• Journal of Environmental Health Sciences
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• v.31 no.1
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• pp.86-93
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• 2005

Because generally large amount of sludges are generated from the process of sewage and wastewater treatment, the management and controlment of those sludge has become a important issue in many researches. In this dissertation, we conducted the research to see the physico-chemical characteristics of sludges generated from various sources. Moisture of sludges were 81.5% in textile industries, 81.4% in frame metal industries, 80.7% in 1st metal industries. Volatile solid were 22.1% in hide · rubber industries, 21.9% in coke · petroleum industries. Fixed solid were 18.5% and 17.7% in the 1st metal industries and frame metal industries. High heating value by wet base were 1,850 kcal/kg in coke · petroleum industries, 1,220 kcal/kg in hide · rubber industries, but sludges from the 1st metal industries and frame metal industries were impossible to incinerate because most of those sludges were inorganic. The leaching test showed that hazardous materials was detected in nearly every kinds of sludges. Some of sludges from hide · rubber industries and frame metal industries exceeded the leaching criteria and so they were classified as specific wastes. And other sludges generated in sewage treatment plants or other industries was below the leaching criteria.

• Journal of Environmental Science International
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• v.14 no.4
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• pp.413-425
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• 2005

The 16 priority PAHs (Polycyclic Aromatic Hydrocarbons) designated by US Environmental Protection Agency were analyzed for some digested sludges from wastewater treatment plants in Korea. PAHs are an important group of organic contaminants present in sewage sludge due to their persistence and toxic potential. PAHs were extracted from freeze-dried sludges using a methylene chloride-methanol (2:1) mixture in a soxhlet extractor. The extracts were cleaned-up by silica gel/alumina combination column and subsequently fed into gas chromatograph/mass spectrometer (GC/MS) for determining PAH contents. The sum of the 16 PAHs in the sewage sludge varied from 534.8 to $5754.5 {\cal}ug/{\cal}kg$, dry wt.. In the sewage sludge, phenanthrene appears as the most abundant PAHs, followed by naphthalene, pyrene, fluoranthene. Source of the investigated sewage sludges relatively predominated pyrogenic. PAHs levels of sewage sludges in Korea appeared to be lower than those in other countries.

• Korean Journal of Microbiology
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• v.40 no.4
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• pp.307-312
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• 2004

Diversity of the bacterial communities and the relation between community structure and components of waste­water were analyzed by 16S rRNA-based molecular techniques. Clone libraries of the 16S rDNAs from the sludges were constructed by PCR and cloning. The 1,151 clones from a sludge sample of sewage treatment plant were clustered into 699 RFLP phylotypes and the 1,228 clones from the wastewater disposal plant of chemical industry were clustered into 300 RFLP phylotypes. Shannon-Weiner diversity indices of two sampling sites were 8.7 and 6.1, indicating that the bacterial community structure of sewage treatment plant was more diverse than that of wastewater disposal plant of chemical industry. Forty clones belonging to predominant RFLP types were selected and sequenced. Seventy percent (28 clones) of the sequenced clones were related to the uncultured bacteria in public databases. The ${\beta}-Proteobacteria$ dominated in the bacterial communities of investigated two sludge samples. 16S rDNA sequences of the sewage treatment plant were similar to those of other activated sludges, while the bacterial community in wastewater disposal plant of chemical industry rep­resented the strains identified from high-temperature, anaerobic, hydrocarbon-rich, and sulfur-rich environ­ments. This result suggested that bacterial communities depended upon the components of wastewater.

