• Membrane and Water Treatment
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• v.15 no.2
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• pp.59-66
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• 2024

This study evaluated the performance of a membrane aerated biofilm reactor (MABR) for nitrogen removal from a high-strength ammonia nitrogen-containing wastewater. The experimental setup consisted of four compartments that are sequentially anaerobic and aerobic to achieve complete nitrogen removal. The last compartment of the reactor setup contained a membrane bioreactor (MBR) to reduce sludge production in the system and to obtain a better-quality effluent. Continuous experiment over a period of 47 days showed that MABR exhibited excellent NH₄⁺-N removal efficiency (99.5%) compared to the control setup without MABR (56.5%). The final effluent NH₄⁺-N concentration obtained in the MABR was 2.99±1.56 mg/L. In contrast to NH₄⁺-N removal, comparable TOC removal values in the MABR and the control reactor (99.2% and 99.3%, respectively) showed that air supply through MABR is much more critical for denitrification than for organic removal. Further study to understand the effect of air supply rate and holding pressure on NH₄⁺-N removal in MABR revealed that an increase in both these parameters positively impacted reactor performance. These parameters are related to oxygen supply to the biofilm formed over the membrane surface, which in turn influenced NH₄⁺-N removal in MABR. Among the two different strategies to control biofilm over the membrane surface, results showed that scouring for a duration of 10 min on a weekly basis, along with mixing air supply, could be an effective method.

• Journal of Animal Science and Technology
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• v.51 no.6
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• pp.503-510
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• 2009

This study investigated the effects of tannic acid (TA) in the diets for weanling pigs prepared with/without supplemental Fe on performance, hematology, fecal microflora and diarrhea incidence. Limestone and calcium phosphate used in Experiment 1 and 2 were of semi-synthetic and feed-grade quality, respectively; while the trace-mineral premix used in both the experiments was prepared without any added Fe source. In Experiment 1, 108 weaned pigs (Landrace ${\times}$ Yorkshire ${\times}$ Duroc, initially 6.46 ${\pm}$ 1.04 kg BW) were allotted to 3 treatments including control (diet added with $FeSO_4$ and antibiotic), T1 (diet devoid of $FeSO_4$ and antibiotic) and T2 (T1 diet added with 125 mg/kg TA). Each treatment had 4 replicates with 9 pigs in each pen. Feeding of T1 diet had a negative effect on the performance and plasma Fe status of pigs, while addition of TA to T1 diet resulted in performance of pigs comparable to pigs fed the control diet, reduced diarrhea incidence but had a negative influence on the hematological and plasma Fe indices. Additionally, pigs fed T2 diet had fewer (p<0.05) total anaerobic bacteria, Clostridium spp. and coliforms than pigs fed T1 diet, and greater number of Bifidobacterium spp. and Lactobacillus spp. in feces when compared with pigs fed control and T1 diets. In Experiment 2, 144 weaned pigs (Landrace ${\times}$ Yorkshire ${\times}$ Duroc, initially 6.00 ${\pm}$ 1.07 kg BW) were allotted to 4 dietary treatments including control (diet added with $FeSO_4$ and antibiotic) and diets devoid of supplemental Fe added with antibiotic (An), TA and both (AnTA). Each treatment had 4 replicates with 9 pigs in each pen. Addition of An, TA or both to diets devoid of supplemental Fe did not have any effect on performance, blood hematology and plasma Fe but resulted in reduced (p<0.05) diarrhea incidence and lower (p<0.05) fecal coliform population than pigs fed the control diet. These results suggest that TA has a negative influence on blood hematology and plasma Fe status when diets are inadequate in Fe; however, TA reduced diarrhea incidence and might have antimicrobial activity.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.687-692
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• 2006

