradient gel electrophoresis revealed that iron-reducing bacteria were the dominant species in control and non-calcined oyster shell columns, whereas certain sulfur-oxidizing bacteria were identified in the column treated with calcined oyster powder.

• Journal of Korean Society of Water and Wastewater
• /
• v.10 no.3
• /
• pp.73-82
• /
• 1996

The removal efficiencies of organic substrates, nitrogen and phosphorus in the anaerobic-aerobic biological phosphorus removal process were investigated by addition of acetic acid, propionic acid and butyric acid which are normal volatile fatty acids contained in anaerobic digester supernatants. Substrate utilization coefficients for the phosphorus release and uptake were also estimated. The effect of a VFA, which showed higher phosphorus removal efficiency than the other VFAs did, was also studied in an anaerobic-aerobic-anoxic biological nutrient removal process. For the anaerobic-aerobic process added by VFA, the phosphorus removal efficiencies were up to about 68%, 55% and 61% for the reactors of acetic acid, propionic acid and butyric acid added, respectively, which indicates the efficiencies were increased by about 8-21%, comparing to that of 47% for the reactor with no VFA added. There were no significant difference in removal efficiencies for organic substrate and $NH_3-N$ without regard to addition of VFA. However, the removal efficiency of total nitrogen was increased in the case of VFA added, since $NO_3-N$ was less produced. For the anaerobic-aerobic-anoxic process added VFA, the removal efficiencies for $NH_3-N$ and $PO{_4}^{3-}-P$ were increased by 5% and 13%, respectively, comparing with them in the reactors not added VFA.

• Journal of Environmental Science International
• /
• v.20 no.1
• /
• pp.35-47
• /
• 2011

The effect of the variation of aeration time on the removal of organics, nitrogen and phosphorus using synthetic wastewater was investigated in sequencing batch reactors (SBRs) which included DNPAOs and DNGAOs. The cycling times in four SBRs were adjusted to 12 hours and then included different aerobic times as 1 hr, 2.5 hr, 4 hr and 5.5 hr, respectively. Four SBR systems have been operated and investigated for over 40 days. Average TOC removal efficiencies were about 71 % in all SBRs. The $NH_4^+$-N removal efficiency was increased as the increase of aeration time. After changing aeration time, the total nitrogen removal efficiencies of SBRs were shown as 35 %, 85 %, 75 % and 65 %, respectively. Higher phosphorus release and uptake were occurred as the decrease of the aeration time. After all, the overall phosphorus removal efficiency decreased and the deterioration of phosphorus removal was occurred when aeration time was over 4 hr. Denitrification in aerobic conditions was observed, which showed the presence of DNPAOs and DNGAOs. In batch experiments, PAOs were shown as the most important microorganisms for the phosphorus removal in this experiment, and the role of DNGAOs was higher than that of DNAPOs for the nitrogen removal.

• Journal of environmental and Sanitary engineering
• /
• v.13 no.1
• /
• pp.44-56
• /
• 1998

This study was performed to investigate the reaction characteristics of piggery wastewater for biological nutrient removal. The reaction characteristics were discussed the fraction of organics, the behavior of nitrogen, nitrification, denitrification, and the behavior of phosphorus. The fraction of readily biodegradable soluble COD was 11-12 percent. The ammonia nitrogen was removed via stripping, nitrification, autotrophic cell synthesis, and heterotrophic cell synthesis. The removal percents by each step were 12.1%, 68.9%, 15.0%, and 4.0%, respectively. Nitrification inhibition of piggery wastewater was found to occur at an influent volumetric loading rate over 0.2 NH$_{3}$-N kg/m$^{3}$/d. Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent. The phosphorus removed was released in the form of ortho-p in the aerobic fixed biofilm reactor, it was caused by autooxidation. The synthesis and release of phosphorus were related to the ORP and the boundary value for the phase change was about 170mV. In the synthesis phase, the phosphorus removal rate per COD removed was 0.023mgP$_{syn}$/mgCOD$_{rem}$. The phosphorus contents of the microorganism were 4.3-6.0% on a dry weight basis.

