• Journal of Korean Society of Environmental Engineers
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• v.37 no.7
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• pp.412-417
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• 2015

This study investigated to recycle geobond and ash produced in thesewage sludge incinerator using reduction/stabilization. Nonsintering process was performed by binding cement (High Early Strength Portland cement, Micro cement), geobond and sand mixed with sewage sludge ash (SSA). Chemical ingradients of the sewage sludge ash was mainly composed of $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO and others, which were similar to those of the each binders consisting High Early Strength Portland cement, Micro cement and geobond. Results showed that unconfined the long term compressive strength could be obtained components of sewage sludge ash. It exceeded more than double score 64.6 MPa of the Korean standard ($22.54MPa=229.7kg/cm^2$). Microstructure of solidified block for the different admixture was related to the compressive strength according to SEM analysis. Optimum mixing range of the sewage sludge ash to each binders were found to be 10~40% which can widly safely regulate the confined a long term compressive strength. The best binder of long term compressive strengh was revealed Geobond more than High Early Strength Portland cement and Micro cement. This study revealed the sewage sludge ash can be partial replacement of the inorganic binder & application block for recycling.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.1
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• pp.1-9
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• 2007

The performance of the small scale cyclone incinerate system (100kg/hr) to process the sewage sludge containing high moisture is evaluated. The incinerate system design is based on properties of the domestic sewage sludge. The combustion characteristics of the incinerate system is tested and analyzed with the various operation conditions of the moisture level, the sludge feed rate and the auxiliary fuel feed rate. The pressure loss of the whole system is appeared relatively small of 700mmAq under the normal operating condition and the temperature distribution of the incinerator internal combustion is maintained less than 1000C. Auxiliary fuel of 4.7 1/hr is required to incinerate 100kg sludge which include 87% moisture. Because the inside temperature of the incinerator is maintained less than $1000^{\circ}C$, it is predicted that the most NOx measured is produced not from the heat during the combustion process but from the oxidation of the N ingredient in the sludge. From the component analysis of ash, the organic matter is not entirely detected. Accordingly, it is estimated that the complete combustion has been accomplished in the incinerator.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2000.05a
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• pp.259-260
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• 2000

충남 지역에서 발생되는 하수 슬러지의 물리$\cdot$화학적 특성을 고려하여 적정 처분 방안을 검토하기 위하여 중금속 및 비휘발성 고형물 분석을 수행하였다. 충남 지역에서 발생되는 하수 슬러지의 중금속 함유량은 기준치 이하로서 다소 안전하다 할 수 있으나 지속적인 관리가 요구되며, 이러한 중금속의 함유량도 타폐기물과의 혼합으로 희석효과를 가질 수 있을 것으로 사료된다. 또, 하수 슬러지의 광물 낙석 결과 하수 슬러지의 비휘발성 고형분의 성분은 시멘트 원료로 쓰이는 점토질과 유사하며 소각후에 연소재를 이용한 경량 골재 및 다른 2차 제품의 제조 가능성이 높은 것으로 판단된다.

• Resources Recycling
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• v.25 no.1
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• pp.10-15
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• 2016

In recent years, in terms of environmental protection and efficient use of the land, efficient utilization of byproducts and wastes generated in industrial areas are emerging. In this study, for the effective utilization of using ever increasing amount of utilizing sewage sludge incineration ash to increase sewage sludge, it is evaluated the use of as an construction material. After making concrete specimens, it is evaluated compressive strength, carbonation and environmental resistance. From the experimental results, compared with concrete without sewage sludge it is obtained satisfactory results for compressive strength and carbonation and results of the leaching test also satisfies the standard value. So, it is sufficient possibility using of concrete aggregate and the replacement rates is judged to be about 10%.

• Journal of the Korean Ceramic Society
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• v.41 no.4
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• pp.323-327
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• 2004

This study has been carried out to use the municipal solid waste sewage sludge ash generated at sewage disposal field as the raw materials of Ordinary Portland Cement (OPC). Limestone, shale, converter slag, and fly ash were used as the main raw materials. After the raw materials were mixed, these were fired at 1,300, 1,350, 1,400, 1,450, and 1,500$^{\circ}C$ for 1 h and cooled rapidly in air. The properties of clinker synthesized were examined with XRD, SEM, and burnability index by polysius method.

