• 자원리싸이클링
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• 제15권3호
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• pp.38-45
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• 2006

슬러지 층에 열을 가함으로서 내부증발압, 여액 점도 저하에 따른 유동성 증대 그리고 기공형성 용이성을 통하여 슬러지의 탈수율을 향상시킬 수 있는 열 필터프레스 탈수 기술을 개발하였다. 크기 $470{\times}470mm$인 PP재질의 맨브레인 플레이트 사이에 열수가열판을 장착하여 온도 $95^{\circ}C$, 압력 $1.2kg_f/cm^2$의 열 수를 공급한다. 그리고 슬러지는 최초 슬러지의 $5kg_f/cm^2$의 공급압력에 의해 1 차 탈수가 이루어지며, 맨브레인의 압착력 $15kg_f/cm^2$에 의해 2차적 탈수 공정으로 이루어진다. 갈수기와 우수기때의 슬러지의 초기 함수율 및 유기물 함량을 고려하여 열 탈수 특성을 평가한 결과 우수기의 슬러지는 케이크의 함수율이 약 35 wt%이며, 탈수 속도는 $4DSkg/m^2{\cdot}hr$로 매우 탈수성 우수하였으며, 갈수기 때의 슬러지 또한 함수율이 50 wt%, 탈수속도가 $1.5kg/m^2{\cdot}hr$이상으로 기계식 탈수의 탈수율(함수율 70 wt%, 탈수속도 $0.9kg/m^2{\cdot}hr$)에 비하여 우수하였다. 이를 바탕으로 열 필터프레스 탈수장치의 추가 소요 에너지를 평가한 결과 고형물(DS) 1 kg처리하는데 소요되는 에너지는 약 300kJ로 평가되었다. 이는 탈수케이크를 재차 건조하는 시스템과 의 에너지 투입비를 분석해 본 결과 열 탈수장치의 에너지 소요량은 약 1/3정도로 감소된 것으로 분석되었다. 본 기술은 기존의 필터프레스에 비하여 탈수 속도가 빠르고 저 함수율 탈수 케이크 생산이 용이할 뿐만 아니라 건조장치에 비하여 에너지 소모량이 적어 경제성이 우수한 시스템으로 파악되었다.

• 대한환경공학회지
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• 제28권10호
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• pp.1016-1023
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• 2006

기존의 밸트프레스 탈수장치로부터 생산되는 탈수 케이크의 함수율이 75 wt% 이상으로 매우 높아 탈수 케이크 처리에 있어 경제적, 환경적 측면에서의 한계를 내포하고 있다. 이를 극복하기 위한 방안으로 구축된 열 탈수장치를 슬러지 처리 현장에 설치하여 밸트프레스 탈수장치와 탈수성능을 서로 비교함으로서 열 탈수장치의 적용성을 평가하였다. 이를 위해 우선 정수 슬러지에 대한 탈수특성을 월별로 분석하였다. 1년 중 갈수기의 슬러지에는 유기물 함량이 높아 탈수가 어려운 반면 우수기의 슬러지는 유기물 함량이 낮아 탈수가 잘 되었다. 이와 같은 슬러지의 탈수 특성을 바탕으로 1년 동안 두 장치에 대한 슬러지의 탈수 특성을 비교한 결과, 갈수기의 슬러지에 대하여 열 탈수로 생산한 탈수 케이크 함수율은 $41.6{\sim}48.3$ wt%, 기계식 벨트프레스에 의해서는 $71{\sim}84$ wt%, 우수기의 경우 열 탈수에 의해 생산된 탈수 케이크 함수율은 $34{\sim}37.7$ wt%, 기계식 벨트프레스에 의해서는 $57{\sim}70$ wt%로 나타났다. 열탈수에 의한 함수율 저감이 현격하게 나타나는 것을 파악하였다. 탈수 케이크 함수율 저감에 따른 케이크 처리량 감소 등을 고려하여 두 장치에 대한 경제성을 평가한 결과 열 탈수의 비용 지수를 100으로 하였을 때 벨트프레스는 121, 즉 열 탈수는 벨트프레스에 비하여 설치 및 운용적인 측면에서 약 20% 이상 경제적인 효과 있는 것으로 분석되었으며, 필터프레스의 경우 11%, 데칸터의 경우 24% 경제적 이점이 있는 것으로 평가되었다. 결론적으로 열 탈수장치는 저 함수율 탈수 케이크를 생산할 수 있을 뿐만 아니라 장치 운용 비용이 저렴한 시스템으로 평가되었다.

