• Journal of Environmental Health Sciences
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• v.23 no.2
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• pp.44-56
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• 1997

When sewage sludge is treated by cornposting, higher moisture content and lower C/N ratio on sewage sludge is problems. This paper project to alesolve two problems. The almost trends in run 3 of MC 70% are similar to these in run 1 and 4 of MC 65%. A retention time of the highest temperature (>50$\circ$C) and increase rate of temperature in run 3 are an affinity to these in run 4. Particularly, decrease rate of temperature in run 3 is slower than others and this data shows the more activity of thermal microbial in run 3 than that in others. C/N ratio trends in run 3 shows slow reaction in initial stage but, after 9 days, is similar to that in run 1 and 4. Carbon trends in each run are a similarity to C/N ratio trends. Temperature, MC, carbon and C/N ratio trends in run 5, whose C/N ratio is 15, show less microbial activity than that in run 6, whose C/N ratio is 20. But temperature increase of the beginning stage and pH of the final stage in run 5 are greater than that in run 6. Final MC and carbon content in run 5 and 6 have a similar values. That is, final MC in run 5 and 6 is 49.39% and 48.97% and final carbon content in each run is 25.15% and 22.20%. Expecially, a temperature increase and C/N ratio decrease rate of the beginning stage in run 5 are greater than these in run 6. This shows the shorter lag time in run 5 than lag time in run 6.

• Journal of the Korean Applied Science and Technology
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• v.33 no.2
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• pp.239-246
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• 2016

In this study, recycling sludge water of Ready-mixed concrete, and was carried out to optimize the system for recycling of the $CO_2$. The most important process in the liquid phase using a carbonation reaction can be recovered ready-mixed concrete is a process for the $Ca^{2+}$ release. $Ca^{2+}$ concentration of the experiment relative to the pH being lowered by the acidic substance during elution was performed. $CO_2$ was trapped in the MEA solution using a generator flue gas. In ready-mixed concrete can be synthesized $CaCO_3$ up to 11kg/1ton. The resulting $CaCO_3$ analysis results show that it is possible to use paper industry.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.2
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• pp.168-174
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• 2008

Diagnosis on setteability based on human operator's experimental knowledge, which could be established by long term operation, is a limit factor to construction of automation control system in wastewater treatment plant. On-line SVI(Sludge Volume Index) analyzer was developed which can measure SV30 automatically by image capture and image analysis method. In this paper, information got by settling process was studied using On-line SVI analyzer for better operation & management of WWTPs. First, SV30 detection algorithm was developed using image capture and image analysis for settling test and it showed that automatic detection is feasible even if deflocculation and bulking was occurred. Second, turbidity assessment model was developed using image analysis.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.452-455
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• 2000

There are increasingly important financial incentives and environmental consideration to improve the effluent quality of wastewater from domestic and industrial users. The activated sludge process is a widely used biological wastewater treatment process. The activated sludge process is complicated due to the many factors such as the variation of influent flowrate and concentration, the complexity of biological reactions and the various operation conditions. Nowadays, not only suspended solids and residual carbon, but also nitrogen and phosphorous concentration of the effluent water must be taken into account for the design and operation of wastewater treatment plants. Also, the effluent quality to be met are more stringent. Therefore, an intelligent control approach is required in order to successful biological nitrogen removal. In this paper, the strategies for dosage of extra carbon in the anoxic zone and DO concentration in the aerobic zone are presented and evaluated through the simulation using the denitrification layout of the IWA simulation benchmark implemented by Matlab$\^$/5.3/Simulink$\^$/3.0. The control strategy to achieve sufficient denitrification rates in an anoxic zone. Methanol is used as an external extra carbon source. The external extra carbon source is required for the nitrogen removal process because nitrogen and organic concentration are fluctuated in the influent flowrate. The dissolved oxygen is calculated by So concentration in the activated sludge model NO.1. The air flowrate of each aerobic reactor is intelligently controlled to achieve the predefined setpoints. Air flowrate is adjusted by the fuzzy logic controller that includes two inputs and one output. The objective function for the optimization procedure is designed to improve effluent quality and reduce the operating cost.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.146-152
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• 2018

In the construction sector, new demands for aesthetics are increasing due to structural stability and improvement of living standard and consciousness level. On the other hand, Red Mud sludge is generated from aluminum hydroxide extraction process from Bauxite. Red mud sludge contains about 20% of $Fe_2O_3$ and represents a natural reddish brown. It is highly applicable to the construction industry. In this paper, red mud sludge with a water content of 50%, which is a by - product of the industry, was prepared as a liquid phase. The liquefied red mud was added to cement mortar and the strength and color difference of cement mortar were investigated according to the addition amount of liquefied red mud. As a result, the compressive strength decreased with increasing amount of liquefied red mud. The color of cement mortar containing liquefied red mud was found to be distributed in the range of YR series in all samples. As the amount of liquefied red mud increased, the color became darker.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.6
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• pp.735-745
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• 2014