• Water for future
• /
• v.22 no.1
• /
• pp.117-125
• /
• 1989

This study deals with the performance of an acivated sludge system which is modified by the researcher to function without any additional chemical or internal recyle in removing organics, nitrogen, and phosphorus from synthetic wastewater. To improve the nutrient removal efficiency, the researcher utilized the anoxic, anaerobic, and aerobic reactor sequences with a single sludge return, whiched to nitrification/denitrification and phosphorus release/overplus accumulation. A bench scale system was operated with a view to investigating the reaction characteristics of each reactor, and to measuring the biological kinetic coefficients(Y, $K_d$, k, $K_s$) for theremoval of COD in relation to the mean cell residence time at five different MLSS concentrations, 5000, 4200, 3300, 2600, and 1900 mg/l. The results of the research showed that organic substance and nutrient were removed simultaneously by this modified activated sludge process. And the process kad 66%-99% ortho-p removal efficiency.

• Korean Journal of Ecology and Environment
• /
• v.36 no.2 s.103
• /
• pp.161-171
• /
• 2003

The present study evaluated water quality variation, limiting nutrient, and sediment of a shallow eutrophic lake (Lake Ilgam) in the metropolitan area from 2000 to 2002. According to annual mean chl.a ($77.2{\pm}36.6\;{\mu}g/l) and TP ($66.6{\pm}20.5\;{\mu}g/l) concentration and trophic state index (>60), Lake llgam was in very eutrophic status. Both inorganic nitrogen ($NH_3-N$ and $NH_3-N$) and phosphorus (SRP) concentrations in the water column increased during winter and spring, but decreased during summer followed by the phytoplankton development. Evidence for phosphorus and nitrogen as being the potential limiting nutrients for phytoplankton growth was supported by the ratio of DIN/DIP (by mass) (${\sim}$835.8), TSI derivations analysis, and algal growth potential bioassay. Based on the results of TSI derivations, strong nutrient limitation by both N and P occurred from September to November when P content in sediment (114.6 mg P/kg) was relatively low compared with the summer. Sediment contained a large amount of nitrogen (TKN: 4,452${\pm}$283.0mg N/kg dry sediment). Phosphorus content in sediment (TP: 313${\pm}$155 mg P/kg) was relatively low with temporal change. P release rate (0.29${\pm}$0.02 mg $m^{-2}$ $day^{-1}$) was high under the aerobic condition at pH 9. These results indicate that the sediment could play an important role as a source of a limiting nutrient, and temporal change of P content in the sediment is closely related with water quality, especially algal biomass change in Lake llgam.

• Ocean and Polar Research
• /
• v.38 no.1
• /
• pp.47-57
• /
• 2016

Effects of environmental factors on the zoospore release and germling growth of Chaetomorpha linum were examined. Zoospore release and germling growth experiments were carried out under a combination of temperatures ${\times}$ irradiances, and a single factor of irradiances, salinities, daylength and nutrients (nitrogen, phosphorus). Zoospore release was maximal under condition of $20^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in a factorial experiment (temperatures ${\times}$ irradiances), at $100{\mu}mol\;photons\;m^{-2}s^{-1}$ in irradiance experiment and at 34 psu in salinity conditions. After 24 days in culture, germling growth was maximal at $25^{\circ}C{\times}100{\mu}mol\;photons\;m^{-2}s^{-1}$ in temperatures ${\times}$ irradiances and at normal seawater (34 psu) in salinity. Germling growth is faster at higher irradiance under same temperature condition and it increased with increasing daylengths (8-16 h). Chaetomorpha linum grew in wide range of N and P concentrations. The growth of germling was maximal at $50{\mu}M\;{PO_4}^{3-}$ and $40{\mu}M\;{NH_4}^+$. Germling growth was more effective under nitrogen addition than phosphorus addition in culture. In conclusion, optimal environmental conditions for zoospore release were $20^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, and 34 psu. In addition, the optimal germling growth was observed at $25^{\circ}C$, $100{\mu}mol\;photons\;m^{-2}s^{-1}$, 34 psu, 16 h, $50{\mu}M\;({PO_4}^{3-})$ and $40{\mu}M\;{(NH_4}^+)$.