• Biotechnology and Bioprocess Engineering:BBE
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• v.5 no.6
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• pp.431-435
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• 2000

The goal of this research is to compare the metal binding characteristics of an anoxic selector activated sludge system and a conventional activated sludge system. Metal biosorption by biomass harvested from experimental systems was determined by a series of batch experiments. Heavy metals studied in this research were zinc, cadmium, and nickel. The sorption isotherm showed that the selector sludge had significantly higher sorption capacity than did the control sludge. Metal biosorption behavior closely followed a Freundlich isotherm model for equilibrium concentrations. ECP contents of biomass estimated by alkali extraction technique showed that ECP levels in the selector sludge significantly higher than that in the sludge harvested from the conventional system, indicating that the higher metal sorption capacity of selector sludge may be due to the selection of the ECP-producing bacteria (i.e., Zoogloea sp.) by the selector system.

• Korean Journal of Food Science and Technology
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• v.11 no.1
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• pp.1-7
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• 1979

This experiment was carried out to investigate the nutritive value of brewery's activated sludge on the performance and nutrients utilization of egg type chicken of babcock fed the different levels of sludge. The chemical composition, content of amino acids and mineral in brewery's activated sludge were also analyzed. 3,6,9 and 12% of brewery's activated sludge were supplemented with basal ration as a substituted ingredient to soybean oil meal in experimental ration. The results obtained were as follow: 1. Chemical composition analysis 1) Brewery's activated sludge had 42.50% of crude protein on the air dried basis, and had 15,69% of crude ash, and had 2,060 kcal of metabolizable energy per kg of sludge. 2) Total amino acid content of brewery's activated sludge was 42.50% and 99% crude protein of brewery's activated sludge was a true amino acid, and brewery's activated sludge contained especially more methionine and threonine that those of soybean oil meal. 3) In case of mineral content of brewery's activated sludge, phosphorus, magnesium, copper and iron were plentifully included. However, calcium content in brewery's activated sludge was very low. 2. Feeding trial 1) Body gain of chicken fed the different levels of sludge was decreased in proportion to increasing level of sludge was decreased in proportion to increasing level of sludge. However, no statistical differences were found out between treatments. 2) Diet intake of chicken fed the different levels of sludge was significantly (p<0.05) increased as the supplementation level of sludge in ration increased. 3) Feed conversion of chicken fed the different levels of sludge was high in proportion to increasing level of sludge in ration. However, there were no significant differences between treatments. 3. Digestion trial 1) Utilization of dry matter of chicken fed the different levels of sludge was decreased as the level of sludge in ration increased. However, no statistical differences were found out between treatments. 2) Utilization of crude protein of chicken fed the different levels of sludge was significantly (p<0.01) increased as the level of sludge was higher. Utilization of crude protein of control treatment and of sludge 3% treatment was higher than that of other treatments. 3) Utilization of crude ash of chicken fed the different levels of sludge was significantly (p<0.05) decreased in proportion to increasing level of sludge in ration. 4) Utilization of NFE of chicken fed the different levels of sludge was slightly decreased in proportion to increasing level of sludge in ration. However, no statistical differences were found out between treatments. Therefore according to this experiment, it may be concluded that brewery's activated sludge can be supplemented with chicken ration by $6{\sim}9%$.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.3
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• pp.67-78
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• 1997

The objective of study was to examine to transient response of hydraulic shock loading in activated sludge process for treatment of municipal sewage. The general experiment approach was to operate the system under steady-state(pre-shock), then to apply step changes during 24hours in fourfold hydraulic shock loading at the same organic loading. Performance was assessed in both the transient state and the new steady-state(post-shock). Three bench scale activated sludge reactors were operated to investigate the effect of fourfold hydraulic shock loading on TSS and COD removal efficiency. In activated sludge reactors operated with 13hours and 7hours of HRT, effluent quality of all reactors was not changed for few effects, and also showed no foaming and no sludge bulking. Those results are the same as sludge withdrawn reactors. The effect of fourfold hydraulic shock loading on the activated sludge reactors operated with 3hours of HRT was most severe. The effluent quality was deteriorated significantly and generate foaming in reactors. Less than 24hours after the fourfold shock loading applied, the activated sludge system seemed to attain a new steady-state condition as show by effluent.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.2
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• pp.153-162
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• 2021

The effects of activated carbon originated Ballasted Flocculant (BF) on the settleability of activated sludge and the recovery of BF by Hydro-cyclone (HC) were analyzed experimentally. Two kinds of BF (M-I: 125-250 ㎛, M-II: 250-425 ㎛ in dia.) and three kinds of activated sludges with different SS concentration (2,300-7,100 mg/L) were applied for this study. With the dosage variation of BF from 0.14 to 1.3 g-BF/g-SS, we could obtain 24-31% improvement in SV30 (Sludge Volume after 30min sedimentation) for the lowest SS concentration sludge (2,300 mg/L). Whereas the SV30 improvement was much higher as 44-48% for the highest SS concentration sludge (7,100 mg/L). The settling characteristics of the sludge with BF followed Vesilind model the best among three models (Vesilind, Takacs and Cho model). HC could effectively separate BF with the separation efficiency of 70-90% and over 95% separation efficiency could be obtained when the HC was applied twice.

