• Journal of Korean Society of Environmental Engineers
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• v.35 no.12
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• pp.960-966
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• 2013

In this study, operation data from an actual plant in M city were analyzed to evaluate effects of water supply into sewage sludge on the co-incineration of municipal solid waste (MSW) and sewage sludge. Design capacity of the stoker incinerator is 50 m3/day. Maximum portion of sewage sludge in the total waste input was 20%. According to this research, moisture content increase up to 85% of sewage sludge could be possible by water supply on MSW input to the incinerator. Therefore, stable operation of incinerator could be achieved. As water was added into sewage sludge up to 85%, input quantity of sewage sludge to frequency (Hz) was similar to theoretical input. Also, it is concluded that stable management of incinerator without leachate combustion and damages of refractory bricks and castable could be achieved by the reduction of low heating value.

• Journal of Hydrogen and New Energy
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• v.19 no.2
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• pp.145-155
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• 2008

This paper deals with an economic evaluation of hydrogen production by fermentation. We evaluate the economic feasibility of domestic hydrogen production by fermentation utilizing glucose and waste water sludge in terms of hydrogen production prices. In addition, we make some sensitivity analysis of hydrogen prices by changing the values of input factors such as the price of glucose, the capital cost of the hydrogen production system, and the hydrogen production yields. The estimated hydrogen prices of the two-step dark-light hydrogen production by fermentation utilizing glucose was $5,347won/kgH_2$, and the single-step hydrogen production by anaerobic fermentation utilizing waste water sludge was $4,255won/kgH_2$, respectively. It is expected that the hydrogen production price by anaerobic fermentation can be reduced if we produce methane or hydrogen utilizing by-products such as alcohols and organic acids, or the government imposes some legal regulations on the treatment of waste water sludge.

• Journal of the Korean GEO-environmental Society
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• v.14 no.4
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• pp.29-37
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• 2013

In order to recycle both water sludge and waste fishing net(WFN), it was investigated in this paper the engineering characteristics of mixtures that consisted of different content of water sludge(0%, 10%, 30%, 50%) and reinforced with waste fishing net(unreinforced, untreated WFN, glue treated WFN). WFN or glue treated WFN(1&2 layers) was also added to the mixture to improve the interlocking between the soil particle and WFN. Several series of laboratory tests such as compaction test, triaxial test, oedometer test, permeability test and leaching test were carried out. The experimental test results indicated that, as water sludge content increases, maximum dry unit weight, cohesion, friction angle, and permeability of the mixture decrease, while optimum moisture content, compression index, expansion index and compressibility increase. For the case of reinforced mixture, its cohesion and friction angle are increased due to the inclusion of WFN and glue treated WFN. Leaching result of mixture was satisfied with standard of ministry of environment.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.05a
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• pp.11-14
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• 2000

Wastewater sludge and composted food wastes were examined as the alternatives of a landfill cover for soils to eliminate the emission of VOCs. The benefit of these alternatives is in their high sorption capacity, which is 5 to 50 times higher than natural soils. After sorption is finished, biodegradation is an important mechanism in decrease of VOCs concentration. In order to investigate appropriate VOCs degradation condition, biodegradation batch experiment is being conducted with isolated strain X9-c. Both benzene and TCE were degraded only in soil with 12%(water volume/sorbent volumn) water condition. When the water condition varied from 12 to 48% in compost, optimum water conditions of composted food waste was 36%.

• Journal of the Korean Professional Engineers Association
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• v.18 no.3
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• pp.28-35
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• 1985

As the paper industry consumes much water in process and discharge wastewater containing suspended solid and COD(chemical oxygen demand), relevant law against this discharge has been set up to limit the total containment of COD in discharge. This study has been carried out to improve the treatment method for the soluble COD in wastewater produced during the process of paste-board production, which is made of semichemical pulp and waste paper. Applicated methods are, O$_2$AS : O$_2$ activated sludge process DAS : Deep well activated sludge process SAS : standard activated sludge process and proper combination of DAS and SAS 1) As a result of this experiment, we get the following conclusion between in COD sludge loading "X" and COD removable rate in the process of treating waste-water. COD removable rate(％)=(0.778+0.0146/X)${\times}$100(％)……(7) 2) In case that the COD sludge loading is high, it has been cleared out that the COD removable rate shall become low due to unknown unsoluble substances contained in the process. Meanwhile, to increase the efficiency rate of treatment, it is thought to be necessary, to provide long-time contacts with activated sludge. 3) Once the COD of original waste-water and the target COD of treated water are decided, COD sludge loading is obtained from equation(7), and capacity of aeration tank in the effective systems such as O$_2$AS, DAS, to bet the required COD removable rate can be decided. Therefore the choice among SAS, O$_2$AS, DAS methods is made in consideration of required COD removable rate and allowable installation area. 4) In the sedimentation tank with sludge bulking, it is possible to increase the COD removable rate by 3～7％ but still there exist many obstacles to manage this operation.

