• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
• /
• pp.157-160
• /
• 2005

The purpose of this study is to efficiently treat the sewage sludge discharged from sewage treatment plants and evaluate the feasibility of the manufacture of lightweight aggregates(LWA) using a large quantity of sewage sludge and inorganic waste binder ;f1y-ash, waste-stone, tailing, phosphogypsum. Then they were burned in different soak temperatures from 1190$^{circ}C$ to 1290$^{circ}C$ with fixed soak time and heating rate at 5 minutes and 20$^{circ}C$/min respectively in order to produce lightweight aggregate (LWA). Experiment were generated to evaluate the quality of LWA as well as the relationship between burning condition and product's quality.

• Environmental Engineering Research
• /
• 제21권4호
• /
• pp.319-332
• /
• 2016

Micropollutants are often discharged to surface waters through untreated wastewater from sewage treatment plants and wastewater treatment plants. The presence of micropollutants in surface waters is a serious concern because surface water is usually provided to water treatment plants (WTP) to produce drinking water. Many micropollutants can withstand conventional WTP systems and stay in tap water. In particular, pharmaceuticals and endocrine disruptors are examples of micropollutants that are detected at the drinking water, ppb, or even ppb level. A variety of techniques and processes, especially advanced oxidation processes, have been applied to remove micropollutants from water to control drinking water contamination. This paper reviews recent researches on the occurrence and removal of micropollutants in the aquatic environments and during water treatment processes.

• 수도
• /
• 제24권5호통권86호
• /
• pp.16-28
• /
• 1997

As sewerage works has become one of the major public works in Korea, the employment of advanced and more appropriate sewerage technology has become essential to improve the efficiency of sewerage works. During last 10 years, the Korean Government has made tremendous amount of investment on sewerage works so that treatment plants in 58 cities have treatment capacity which is equivalent to 52.8% of total daily sewage generation in Korea. This remarkable development, however, has heavily depended on one technology, the conventional activated sludge process as more than 95% of the existing plants employ this process, Recently, the Korean Government and local authorities have plans to introduce more appropriate sewage treatment technologies and research and development in this area has become very active. To encourage employing new and appropriate technologies, however, the proper technology evaluation and verification program for new process is needed. The public sector should play a key role in this program since the sewerage works is one of the major public works. In this paper, the technology evaluation and verification programs related with sewerage facilities in the US and Japan are briefly reviewed. The Innovatived and Alternative Technology programs which was operated by US EPA until recently and Environmental Technology Verification(ETV) program which was commenced in 1995 are introduced. The technology verification programs operated in Japan and also in Korea are also reviewed in this paper to propose a future direction for development of the appropriate evaluation and verification system.

• 상하수도학회지
• /
• 제29권1호
• /
• pp.57-63
• /
• 2015

Recently, Korea's municipal wastewater treatment plants generated amount of wastewater sludge per day. However, ocean dumping of sewage sludge has been prohibited since 2012 by the London dumping convention and protocol and thus removal or treatment of wastewater sludge from field sites is an important issue on the ground site. The hydrothermal carbonization is one of attractive thermo-chemical method to upgrade sewage sludge to produce solid fuel with benefit method from the use of no chemical catalytic. Hydrothermal carbonization improved that the upgrading fuel properties and increased materials and energy recovery, which is conducted at temperatures ranging from 200 to $350^{\circ}C$ with a reaction time of 30 min. Hydrothermal carbonization increased the heating value though the increase of the carbon and fixed carbon content of solid fuel due to dehydration and decarboxylation reaction. Therefore, after the hydrothermal carbonization, the H/C and O/C ratios decreased because of the chemical conversion. Energy retention efficiency suggest that the optimum temperature of hydrothermal carbonization to produce more energy-rich solid fuel is approximately $200^{\circ}C$.

• 한국수처리학회지
• /
• 제26권6호
• /
• pp.73-80
• /
• 2018

In this study, the solids removal characteristics using T-P sludge generated from PACl coagulation were analyzed by laboratory scale and full scale experiment. As the amounts of T-P sludge injection into the raw sewage influent increased at the rate of 0, 1, 2, 3, 4 %, the suspended solids concentrations after 20 minutes setting test decreased to 210, 137, 91, 64, 43 mg/L, respectively. The filtration time required for dewatering test of the raw sewage influent decreased to 982, 728, 658, 581, 492 sec for 0, 1, 2, 3, 4% of T-P sludge injection, respectively. As the amounts of PACl coagulant into the effluent from final setting tank increased at 0, 10, 20, 30, 40 mg/L, the required filtration times for T-P sludge increased into 12.3, 41.7, 53.7, 67.2, 79.5 sec and the dewaterability of T-P sludge decreased. After T-P sludge returned into the primary settling tank on J-si sewage treatment plants, the effluent concentrations of COD, SS, T-N and T-P from primary settling tank into bioreactor decreased by 35.9, 27.9, 22.2, and 52.6% due to the coagulation effects of the T-P sludge. Finally, it was found that the return of T-P sludge into the primary settling tank could result into the sludge reduction having a lower water content of 3.03% p than in case of the only T-P sludge dehydration.