This experiment was performed to evaluate the characteristics of BNR system performance, behavior of pollutants as organic and nitrogen at each basin and the effects of C/N ratio on biological nitrogen removal with methanol as an external carbon source for a low C/N ratio municipal wastewater. A lab-scale $A_2O$ system by employing the aerobic basin with the fluidized polyurethane media, which was $10{\sim}20$ mm rube type like a sponge, was used. The aerobic basin was hybrid type to be suspended and fixed biomass. The obtained results from this study were as follows; When no methanol was added, suspended biomass was 3 times more than that of the fluidized media in this system(total biomass 80 g). Biomass growed by an external carbon was firstly attached on media, and then suspended. $COD_{Cr}$ concentration for the effluent was a range of 13 to 29 mg/L regardless of pouring an external carbon. For nitrogen, the effluent concentration was $20.0{\sim}35.9mg/L$(removal efficiency; 18%) in case of no addition of an external carbon, but was $2.5{\sim}9.0mg/L$(removal efficiency ; $71{\sim}83%$) with addition of methanol. For the characteristics of pollutants removal, most of $COD_{Cr}$ were removed at the anaerobic basin when no external organic carbon was added, and were removed at the anoxic basin in case of adding external organic carbon but at the aerobic basin in case of adding excess external organic carbon. On the other hand, most TIN(total inorganic nitrogen) were removed at the anaerobic basin when no external organic carbon was added, but when an external organic carbon was added, they were removed at the anaerobic basin under unstable condition and at the anoxic basin under stable condition.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.1
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• pp.64-70
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• 2017

Objective: In the present study, role of increasing levels of Ecklonia cava (seaweed) supplementation in diets was investigated on growth performance, coefficient of total tract apparent digestibility (CTTAD) of nutrients, serum immunoglobulins, cecal microflora and intestinal morphology of weanling pigs. Methods: A total of 200 weaned pigs (Landrace${\times}$Yorkshire${\times}$Duroc; initial body weight $7.08{\pm}0.15kg$) were randomly allotted to 4 treatments on the basis of body weight. There were 5 replicate pens in each treatment including 10 pigs of each. Treatments were divided by dietary Ecklonia cava supplementation levels (0%, 0.05%, 0.1%, or 0.15%) in growing-finishing diets. There were 2 diet formulation phases throughout the experiment. The pigs were offered the diets ad libitum for the entire period of experiment in meal form. Results: The pigs fed with increasing dietary concentrations of Ecklonia cava had linear increase (p<0.05) in the overall average daily gain, however, there were no significant differences in gain to feed ratio, CTTAD of dry matter and crude protein at both phase I and phase II. Digestibility of gross energy was linearly improved (p<0.05) in phase II. At day 28, pigs fed Ecklonia cava had greater (linear, p<0.05) Lactobacillus spp., fewer Escherichia coli (E. coli) spp. (linear, p<0.05) and a tendency to have fewer cecal Clostridium spp. (p = 0.077). The total anaerobic bacteria were not affected with supplementation of Ecklonia cava in diets. Polynomial contrasts analysis revealed that villus height of the ileum exhibited a linear increase (p<0.05) in response with the increase in the level of dietary Ecklonia cava. However, villus height of duodenum and jejunum, crypt depth, villus height to crypt depth ratio of different segments of the intestine were not affected. Conclusion: The results suggest that Ecklonia cava had beneficial effects on the growth performance, cecal microflora, and intestinal morphology of weanling pigs.

• Journal of Ginseng Research
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• v.42 no.2
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• pp.192-198
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• 2018

Background: Ginseng has been used as an ergogenic agent, although evidence for its effectiveness is weak. A randomized, double-blind, placebo-controlled clinical trial was conducted to evaluate the effect of a ginsenoside complex (UG0712) on changes in exercise performance. Methods: Sedentary individuals (n = 117) were randomly assigned into one of three groups: low-dose ginsenoside supplementation (100 mg/d, n = 39), high-dose ginsenoside supplementation (500 mg/d, n = 39), or a placebo group (500 mg/d, n = 39). All participants underwent a supervised 12-wk aerobic and resistance exercise training course. To assess the effects of supplementation on physical performance, maximal oxygen consumption ($VO_2max$), anaerobic threshold (AT), lactic acid, and muscle strength of the dominant knee were measured at baseline, every visit, and after the training program. Results: Both ginsenoside groups showed significant increases in $VO_2max$ and muscular strength during exercise training. There were no definite changes in AT and lactic acid levels over time. After exercise training, there were definite differences in the $VO_2max$ (28.64.9 to $33.7{\pm}4.9ml/kg/min$ in high-dose group vs. $30.4{\pm}6.7$ to $32.8{\pm}6.6ml/kg/min$ in placebo, p = 0.029) and AT ($19.3{\pm}4.2$ to $20.9{\pm}3.5ml/kg/min$ in high-dose group vs. $20.0{\pm}5.1$ to $20.0{\pm}4.9ml/kg/min$ in placebo, p = 0.038) between the high-dose ginsenoside and placebo groups. However, there was no difference in $VO_2max$ between the low-dose ginsenoside and placebo groups (p = 0.254). There were no differences in muscular strength during exercise training among the three groups. Conclusion: High-dose ginsenoside supplementation (UG0712) augmented the improvement of aerobic capacity by exercise training.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.610-618
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• 2008

