• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.698-701
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• 2000

To prevent surface and underground water pollution, wastewater treatment is essential. Four bench-scale activated sludge units (10 L operational volumes) were operated at 5, 10 and $20^{\circ}C$ for evaluation of treatment efficiencies with typical wastewater from swine housing. The units were set for a 24-hour cycle. As compared to the conventional process, high removal efficiencies for organic substances, nitrogen and phosphorus in swine wastewater were obtained simultaneously with an intermittent aeration process (lAP). The NOx-N produced during an aeration period was immediately reduced to nitrogen gas (e.g. $N_2$ or $N_2O$) in the subsequent non-aeration periods, and nitrification in aeration periods occurred smoothly. Under these conditions, phosphorus removal occurred with the release of phosphorus during the non-aeration periods followed by the excess uptake of phosphorus in the activated sludge during aeration periods. It was confirmed that the lAP had a better ability to remove pollutants under both low temperatures and high nitrogen loading conditions than the ordinary method did. In addition to that, the total emission of $N_2O$ from lAP was reduced to approximately 1/50 of the conventional process for the same loading. By adopting an adequate aeration programme for individual swine wastewater treatment, this system will provide a promising means for nitrogen and phosphorus control without pH control or addition of methanol.

• Journal of Korean Society on Water Environment
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• v.33 no.1
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• pp.63-69
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• 2017

Small size privately owned wastewater treatment plants have been difficult to treat their wasted sludge and maintain steady effluent quality compared with publicly owned wastewater treatment plants. Therefore, this study has focused on treatment efficiency enhancement, specially nitrogen removal efficiency by recycling dewatering filtrate as an alkalinity additive from filter press using $CaCO_3$. As the result, it was found that the optimal mixing ratio between the excess sludge and $CaCO_3$ was 1:2. The major operation parameters such as specific substrate utilization rate, specific nitrification rate, and specific denitrification rate were also improved 64% ($0.048-0.079mg\;BOD_5/mg\;MLVSS{\cdot}day$), 35% ($0.020-0.027mg\;NH_3-N/mg\;MLVSS{\cdot}day$) and 68% ($0.051-0.086mg\;NO_3{^-}-N/mg\;MLVSS{\cdot}day$), respectively, after the adoption of new methods. Therefore, both the problem of sludge treatment at small scale plants and the need for efficiency improvement could be solved.

• Analytical Science and Technology
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• v.13 no.3
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• pp.351-356
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• 2000

The decolorization of wastewater and the collecting conditions of final sludge from hanji production were investigated. Black wastewater (50 mL) from the process cooking with NaOH could be effectively decolorized by 2.0 g of $Ca(OCl)_2$ So, if excess bleach $Ca(OCl)_2$ used in bleaching process were recycled, the decolorization of wastewater by adding less $Ca(OCl)_2$ would be successfully realized. However, the decolorization by electrolyzed oxidation was ineffective. The final sludge could be effectively collected by polymer coagulator, but the addition of $Al_2(SO_4)_3$ was required, and the pure fibrous sludge could not be collected. Therefore, surfactants such as triethanolamine and Triton X-100 were used instead of polymer coagulator. The collecting yield was obtained about 85% as good as those by polymer coagulator. When mixed surfactants were used in collecting the final sludge, $Al_2(SO_4)_3$ was not required. In addition, as the pure fibrous sludge could be collected, the effective recycling of sludges would be done.

• Journal of Korean Society of Water and Wastewater
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• v.8 no.3
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• pp.9-18
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• 1994

Activated sludge pilot plant testing was conducted to determine the ability of a well-designed activated sludge treatment system to remove chromic toxicity from the bleached kraft pulp mill effluent. Removals of conventional(BOD and SS) and nonconventional(resin and fatty acids, color, AOX) pollutants were estimated. The pilot plant was operated at steady state for about 10 weeks at an F/M of 0.28 and a sludge age of 8.4 days. The average MLSS concentration was 4,309mg/l, of which volatile fraction was 57%. During the operation period, the BOD removal reaction rate(k) was determined to be 8.2/day at $30^{\circ}C$. The BOD removal was 84 percent, which was 3 to 6 percent lower than expected for full-scale treatment. The chronic toxicity of the activated sludge effluent was tested by employing both Dinnel and the BML protocols. It was found that the pilot plant could achieve in excess of 90 percent reduction in chronic echinoderm toxicity. The data show slight reduction of color and AOX across the activated sludge system. The pilot system, however, demonstrated on excellent removal of resin and fatty acids.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.77-88
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• 1994

This experiment was carried out to investigate the effect of sewage sludge compost amended soils on the growth and accumulation patterns of heavy metals in plant parts of Orchardgrass seedlings, changes in physical properties and chemical composition, and heavy metal residue in soils. Mixture ratios of sewage sludge compost and soil(loam) were 100:0, 80:20, 60:40, 40:60, 20:80 and 0:100(control), respectively. The results obtained were as follows; 1. The physical properties and chemical compostion of soils were improved by increase in mixture ratios of sewage sludge compost. 2. The biological yield of Orchardgrass seedlings was increased with mixture ratios of sewage sludge compost. 3. The dry weight of shoot(SH) was increased with both of yield components(NT and WT) and biological yield of Orchardgrass seedlings. 4. The total nitrogen concentrations(TN) of plants was increased with quadratically up to the biological yield of 100% mixture ratio of sewage sludge compost. 5. Lead(Pb) concentration of soil in over the 60% mixture ratios of sewage sludge compost were in excess of limiting level(50ppm) of organic fertilizers.