• 대한환경공학회지
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• 제28권10호
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• pp.1009-1015
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• 2006

정수 슬러지의 감량화와 탈수장치의 성능향상을 위하여 필터프레스 탈수장치의 각 Plate 사이에 음극판과 양극판을 설치하여 케이크 층에 전기장을 투입하는 전기식 필터프레스 탈수장치(EDFP)를 구축하여 기존의 기계식 필터프레스 탈수장치(MDEF)와의 탈수성 비교, 그리고 EDFP의 탈수성 향상에 따른 경제적인 측면 등을 분석하였다. 동일조건에서 탈수실험을 수행한 결과 EDFP를 통해 배출된 여액량은 43.2 kg으로 MDFP에 비하여 증가하였으며, 케이크 무게는 4 kg으로 MDFP에 비해 2배 증가하였고 탈수 케이크의 함수율은 55 wt%로 MDFP에 비하여 약 20% 감소하였으며 탈수속도는 2.3 $kg/m^2{\cdot}cycle$로 약 30% 증가하였다. 즉 전기탈수(Electrodewatering)의 원리로 구축된 EDFP는 기계탈수(Mechanical Dewatering)에 의한 MDFP 비하여 여액배출량을 증가시키고 저함수율 탈수 케이크를 생산하며 탈수속도를 증가시키는 특성이 있다. EDFP의 소모된 전력량은 400 kwh/DS ton으로, 투입된 전력량과 저함수율 탈수 케이크 생산에 따른 부피 감소로 인한 처리경비 저하의 효과를 서로 고려하여 경제성을 분석한 결과 1 ton(Dry Solid base) 처리하는데 약 20,000원 경제적 절감 효과가 있었다. 이 외 탈수속도가 빨라진 부가적 이점을 감안하면, EDFP는 탈수 성능 면에서 우수할 뿐만 아니라 경제적 타당성이 있는 장치로 평가할 수 있다.

• 상하수도학회지
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• 제9권2호
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• pp.84-96
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• 1995

The dewatering characteristics of the sewage sludge was investigated through the experimental observations and model simulations. The activated sludge and the anaerobically digested sludge were examined for the dewaterability evaluation within the pressure range of $0{\sim}10^6N/m^2$. Modified Buchner funnel test and compression test by the consolidometer were conducted to evaluate average specific resistance, porosity, and moisture percentage of filter cake. Shirato's technique of compression-permeability test was followed for the pressure range lower than about $10^2N/m^2$. The flocculation effects on sludge dewatering was also examined for ferric chloride and polymeric flocculant. The application of hydrated lime which can be used for flue-gas desulfurization showed improved moisture percentage, and was thought to have positive feasibility in combined system of sludge dewatering and incineration. Determined characteristic constants were applied to Tiller's cake filtration model to simulate liquid pressure distribution and porosity distribution in cake. Model simulations showed a sharp drop of the porosity close to the cake-medium interface for the highly compressible material such as the activated sludge and the anaerobically digested sludge.

• 한국환경보건학회지
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• 제37권6호
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• pp.467-473
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• 2011

Objectives: Wastewater treatment plants typically produce a large volume of waste sludge. In this study, the conditioning and dewatering properties of a digested and thickened sludge from an industrial wastewater treatment plant were investigated in order to improve the dewaterbility of the sludge. Methods: Jar-tests and Buchner funnel tests were carried out to assess the conditioning and dewatering properties of a waste sludge. TTF (Time to Filter Test) and SRF (Specific Resistance to Filtration) were adopted as the indices of sludge dewaterbility. Results: The valuation indices influencing the dewaterbility of the waste sludge, including TTF, SRF, water contents, VS/TS ratio and turbidity, were measured. The TTF and SRF of the digested and thickened sludge were decreased to 40 sec, $3.43{\times}10^{12}$ m/kg, and 39 sec, $1.09{\times}10^{12}$ m/kg, respectively. Conclusions: The conditioner composed of natural inorganic materials turned out to be effective in the reduction of sludge water contents.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.443-447
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• 2001

A laboratory-scale electrodewatering system for enhancing conventional filter pressure dewatering by an electric field has been developed to decrease the water content of sludge generated in the wastewater treatment. It consists of a piston-typed filter press, a power supply and data acquisition system. The offset of electrodewatering is investigated as a function of applied pressure, applied voltage, sludge type and filtration time. Also the optimal conditions for maximizing the dewatering efficiency in the eletrodewatering system are investigated. Electric field strength and mechanical pressure are in the range of from 0 to 120 V/cm and from 98.1 to 392.4 kPa. The dewatering rates increased with increasing electric strength. These experiments produced a final sludge cake with water content of 60 wt% using electrodewatering technology, compared with a 80 wt% using pressure filtration alone. The conventional filtration system using the electrodewatering shows the potential to be effective method for improving dewatering Sludge.