It is not easy to compare the treatment processes and find an optimum operating condition by the experiments due to influent conditions, treatment processes, various operational conditions and complex factors in real wastewater treatment system and also need a lot of time and costs. In this paper, the activated sludge models are applied to four principal biological wastewater treatment processes, $A_2O$(anaerobic/anoxic/oxic process), Bardenpho(4 steps), VIP(Virginia Initiative Plant) and UCT(University of Cape Town), and are used to compare their environmental and economic assessment for four key processes. In order to evaluate each processes, a new assessment index which can compare the efficiency of treatment performances in various processes is proposed, which considers both environmental and economic cost. It shows that the proposed index can be used to select the optimum processes among the candidate treatment processes as well as to find the optimum condition in each process. And it can find the change of economic and environmental index under the changes of influent flowrate and aerobic reaction size and predict the optimum index under various operation conditions.

• Membrane and Water Treatment
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• v.11 no.1
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• pp.79-85
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• 2020

A single-stage deammonification with a sequencing batch reactor (SBR) that simultaneous nitritation, anaerobic ammonia oxidation (anammox), and denitrification (SNAD) occur in one reactor has been widely applied for sidestream of wastewater treatment plant. For the stable and well-balanced SNAD, a feeding strategy of influent wastewater is one of the most important operating factors in the single-stage deammonification SBR. In this study, single-stage deammonification SBR (working volume 30L) was operated to treat a high-strength ammonium wastewater (1200 mg NH₄⁺-N/L) with different feeding strategies (single feeding and nine-step feeding) under the condition without COD. Each cycle of the step feeding involved 6 sub-cycles consisted of aerobic and anoxic periods for partial nitritation (PN) and anammox, respectively. Contrary to unstable performance in the single feeding, the step feeding showed better deammonification performance (0.565 kg-N/m³/day). Under the condition with COD, however, the nitrogen removal rate (NRR) decreased to 0.403 kg-N/m³/day when the Nine-step feeding strategies had an additional denitrification period before sub-cycles for PN and anammox. The NRR was recovered to 0.518 kg-N/m³/day by introducing an enhanced multiple-step feeding strategy. The strategy had 50 cycles consisted of feed, denitrification, PN, and anammox, instead of repeated sub-cycles for PN and anammox. The multiple-step feeding strategy without sub-cycle showed the most stable and excellent deammonification performance: high nitrogen removal efficiency (98.6%), COD removal rate (0.131 kg-COD/m³/day), and COD removal efficiency (78.8%). This seemed to be caused by that the elimination of the sub-cycles might reduce COD oxidation during aerobic condition but increase the COD utilization for denitrification period. In addition, among various sensor values, the ORP pattern appeared to be applicable to monitor and control each reaction step for deammonification in the multiple-step feeding strategy without sub-cycle. Further study to optimize the number of multiple-step feeding is still needed but these results show that the multiple-step feeding strategy can contribute to a well-balanced SNAD for deammonification when treating high-strength ammonium wastewater with COD in the single-stage deammonification SBR.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.4
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• pp.556-562
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• 2007