• Environmental Engineering Research
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• v.20 no.1
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• pp.105-109
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• 2015

Triclosan is a synthetic antimicrobial agent used in numerous industrial and personal care products. Triclosan collected in wastewater treatment plants can be biodegraded up to 80%. However, little is studied about the abundances of known triclosan-degrading bacteria in activated sludge systems. A previous study reported that Sphingopyxis strain KCY1 isolated from activate sludge can cometabolically degrade triclosan. Recently, a quantitative PCR (qPCR) assay specific to strain KCY1 has been developed. Thus, this study investigated the abundance of strain KCY1 in three different activated sludge wastewater treatments using a qPCR assay. Additionally, ammonia-oxidizing bacteria (AOB), known as triclosan-degraders, and amoA gene were quantified. Strain KCY1 were detected in activated sludge samples from three different wastewater treatment plants. The concentrations of strain KCY1 and AOB were on the order of $10^5-10^6$ gene copies/mL, while amoA gene concentration was on the order of $10^4$ gene copies/mL.

• Journal of Environmental Science International
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• v.17 no.12
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• pp.1343-1351
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• 2008

The activated sludge obtained from wastewater coke oven plant was immobilized by entrapment with polyethylene glycol (PEG). The effects of several factors on the biodegradation of $CN^-$ from. synthetic wastewater were investigated using batch and continuous reactors. The degradation rate of $CN^-$ increased with increasing of the immobilized bead volume in the reactor. Approximately 7.65mg/L of $NH_4-N$ was produced upon the degradation of 35mg/L of $CN^-$. When high concentrations of the toxic cyanide complex were used in the testing of cyanide degradation, the free activated sludge could be inhibited more than that of the immobilized activated sludge. When the phenol concentration was higher than 400mg/L in the synthetic wastewater, approximately 98.4% of $CN^-$ was removed within 42 hours by the immobilized activated sludge. However, the cyanide was not completely degraded by the tree activated sludge. This indicates that high phenol concentrations can act as a toxic factor for the free activated sludge. A $CN^-$ concentration of less than 1mg/L was achieved by the immobilized sludge at the loading rate of 0.025kg $CN^-/m^3-d$. Moreover, it was found that the HRT should be kept for 48 hours in order to obtain stable treatment conditions.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.5
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• pp.551-559
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• 2008

An experimental study was carried out to evaluate the potential of flotation process for the secondary clarifier of an activated sludge process. Flotation techniques, applied in this study, include electrofloation (EF) which generated fine bubbles smaller than $35{\mu}m$ in average and diffuser flotation (DF) which generated fine bubbles smaller than $55{\mu}m$ in average. The batch experiments were done with activated sludge displaying various characteristics. It was shown that the efficiency of solids/liquid separation was reduced as the diluted sludge volume index ($DSVI_{30}$) of activated sludge increased. The dependency, however, gradually decreased as the gas to solids (G/S) ratio increased. Thickening efficiency of EF was more than 2~10 times and DF process was more than 1.5~5 times as compared with gravity sedimentation (GS). Stable sludge blanket was maintained regardless of sludge settleability when the G/S ratio was 0.019 in the EF. On the other hand, Serious deterioration in the sludge blanket was observed in the DF depends on G/S ratio and sludge settleability. And For EF and DF, the suspended solids concentration of effluent was not nearly influenced on settleability of activated sludge and more clear than GS. A biological nutrient removal (BNR) process, combined with EF as a secondary clarifier was operated for three months. The mean MLSS (mixed liquid suspended solids) concentration in the reactor and mean solids concentration of return sludge were estimated to be 5,340 mg/L and 16,770 mg/L, respectively. The water quality of effluent was considerably stable and low value was accomplished, that was, standard suspended solids concentration $0.07{\pm}0.51mg/L$ and standard turbidity $1.44{\pm}0.56NTU$. The EF could be applicable for enhancement of efficiency of activated sludge system as well as improvement of the water quality of effluent.

• KSBB Journal
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• v.25 no.1
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• pp.67-72
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• 2010

In this study, we developed a comprehensive correlation for better prediction of the activated sludge concentration in the relationship between measurement of optical density by the Beer's law and sludge properties. Effects of activated sludge properties, which are sludge types and anaerobic storage time, show that absorbance deviation for sludge properties decreased on wavelength of light source near to 950 nm. We also developed a method to measure limitation with non-linear correlation on the measurement of high concentration by the Beer's law using a double layer probe cell and empirical equations.

• Journal of Korean Society of Water and Wastewater
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• v.19 no.3
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• pp.295-300
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• 2005

The performances of electroflotation (EF) on the thickening of activated sludge were investigated using laboratory scale batch flotation reactors. Four activated sludges including bulking sludges were tested. After 30minutes of EF operation, 57-84 % of sludge volume reduction could be achieved by EF, while only about 1.5-14% could be obtained by gravity thickening for the same period. After thickening the effluent water quality in terms of TCOD, SS, and turbidity was improved by EF operation for all sludge samples. It is induced that the air bubbles entrapped in the thickened sludge play a key role in the observed improvement of sludge thickening and effluent quality.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.62-67
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• 2016

In this study, a pellet-type adsorbent was prepared by using the water-treatment sludge as a raw material, and its physical and chemical properties were analyzed through $N_2$-adsorption, XRD, XRF, and $NH_3$-TPD measurements. Adsorption performance for gaseous ammonia and formaldehyde was compared between the pellet-type adsorbents prepared from water-treatment sludge and the impregnated activated carbon. Although the surface area and pore volume of the pellet-type adsorbent produced from water-treatment sludge were much smaller than those of the impregnated activated carbon, the pellet-type adsorbent produced from water-treatment sludge could adsorb ammonia gas even more than that of using the impregnated activated carbon. The pellet-type adsorbent prepared from water-treatment sludge showed a superior adsorption capacity for ammonia which can be explained by chemical adsorption ascribed to the higher amount of acid sites on the pellet-type adsorbent prepared from water-treatment sludge. In the case of formaldehyde adsorption, the impregnated activated carbon was far superior to the adsorbent made from the water-treatment sludge, which can be attributed to the increased surface area of the impregnated activated carbon.