• 상하수도학회지
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• 제32권3호
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• pp.269-277
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• 2018

Burials for the rapid disposal of carcasses have diverse and profound effects on the rural living condition, natural environment, and local economy throughout construction, management and final destruction of burials. In this study, possible residue excavated from standard burials, storage using FRP (Fiberglass Reinforced Plastic) tanks, and microbial-treated burials are characterized as carcasses, contaminated soil by leachate, and wasted plastic film. Treatment technologies for volume reduction of the residue including composting, rendering, and thermal hydrolysis were investigated. If the solid and liquid residues generated during volume reduction treatment are directly transferred to the environmental facilities, it may cause disorder due to high concentrations of organics, antibiotics, and lipid. Benefits and drawbacks of composting as a volume reduction techniques are extensively investigated. We also discussed that proper treatment of excavated soils and the reusing the treated soil as agricultural purpose. For the protection of public health and worker's hygiene, treatment criteria including produced residue qualities, and quality standards for the treated soil as agricultural use are required. In addition, Scientific manual for the proper treatment of residues is required. It is necessary to consider the establishment of a pretreatment facility to the occurrence of large-scale residue treatment.

• 한국물환경학회지
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• 제20권4호
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• pp.346-351
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• 2004

Because of being produced a great deal of excess sludges from biological wastewater treatment process, the subject regarding treatment and disposal of them has been significantly handled in real plants. It should be considered the alternative treatment with easy operating and cost effective process in rural areas. For the thickening of wasted activated sludge from small scale wastewater treatment facilities, thus, the provisional sludge thickening system was developed by the application of mesh filter module. Three meshes with different pore size(100, 150, $200{\mu}m$) were prepared for filter modules that were used to withdraw effluent from thickening system. A filter module with $100{\mu}m$ mesh was chosen as the most effective thickening material in the viewpoint of volume reduction and effluent quality: the volume reductions of initially injected sludge with 3,600 mg/L and 9,100 mg/L were 95% and 85%, respectively, and the filtered effluents were enough good to be shown below 1.0 mg/L of SS and 1.0 NTU of turbidity. Since the filtration of thickening was influenced by the cake layer formed on mesh filter module and this system was operated in the combination of sludge thickening with gravity settling, the filter modules with smaller pore size and the larger floc size were required for long term operation safely.

• 한국물환경학회지
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• 제33권1호
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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.

• 상하수도학회지
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• 제31권3호
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• pp.257-262
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• 2017

Several disposal processes for waste sludge from wastewater treatment plants such as landfill, ocean dump, incineration, reuse as fuels or fertilizers are practiced. However, ocean dumping is prohibited by international treat. New constructions of landfill sites or incineration facilities are limited by NIMBY and reuse processes are still suffering from low energy yield. Therefore, development of alternative processes for sludge disposal are currently needed. In this study, alternative technique for sludge solubilization using HVI (high voltage impulse) was suggested and verified experimentally. Sludge solubilization was carried out for 90 minutes using HVI discharge with peak voltage of 16 kV and pulse duration for 40 microsecond. About 3~9 % of MLSS and MLVSS concentration were reduced, but the soluble COD, TN, TP of the sludge increased to 372 %, 56 % and 102 % respectively. It indicates that the flocs and/or cells of the sludge were damaged by HVI. These resulted in flocs-disintegration and cells-lysis, which means the internal matters were bursted out of the flocs as well as the cells. Thus, electrical conductivity in bulk solution was increased. All of the results verified that the HVI could be used as an alternative technique for sludge solubilization processes.

• 한국지열·수열에너지학회논문집
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• 제18권1호
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• pp.12-19
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• 2022

Desalination has the advantage of being easy to supply water resources. However most desalination devices are developed mainly for large plants and it is not common to use desalination system for a small fishing ship. More than 50% of the input fuel energy of the small shipbuilding's engine is wasted without reused in a ship, and it is necessary to improving the fuel efficiency of the small fishing ship. In this study, a desalination device using waste heat from engine of the ships was developed. As results, it was found that if the condensing chamber uses a fan to circulate the water vapor, the freshwater production was up to 40.0% higher, and the freshwater production efficiency was up to 30.1% increased when the fan was operated.

