• Magazine of the Korean Society of Agricultural Engineers
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• v.39 no.3
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• pp.64-71
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• 1997

Floating aquatic plant system using water hyacinth was applied to examine feasibility as a wastewater treatment system for the industrial complex in rural area. The wastewater from the industrial complex does not likely contain toxic pollutants because the industries which generate wastewater with toxic compounds are not allowed to move in. Pilot plant was installed at Baeksuk Nongkong Danzi in Chunahn-City, Chunchungnam - Do , and field study was performed during summer and fall of 1996. Hydraulic loading rate was 0. $0.19m^3/m^2$.day. The effluent concentration of DO was higher than influent, and it implies that 0.6m depth reactor was reaerated enough to increase DO level. The influent concentration of BOD varied significantly from less than 30 to 120mg/${\ell}$ during the study period, however, effluent concentrations were generally lower than the water quality standard and removal efficiency was up to 85%. The influent concentration of COD also showed wide variation from less than 40 to 160mg/${\ell}$ and effluent concentration was higher than water quality standard when influent concentration was over l00mg/${\ell}$. The influent concentrations of T-N and T-P were lower than water quality standard and no further treatment was required, and these compounds were also removed in the system. Although some improvement and refinement are still required, overall* the floating aquatic plant system was proved to be feasible to apply to treat wastewater from industrial complex in rural area.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.149-154
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• 1985

Removal of water pollutants by water hyacinth was examined with two nutrients, $NO_3$-N, $PO_4$-P and four heavy metals, Cu, Pb, Cd, Cr under laboratory conditions. $NO_3$-N was reduced to 0.7, 0.9 and 1.2 ppm, and 0.1, 0.2 and 0.5 ppm in $NO_4$-P from 10, 25 and 50 ppm 3 days after treatment, respectively. Among heavy metals Cu and Pb were removed faster and higher than Cd and Cr and also amount of heavy metals absorbed by water hyacinth was higher in the order of Cu > Pb > Cr > Cd. Distribution of heavy metals in this plant was higher in roots than in leaves and amount absorbed in roots was related to the treated concentrations. The harmful effect on growth of water hyacinth was observed in Cu and Cd.

• Korean Journal of Weed Science
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• v.5 no.2
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• pp.143-148
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• 1985

Water hyacinth, unused and tropical plant was examined in order to know the feasibility of application for purification of municipal drainage and industrial wastewater. This plant was effective to remove the COD from wastewater, although its removal ability was dependent on the organic sources. The effects of pH, NaCl concentration, water temperature and shading condition on the growth of water hyacinth were investigated. The optimum ranges of pH were weak acid- neutral, of water temperature were 17-$21^{\circ}C$, and unshading condition was better. The rapid propagation of this plant was also observed during hot summer season.

• Environmental Engineering Research
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• v.20 no.3
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• pp.212-222
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• 2015

Experiments were conducted on the immobilization of eight heavy metals (HMs) (Zn, Cu, Mn, Fe, Ni, Pb, Cd, and Cr) during 20-day rotary drum composting of water hyacinth. The Tessier sequential extraction procedure was used to investigate the fractionation of HMs. The eco-toxicity risk of HMs was assessed by risk assessment code (RAC). In the results, the bioavailability factor (BAF) for different HMs presented in the following order: Mn > Zn = Fe > Cu > Cr > Cd = Pb > Ni. The total concentration of Pb was higher than that of Zn, Cu, Mn, Cd and Cr; however, its BAF was the lowest among these HMs. These results confirmed that the eco-toxicity of HMs depends on bioavailable fractions rather than on the total concentration. The greatest reduction in bioavailability and eco-toxicity risk of HMs occurred in lime 1% and 2% as compared to control and lime 3%. The eco-toxicity risk of Fe, Ni, Pb, Cd and Cr was reduced from low risk to zero risk by rotary drum composting. These studies demonstrated the high efficiency of the rotary drum for degrading compost materials and for reducing the bioavailability and eco-toxicity risk of HMs during the composting process.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.4
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• pp.537-542
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• 2002

