• Korean Journal of Organic Agriculture
• /
• v.9 no.1
• /
• pp.61-73
• /
• 2001

This study was conducted to investigate the effect of sewage sludge application on the growth of chinese cabbage and the changes of chemical properties of soil. The experiment were set up with two different place and cultivated from Feb. 10 to June. 20 of 2000. Treatments are 0, 1.25, 2.5, 5, 10 and 20kg/3.3$\m^2$ of sewage sludge applicated into the soil and recorded the growth characteristics. Chemical properties of soil were also analysed before and after treatment. The application of the sewage sludge resulted in increasing the content of EC, cations exchange capacity, available phosphate and organic matter. And increased the growth characteristics in terms of the number of leaves, leaf area, fresh and dry weight regardless of crops experiments. Optimum amount of the sewage sludge depended on chemical properties of soil used. This results demonstrated that application of sewage sludge in the soil attribute to have play an important both improving soil chemical properties and promoting the crop growth. As lowering the soil pH(pH 6) heavy metal content increased compared with higher pH(pH 7). Feasibility was recognized in the application of sewage sludge as a fertilizer for the growth of chinese cabbage. Detrimental effects such as heavy metal in the soil and crop followed by the application of sewage sludge was not observed.

• 한국연소학회:학술대회논문집
• /
• 2006.10a
• /
• pp.42-45
• /
• 2006

A new and reusable energy source is water-treatment sludges. There is a significant need for understanding the characteristics of sludge combustion related to improving efficiency and ensuring the safety of this new energy source. Because sludges are composed of solids and gas mixture, the combustion of the mixture may become quite complex. Not only decomposition of conventional organic elements but also dust explosion may be important during the process of converting sludges into a new and safe form of energy. Sludge combustion mainly involves hydrogen, methane, hydro carbons, carbon, and organic particles. Dust explosion during the gasification stage may depend on the surrounding temperature and the composition of gases. The uncertainty in the explosive behavior of energetic source is noted in this work. We study the explosion characteristics of sludge combustion while the reusability of sewage sludges as a new form of energy is also investigated.

• 한국연소학회:학술대회논문집
• /
• 2014.11a
• /
• pp.29-32
• /
• 2014

The practical route for disposal of sewage sludge becomes energy recovery by combustion after its ocean dumping is banned in 2012 in Korea. Due to the high moisture content, however, sewage sludge is required to be dried before transport and combustion. In this study, pyrolysis and combustion characteristics of dried sewage sludge was investigated in a small-scale fixed bed reactor in order to provide fundamental data for energy recovery of the fuel. As the first step of combustion, the primary products of pyrolysis were analyzed in a fixed bed reactor for the condensable volatiles (tar), non-condensable gases, and char. For the combustion characteristics, another fixed bed reactor was constructed to monitor the weight and temperature of the fuel particles during ignition and combustion under different air flow rates. The test results were used to derive the ignition and burning rates.

• Journal of the Korean Society of Industry Convergence
• /
• v.1 no.1
• /
• pp.51-58
• /
• 1998

This study was carried out to investigate the leaching characteristics by the landfill of solidified sludge. pH of leachate was 3.7 - 5.8 and 8.0 - 10.4 in each column using sand as a top-soil layer on filled municipal waste and solidified cake. $NH_3$-N in leachate was increasing in the each column using sand as a top-soil layer on filled dewatered sludge and solidified cake, but decreasing in the each column using sand and solidified cake by top-soil layer on filled municipal waste. Also the concentration of $NO_3$-N was on the way of stabilizing but was difficult to find any tendency until now. Zn and Mn in leachates were the highest in the column filled with the solidified sludge, Cr, Pb and Cd were low concentration at each column.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.4 no.4
• /
• pp.215-220
• /
• 2000

This study on the incineration ash and sintering pellet from sewage sludge was carried out to evaluate the possibility of recycling in sewage sludge disposal. The samples used in this experiment were raw sewage sludge, its incineration ash, and sintering pellet. The characteristics of the three sample types were identified using X-ray diffraction(XRD), X-ray fluorescence(XRF), atomic absorption spectroscopy(AAS), and inductively coupled plasma spectroscopy(ICP). The chemical compositions of all three sample types were similar in their clay component, however, the sewage sludge had a high content of organic materials. From an analysis of the mineral content of the three sample types, the conversion of their compositions was found to be relative to temperature. Accordingly, incineration ash and sintering pellet both have potential for use as a functional construction material.