• Journal of the Korea Concrete Institute
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• v.19 no.6
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• pp.667-676
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• 2007

As the 21st century began, cement and concrete that are representatives of modem building materials became a major factor in global warming, air pollution and environmental pollution. Also, the problems that are generated while pursuing high performance and high strength became social issues. Therefore, it has become urgent to prepare counter plans. This study has aimed at the recycling of sewage sludge ash and developing it as a new concept in building material which serves the environmental considerations for long-lasting developmental purpose. Also, the study aimed to find a substitute for scarce natural resources and to secure high techniques for waste recycling. The purpose of this study was also to solve fundamentally secondary environmental pollution. The results revealed that the chemical components of sewage sludge ash are mainly $SiO_2\;and\;Al_2O_3$ which are similar to the components of pozzolan. Also, it was identified that sewage sludge ash can be utilized as a hardened specimen with an alkali activated pozzolan reaction. Considering the possibility of appropriate strength development and the advantage of drying shrinkage, compared with that of cement, it was believed that sewage sludge ash can demonstrate a function as a substitute for cement given.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.29-37
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• 2018

In this study, optimum extraction conditions for phosphorus recovery from sewage sludge ash(SSA) were investigated. For this purpose, an experiment was conducted to determine optimal recovery conditions for Ca-P type phosphorus by using calcium component in the recycled aggregate residue. The phosphorus content of sewage sludge ash was confirmed to be 5.0 %. When $H_2SO_4$ was used as an extract, concentration of 1 N $H_2SO_4$, L/S ratio of 10, and extraction time of 30 min were found to be the optimal extraction conditions. Phosphorus was extracted by using optimal extraction conditions, and then the heavy metals eluted with phosphorus were removed using 1~20 g of cation exchange resin. In 20 g of cation exchange resin, Fe 71.3%, Cu 82.4%, Zn 79.9%, and Cr 15% were removed. After that, the mixing ratio of the calcium extract obtained from the recycled aggregate residue (RAR) was changed to 1:1, 1:5, 1:10. The pH of the SSA to RAR mixture was adjusted to 2, 4, 8 and 12 by the addition of 5 N NaOH to the mixture of 1:5, and the phosphorus was recovered as Ca-P type precipitate. The optimum pH was 8. When recycled aggregate residues were used, the weight of calcium phosphate increased, but the amount of wastewater generated also increased. Therefore, it was concluded that the use of recycled aggregate residue was not economically feasible.

• Resources Recycling
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• v.17 no.4
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• pp.30-36
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• 2008

The preparation of porous lightweight materials as well as the measurement of physical properties has been performed by using SSA(sewage sludge ash) as the raw material. For this aim, two types of lightweight filler, that is, perlite and silica sphere were employed respectively and bentonite was also used as an inorganic binder. The properties of lightweight specimen calcined at 1,000 were measured in terms of density, compressive strength, thermal conductivity and sound absorption to examine the effect of material composition as well as the preparation condition on the properties of lightweight material. As a result, the density of specimen prepared with perlite was ranged from 1.23 to $1.37g/cm^3$ and the compressive strength was ranged from 242.3 to $370.5kg/cm^2$. In case of specimen prepared with silica sphere, it was found that the compressive strength was less than $100kg/cm^2$ even though density was lower than that of specimen with perlite. As far as the thermal conductivity of specimen was concerned, it was ranged from 0.3 to $0.5W/m^{\circ}K$ depending on material composition so that the insulation effect was superior to conventional concrete.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.2
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• pp.114-118
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• 2009

With the advance of industrialization and urbanization, a lot of waste has been discharged and treated by incineration. But fly and bottom ashes are generated in this process. In addition, the treatment method to recycle sewage sludge and melting slag is required to manage these wastes. The objective of this research was to prepare of multi-functional brick which were made from MSWI (Municipal solid wastes incinerator) fly ash, sewage sludge and slag. The bricks were made by mixing raw materials and then drying for 24 hours. Next, they were dried for 24 hours at $160^{\circ}C$ and fired for 2 hours. Calcination temperature was changed to discuss the effect of temperature from $1,080^{\circ}C$ to $1,130^{\circ}C$. Compressive strength of a brick was creased with the increase of temperature. To increase mixing ratio of fly ash and slag reduce the compressive strength the optimal condition was the mixing ratio of fly ash : melting slag : sewage sludge : clay as 10 : 20 : 5 : 65 and $1,150^{\circ}C$ of calcination temperature. Compressive strength was obtained as about 41 MPa at this condition.

• Clean Technology
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• v.24 no.2
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• pp.87-98
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• 2018

Phosphorus (P) is an essential and irreplaceable element for all living organisms, and it is widely used as a fertilizer. Unfortunately, it is estimated that phosphate reservoir is depleted within about 100 years. Sewage sludge ash (SSA) is an alternative resource for P recovery because of its high P content. However, SSA cannot be directly used as a fertilizer due to heavy metals in it and low P bioavailability. Thermochemical treatment with Cl donor is known to reduce heavy metal contents and increase P bioavailability of SSA. Literature review on thermochemical technologies of SSA for the reduction of heavy metals and bioavailability enhancement has been carried out to estimate the status of current P recovery technology and to develop strategic future research plan for P recovery. The review showed that $CaCl_2$ and $MgCl_2$ were the most effective Cl donors and reaction temperature (< $1000^{\circ}C$) was the critical operation condition for the reduction. The removal efficiency depends on the species of heavy metals. Thermochemical technology of SSA for P recovery showed the possibility of commercial application in the near future to overcome the coming crisis of human sustainability by P depletion, but it needs cost effectiveness and more ecofriendly process to reduce energy consumption.