• Journal of Korean Society on Water Environment
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• v.18 no.2
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• pp.123-130
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• 2002

Bench scale experiments were carried out with two biological nutrient removal(BNR) units, A/O and $A^2O$ processes, to investigate the behavior of phosphorus in the system and to compare the characteristics of phosphorus removal in two BNR processes. To achieve this goal, COD/T-P and COD/TKN ratios of the influent was varied in the range of 23~64 and 5~24, respectively. In A/O process, influent COD/T-P ratio should be kept higher than 44mg/L to meet the final effluent T-P concentration lower than 1mg/L and in $A^2/O$ process, influent COD/T-P and COD/TKN ratios higher than 56 and 10, respectively, were required for good phosphorus release and uptake with no influence of nitrate nitrogen in return sludge. At this conditions, the rate of phosphorus release in the anaerobic basin should be kept higher than 0.1 kg S-P/kg MLVSS d In A/O process, the phosphorus content of anaerobic and aerobic sludges was increased as SRT of total system was becoming longer resulting in decreasing the difference of phosphorus content between two sludges while phosphorus release in anaerobic basin and phosphorus uptake in aerobic basin was not incident. In $A^2/O$ process, the phosphorus content of anaerobic and aerobic sludges were not increased with higher SRT of total system due to the relatively high nitrate concentration in return sludge. However, the difference of phosphorus content between anaerobic and aerobic sludges was incident when phosphorus release and uptake was observed.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.104-111
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• 2000

The study war carried out to evaluate the characteristics of inorganic phosphate factions in soil mixed with paper mill sludge compost(PMSC). The experiments were conducted by an incubation test. For the incubation test, application rates of PMSC to soil were 0, 2, 8, and 16%. Water content of the samples mixed with PMSC were adjusted to 10% and 15% and incubating temperatures of the samples were kept at $4^{\circ}C$ and $30^{\circ}C$, respectively. The results can be concluded as follows; pH increased depending on the higher rates of PMSC application to the soil during the incubation tests, because calcium content was $4.9cmol_c/kg$ and contents of nutrients were high. When the application rates of PMSC were increased Saloid-P and Fe-P decreased, while Al-P and Ca-P in soil increased during the incubation tests.

• Journal of Korean Society of Water and Wastewater
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• v.37 no.5
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• pp.253-259
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• 2023

Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×10² mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.50-57
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• 1985

An attempt was made to determine the optimum levels of sewage sludge application for seogwangbyeo in the farmer's field. 1. Optimum amount of sewage slude application was 338kg/11a at the fertilizer (N-P-K) level of 15-10-10kg/10a, 430kg/10a at that of 7.5-10-10kg/10a and 544kg/10a at no fertilizer. 2. Number of tillers during all growing period were increased with amounts of sewage sludge and/or chemical fertilizers. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components sotood out as an important one to be solved for higher yield. 3. Panicles per hill was increased but percent ripeness was decreased with the application of increasing level of sewage sludge and/or chemical fertilizer. In particular, the decrease of ripeness among yield-related components stood out as an important one to be solved for higher yield. 4. Ripeness was remarkably decreased in high nitrogen content of soil and rice plant under heavy amounts of sewage sludge and/or chemical fertilizer. 5. Ripeness that had direct effect on yield showed significantly possitive correlation with the content of $SiO_2$ and $SiO_2/N$ in rice plant from 25 days after transolanting to harvesting stage. 6. Maximumutillzation of nitrogen and its production efficiency of absorbed nitrogen in sewage sludge were 16.6% and 31.9kg (Yield/kg, N) at the level 15-10-10kg/10a as fertilizer with amounts of sewage sludge application, and 19.0% and 31.8kg (yield/kg, N) at sewage sludge application without fertilizer.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.2
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• pp.113-120
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• 1985

A filed experiment was carried out to investigate the effects for growth, yield of red lopper (Saelona) and properties of soil by beer sewage sludge application to the sandy loam which fertility was common. The results obtained were summerized as follows. 1. Growth of red pepper in sludge plot was very poor by drought in early stage, but color of loaves was green and growth strength was better than nontreated plot after rainfall in last stage. There were no significant differencies between plant height, number of branch on main stem and stem height in sludge and standard plot. 2. Yield of matured red pepper per plant in NPK+, and PK+ sludge 1200kg, 2400kg and 4800kg/10a plot were less than those in standard plot respectively. 3. Ratio of dry weight of matured red pepper in NPK+, and PK+ sludge 1200kg, 2400kg and 4800kg/10a were high than those in standard plot appreciably. 4. Sewage sludge application (1200kg/10a. N=51kg) was available as nitrogen source of organic fertilizer considerably, but there were some growth inhibition by excess of amount applied. 5. Sewage sludge application decreased the pH of the soil and increased the content of organic matter and exchangeable babe in the soil appreciably.