• Proceedings of the SAREK Conference
• /
• 2008.06a
• /
• pp.1128-1133
• /
• 2008

Drying process in the thin film layer of sludge with the thickness less than a few millimeters has been investigated using the simple one-dimensional model. Thin film drying is usually used to dry the viscous materials like sewage sludge. The thin film layer of sludge is dried on the metallic surface through which thermal energy is supplied to the layer during drying. In order to solve the equations, the mass transfer rate on the drying surface should be determined. The mass flux of evaporated water vapor on the surface is estimated with the formulation given in the literature. The effect of heating temperature, film thickness, and air velocity on drying has been examined to figure out the drying characteristics of the sludge layer.

• Journal of Korean Society of Water and Wastewater
• /
• v.25 no.5
• /
• pp.777-782
• /
• 2011

The residual treatment facilities in WTP(water treatment plant) play an important role in solid-liquid separation. At present, it is difficult to solve problems related with thickening and dewatering of WTP sludge, and discharging waste water to river. The quantity of residuals generated from water treatment plants depends upon the raw water quality, dosage of chemicals used, performance of the treatment process, method of sludge removal, efficiency of sedimentation, and backwashing frequency. Sludge production by the physical separation of SS(Suspended Solid) occurs under quiescent conditions in the primary clarifier, where SSs are allowed to settle and to consolidate on the clarifier bottom. Raw primary sludge results when the settled solids are hydraulically removed from the tank. In this study, Drawing characteristics of the sludge thickening in the thickener of Water Treatment Plants was simulated by Using CFD(Computational Fluid Dynamics.

• Environmental Engineering Research
• /
• v.24 no.4
• /
• pp.591-599
• /
• 2019

To convert sewage sludge to energy, drying-gasification characteristics during microwave heating were studied. During the gasification of carbon dioxide, the main products were gas, followed by char, and tar in terms of the amount. The main components of the producer gas were carbon monoxide and hydrogen including a small amount of methane and light hydrocarbons. They showed a sufficient heating value as a fuel. The generated tar is gravimetric tar, which is total tar. As light tars, benzene (light aromatic tar) was a major light tar. Naphthalene, anthracene, and pyrene (light polycyclic aromatic hydrocarbon tars) were also generated, but in relatively small amounts. Ammonia and hydrogen cyanide (precursor for NO_x) were generated from thermal decomposition of tar containing protein and nitrogen in sewage sludge. In the case of sludge char, its average pore diameter was small, but specific area, pore volume, and adsorption amounts were relatively large, resulting in superior adsorption characteristics.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.41 no.6
• /
• pp.97-104
• /
• 1999

An experimental investigation was carried out to study the feasibility of using the stabiliozed sludge, as a backfill and cutoff-water materials for embankment structures. For stabilizing of sludge, hydrated lime and quick lime were used as additive, and a series of tests were performed on the sludge and the stabilized sludge to examine their physical and mechanical properties , compaction, compressive strength, hydraulic conuctivity and consolidation characteristics. From the test results, physical and mechanical properties of the stabilized sludge were improved as compared with the sludge. Especially from the viewpoint of physcial property, consolidation or settlement and cutoff-water, quick lime is more effective than the hydrated lime as a stabilization addtive. But, viewpoint of compaction and shear strength, hydrated lime is more effective than the quick lime as a atabilization additive. As a result of this study, it was found that the stabilized sludge can be developed the backfill and cutoff-water materials, improved the stabilizing method of sludge.

• Journal of Microbiology and Biotechnology
• /
• v.26 no.1
• /
• pp.110-119
• /
• 2016

High-solid anaerobic digestion of sewage sludge achieves highly efficient volatile solid reduction, and production of volatile fatty acid (VFA) and methane compared with conventional low-solid anaerobic digestion. In this study, the potential mechanisms of the better performance in high-solid anaerobic digestion of sewage sludge were investigated by using 454 high-throughput pyrosequencing and real-time PCR to analyze the microbial characteristics in sewage sludge fermentation reactors. The results obtained by 454 highthroughput pyrosequencing revealed that the phyla Chloroflexi, Bacteroidetes, and Firmicutes were the dominant functional microorganisms in high-solid and low-solid anaerobic systems. Meanwhile, the real-time PCR assays showed that high-solid anaerobic digestion significantly increased the number of total bacteria, which enhanced the hydrolysis and acidification of sewage sludge. Further study indicated that the number of total archaea (dominated by Methanosarcina) in a high-solid anaerobic fermentation reactor was also higher than that in a low-solid reactor, resulting in higher VFA consumption and methane production. Hence, the increased key bacteria and methanogenic archaea involved in sewage sludge hydrolysis, acidification, and methanogenesis resulted in the better performance of high-solid anaerobic sewage sludge fermentation.