• 한국환경농학회지
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• 제28권1호
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• pp.38-46
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• 2009

Livestock manure is an important source of nutrients for crop production. However, farmers typically do not know the exact nutrient values for livestock manure. In many instances, manure has been viewed as a waste, and as a result it is applied close to the source resulting in over application of nutrients. Thus, the goal of nutrient application has often been applied to reduce the application expense rather than to maximize crop income. This results in wasted money and potentially negative impacts on water quality. Several livestock manure management scenarios were created based on agronomic nutrient requirements using the Utilization of Animal Manure as a Plant Nutrient (AMANURE) software to investigate water quality impacts with the National Agricultural Pesticide Risk Analysis (NAPRA) WWW modeling system. Application of manure at agronomic rates can result in high nitrate-nitrogen losses for some soil types, especially when applied in late fall. The application of manure at an agronomic rate does not necessarily equate to adequate water quality protection, and farmers must take care applying manure at agronomic rates, because nitrate-nitrogen loss potential varies spatially and temporarily. Nutrient loss probability maps for Indiana at 5%, 10%, 25%, and 50% values were created to demonstrate potential water quality impacts when livestock manure is applied to cropland at agronomic rates. The NAPRA WWW system coupled with AMANURE can be used to identify site-specific livestock manure management plans that are environmentally sound and agronomically appropriate.

• Environmental Engineering Research
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• 제12권1호
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• pp.1-7
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• 2007

Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.

• 자원환경지질
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• 제36권2호
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• pp.103-109
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• 2003

동해탄광 지역의 산성광산배수에는 Ca, SO$_4$, Mg, Al의 함량이 높게 나타난다. 이 일대의 산성광산배수를 증발시켰을 때 생성된 증발잔류물에서는 주로 석고(CaSO$_4$${\cdot}$2$H_2O$)가 생성되었으며 그 외에 소량의 알루노겐(Al$_2$(SO$_4$)$_4$${\circ}$17$H_2O$) 과 헥사하이드라이트(MgSO$_4$${\circ}$6$H_2O$)가 형성되었다. 석고를 형성하는 Ca는 주변의 모암속에 포함된 방해석에서, SO$_4$ 는 폐석에 포함된 황철석에서 기원한 것으로 생각된다. 함수 알루미늄황산염광물인 알루노겐은 침상의 결정으로 나타난다. 하천수의 Al은 모암이나 폐석에 포함된 엽납석, 일라이트, 녹니석과 같은 층상규산염광물의 화학적 용해작용에 의해 부과된 것으로 추정된다. 함수 마그네슘황산염광물인 헥사하이드라이트는 침상이나 섬유상의 결정으로 생성되었으며 Mg의 기원은 모암내의 돌로마이트와 광산폐셔의 주 구성광물인 녹니석으로 판단된다.

• 한국수자원학회논문집
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• 제47권11호
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• pp.1087-1094
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• 2014

해안지역에서 지하수 해수침투 저감을 위하여 해수 양수 관정을 가동할 때 해수정으로 많은 양의 담수가 낭비되는 사례가 있다. 해수 침투를 저감시키고 낭비되는 담수를 유용하게 활용하기 위하여 이중 양수정이 제안된 바 있다. 이중 양수정은 해수 양수를 위한 해안 쪽의 해수정과 담수 양수를 위한 내륙 쪽의 담수정으로 구성된다. 선행 연구에서는 담수정의 해수 비율을 최소화시키기 위한 해수정의 양수량을 산정하였으나 담수정의 해수비율이 1~15% 범위로 나타나 담수정에서 담수를 확보하기 어렵다고 판단하였다. 본 연구에서는 이송이 지배적인 상황에서 이중 양수정의 효과를 분석하였다. 연구 결과 담수정에서 저염도 지하수를 확보할 수 있음을 밝혔다. 또한 해안 유역 차원의 적정 지하수관리를 위해서는 담수정의 해수비율을 최소화하는 것 외에도 해수정으로 낭비되는 담수량을 최소화하는 것도 함께 고려해야한다.

• 한국유체기계학회 논문집
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• 제11권5호
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• pp.44-49
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• 2008

As the alternative energy, renewable energy should have been developing by many techniques, in order to substitute the fossil fuel which will be disappeared in the near future. One of the small hydropower generator, main concept of tubular turbine is based on using the different water pressure levels in pipe lines, energy which was initially wasted by using a reducing valve at the end of the pipeline, is collected by turbine in the hydro power generator. A propeller shaped hydro turbine has been used in order to use this renewable pressure energy in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the guide vane opening angle are examined in detail. First, it ensures the reliance of CFD by that of compared with experiment data. After all, the results of performance characteristics of the CFD and experiment show to confirm the data that power, head and efficiency of less than 4%, 2% and 5% respectively. Moreover influences of pressure, tangential and axial velocity distributions on turbine performance are investigated.