• Journal of Korean Society of Environmental Engineers
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• v.30 no.8
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• pp.775-780
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• 2008

Sludge conditioning is widely used to improve aggregation and dewaterability of waste sludge in sludge treatment processes. The study aims to examine quantitative correlations between coagulant dosage and sludge cake dewaterability using three kinds of coagulants, such as an aluminum sulfate, a ferric chloride, and a poly aluminum chloride(PAC). When an aluminum sulfate, a ferric chloride, and a PAC were injected with 0.79$\sim$1.19 mmol/g, 0.61$\sim$1.25 mmol/g TSS, and 0.21$\sim$0.39 mmol/g TSS, respectively, specific resistances to filtration of the sludge were decreased at 95.0% or more. This study shows that the correlation between coagulant dosage per g sludge(D) and normalized specific resistance to filtration(R) could be expressed by the exponential functions.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.1
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• pp.62-75
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• 2000

Most of biological treatment to remove contaminants in municipal wastewater have been conducted by activated sludge process. But, the process have several probIems such as enormous site needed for construction of treatment facilities, unstable treatment due to limited ability to control load fluctuation, frequent sludge bulking and appearance of lots of surplus sludge. In this study, the experiments were performed through submerging biofilm of PEPP media in existing aeration tank with raw water from municipal wastewater treatment plant and then submerging PVDC and PEPP media, different from shape and chemical peculiarity in anoxic reactor. Throughout the experience, nutrient removal efficiency according to HRT, nitrogen phosphorous removal efficiency, behavior of nitrogen and dewatering efficiency have been compared and analysed with those of activated sludge process. As the results, BOD removal efficiency according to BOD volumetric load and F/M ratio was not found any differency in two processes, but was decreased below 90% as going along the condition of high load in activated sludge process. Kinetic coefficient was $K_{max}=1.162day^{-1}$, $K_s=53.77mg/L$, $Y=0.166mgVSS/mgBOD_{rem}$. and $K_d=0.019day^{-1}$. It was found that the removal efficiency, even though in aerobic condition, in biofilm process equipped anoxic reactor was higher than the one in activated sludge process within the range of 70~80%, and became better as HRT increased. Phosphorous removal efficiency was not found any differency in two processes. In biofilm process, treament efficiency even in conditions of high load was not decreased, because the biomass concentration could be maintained in high condition compared with activated sludge process. As HRT increased, suspended and attached biomass was increased and the other hand, F/M ratio was decreased as biomass' increasing. Biomass thickness was increased. from $10.43{\mu}m$ to $10.55{\mu}m$ as HRT increased and density of biomass within $40.79{\sim}41.16mg/cm^2$. The results also present that the dewatering efficiency of sludge generated in biofilm process was higher than in activated sludge process, and became better as HRT increased.

• Journal of Wetlands Research
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• v.15 no.4
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• pp.471-476
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• 2013

The operating conditions of sludge disposal for sanitary paper manufacturing wastewater treatment plant were monitored on the basis of daily check sheets during the 3 years of operation. Generated wastes were mainly composed of 79% of sludge, 14% of ash, 5% of waste synthetic resin and 2% of etc. Maximum sludge was produced to 233 ton and the average was 113 ton daily, where the primary sludge occupied 85% and 15% for the secondary sludge. The concentration of coagulant for sludge dewatering was extremely exceeded and the additional experiment such as jar-test was required for the establishment of proper dosage. Presently, the generated sludges were partially treated outside and were also partly handled inside. In the future, most sludges will be expected to be treated to recycling material for the iron industry.

• The KSFM Journal of Fluid Machinery
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• v.8 no.1 s.28
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• pp.30-36
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• 2005

A sludge treatment system for introducing the waste water mixture with paint sludge from the water bath of paint booth and for recycling cleaned water to paint booth after sludge separation is developed. Floated sludge is introduced from the water surface in the bath by using floating-skimmer, and is conveyed by pump to the centrifugal separator where sludge and cleaned water are separated. From the operation results of the present sludge treatment systems applied in actual paint booths, paint sludge can be separated automatically and effectively from water bath with its water content of $60-70\%$, and sludge-free clean water is returned to paint booth.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.259-266
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• 2004

Developed is a sludge treatment system for introducing the waste water mixture with paint sludge from the water bath of paint booth and for recycling cleaned water to paint booth after sludge separation. Floated sludge is introduced from the water surface in the bath by using floating skimmer, and is conveyed by pump to the centrifugal separator where sludge and cleaned water are separated. From the operation results of the present sludge treatment systems applied in actual paint booths, paint sludge can be separated automatically and effectively from water bath with its water content of $60-70\%$, and sludge-free clean water is returned to paint booth.