A study was conducted to evaluate the nutritive potential value of different aquatic plants: duckweed (Lemna trisulaca), duckweed (Lemna perpusila), azolla (Azolla pinnata) and water-hyacinth (Eichhornia crassipes) from Bangladesh. A wide variability in protein, mineral composition, gas production, microbial protein synthesis, rumen degradable nitrogen and in situ dry matter and crude protein degradability were recorded among species. Crude protein content ranged from 139 to 330 g/kg dry matter (DM). All species were relatively high in Ca, P, Na, content and very rich in K, Fe, Mg, Mn, Cu and Zn concentration. The rate of gas production was highest in azolla and lowest in water-hyacinth. A similar trend was observed with in situ DM degradability. Crude protein degradability was highest in duckweed. Microbial protein formation at 24 h incubation ranged from 38.6-47.2 mg and in vitro rumen degradable nitrogen between 31.5 and 48.4%. Based on the present findings it is concluded that aquatic species have potential as supplementary diet to livestock.

• Journal of Wetlands Research
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• v.4 no.2
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• pp.23-41
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• 2002

In this paper, changes of the coliform bacteria were investigated when aquatic plant pond was used for separating algal particles from waste stabilization ponds(WSPs). Three different types of integrated natural systems were operated. It was found that there were no significant interferences for the disinfection efficiency of two integrated systems (WSPs coupled with water hyacinth ponds) used for treating domestic sewage and upgrading the secondary effluent as well. However, when constructed wetland (CW) was combined with the shallow algal ponds and used for the secondary effluent, it seriously interfered with the disinfection efficiency due to the regrowth and/or after-growth of the coliform bacteria, which can readily metabolize the amino acids and sugars leached from plants. In order to find out the primary disinfection parameters, several sets of the batch test were run. It was found that sunlight is the most predominant factor for the coliform decay. During the night, algal toxicity partly supports the decay but during the day, deteriorates it by attenuating the sunlight. The pH in the range of 4 to 10 did not affect the decay in the dark.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.5
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• pp.646-653
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• 2013

Four crossbred Sindhi heifers with an average body weight (BW) of 135 kg and a mean age of 17 months were used to investigate the effect of feeding different combinations of rice straw and ensiled water hyacinth (EWH) supplemented with a source of protein in the form of cottonseed cake (CSC) on intake and digestibility. Four treatments consisting of graded levels of EWH were arranged in a $4{\times}4$ Latin square. The levels of EWH were set at: 0 (EWH0), 15 (EWH15), 30 (EWH30), and 45% (EWH45) of an expected total dietary dry matter (DM) intake of 30 g total DM per kg BW per day. Rice straw was offered ad libitum, while CSC was given at a fixed level of 5 g DM/kg body weight (BW). Voluntary intake and digestibility were measured consecutively in the 4 experimental periods which each lasted 28 days. The crude protein (CP) content of EWH, rice straw and CSC were 174, 53 and 370 g/kg DM, respectively. Rice straw had the highest neutral detergent fibre (NDFom) content (666 g/kg DM), followed by EWH (503 g/kg DM) and the lowest content was 418 g/kg DM in the CSC. The actual EWH contents in the consumed diets were 0, 17, 32 and 52% for EWH0, EWH15, EWH30 and EWH45, respectively. Rice straw intake decreased with level of EWH offered from 3049 for EWH0 to 1014 g/day for EWH45. Crude protein intake was 16, 25 and 33% higher (p<0.001) in EWH15, EWH30 and EWH45 treatments, respectively, as compared to EWH0. Digestibility of organic matter (OM), CP, NDFom and acid detergent fibre (ADFom) increased with increasing level of EWH offered. The highest OM digestibility (72.2%) was found for treatment EWH45 and the lowest (47.4%) for treatment EWH0. In spite of similar dietary CP contents, CP digestibility increased by 21 (EWH15), 31 (EWH30) and 40% (EWH45) with increasing level of EWH in comparison with treatment EWH0. It is concluded that increasing level of EWH in cattle diets considerably improved CP intake and digestibility of nutrients.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.3
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• pp.275-280
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• 1995

