• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.1
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• pp.105-114
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• 2007

In this paper, we propose sludge collection strategies which allocate each sewage store of village to sewage treatment plants and decide the schedule of sludge collection in order to collect sludge efficiently. The strategies aim to decrease transportation cost with deciding proposed vehicle routing and scheduling the sludge collection. When we decide route of vehicles, we consider the collection time in sewage store of village, distance between sewage store of villages and vehicle information as average velocity of vehicle, operation time of vehicle driver. We also develop the SCMS (Sludge Collection Management System) based on windows system with real data which is used in certain circumstance. And we experiment to figure out vehicle route and transportation cost throughout changing input data.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.81-87
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• 2008

We have investigated the efficacy and efficiency of the used briquets for the sewage treatment in this study. The effluent of wastewater treated by Used Briquets Process (UBP) showed very low values of $BOD_5$, CODcr, and SS (1.1 mg/L, 9.5 mg/L, and 3.8mg/L, respectively), which corresponded to 99%, 92.7%, and 96.3% of removal efficiency to the raw wastewater. The number of total bacteria and E. coli in the effluent water treated by UBP was found to be 9 and 1.2 cfu/ml, respectively, showing the remarkable decrease in number, when compared to that of other sewage treatment plants. In the long period of experiment over 1 year, UBP has also shown the high removal efficiency with less sludge production, and low seasonal fluctuation of the values. This UBP is very environmentally-friendly process in the aspects of recycling used briquets and reducing the sludge production. We think that this process will be useful for both the small-scale sewage treatment and reuse of the effluent water.

• Journal of Environmental Health Sciences
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• v.19 no.4
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• pp.44-50
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• 1993

This paper has concentrated on estimating the improvement of sludge dewaterability for the application of ozone in sewage treatment plant sludge. The experiment for the study was conducted by batch reactor, contacting ozone (5.0 g O$_3$/hr/l) to waste sludge and measured the Specific Resistance to Filtrate (SRF) varying pH, pressure and reaction time of ozone. And then checked the dissolved solids concentration of flitrate. The results of experiment were as follows: 1. When the total solids concentration of excess sludge was 9, 000 mg/l, the optimum injection rate of ozone was 5.0 g O$_3$/hr/l, and then pressure was 50 cm Hg for the measuring SRF. 2. In the range of pH 3~5, the effect of ozone injection was excellent, but it was unsatisfactory in the range of pH 9~11. Therefore, the ozone injection by acidifying pH level was effective in improving the dewaterability of sludge. 3. It was estimated that the dissolved solids concentration of flitrate was increased in proportion to the injection rate of ozone.

• Journal of Environmental Science International
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• v.31 no.12
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• pp.1051-1059
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• 2022

This study investigated microbial communities and their diversity in a full-scale mesophilic anaerobic digester treating sewage sludge. Influent sewage sludge and anaerobic digester samples collected from a wastewater treatment plant in Busan were analyzed using high-throughput sequencing. It was found that the microbial community structure and diversity in the anaerobic digester could be affected by inoculation effect with influent sewage sludge. Nevertheless, distinct microbial communities were identified as the dominant microbial communities in the anaerobic digester. Twelve genera were identified as abundant bacterial communities, which included several groups of syntrophic bacteria communities, such as Candidatus Cloacimonas, Cloacimonadaceae W5, Smithella, which are (potential) syntrophic-propionate-oxidizing bacteria and Mesotoga and Thermovigra, which are (potential) syntrophic-acetate-oxidizing bacteria. Lentimicrobium, the most abundant genus in the anaerobic digester, may contribute to the decomposition of carbohydrates and the production of volatile fatty acids during the anaerobic digestion of sewage sludge. Of the methanogens identified, Methanollinea, Candidatus Methanofastidiosum, Methanospirillum, and Methanoculleus were the dominant hydrogenotrophic methanogens, and Methanosaeta was the dominant aceticlastic methanogens. The findings may be used as a reference for developing microbial indicators to evaluate the process stability and process efficiency of the anaerobic digestion of sewage sludge.