• Journal of Korean Society on Water Environment
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• v.35 no.4
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• pp.299-307
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• 2019

The purpose of this study was to investigate the effect of low temperature thermal pre-treatment on biodegradation of waste activated sludge for anaerobic digestion as a countermeasure for increasing sludge generation. The experimental condition was accomplished in 2 %, 4 %, and 6 % TS concentration, and $70^{\circ}C$, $80^{\circ}C$, $90^{\circ}C$ of temperature for a maximum of 120 minutes retention time. Then, it was followed by analysis of physical/chemical properties, BMP test and composition of biogas. The biogas characteristic was evaluated by applying the modified Gomperz model. As a result, solubility of dissolved substrate, such as $SCOD_{Cr}$, soluble carbohydrate, and soluble protein, and biogas production increased as temperature increased. Solubilization efficiency at $90^{\circ}C$ was 18.4 %, 17.03 % and 16.88% in 2 %, 4 %, and 6 % TS concentration respectively. Also, solubilization rates of carbohydrate and protein similarly increased. BMP test results also showed that methane production in excess sludge increased to 0.194, 0.187 and $0.182m^3/kg$ VS. respectively, and lag phase decreased to 0.145, 0.220, 0.351 day due to acceleration of the hydrolysis step. Consequently, low-temperature thermal pre-treatment could increase biodegradability of sludge, positively affecting biogas production and sludge reduction.

• Environmental Engineering Research
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• v.12 no.2
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• pp.81-91
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• 2007

A membrane bioreactor (MBR) was used to investigate the aerobic degradation of foam active substance - non-ionic surfactant, APG 2000 UP. The surface aeration using the propeller loop reactor (PLR) guaranteed sufficient $O_2$ for substrate removal and bacteria growth and avoided foam development. Moreover, the cross-flow membrane filtration enabled the separation of the bacteria still loaded with surfactant in the collecting container. The biological degradation of the surfactant with varying hydraulic retention time (HRT) and influent concentration $c_{S0}$ showed high substrate removal of nearly 95% at high volumetric loading rates up to $7.4\;kgCOD\;m^{-3}d^{-1}$ and at sludge loading rates up to 1.8 kgCOD $(kgVSS\;d)^{-1}$ for biomass concentration $c_B\;{\approx}\;constant $. The increasing $c_B$ from 3.4 to $14.5\;gL^{-1}$ TSS respectively sludge retention time (SRT) from 5.1 to 442 d under complete biomass retention by the membrane filtration resulted in high removal of substrate ${\alpha}\;>\;90%$ with reducing excess sludge production.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.124-130
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• 2007

Excess application of paper mill sludge (PMS) in field can limit phosphorus uptake by crops because aluminum presented in the sludge can fix or adsorb available phosphorus which is necessary for crop growth. To investigate phosphorus (P) adsorption characteristics of PMS, we examined P adsorption maximum $(X_m)$ using Langmuir isotherm and P adsorption energy constant $(K_f)$ using Freundlich isotherm for PMS without alum, PMS with alum, and composted PMS with alum through a laboratory incubation test. The maximum P adsorption capacities were 800 ${\mu}g\;g^{-1}$ in soil, 47 $mg\;g^{-1}$ in PMS without alum and 61 $mg\;g^{-1}$ in PMS with alum. P adsorption capacity with alum treatment for PMS increased by 30%. That of PMS compost was 68 $mg\;g^{-1}$ and showed that composting increases 11% of P adsorption. Freundlich constant $K_f$ was 22 in check soil, while $K_f$ values in PMS without alum and in PMS with alum were 398 and 426, respectively. After composting, $K_f$ value of PMS compost significantly increased as 1,819. In conclusions, p adsorption capacity for PMS were increased by alum treatment or composting and therefore excess or continuous land application of alum-amended or composted PMS can limit P uptake for crops by reducing available P in sell.

• 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.

• Resources Recycling
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• v.31 no.6
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• pp.60-65
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• 2022

This study presents the carburization process for recycling sludge, which was formed during silicon wafer machining. The sludge used in the carburization process is a mixture of silicon and silicon carbide (SiC) with iron as an impurity, which originates from the machine. Additionally, the sludge contains cutting oil, a fluid with high viscosity. Therefore, the sludge was dried before carburization to remove organic matter. The dried sludge was washed by acid cleaning to remove the iron impurity and subsequently carburized by heat treatment under vacuum to form the SiC powder. The ratio of silicon to SiC in the sludge was varied depending on the sources and thus carbon content was adjusted by the ratio. With increasing SiC content, the carbon content required for SiC formation increased. It was demonstrated that substoichiometric SiC_x (x<1) was easily formed when the carbon content was insufficient. Therefore, excess carbon is required to obtain a pure SiC phase. Moreover, size reduction by high-energy milling had a beneficial effect on the suppression of SiC_x, forming the pure SiC phase.