• Journal of Environmental Health Sciences
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• v.35 no.1
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• pp.58-63
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• 2009

This study investigated improvement to sludge dewaterability and coagulation for sewage treatment plant sludge by using sodium hypochlorite solution (NaOCl), ferric sulfate [$Fe_2(SO_4)_3$] and zeolite. The specific resistance to filtration(SRF), chloride, pH and turbidity were used to evaluate the sludge dewatering behaviors. The results of study were as follows: By varying the amount of NaOCl added the optimum result in terms of enhancement for pretreatment occurred when 34 mg/l of NaOCl was injected. When the total solids concentration of the sludge was 10,000 mg/l, the optimum ferric sulfate dosage for the sludge dewaterability was 150 mg/l and the corresponding SRF was $1.7{\times}10^7sec^2/g$. It was observed that injecting zeolite into sludge was effective in improving the dewaterability of sludge.

• Journal of Environmental Science International
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• v.7 no.6
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• pp.867-873
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• 1998

Laboratory study was conducted to provide basic data for operating anaerobic sequencing batch reactor(ASBR) process for treatment of nightsoil. The experiments were concerned with digestion characteristics, settleabiltity and dewaterability of digested sludge in ASBR system. Completely-mixed dally-fed control reactor without solid-liquid separation step was also operated to evaluate the baseline performance since the nature of nightsoil was changed with time. In all case, gas production from the ASBR shows 1.3 to 1.44 times higher than that from control, in spite of almost similar trend in organics removal. During thickening period, remarkable decrease in surface settling velocity was observed at the ASBRs compared with the control. In case of the ASBR run, flotation of mixed digested sludge was not occurred. Also, ultimate thickened volume of ASBRs increased 1.2~1.5 times compared with control. Dewaterability of digested sludge without conditioning decreased when the completely-mixed daily-fed reactor for ASBR run was converted to the ASBR. However, improvement of dewaterability of digested sludge from the ASBRs was observed as a result of addition of FeCl$_3$ to digested sludge for conditioning.

• Proceedings of the Korean Geotechical Society Conference
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• 1998.03a
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• pp.291-298
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• 1998

• Journal of Korean Society of Water and Wastewater
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• v.10 no.1
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• pp.85-95
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• 1996

Although the specific resistance to filtration is the most frequently employed means for characterizing dewaterability of a sludge, it presently is not possible to design nor to prediet performance of dewatering facilities using traditional linearized parabolic filtration equation, that is, the specific resistance model because of theoretical and practical inadequacies of the concept. Limitations of the specific resistance model reflect the need to examine fundamental sludge properties and filtration behaviors affecting dewaterability. From this study, two major limitations of the specific resistance model were noted. First, specific resistance values are very dependent on the sludge concentration because of the variations of particle size distribution and cake clogging to occur when surface area mean diameter is less than $25{\mu}m$ for activated sludge, $18{\mu}m$ for water treatment plant sludge. Second, nonparabolic filtration behavior can result from cake clogging, caused by the migration of fine particles into the cake pores, accelated by skin effect with highly compressible sludges.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.25-32
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• 2021

Geotextile tube technology has been perceived as an economical solution for liquid sludge treatment, and analyzing its consolidation behavior is necessary to be able to evaluate the dewatering capabilities of large geotextile tubes filled with contaminated soil, tailings, sewage sludge, and so on. The objectives of this study are to present a method that can adequately convey the consolidation behavior of geotextile tubes filled with sewage sludge, and to investigate the effects of various geotextile tube consolidation parameters. In this study, variable coefficients of consolidation are utilized to analyze the consolidation process of geotextile tubes filled with sewage sludge. The consolidation solution was verified by comparing the measured and predicted data from a hanging bag test conducted in the literature. After verifying the proposed solution, the consolidation parameters of a geotextile tube composed of a woven polypropylene outer layer and a non-woven polypropylene layer filled sewage sludge were obtained. Using the obtained parameters, the consolidation behavior of a large-scale composite geotextiles tube was predicted.