• Environmental Engineering Research
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• v.19 no.1
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• pp.59-66
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• 2014

The aim of this study was to assess the effect of pre-aeration on sludge solubilization and the behaviors of nitrogen, dissolved sulfide, sulfate, and siloxane. The results of this study showed that soluble chemical oxygen demand in sewage sludge could be increased through pre-aeration. The pre-aeration process resulted in a higher methane yield compared to the anaerobic condition (blank). The pre-aeration of sewage sludge, therefore, was shown to be an effective method for enhancing the digestibility of the sewage sludge. In addition, this result confirms that the pre-aeration of sewage sludge prior to its anaerobic digestion accelerates the growth of methanogenic bacteria. Removal rates for $NH_3$-N and T-N increased simultaneously during pre-aeration, indicating simultaneous nitrification and denitrification. The siloxane concentration in sewage sludge decreased by 40% after 96 hr of pre-aeration; in contrast, the sulfide concentration in sewage sludge did not change. Therefore, pre-aeration can be employed as an efficient treatment option to achieve higher methane yield and lower siloxane concentration in sewage sludge. In addition, reduction of nitrogen loading by pre-aeration can reduce operating costs to achieve better effluent water quality in wastewater treatment plant and benefit the anaerobic process by minimizing the toxic effect of ammonia.

• Journal of Korean Society on Water Environment
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• v.31 no.5
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• pp.476-481
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• 2015

Water permeable block was manufactured using waste sewage sludge, loess and clay for the purpose of recycling waste sludge due to the prohibition of waste sludge ocean dumping. Experiments for determining optimum mixing ratio was conducted by changing sludge content in water permeable block as 5~20%. In respect of compressive strength, $1,600N/cm^2$ ($163.3kg/cm^2$) was obtained when the mixing ratio of sludge : loess : clay were maintained by 5% : 65% : 30%, 10% : 65% : 25% and 15% : 65% : 20%, respectively. These mean that relatively high compressive strength can be obtained when the sludge content is maintained 5, 10, 15% at the 65% of loess content. In terms of water permeability and absorption rate, the higher values can be obtained as the sludge content increases. The optimum mixing ratio of sludge : loess : clay came out to be 15% : 65% : 20% when water permeability, absorption and strength were considered altogether, which matches the result observed by an electron microscope. The heavy metal leaching test result of the prepared permeable block appeared to satisfy the environmental standard in the content of Cd, Cu, Pb and As.

• Journal of the Korea Organic Resources Recycling Association
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• v.3 no.1
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• pp.73-83
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• 1995

Effect of water treatment sludge(alum sludge) application on the growth of Korea local corn(Zeas Mays L.) was evaluated and phytotoxicity of alum sludge on the growth of corn roots and plant height was tested. Alum sludge itself and composted alum sludge compost were applicated by 1500kg/ha in the plot respectively. For the fertility test, yield, chlorophyll content, plant height of corn treated by alum sludge and composted alum sludge were better than that of control. No clear toxixity of alum sludge was found. At the food chemical analyses of seed corn, no obvious component variation were evaluated either. Test of pH effect on phytotoxicity of alum sludge on corns showed that plant height and root growth of corns were inhibited at low pH 4 solution. Phytotoxicity test of alum sludge extract which was extracted at various pH solutions, showed that growth and cations uptake inhibition were found the more serious the lower the pH. Plant height and root growth injury were serious at higher than 100ppm Al content solution.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.3
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• pp.35-41
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• 2023

In this study, silicon sludge generated in semiconductor manufacturing process is recycled and applied as materials for pigments and paints. In detail, metallic impurities are removed from silicon sludge to obtain plate-like silicon sludge powder (SW-sludge), which is then coated with titanium dioxide via sol-gel method (TCS-sludge). SW-sludge and TCS-sludge are dispersed in hydrophilic transparent varnish and sprayed onto glass substrates to observe the possibility for the application as materials for pigments and paints. Notably, the applicability of TCS-sludge-based paint is improved compared to SW-sludge-based paint after the titanium dioxide coating. Moreover, the color of TCS-sludge-based paint turns into white. Accordingly, it is confirmed that the applicability and hydrophilicity are improved by the presence of outer titanium dioxide layer. In this regard, it is expected that the recycled TCS-sludge may be a future material for the application as pigments and paints.