A total of 126 crossbred weanling pigs (average body weight of $6.3{\pm}0.3$ kg) were used to investigate the effect of chito-oligosaccharide (COS) on growth performance, nutrient digestibility, pH of gastro-intestinal tract (GI), intestinal and fecal microflora of young piglets. Pigs were allocated to three dietary treatments based on body weight and gender in a single factorial arrangement. Treatments were control (No COS), T1 (0.2% COS during starter (6-13 kg) and 0.1% COS during grower (13-30 kg) phases, and T2 (0.4% COS during starter (6-13 kg) and 0.3% COS during grower (13-30 kg) phases, respectively. Each treatment had 3 replicates and 14 pigs were raised in each pen. COS is a low molecular weight water-soluble chitosan that can be obtained from chitin of the crab shell after deacetylation with concentrated sodium hydroxide at high temperature and then further decomposition by chitosanase enzyme in the presence of ascorbic acid. For the starter and grower periods, there were no significant differences (p>0.05) in average daily gain (ADG) and feed to gain ratio among treatments. However, during the overall period (6-30 kg), T2 showed better (p<0.05) feed to gain ratio than other treatments. A digestibility study was conducted at the end of grower phase which showed improvement (p<0.05) in DM and crude fat digestibility in T2 over the control. At 25 kg body weight, 6 pigs per treatment (2 per replicate) were sacrificed to determine the effect of diets on pH and microbial count at different sections of the GI tract. The pH of the cecal contents in pigs fed 0.1% COS was higher (p<0.05) than in the other treatments. Total anaerobic bacterial number increased from cecum to rectum in all treatments. The weekly total bacterial counts showed higher (p<0.05) in feces of pigs fed COS than that of untreated pigs at the $8^{th}$ week. The number of fecal E. coli in untreated pigs at $4^{th}$ wk was 7.35 log CFU/g compared to 6.71 and 6.54 log CFU/g in 0.1 and 0.3% COS-treated pigs, respectively. Similarly, at $8^{th}$ wk, fecal clostridium spp. were lower in pigs fed 0.3% COS (5.43 log CFU/g) than in untreated pigs (6.26 log CFU/g). In conclusion, these results indicated that chito-oligosaccharide could improve feed efficiency in young pigs and inhibited the growth of harmful bacteria.

• Journal of Korean Society on Water Environment
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• v.25 no.2
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• pp.227-234
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• 2009

In this research, a retrofitting process, which consists of a pretreatment system (coagulation) for dye wastewater combined with a biological nutrient system (MLE process using media), for a sewage treatment plant that has to treat dye wastewater efficiently with domestic wastewater were developed and a pilot plant was operated for verifying adoptability and performance of the developed advanced process for dye wastewater. From the results of the pilot plant operation, BOD 52.9%, $COD_{Cr}$ 55.9%, and color 71.3% were removed in pretreatment of coagulation process and the biodegradability of dye wastewater was improved to $0.32{\sim}0.59BOD/COD_{Cr}$ of the coagulated wastewater from $0.29{\sim}0.43BOD/COD_{Cr}$ of the raw dye wastewater. The final effluent concentrations were BOD of 8 mg/L, $COD_{Cr}$ of 43 mg/L, $COD_{Mn}$ of 18 mg/L, T-N of 8 mg/L, and T-P of 1.3 mg/L, respectively. Color was removed from 1655 to 468 unit by coagulation and then to 123 unit by MLE process. The HPLC analysis of aromatic amines in wastewater showed that decolorization was achieved by cometabolism while aromatic amines were produced by cleavage of azo bonds under anaerobic conditions and these products were removed in an aerobic tank subsequently. Nitrification rates of attached and suspended microorganisms were evaluated comparatively and the acclimating conditions of bacteria on media were validated by the scanning electron microscope.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1798-1807
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• 2017

The differentiations in nitrogen-converting activity and microbial community structure between granular size fractions in a continuous completely autotrophic nitrogen removal over nitrite (CANON) reactor, having a superior specific nitrogen removal rate of $0.24g/(g\;VSS{\cdot}h)$, were investigated by batch tests and high-throughput pyrosequencing analysis, respectively. Results revealed that a high dissolved oxygen concentration (>1.8 mg/l) could result in efficient nitrite accumulation with small granules (0.2-0.6 mm in diameter), because aerobic ammonium-oxidizing bacteria (genus Nitrosomonas) predominated therein. Meanwhile, intermediate size granules (1.4-2.0 mm in diameter) showed the highest nitrogen removal activity of $40.4mg/(g\;VSS{\cdot}h)$ under sufficient oxygen supply, corresponding to the relative abundance ratio of aerobic to anaerobic ammonium-oxidizing bacteria (genus Candidatus Kuenenia) of 5.7. Additionally, a dual substrate competition for oxygen and nitrite would be considered as the main mechanism for repression of nitrite-oxidizing bacteria, and the few Nitrospira spp. did not remarkably affect the overall performance of the reactor. Because all the granular size fractions could accomplish the CANON process independently under oxygen limiting conditions, maintaining a diversity of granular size would facilitate the stability of the suspended growth CANON system.