This paper presents PKES(PuKyung -Excel based Simulator) for WWTPs(wastewater treatment plants) by using MS Excel and VBA(Visual Basic for Application). PKES is a user-friendly simulator for the design and optimization of the whole plant including biological and physico-chemical processes for the wastewater and sludge treatment. PKES calculates the performance under steady or dynamic state and allows changing the mathematical model by the user. Mathematical model implemented in PKES is a improved integration model based on ASM2d and ADM1 for simulation of AS(activated sludge) and AD(anaerobic digestion). Gaseous components of $N_2$, $N_2O$, $CO_2$ and $CH_4$ are added for estimation of GHGs(greenhouse gases) emission. The simulation results for comparison between PKES and Aquasim(EAWAG) showed about the same effluent concentrations. As a result of verification using by measured data of BOD, TSS, TN and TP for 2 years of operation, calculated effluent concentrations were similar to measured effluent concentrations. The values of average RMSE(root mean square error) were 1.9, 0.8, 1.6 and 0.2 mg/L for BOD, TSS, TN and TP, respectively. Total GHGs emission of WWTP calculated by PKES was 138.5 ton-$CO_2$/day and GHGs emissions of $N_2O$, $CO_2$ and $CH_4$ were calculated at 21.7, 28.9 and 87.9 ton-$CO_2$/day, respectively. GHGs emission of activated sludge was 32.5 % and that of anaerobic digestion was 67.5 %.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.5
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• pp.389-395
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• 2017

In this paper, we investigate the characteristics of membrane fouling caused by water temperature in the Membrane bioreactor(MBR) process and try to derive the membrane fouling control by chemical enhanced backwashing(CEB). The extracellular polymeric substances(EPS) concentration was analyzed according to the water temperature in the MBR, and the membrane fouling characteristics were investigated according to the conditions, with sludge & without sludge, through a lab-scale reactor. As shown in the existing literature the fouling resistance rate was increased within sludge with the water temperature was lowered. However, in the lab-scale test using the synthetic wastewater, the fouling resistance increased with the water temperature. This is because that the protein of the EPS was more easily adsorbed on the membrane surface due to the increase of entropy due to the structural rearrangement of the protein inside the protein as the water temperature increases. In order to control membrane fouling, we tried to derive the cleaning characteristics of CEB by using sodium hypochlorite(NaOCl). We selected the condition with the chemicals and the retention time, and the higher the water temperature and the chemical concentration are the higher the efficiencies. It is considered that the increasing temperature accelerated the chemical reaction such as protein peptide binding and hydrolysis, so that the attached proteinaceous structure was dissolved and the frequency of the reaction collision with the protein with the chemical agent becomes higher. These results suggest that the MBRs operation focus on the fouling control of cake layer on membrane surface in low temperatures. On the other hand, the higher the water temperature is the more the operation strategies of fouling control by soluble EPS adsorption are needed.

• Journal of Korean Society on Water Environment
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• v.22 no.3
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• pp.557-565
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• 2006

Proper operation of clarifier partly depends on outlet conditions. Effluent has to be uniformly withdrawn to prevent scouring of settled sludge and carry over of settling sludge from the clarifier. In this paper, 3-D numerical model was employed to analyze the flow and settling performance of the rectangular clarifier. There were two simulation conditions of which in the same clarifier, the first one was assumed to have a 11.5 meter weir length and the second has 8.5 meters. Shape, location and placement of the weir structure were different, but both of those outlets meet weir loading design criteria. Simulation results indicate that clarifier with longer weir generally gave strong and unstable currents at the mid-stream where the weir starts while in the clarifier with short and relatively simple weir, uniform and stable flow was observed in most parts of the settling zone, and especially at the weir region. These flow conditions affected settling performance. Effulent SS concentration from clarifier equipped with the long and complicated placement of weir was 24.5 mg/L, but 7.0 mg/L from the clarfieir having short weir length. From this study, it can be concluded that as reported from other studies, weir loading does not guarantee settling performance and 3-D numerical model can be a useful tool for determining and validating outlet structure.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.1
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• pp.41-46
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• 2008

In this study, dewaterability, one of the important properties of wastewater sludge, was investigated using a simple capillary suction time (CST) measurement method. It turned out that one could use the results of CST to find optimum flocculants ratio to improve drainage in wastewater treatment for the printing paper, tissue paper, and newsprint paper mill. Since the optimum ratio of flocculants could be determined with the value of CST, COD removal efficiency could be improved and optimum floc strength could be achieved with precise ratio of flocculants. It was thus that using CST for determining the optimum ratio of flocculants could be economical by reducing the amount of flocculants. Dewaterability could be measured within several seconds using the values of CST in a precise way. The dewaterability could also be useful in investigating the optimum ratio of flocculants.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.1-8
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• 1990

The paper board sludge(PBS) itself and compost sludge manure(CSM) mixed with sawdust, fowl droppings and urea to the PBS were treated to soybean plants to find the effects of growing characters, yield components, and nutritional compounds in the plant tissues. 1. Percentages of missing plants were 5-9% and 3.6-4.1% in the treatments of PBS and CSM, respectively. After that, the plants were restored to normal conditions. Anyway it is not desirable to use the paper board sludge and immature compost sludge manure in seeding time or to young seedlings. 2. Growth of the plant height was retarded in early growing phase, but it was normal in later stages. And the width and length of the largest leaf, numbers of main stem nodes and pods were not significant among the treatments. 3. The yield intends to increase through the treatments of 1,200, 1,600, and 2,000Kg PBS per 10a. In the CSM treatments with high rate of sawdust, fowl droppings and urea, the numbers of pods and grains were higher than the treatment of high content of PBS. 100-grain and one liter weights were opposite intention. It was suggested that the excess nitrogen amounts from the compost sludge manure than conventional fertilization affected to the yield components. 4. The contents of the main chemical compounds such as N, $P_2O_5$, $K_2O$, Ca, Mg were determined. The concentrations of nitrogen were higher in the treatment of PBS and CSM than none and control. 5. In conclusion, the nutritional effects of PBS were in evidence. To use the sludges, it should be fermented with adequate additives to improve the aeration, C/N ratio, activity of microbial, and other conditions. The sludges could be used to crops as a fertilizers effectively.