• Resources Recycling
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• v.13 no.3
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• pp.12-18
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• 2004

A study on the enhancement of the dewaterability of sewage sludge was carried out by using the sea waste materials as a dewatering aid. It was made from a starfish and a shell by heating at $105∼700 ^{\circ}C$ and centrifuge and belt press were used as a mechanical dewatering process. The moisture content of sludge cake was reduced by 15∼22% (w/w) after addition of the dewatering aid at the dose of 1∼8 g/100mL of digested sludge. CST (capillary suction time) was measured to evaluate the effect of dewatering aid on sludge dewatering properties. CST was reduced after addition of a shell while increased after addition of a starfish. Enhancement of dewaterability after addition of a shell was better than that of a starfish. The heating temperature effect of the dewatering aid on dewaterability was not clear.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.43-51
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• 2009

Paper mill sludges are discharged around 870,000 M/T annually. Only 30% of the paper mill sludge have been recycled and the rest has been disposed by land fill, incineration, ocean abandonment and other ways. Because of overall prohibition of sludge disposal by London Dumping Convention in 2012, a urgent counter measure for paper mill sludge must be provided. In this paper, some basic experiments were carried out to develop a tray cell pot using paper mill sludge for increasing the recycling potential of the wasted sludge. To establish the manufacturing parameters, the tray cell pots were made with three types of materials including virgin pulp, old news paper and corrugated board mixed in a blend tank of a molding machine. The bending force and moisture content of the produced tray cell pots was measured to confirm the application capability. The tray cell pot could be manufactured under the condition of over 20% of virgin pulp, 40% of old news paper added. However, the corrugated board could not be used because of the glutinous substance included. The produced tray cell pot absorbed water very easily and the bending force decreased rapidly. The waterproof material must be used to applicate the produced tray cell pot in plant growing fields.

• Journal of the Korea Organic Resources Recycling Association
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• v.13 no.2
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• pp.74-84
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• 2005

The objectives of this study was to investigate the improvement of thermal kinetics for disposal of sewage sludge using thermal wind drying. The operational parameters varied are the temperature of $130{\sim}170^{\circ}C$ and evaporation velocity WD. Important parameters effect on thermal kinetics for evaporation of water in sewage sludge studied include the drying time, water content of sewage sludge, solids amount of sewage sludge(TS%) by the varied temperature. The saturation point of water evaporation was observed at the drying time of 60 min in conditions of drying temperature $170^{\circ}C$ and drying time of 120 min by drying temperature $130^{\circ}C$ and WD=0.95 m/s. Operation at drying temperature of $170^{\circ}C$ led to higher rate of evaporation than those 130, $150^{\circ}C$ at WD=1.0 m/s and WD=1.0 m/s was higher than WD=0.5 m/s at drying temperature of $130^{\circ}C$.

• Journal of the Korea Organic Resources Recycling Association
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• v.12 no.2
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• pp.52-60
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• 2004

The basic approach to sewage sludge is organic waste minimization, promotion of energy recovery; volume and weight reduction by final treatment, and environmentally final disposal of natural circulation. Dry and pyrolysis of maize was experimentally investigated in full-scale rotary kiln in semi-continuous operation. The operational parameters varied are the operating temperature $160{\sim}175^{\circ}C$ of dry and $450{\sim}800^{\circ}C$ of pyrolysis, the solids residence time 9 min for pyrolysis. Important parameters studied include the running time, water content of sewage sludge, solids amount of sewage sludge(TS%) by the varied temperature. Also, with the increasing of temperature, how the yield of oil and char product change was observed, and the distribution of gas production components was observed. The gas of $C_1{\sim}C_3$ yield increased and oil of $C_4{\sim}C_6$ yield decreased along with pyrolysis temperature of $670^{\circ}C$ by the run time of 9 min.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.85-88
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• 2005

The stone powder sludge occurred at aggregate production process is classified the specified waste, so it is disposed by appropriate method. But the problems of the shortage of the disposal-site, the environment pollution, and the increase of disposal cost can be occurred in handling process, therefore the stone powder sludge is required the development of recycling technique. The stone powder sludge includes SiO2 of about $63\%$. This characteristic is important at the production of hardened specimens under condition of hydro-thermal reaction. In this study, we investigated the strength properties of concrete used stone powder sludge as siliceous material. The test results under condition of hydro-thermal reaction shows the two main facts. The first, the stone powder sludge is affected to fluidity because the surface of the stone powder sludge has characteristics of flakily and angularity. The second, weight content of the stone powder sludge, is not effective factor to the properties of strength.

• Proceedings of the Korean Institute of Building Construction Conference
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• v.y2004m10
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• pp.21-26
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• 2004

This study deals with the Hydrated Ability of the Ready-Mixed Concrete's Sludge which is the recycling technology of that sludge. The experiment gathers sludge from Ready-mixed factory. shatters these into pieces in dry condition and understands the differences between current using Portland cement. And then. this examines the possibility of the recycle as a bonding agent through the Compressive Strength and considers the recovery of the hydration. This experiment concludes the same Chemical Composition with the normal Portland cement. while. under the appropriate procedure in hydration recovery. this sludge can be used as the bonding agent in cement. The chemical composition of solid Remicon sludge shows that it has 1.8 times $SiO_2$ than the normal Portland cement. meaning lots of aggregate in Remicon sludge. Also. the specific gravity of Remicon sluge increases with the rise of Baking Temperature and has no difference between 2.77 and 2.94. The mortar flow used for combining the baking material of Remicon sludge does was not changed and is the highest between $750^{\circ}C{\cdot}120min\;and\;800^{\circ}C{\cdot}180min$. Additionally. the Compressive Strength increases with the age, certifying the same Hydrated Ability like cement and the best condition for hydration is $750^{\circ}C{\cdot}120min.$