• Journal of Microbiology and Biotechnology
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• v.15 no.2
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• pp.287-295
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• 2005

In order to compare bacteria] community structure and diversity in activated sludges, terminal restriction fragment length polymorphism (T-RFLP) of PCR-amplified 16s rDNAs was analyzed for 31 domestic and industrial wastewater treatment plants (WTPs). Regardless of the characteristics of the wastewaters, the bacteria] community structures of activated sludges appeared diverse and complex. In particular, activated sludges in domestic WTPs contained higher bacterial diversity than those in industrial WTPs. It was also found that terminal restriction fragment (T-RF) profiles derived from domestic WTPs were very similar with each other, although activated sludges were collected from different plants at different locations. Interestingly, activated sludges of a WTP where restaurant and toilet sewages of a company were managed showed a bacterial community structure similar to that of domestic WTPs. Activated sludges in leather industria] WTPs also showed a high similarity. However, other wastewaters possessed different bacterial communities, so that overall similarity was as low as about $30\%$. Since activated sludges from WTPs for domestic wastewaters and a company sewage appeared to hold similar bacterial communities, it was necessary to confirm if similar wastewaters induce a similar bacterial community. To answer this question, analysis of T-RFs for activated sludges, taken from another 12 domestic WTPs, was conducted by using a 6­FAM$^{TM}$-Iabeled primer and an automated DNA sequencer for higher sensitivity. Among 12 samples, it was again found that T-RF profiles of activated sludges from Yongin, Sungnam, Suwon, and Tancheon domestic WTPs in Kyonggi-do were very similar with each other. On the other hand, T-RF profiles of activated sludges from Shihwa and Ansan WTPs were quite different from each other. It was thought that this deviation was caused by wastewaters, since Ansan and Shihwa WTPs receive both domestic and industrial wastewaters. From these results, it was tentatively concluded that similar bacterial communities might be developed in activated sludges, if WTPs treat similar wastewaters.

• Journal of the Korea Organic Resources Recycling Association
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• v.24 no.3
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• pp.101-108
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• 2016

Concentrations of Chromium(Cr) and Manganese(Mn) in several kinds of dewatered organic sewage sludges generated from wastewater treatment plants of Pocheon City, Gyeongii Province were examined. In addition, bioaccumulations of Cr and Mn in the body of earthworm Eisenia fetida were also investigated by changing of feed sludge amounts. Cr and Mn concentrations in sludges were in the range of 0.0~0.3 mg/kg and 3.6~17.6 mg/kg, respectively, which would not cause acute toxicities to earthworm population. Cr was bioaccumulated in the earthworm body but bioaccumulation was not proportional to the amount of sludges supplied. The degree of bioaccumulation of Cr decreased in later phase as the supplied amounts of sludges increased. Meanwhile, there were rare bioaccumulation with regard to Mn. In this study, the value ranges of bioaccumulation factor (BAF) for Mn were 0.00~0.12 when 60g of sludges was supplied. In the case of Cr, the value of BAF was 19.33 when 60g of human manure sludge was provided.

• Korean Journal of Soil Science and Fertilizer
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• v.31 no.2
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• pp.189-196
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• 1998

Swage sludge cakes produced from domestic wastewater treatment plants were collected from 21 different sites throughout Korea, and chemical properties of the sludge samples were determined. Inorganic nutrient contents did not indicate great differences among swage sludges from each sites, whereas the toxic heavy metal contents differed greatly. T-N, $NH_4{^+}-N$ and $NO_3{^-}-N$ contents from 21 sites sludges ranged 2.3-6.0, 291-4284, $1.4-58.8mg\;kg^{-1}$, respectively. Heavy metal (Cd, Cu, Pb and Zn) contents ranged 2.86-58.22, 144.0-5417.3, N.D.-943.5, and $N.D.-8,083mg\;kg^{-1}$, respectively. One of the sludges was treated to soils at rates of 12.5, 25, 50. and 100, $Mg\;ha^{-1}$ and incubated for 12 weeks to determine nitrogen materialization rate. Ammoniun nitrogen content decreased sharply at higher rates of sludge treatment up to 8 weeks after treatment and did not change much, while $NO_3{^-}$ increased at all treatment levels. The net amount of mineralized N of sludge treatment rates (12.5, 25, 50, and $100Mg\;ha^{-1}$) during 12weeks incubation were 189.0, 277.2, 303.8 and $376.6mg\;kg^{-1}$.