• Journal of Hydrogen and New Energy
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• v.15 no.3
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• pp.187-193
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• 2004

In this study, Anaerobic sewage sludge in a batch reactor operation at $35^\circ{C}$ was used as the seed to investigate the effect of pretreatments of waste activated sludge and to evaluate its hydrogen production potential by anaerobic fermentation. Various pretreatments including physical, chemical and biological means were conducted to utilize for substrate. As a result, SCODcr of alkali and mechanical treatment was 15 and 12 times enhanced, compared with a supernatant of activated sludge. And SCODcr was 2 time increase after re-treatment with biological hydrolysis. Those were shown that sequential hybridized treatment of sludge by chemical & biological methods to conform hydrogen production potential in bath experiments. When buffer solution was added to the activated sludge, hydrogen production potential increased as compare with no addition. Combination of alkali and mechanical treatment was higher in hydrogen production potential than other treatments.

• Journal of Korean Society of Water and Wastewater
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• v.10 no.2
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.629-636
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• 2012

This study focuses on the feasibility of bio-gas production using anaerobic digestion by measuring methane generation and biodegradability through the BMP test of industrial organic wastes. Organic wastes consist of entrails of pigs and organic residues of rumen generated from slaughter houses, wastewater sludge from slaughter waste water, fish offal and residues of vegetables from public wholesale markets, and wastewater sludge from the process of wastewater treatment in paper mill. The cumulative methane production by BMP test ranges from 149.3 ml/g-VS to 406.6 ml/g-VS and this is similar to methane generation of the normal wastewater sludge and food waste. As a result of measurement of biodegradability, wastewater sludge (S1 ~ S4) is low, ranging from 27.1% to 58.9 % and organic residues of rumen (G1) is low at 49.6 %. In conclusion, it turned out that raising the hydrolysis by various pre-treatments is necessary in order to produce bio-gas by using industrial organic wastes.

• Environmental Engineering Research
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• v.22 no.3
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• pp.277-280
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• 2017

Destablization and demulsification is a difficult task for the treatment of waste oil-in-water drilling fluid because of its "three-high" characteristics: emulsification, stabilization and oiliness. At present, China is short for effective treating technology, which restricts cleaner production in oilfield. This paper focused on technical difficulties of waste oil-in-water drilling fluid treatment in JiDong oilfield of China, adopting physical-chemical collaboration demulsification technology to deal with waste oil-in-water drilling fluid. After oil-water-solid three-phase separation, the oil recovery rate is up to 90% and the recycled oil can be reused for preparation of new drilling fluid. Meanwhile, harmless treatment of wastewater and sludge from waste oil-in-water drilling fluid after oil recycling was studied. The results showed that wastewater after treated was clean, contents of chemical oxygen demand and oil decreased from 993 mg/L and 21,800 mg/L to 89 mg/L and 3.6 mg/L respectively, which can meet the requirements of grade one of "The National Integrated Wastewater Discharge Standard" (GB8978); The pollutants in the sludge after harmless treatment are decreased below the national standard, which achieved the goal of resource recovery and harmless treatment on waste oil-in-water drilling fluid.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.55-60
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• 2017

The dyeing sludge can be weakened by inflow of rainfall or absorption of moisture after it is buried in a waste landfill. This study tested the dyeing sludge and earth/sand mixture to check the problem when the dehydrated dyeing sludge is buried in a waste landfill. When the dyeing sludge was left idle with high water content inside a landfill with poor draining for a long period, the water permeability decreased to around 3/100 level and the compressibility increased by 1.4 times compared to the dyeing sludge at a dyeing factory. The study result indicated that it was important to reduce the water content inside the landfill for stability. Also, the facilities to secure the drainage path and eliminate leachate were needed.