• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.1
• /
• pp.93-100
• /
• 2005

Comparative thickening and dewatering characteristics of municipal wastewater sludge were investigated in terms of separated and combined treatment of primary and secondary BNR sludge. Also, various conditioning methods such as cation polymer addition, steam and ultrasonication treatment were examined to improve dewaterability of sludge. The dewaterability was measured by using specific resistant test, wedge zone simulator and centrifuge. The result of the sludge thickening test revealed that separated thickening was better in terms of solids recovery and supernatant quality. Particularly, the thickening of primary sludge with high solids (about 3.5% TS) showed very poor solid separation. The addition of cation polymer showed better conditioning characteristic for dewatering and the optimal polymer dosage was 0.26% for primary sludge, 0.43% for secondary sludge and 0.38% for combined sludge. Contrary to the result of the thickening, the dewatering test revealed that dewatering of the combined sludge is better than that of separated sludge, representing better solids separation and filtrate quality. The polymer addition was essential to improve dewaterability in filter (belt) press type dewatering but it was inefficient for the dewatering of secondary sludge only. The centrifuge type dewatering showed better performance and the dewaterability was slightly improved when the polymer was added. Based on the results of this research a sustainable sludge treatment process, particularly in terms of the recycle water quality and solids recovery, was proposed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.6B
• /
• pp.661-667
• /
• 2006

In this study, an experiment of sewage sludge dewatering is carried by using electrokinetic method, and the electrokinetic dewatering efficiency of digested sludge is analyzed. Digested sludge without coagulants is selected and gravitational and pressing dewatering methods are applied in combination with electro-osmotic and electro-osmotic pulse technology. After the test of digested sludge, dewatering test of thickened sludge is carried to evaluate the electrokinetic dewatering feasibility of thickened sludge. Under the condition of constantly applied voltage, however, electrical resistance increases with decreasing of water content so that dewatering rate decreases with time. To reduce such a hindrance caused by constantly applied voltage, electro-osmotic pulse technology which is considered to reduce the difference of water content with height, is applied. For the application of electro-osmotic pulse, the dewatered flow rate and the dewatered volume became more increasing from the middle of the dewatering process than that of continuous voltage. Through the test of thickened sludge, electro-osmotic dewatering combined with gravitational and expression also showed high dewatering rate, which proved the possibility of using electrokinetic dewatering.

• Economic and Environmental Geology
• /
• v.57 no.2
• /
• pp.263-270
• /
• 2024

In this study, impact factors for dehydration with KOMIR-Tube system using flocculant and dewatering tube were evaluated for mine drainage sludges. The experiments were conducted on semi-active facility sludges with water contents above 90 % using KOMIR-Tube system. The flocculant and input amount were determined from laboratory experiment and the dewatering efficiency was verified onsite experiment. The sludge characteristics were identified by instrumental analysis such as zeta potential measurement, particle size analysis, XRD, XRF and SEM-EDS. Selection of flocculants for sludge dewatering treatment need to consider not only precipitated rate but also filterated rate. Floc size has to keep at least 0.7 mm. From on-site experiments, sludge dewatering using KOMIR-Tube system suggests to carry out April and May that is low rainfall and humidity considering to climate conditions. Also, dewatering rate depends on the crystal degree of mineral that mainly makes up sludges. Particularly, goethite of the iron hydroxides has better dewatering rate than ferrihydrite. Ferrihydrite is low degree of crystallinity and uncleared or broad shaped crystal, goethite is good crystallinity with needle shaped crystal so that the effect of flocculation and dewatering showed to depend on the crystal. In results, impact factors of dewatering for mine drainage sludges are related to flocculant, climate, crystallinity and shape of iron hydroxides.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11b
• /
• pp.308-309
• /
• 2003

본 연구에서 진행된 전자선과 불가사리 분말을 이용한 탈수슬러지 함수율 저감 시스템으로 슬러지를 전처리한 후 탈수함으로 최소 15 % 이상의 탈수효율 증대로 인한 탈수케이크의 부피감소 및 이에 따른 처리비용의 절감을 가져올 것으로 사료된다. 또한 물리적 개량단계에 이용되는 불가사리 분말은 해양생태계에 악영향을 주는 불가사리의 이용범위를 확대함으로 불가사리 구제 및 수매사업의 활성화와 해양환경보전에 이바지할 수 있다.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.10 no.2
• /
• pp.125-131
• /
• 2002

This study was carried out to evaluated for dewaterability of sewage sludge using waste oystershell and loess. The Jar-Test and the Buchner funnel test were proceeded for the assessment of dewaterability of a thickened sludge and digested sludge. TTF(Time to Filter), SRF(Specific Resistance to Filtration) were adopted as the valuation indices of sludge dewaterability. Dewatering conditioner which composed of both oystershell and loess is much dewaterable than the one composed of only oystershell. In the course of combining with oystershell and loess, the following fact was found that the dewaterability of the combination which have the higher ratio of oystershell than that of loess is superior. The most suitable oystershell :loess ratio of dewatering conditioner is 9:1 in treating both thickened sludge and digested sludge.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.6 no.1
• /
• pp.67-73
• /
• 1998

This study was to experiment, through sewage sludge treatment by Vacuum Drying Method, variation of water content with reaction pressure, reaction time, reaction temperature. The result are as follows; The water content decreased with the same reaction temperature and reaction time at lower pressure and 360~40 mmHg (a close vacuum) showed lower water content at low reaction temperature and short reaction time. The water content rapidly decreased with the same reaction pressure and time at low reaction temperature (above $120^{\circ}C$).