• Clean Technology
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• v.15 no.3
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• pp.154-164
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• 2009

In 2007, 94% of organic wastewater sludge from industries located in Ulsan was disposed of by ocean dump. The ocean dump of organic sludge would be totally prohibited by the year of 2012. However, there is no alternative but incinerating the sludge from the industries located in Ulsan. Securing the technology for sludge treatment and on-land disposal is very important issue among the industries in the Ulsan Petrochemical Industry Complex. In this study, the material aspects of dried and carbonized sludge as a fuel were evaluated for petrochemical and sewage sludge from Ulsan. The dried and carbonized sludges from the factories producing terephthalic acid, BTX, propylene, chemical textile, etc. of which the low heat value exceeded 3,000 kcal/kg had high potential as a fuel according to the results of thermal characteristic analysis. However, the dried sludges with heat values lower than 2,100 kcal/kg and carbonized sludges, lower than 1,100 kcal/kg containing more Inorganic material from the industries producing pulp, paper, methylamine, amide, etc. had a little potential to be used as a fuel. In most cases, drying the sludge showed better results than carbonization in the aspect of thermal characteristics of sludge.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.917-922
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• 2005

The wastewaters from textile and dyeing industries are difficult to treat due to its high pH, temperature, color intensity and non-biodegradable organic contents. This study investigated the removal of recalcitrant organics in a dyeing wastewater by using a packed bed reactor (PBR) that contained cell-immobilized pellets. The feed, obtained from an effluent of a biological treatment plant, had $SCOD_{Cr}$ of 330 mg/L and $SBOD_5$ of 20 mg/L on average. In immobilizing the cells to a Polyethylene Glycol(PEG) based medium, activated sludges from either a sewage treatment plant or an industrial wastewater treatment plant were used. When the empty bed contact time (EBCT) was above 8 hrs in the PBR, the $COD_{Cr}$ removal efficiency was over 50% and the $COD_{Mn}$ concentration was 72 mg/L or lower on average, which was substantially lower than the discharge standard of 90 mg/L. The results indicated that the optimum EBCT in the PBR was 8 hrs. The PBR with cell-immobilized pellets was effective as an advanced treatment process after an activated sludge process for treating dyeing wastewaters.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.8
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• pp.574-582
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• 2012

This study presents the concentrations of the polycyclic aromatic hydrocarbons (PAHs) listed as priority pollutants by United States Environmental Protection Agency (US EPA), in 98 sludges from 54 industrial wastewater treatment facilities of South Korea. The mean concentrations of ${\Sigma}_{16}PAHs$ were ranged from 32.5 ${\mu}g/kg-dw$ to 1189.3 ${\mu}g/kg-dw$ by industries, and the highest content was found in the petrochemical industry, followed by chemical, clothing manufacturing and dying, pulp and papermaking, secondary wastewater treatment, and food/beverage producing industries. Comparisons to the EU and Danish standards of ${\Sigma}_{16}PAHs$ in sewage sludge for land application showed only two samples (one from petrochemical, and the other from chemical industry) exceeded the limits. ANOVA test with PAH concentrations as variables revealed no statistically significant influences by industrial types and sampling time (i.e., seasonal variations). Pearson correlations between individual PAHs showed strong relationships (r>0.7) among 4-ring PAHs. Concentrations of acenaphthylene, anthracene, fluoranthene, benzo(a)anthracene, benzo(f)fluoranthene, benzo(k)fluoranthene, benzo(a)pyrene presented strong correlations to ${\Sigma}_{16}PAHs$. Principal component analysis discriminated entire samples into three groups by two principal components (PC1 and PC2) with 70% of data variations, in which industrial types were not of importance, but a dominance of certain PAHs. Samples in group-I, which is high PC1 and low PC2, were characterized by a dominance of 2-ring PAHs, and in group-II, PC1 and PC2 showed a linear relation, was dominant 4-ring PAHs. Group-III with low PC1 and high PC2 includes 17 samples showing a noticeably high contribution of 3-ring PAHs to ${\Sigma}_{16}PAHs$. This study provides concentrations of PAHs in industrial sludges collected from a wide variety of sources (six industrial types) and two seasons of sampling events, and the comparison of ${\Sigma}_{16}PAHs$ with other studies are also discussed.