The effect of supplemented high protein diet intake on renal urea regulation in swamp buffalo was carried out in the present experiment Five swamp buffalo heifers weighing between 208-284 kg were used for this study. The animals were fed with a supplementary high protein diet and renal function and kinetic parameters for urea excretion were measured. This was compared to a control period where the same animals had been fed only with paragrass and water hyacinth. For 2 months the same animals were fed a mixed of paragrass, water hyacinth plus 2 kgs of a high protein supplement (protein 18.2% DM basis) per head per day. In comparison to the control period, there were no differences in the rate of urine flow, glomerular filtration rate (GFR), effective renal plasma flow (ERPF), plasma urea concentration and filtered urea. In animals supplemented with high protein intake mean values of urea clearance, excretion rate and the urea urine/plasma concentration ratio markedly increased (p < 0.05) while renal urea reabsorption significantly decreased from 40% to 26% of the quantity filtered. In this same study group urea space distribution and urea pool size increased which coincided with an increase in plasma volume (p < 0.05). Plasma protein decreased while plasma osmolarity increased (p < 0.05). Both urea turnover rate and biological half-life of $^{14}C$-urea were not affected by a supplementary high protein intake. The results suggest that animals supplemented with high protein diets are in a state of dynamic equilibrium of urea which is well balanced between urea excreted into the urine and the amount synthesized. The limitation for renal tubular urea reabsorption would be a change in extra-renal factors with an elevation of the total pool size of nitrogenous substance.

• The Korean Journal of Ecology
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• v.15 no.2
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• pp.137-145
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• 1992

When exposed to 1, 700 ml of 0.089, 0.445 or 0.890 mM/l cadmius solution, dock (rumex crispus L)plants from heavily polluted chungrangchon site absorbed 0.0404, 0.2244 or 0.4929 mM of cadmium per g dw during the first 4 hours, which were 5.0~30.8 times faster uptake rate than those of water hyacinth (eichhornia crassipes Solm. - laub). Zinc, with which cadmium generally occurs together, did not affect the uptake rate in the concentration range of 0.0306 ~0.0918 mM/l. rumex cripus from chungrangchon site and from less polluted shingalchon site, when exposed to 1, 700 ml of 0.089 mM/l solution for 3 days, removed 68.4% and 63.2%, repectively, of the cadmium initially present in the solution. And when exposed to cadmium solution of the same concentration for the second time after cadmium-free hydroponic culture for three days, these plants removed 76.1% and 66.8% of cadmium, respectively. These removal rates were not significantly different between collection sites or between exposures, but were about 2 times greater for the first exposure, and 2~5 times greater for the second exposure, than those of water hyacinth. these results incate that rumex cripus can absorb, and thus remove, large amount of cadmium ion in wastewater, and so can be used in wastewater treatment, e.g. soil trench method. since there was large difference among the plants in the ability to absorb cadmium, it should be possible to select for strain with greater ability.

• Korean Journal Plant Pathology
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• v.10 no.3
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• pp.163-168
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• 1994

Erwinia rhapontici causes soft-rot disease in a number of plants such as rhubarb, onion, hyacinth and garlic. Pectate lyase (Pel) depolymerizes pectin and other polygalacturonates, which is though to play a role in bacterial invasion of plants. Pel activity was not detected in E. rhapontici cultured in a minimal salts medium containing glycerol, polygalacturonate, or citrus pectin as a carbon source. However, when sterilized potato tuber and Chinese cabbage slices were added to minimal salts polygalacturonate (0.5%) medium, E. rhapontici produced pectate lyase enzyme. Also Pel activity was consistently detected from macerated potato tubers, Chinese cabbage leaves, lettuce leaves and celery petioles tissue. Pel in the extract of macerated Chinese cabbage caused by E. rhapontici strain 1, resulted in electrolyte loss, tissue maceration and cell death of potato tuber tissue. These results indicate that E. rhapontici produces pectate lyase only in the presence of non-diffusible plant components, and that this enzyme probably contributes to its pathogenicity.