• Journal of the Korea Organic Resources Recycling Association
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• v.18 no.4
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• pp.69-76
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• 2010

After feeding mixed samples, VS ranged from 60 to 80% of total costs in 15 days. EC ranged from1.21 to 2.45, 1.25 to 2.1 and 1.2 to 1.88mS/cm when worms were fed with a mixture of by-products of tidal current and sewage sludge, a mixture of by-products of algae producy, and food wastes and a mixture of by-products of algae producy, sewage sludge and food wastes. That means the kinds of mixture don't have any negative impacts on worms survival. With the feed with a mixture of by-products of algae producy and food wastes and a mixture of by-products of algae producy, sewage sludge and food wastes, pH shows stable 5.4 to 6.7, and 6.2 to 7.4 where is suitable for worms. But a mixture of by-products of algae producy and sewage sludge is out of proper scope for raising worms, in other words, extra care will be necessary. In case of Eh, a mixture of by-products of algae producy and sewage sludge make eh negative (-) in early stage so also when feeding worms, also extra care will be needed. NaCl ranged from 0.32 to 0.82% or form 0.23 to 0.61% when a mixture of by-products of algae producy and food wastes and a mixture of by-products of algae producy, sewage sludge and food wastes were fed. So taking care of salts will be essential whenever feeding.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.53-61
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• 2023

Most of the sewage sludge is organic waste containing a large amount of organic substances decomposable by microorganisms by biological treatment. As for existing sewage sludge treatment methods, reduction and fuel conversion are being carried out using technologies such as drying, incineration, torrefaction, carbonization. However, the disadvantage of high energy consumption has been pointed out as latent heat of 539 kcal/kg is consumed based on drying. Therefore, in this study, we intend to produce solid fuel through hydrothermal carbonization(HTC), which is a thermochemical treatment. To evaluate the value of solid fuel, the characteristics of carbonization and fuel ratio were analyzed. As a result, as the hydrothermal carbonization reaction temperature increased, the lower heating value also increased by about 500 kcal/kg due to the increase in the degree of carbonization. H/C, O/C, ratio showed a decreasing trend from 1.78, 0.46 to 1.57, 0.32. When the ratio of ash to combustible content (fixed carbon + volatile) of dry sludge was 0.25 or more, it was derived that the degree of carbonization and calorific value did not increase even when hydrothermal carbonization was performed.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.739-745
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• 2005

Simultaneous denitrification and methanogenesis at various influent COD/Nitrate-N(below C/N) ratio was investigated with two different anaerobic sludges of which one was inoculated with glucose only and the other was inoculated with glucose and nitrate. Three different C/N ratios of 30, 20, and 10 were applied with each anaerobic sludge in serum bottles agitated in a rotary shaker to monitor the time related changes of amount of gas production and gas composition. Glucose was used as a single carbon source, which was adjusted to 1,000 mg/L as COD and potassium nitrate was used as a nitrogen source to adjust the each C/N ratio. COD removal by methanogenesis was dominant at higher C/N ratios, while COD removal by denitrification was dominant at lower C/N ratios. With the sludges cultured at C/N ratios below 10, SMA and SDNR rising different carbon substrates were investigated. The most efficient carbon substrate was acetate and the highest SMA and SDNR were 0.76 g COD/g VSS day with pure anaerobic sludge and 1.38 g ${NO_3}^--N/g$ VSS day with sludge cultured at C/N ratio of 5, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.2
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• pp.275-284
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• 1992

A generated problem in treated highly concentrated organic wastewater by activated sludge process is the limitation of biomass concentration and oxygen transfer capability in aeration tank. To overcome the limitation, the deep shaft activated sludge process which has high oxygen transfer capability was applied to the wastewater treatment process. This paper investigated the characteristics of liquid circulation, oxygen transfer and biological treatment of paper mill wastewater by the deep shaft activated sludge process. From the obtained results, it was found that the oxygen transfer capability in the deep shaft system was much greater than those in the conventional aeration systems and almost tantamount to the pure oxygen system. The deep shaft system could treat highly concentrated organic wastewater by higher biomass concentration and organic loading rate.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.1
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• pp.23-30
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• 2013

The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.330-332
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• 2006

방사선의 조사 유무에 따른 배추와 상추의 발아지수를 평가함으로써 60일 간의 퇴비화 공정에서의 퇴비 품질과 독성을 평가하고자 하였다. 또한 온도, 휘발성 유기화합물, 퇴비 숙성도 등을 평가함으로써 방사선 조사의 퇴비화 에 대한 영향을 분석하였다. 방사선의 높은 에너지는 하수슬러지 내 미생물을 사멸하고 독성유기물을 분해하여 하수슬러지 퇴비 품질을 향상시키는 것으로 확인했다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.356-359
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• 2003

영화유기화합물의 제거에 있어서 일반적으로 이용되는 금속분말로는 아연, 주석, 니켈, 납, 철 등이 알려져 있으며, 경제성과 반응성이 좋고, 독성을 야기하지 않는다는 측면에서 영가 철이 가장 많이 연구·실용화되어 적용되고 있는 실정이다. 본 연구에서는 제철부산물들의 비표면적 측정, 화학적 구성성분 분석 및 pH의 변화를 통해 TCE, PCE 제거능력 평가 및 탈염소화반응을 확인하였으며, 제철부산물인 사상분진과 열연슬러지가 TCE 및 PCE의 제거효율적인 측면이나 산업폐기물의 재활용적인 측면에서 순수철보다 우수하다는 것을 확인하였다.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.85-92
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• 2010

In this study, odorous compounds emitted from various wastewater treatment were treated with using the non-thermal plasma reaction, and the effluent gas from the plasma reactor was introduced to a waste sludge reactor to achieve simultaneous sludge reduction. Hydrogen sulfide, the model odorous compound, was removed at 70% using the plasma reaction, and greater than 99% removal efficiency was observed when treated by the sludge reactor. In addition, the sludge reactor showed a high efficiency of ozone removal. As ozone reacted with sludge, oxidation with organic matters took place, and total COD decreased by 50~60% and soluble COD increased gradually. As a result, the integrated process consisting of the non-thermal plasma and the sludge reactor can be successfully applied for the simultaneous treatment of malodorous gas and waste sludge.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.195-195
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• 2015

본 연구에서는 인산-망간 피막처리 공정 중에 생성되는 슬러지를 방지하기 위하여 인산-망간 화성처리액에 유기첨가제인 Tartaric acid를 첨가하여 내마모성 및 방청성 향상을 목적으로 슬러지를 방지하기 위한 인산-망간 화성피막의 특성을 연구하였다. Tartaric acid의 농도에 따른 표면 Morphology를 Scanning Electron Microscope (SEM)과 Energy Dispersive X-ray spectroscopy (EDS)을 이용하여 분석하였으며, EDS 분석을 통해 Mn, P, Fe, O, C의 성분을 확인 할 수 있었으며, 인산-망간 화성피막의 상(phase)을 확인하기 위하여 X-ray diffraction (XRD)을 분석을 통하여 $(Mn,Fe)_5H_2(PO_4)_44H_2O$으로 구성된 인산-망간 화성피막을 확인할 수 있었다. 또한 Tartaric acid의 농도에 따른 인산-망간 피막의 내마모 시험(Ball on disc) 및 경도시험을 실시하여 기계적인 특성 및 슬러지의 양에 대하여 분석하였다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2008.11a
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• pp.107-108
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• 2008