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2005.05a
• /
• pp.356-359
• /
• 2005

하수를 처리하는 공정에서 해마다 슬러지의 발생량은 증가하고 있으며, 이를 효과적으로 처리하는 것이 매우 중요하다. 따라서, 본 연구는 경제적이면서도 측정이 간편한CST(Cap-illary Suction Time)을 통해 슬러지 의 탈수성 과 적 정 주입량을 산출하는 방법을 연구하였다. 이를 위하여 본 실험의 대상인 도시 하수슬러지에 대하여 함수율 및 pH변화, 무기 및 유기 응집제의 주입량 변화, 그리고 응집제 투입 후 침전된 응집제량을 조사하여 탈수성을 조사하였다. 슬러지의 함수율을 97%, 98%, 99%로 했을 때, CST는 99%일 때가 가장 적은 값으로 나타났다 응집제 주입 후 침전된 슬러지의 생성량은 응집제가 증가됨에 따라 증가하다가, 최적 주입량보다 더 많은 응집제를 주입할 경우에는 그 양이 감소했다. 이는 형성된 응집물의 구조적 특성의 변화를 나타내고 있음을 알 수 있다. 위와 같은 실험 결과를 통해 CST는 수분이내(< Smin)에 슬러지의 탈수성을 신속하게 측정할 수 있는 방법이며 비교적 정확하게 측정할 수 있음을 알 수 있다. 뿐만 아니라 응집제의 최적 주입량 및 응집물의 구조적 특성을 평가하는 데에도 유용하게 사용할 수 있다.

• Resources Recycling
• /
• v.18 no.3
• /
• pp.55-61
• /
• 2009

Dewatering process to remove water from pigment sludge was important in the diverse aspects of the improvement of product quality, curtailment of the drying cost and the transportation. It was difficult to dewater pigment particles with the mechanical forces because the size was fine under $5{\mu}m$. Thermal filter press dewatering equipment composed of squeezing plate and a fixed heating plate was developed to improve the dewaterability of pigment the sludge as supplying the heat from the fixed heating plate to the cake. Several tests that estimate the dewaterability for pigment sludge as with or without squeezing process and the difference of dewatering time was conducted with this equipment. Dewaterability of thermal dewatering under squeezing process was increased about 20% compared with non squeezing process. Under squeezing process, thermal dewatering tests changing dewatering time with 70 and 80 minute were conducted respectively. The water content of cake was more reduced at dewatering time of 80 minute compared with 70 minute, and dewatering velocity was also decreased, which caused the productivity of thermal filter press to drop. It was observed that clogging of filter cloth didn't almost occur because the liquid was discharged from cake layer easily. In this research, it was resulted that the squeezing process and long dewatering time were effective to improve the dewaterability of pigment sludge. So, this thermal filter press equipment was useful for dewatering the fine particle sludge like pigment.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11b
• /
• pp.310-311
• /
• 2003

본 연구에서는 폐수산자원인 불가사리와 조개껍질 분말을 이용한 탈수보조제(물리개량제)의 가능성을 확인하였다. 불가사리와 조개껍질을 이용한 탈수보조제는 유가자원 소모라는 기존의 탈수보조제의 문제점을 보완하여 폐자원의 자원화라는 이점이 있으며 탈수케이크의 함수율을 효과적으로 낮추어 주어 소각등의 후속공정에 도움을 줄 수 있는 것으로 사료된다. 뿐만아니라 천연 비료로 사용되어지는 불가사리의 활용이라는 점에서 탈수슬러지 퇴비화등 자원 재이용에의 적용성 또한 증대시킬 수 있다.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.10
• /
• pp.1016-1023
• /
• 2006

The water content of dewatered cake produced from belt press dewatering equipment was about 75 wt% which was some high to handle it, so the equipment contained a limit at the economical and environmental aspect. The thermal dewatering equipment built as an alternative to overcome several problems was set up at the sludge treatment field and estimated some feasibility as comparison with the dewatering performance of belt press. First, dewatering properties of waterworks sludge was analyzed by monthly. The sludge of a water shortage season contained a high organic content which led to be difficult to dewater the cake, the other side the sludge of rainwater season was ease to dewater because of low organic content. According to the results to analysis the water content of dewatered cake produced from two equipments on the base of the seasonal dewatering properties, the water content of dewatered cake produced from thermal dewatering for sludge of water shortage season was $41.6{\sim}48.3$ wt% and $71{\sim}84$ wt% from belt press. In the case of rainwater season, the water content of dewatered cake produced from thermal dewatering was $34{\sim}37.7$ wt% and $57{\sim}70$ wt% from belt press. It was understood that thereduction of water content of cake by thermal dewatering was larger than belt press. The economical aspect for two equipments was evaluated on considering the reduction of cake treatment amount as the decrease of water content of cake. When putting the cost index of thermal dewatering into 100, belt press was 121. This meant that thermal dewater was more economical than belt press by about 20% in the side of construction and operation. In conclusion, thermal dewatering equipment was estimated by producing the low water content dewatered cake as well as being operated with low coat.