• 상하수도학회지
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• 제21권6호
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• pp.709-715
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• 2007

The dewaterability of a sludge can be characterized by two ways: the residual moisture content in the sludge cake after dewatering process, and the filtration of the sludge. Time to filter (TTF) represents filtration processes that are special cases of the flow through a solid matrix concept. TTF characterizes a resistance to filtration. The sludge resistance, in turn, can be subdivided into resistances associated with the solid phase and the liquid phase to evaluate the effect of each of the two phases on sludge dewaterability. In order to determine the dewatering characteristics of the water sludge samples, TTF and zeta potential were measured. For these studies cationic polymer was chosen for water sludge dewatering experiments. The zeta potential of thickener sludges neared from minus values to zero values till 4 days after sampling. The dewaterability of thickener sludges using cationic polymer was deteriorated according to the increase of detention time. As the detention time was increased from 4 to 10 days, the optimal dose of the polymer was increased from 4 to 8mg/L. Therefore, the optimal detention time plays an important part for the dewaterability of a sludge.

• KSBB Journal
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• 제25권1호
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• pp.41-46
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• 2010

In this study, we found that dewatering properties were related with physico-chemical properties such as sludge concentration, pH, and zeta potential with sewage sludge, Ionic contents in digested sludge were in the order of $Ca^{2+}$ (14.2 mg/g) > $Mg^{2+}$ (1.9 mg/g) > $Na^+$ (1.4 mg/g) > $K^+$ (1.0 mg/g). Divalent ion more than monovalent have influenced on physico-chemical and dewatering properties. Floc size distribution in activated (AS) and digested sludge (DS) increased on lower pH range to be near isoelectric point and than specific resistance to filtration (SRF) decreased. A linear increase in SRF ($5.25\times10^{13}\sim2.86\times10^{14}$ m/kg in AS and $6.89\times10^{14}\sim1.09\times10^{15}$ m/kg in DS) was observed throughout low concentration range of 1230~9960 mg/L in AS and 2700~5400 mg/L in DS.

• Environmental Engineering Research
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• 제11권4호
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• pp.208-216
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• 2006

In order to create a single flocculant/dual flocculation system, polyacrylamide-co-trimethyl ammonium ethyl acrylate chloride (TAEAC) polymers with varying molecular weights and structures were prepared for use of flocculants. The higher the cationic density of the polymer is higher, the higher was the conversion rate and the ratio of monomer. An acrylamide as nonionic monomer was less reactive than a TAEAC as cationic monomer. The branched polymer which was polymerized with a cross-linking agent, N, N-methylene bis-acrylamide had a higher stability and higher viscosity than a linear polymer but its dewatering efficiency was poor in a single flocculation system. In the case of single flocculant/dual flocculation, the branched polymer has better flocculation efficiency and the water content of the dewatered cakes was lower than the others, as the result of a re-flocculation effect. The optimum conditions for dual flocculation are a sequence in which the $1^{st}$ and $2^{nd}$ dosage are 75% and 25%/total dosage of a single flocculation system. The dewatering efficiency of a dual flocculation system is improved considerably from 10 to 25% under the experimental conditions used herein.

• 한국태양에너지학회 논문집
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• 제34권3호
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• pp.49-56
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• 2014

A fiat-plate or vacuum tube solar collector have been mainly used for hot water supply of house because of some being difficult to get uniform energy density, so little applied into industrial field. This study is to apply the PTC(parabolic trough collector) solar collector into industrial field such as sludge dewatering system for energy reduction. The real scale system which composed of PTC Solar Collector and Thermal Dewatering (TDW) is established. PTC solar collector is designed to produce a hot water with $80^{\circ}C$ of temperature. And size of TDW is $630{\times}630mm$. Hot water produced from PTC solar collector is supplied into heating plate of TDW, and sludge like waterworks or wastewater is dewatered. PTC solar collector with $10m^2$ of area produce energy of average 5,618 kcal. As according to results from real scale performance, solar collector takes charge 94 % of the amount that TDW consume energy which is so large part if compare with boiler. It means that PTC solar collector is useful to apply industrial field under the condition of sufficient solar radiation. And it is analyzed that TDW by PTC solar collector has an economical validity.