• Resources Recycling
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• v.23 no.6
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• pp.47-53
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• 2014

Effective treatment and energy conversion technologies are necessary due to the ban of the dumping of organic waste including the sewage sludge. In this study, the kinetics of pyrolysis and combustion were derived in a TGA and thermobalance reactor, which is essential for thermal conversion of sewage sludge to energy. Three steps are shown for the pyrolysis in TGA and the different pre-exponential factors and activation energies are derived depending on the temperature range. Three models of gassolid reaction were applied to the reaction kinetics analysis for the combustion of sewage sludge char and shrinking core model was an appropriated model. Apparent activation energy and pre-exponential factor were evaluated and the effect of oxygen partial pressure was examined.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.4
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• pp.75-80
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• 2002

The sewage sludge with concentrated MLSS, ranging from 5967 to 8400mg/L was degraded by ultrasound. In this study, ultrasound treatment was used to investigate the behavior characterization of SBOD, sludge biodegradation, C/N ratio, TN, turbidity and sludge morphology. From the experimental results of C/N ratio change and TN removal, the optimal irradiation time was found to be 10 minutes. The results showed the relative index of sludge biodegradation(SBOD/TCOD) was enhanced to 0.76 from the initial value of 0.013 at the 5967mg/L MLSS, during the 60minutes treatment. Throughout this research, the results provide useful engineering reference data for reuse of sewage sludge using ultrasound.

• Journal of Environmental Science International
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• v.13 no.7
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• pp.681-687
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• 2004

This study was focused on the manufacturing method of a dewatering aid, which would reduce the water content of the sludge cake by enhancing the dewaterability of sewage sludge. The pretreatment technology for sludge by using radiation and among diverse discarded resources were starfish selected as the material to manufacture the dewatering aid. Starfish went through the process of washing, drying, and pulverizing. The starfish powder made in this process was applied to the digested sludge generated at the sewage treatment plant of D City, and its effects were investigated. The starfish powder that was 300 ${\mu}m$ in particle size was added to the irradiated digested sludge. After the application of the condensation process, the sludge with the starfish powder added was dewatered using the belt press and centrifuge, which were the traditional pressure dewatering devices. As the result, it reduced the water content of the sludge 20% higher than the dewatered cake with no dewatering aid added and irradiation. When the powder was added, it contributed to less use of the coagulant added. The more irradiation dose, the lower water content did the dewatered cake have and the more coagulant was needed for condensation, which seems to be a disadvantage that can be compensated for by the starfish dewatering aid. A small-scaled treatment of the study to a radiation technology and dewatering aid using a discarded resource confirmed the potential of dewaterability. Based on the results saying that the dewatering aid and radiation technology can improve dewatering effects using the traditional dewatering devices, this pretreatment technology will be expected to be applied to sewage treatment plants.

• Proceedings of the KAIS Fall Conference
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• 2007.05a
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• pp.287-290
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• 2007

We investigated the effect of ultrasound on the dewaterability of sewage sludge. Because, dewatering and disposal of waste sludge is a major economical factor in the operation of wastewater treatment plants. Capillary Suction Time(CST) and Specific Resistance to Filtration (SRF) were used to evaluate the sludge dewatering behaviors. From the results of the experiment, it was found that ultrasonic treatment can improve the dewaterability. We discovered that CST and SRF were highly related, according to the correlation coefficient($R^{2}$).

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.10a
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• pp.209.1-209
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• 1978

Treatment of domestic sewage discharged from big cafeteria kitchen, especially rice-washing water, was examined by the use of activated sludge process and phytoplankton cultivation. Only with a activated sludge process COD value decreased from around 1000 mg/ι to 100 mg/ι, but nutrients, such as nitrogen and phosphate could not be removed sufficiently phytoplankton cultivation in combination with a activate sludge process could decrease COD value down to 50 mg/ι and nutrients values were also reduced substantially. However, the initial concentration of 20 mg/ι in the rice-washing water could not be removed completely without addition of activated sludge as a nitrogen source.

• Resources Recycling
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• v.13 no.4
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• pp.17-22
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• 2004

This study was focused on the treatment of thickened sewage sludge. General bacteria and E. coli were disinfected over 99％ and organic compounds were decomposed after irradiation. It was suggested that this process can be an alternative for digestion Process. The moisture content in sludge was decreased over 10％ (w/w) and the coagulation of sludge particles was enhanced by irradiation at the dose of 15 kGy and addition of sea waste resource (star-fish) as a dewatering aid.