• Journal of the Korea Concrete Institute
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• v.29 no.4
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• pp.399-406
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• 2017

CaO-based by-product, which consist of CaO, $SO_3$, $Al_2O_3$ and so on, has being used to raw materials of CaO compound. When It was applied to recycling water of remicon, concrete performance can be enhanced because hydration reaction of powder material is accelerated. In this study, activated-sludge, which was putted desulfurization gypsum of CaO-based in recycling water, was manufactured to verify effect of them, and then they was investigated by characteristics of cement matrix and mortar. As a results, they indicated reduction of setting time and high soundness in cement matrix, and acceleration of hydration reaction can be verified by XRD analysis. Also, it can be maintained good workability if water content by usage of desulfurization gypsum, which used for production of activated-sludge, was adjusted. In addition, it can be verified strength development by activated-sludge although cement content by usage of desulfurization gypsum was reduced.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.10
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• pp.574-579
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• 2016

This study assessed feasibility of making granular fertilizer with fly ash from a sewage sludge incinerator in Korea. Composition, characteristics, strength, and heavy metal contents of the granular fertilizers were investigated. Due to its high contents of phosphorus, fly ash from a sewage sludge incinerator could be used to make fertilizers. Granulation rates (2-4 mm granules) over 80% could be achieved as the fly ash contents were 15% or less of the fertilizer. Leaching tests of the fertilizers, based upon the Korean Standard Methods for Solid Wastes, showed the concentrations of heavy metals less than the risk limits. However, contents analysis of the fertilizers, based upon the Korean Standard Methods for Soils, experienced higher levels of heavy metals than the risk limits as the fly ash content exceeded 7% of the fertilizer. Thus, the fly ash needs to be added less than 7% of the fertilizer if there is no pretreatment to remove heavy metals.

• Journal of the Korea Organic Resources Recycling Association
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• v.27 no.2
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• pp.19-30
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• 2019

Objective of this study was to develop an organic fertilizer utilizing domestic livestock horn meal and to investigate the application effect of rice and eggplant. The possibility of utilization of livestock horn meal as an organic resource to replace imported expeller cake fertilizer was examined. In order to select domestic organic resources with high nitrogen content, 8 kinds of organic matter such as chicken manure, fish meal, soybean meal, sesame meal, perilla meal, blood meal, livestock horn meal, and beer sludge were analyzed and organic resources with high nitrogen content were selected. In addition, the conditions for the production of organic fertilizers that can be used in organic agriculture were established by mixing of the rice husk biochar and the rice bran as the supplements with the raw materials for mixing ratios. The content of total nitrogen (T-N) in the livestock horn meal was 12.0 %, which was the next low in 13.5 % blood meal. The content of total nitrogen was 5.9 ~ 7.9 % in fish meal and oil cakes. Total nitrogen content of non-antibiotic chicken manure for organic farming was 3 % and nitrogen content in beer sludge was 3.5 %. Organic fertilizer was produced by using biochar, rice bran as a main ingredient of non-antibiotic chicken manure, livestock horn meal and beer sludge. Compared to nitrogen content (4.0 to 4.2 %) of imported expeller cake fertilizer (ECF), the nitrogen content of organic fertilizer utilizing domestic livestock horn meal is as high as 7.5 %. The developed organic fertilizer is met as Zn 400 mg/kg, Cu 120 mg/kg the quality of organic agricultural materials such as or less. To investigate the effect of fertilizer application on the crops, prototypes of developed organic fertilizer were used for the experiment under selected conditions. As a result of application the developed organic livestock horn meal fertilizer (LHMF) for cultivation of the rice and eggplant, the application quantity of the developed organic LHMF 100 % was decreased by 40 % compared to that of the mixed expeller cake fertilizer (MECF). The application of LHMF, which refers to the application rate corresponding to the nitrogen fertilization recommended by the soil test, was reduced by 40% compared to the application rate of MECF, but the same results were obtained in crop growth and yield. The selection of a new high concentration nitrogen source utilizing domestic organic resources and the development of organic fertilizer is the starting point of the research for substitution of imported ECF using domestic local resources at the present time that the spread of eco-friendly agriculture is becoming increasingly important. If it is expanded in the future, it is expected to contribute to the stable production of eco-friendly agricultural products.

• Journal of the Korean institute of surface engineering
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• v.53 no.2
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• pp.72-79
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• 2020

Two Fe-Cr steels of T22 steel and STS430 steel were corroded at 650 and 750℃ for 100hr in sewage sludge-(0.3% SO₂-6% O₂-10% H₂O-balance CO₂) mixed gas environment. T22 steel corroded faster than STS430, indicating that the Cr content significantly influence the corrosion rates. T22 formed thick and non-protective Fe₂O₃ as the major oxide and Fe₃O₄ as the minor one. With an increase in corrosion temperature, their corrosion rates increased, being accompanied with formation of pores and cracks in the thickened oxide scales that were non-adherent. STS430 steel formed Fe₂O₃, Fe₃O₄ as the outer scale and (Fe, Cr)-O as the inner layer by which its corrosion rate is greatly reduced. Both the T22 and STS430 steel samples formed multi-layered scales by outward diffusion of Fe ions and inward diffusion of oxygen and sulfur ions at high-temperature more than 650℃.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.3
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• pp.119-126
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• 2001

A process for the production of bioplastics from wastewater with an open microbial culture was developed and evaluated. The process consists of a selection reactor to select bacteria in feast/famine regime and an accumulation reactor to produce PHA using selected bacteria. Polyhydroxyalkanoate(PHAs) accumulating bacteria could be efficiently grown in a sequencing batch reactor(SBR) without any growth limitation. For the high production of PHA limitation such as oxygen and nutrients seemed to be needed. Accumulation experiments were performed to evaluate the level of accumulation of PHA. Limited aeration had no effect, but nutrients limitation showed high accumulation. Bacteria which were selected in the SBR could accumulate PHA till 60% of cellular dry weight in accumulation experiments under nitrogen limitation. PHA accumulation rate decreased with increasing PHA content in the cells. Clearly, PHA accumulation rate has a strong correlation with the PHA content of the cells.