• 대한환경공학회지
• /
• 제35권5호
• /
• pp.363-370
• /
• 2013

소수력발전은 하수처리장 에너지 자립을 위한 효과적인 대안이다. 본 연구는 유량변동이 크고 유효낙차가 낮은 중소형 하수처리장(기흥레스피아) 적용을 위해 피치조절형 세미카플란(semi-kaplan) 마이크로수력발전의 적용 타당성을 평가하였다. 가변피치 semi-kaplan 수차는 유량조절을 위한 가이드베인은 생략하고 피치조절형 런너를 장착하여 기계적 결함은 줄이면서 유량변동이 큰 처리장에 특화된 기술이다. 마이크로수력발전 시스템은 설계조건(유량 0.35 $m^3/s$, 유효낙차 4.7 m)에서 90.2%의 수차효율 달성이 가능하였고 발전용량은 13.4 kW로 산정되었다. 설비가동률 74%로 가동 시 연간 약 86.8 MWh 에너지 생산을 통해 2.1%의 에너지 자립이 가능하고 이는 연간 49톤의 $CO_2$ 감축효과와 맞먹는다. 경제성 평가결과 초기 건설공사비가 200,000,000원 이하인 경우에는 내부수익률은 6.1%, 순현가는 15,539,000원, 편익-비용률은 1.08, 투자회수년은 15.5년으로 경제성이 충분한 것으로 나타났다.

• 한국환경농학회지
• /
• 제25권1호
• /
• pp.25-33
• /
• 2006

농어촌 등 소규모로 발생되는 생활하수를 자연친화적으로 처리하기 위한 대책의 일환으로 인공습지에 적용되는 최적의 수생식물을 선발하기 위하여 다년생 수생식물 10종을 하수처리장에 식재한 후 하수 처리효율, 처리시기별 수생식물의 생육상 및 무기성분 흡수량 등을 조사하였다. 인공습지 하수처리장에서 하수중 BOD, COD, T-N 및 T-P의 수처리효율은 호기성조를 통과한 호기성조 처리수에서 각각 92%, 74%, 25% 및 57%이었고, 혐기성조를 통과한 방류수에서 각각 96%, 84%, 44% 및 71%이었다. 수생식물 생육 150일 후의 질소 및 인 흡수량은 호기성조에서는 물억새가 각각 17.7 및 2.41 g/plant로 가장 높았으며, 혐기성조에서는 큰고랭이가 각각 8.7및 1.1 g/plant로 가장 높았다. 인공습지 하수처리장의 호기성조에서 최적 수생식물은 물억새>달뿌리풀>갈대의 순이었고, 이들 수생식물은 대부분 뿌리의 발육이 좋은 심근성 수생식물이었고, 여재층 내로 산소를 공급하기 쉬운 통기조직이 발달된 수생식물들이었다. 인공습지 하수처리장의 혐기성조에서 최적 수생식물은 줄>큰고랭이>부들>노랑꽃창포>삿갓사초의 순이었고, 이들 수생식물은 대부분 뿌리의 발육보다 줄기와 잎의 발육이 좋은 천근성 수생식물로서 호기 성조의 최적 수생식물의 역할과는 달리 영양물질의 흡수량이 우수한 수생식물이 선정되었다.

• 한국물환경학회지
• /
• 제36권6호
• /
• pp.535-545
• /
• 2020

This study aims to conserve and monitor energy use in public sewage treatment plants by utilizing data from the SCADA system and by controlling the aeration rate required for maintaining effluent water quality. Power consumption in the sewage treatment process was predicted using the equipment's uptime, efficiency, and inherent power consumption. The predicted energy consumption was calibrated by measured data. Additionally, energy efficiency indicators were proposed based on statistical data for energy use, capacity, and effluent quality. In one case study, a sewage treatment plant operated via the SBR process used ~30% of energy consumed in maintaining the bioreactors and treated water tanks (included decanting pump and cleaning systems). Energy consumption analysis with the K-ECO Tool-kit was conducted for unit processing. The results showed that about 58.7% of total energy consumed was used in the preliminary and biological treatment rotating equipment such as the blower and pump. In addition, the energy consumption rate was higher to the order of 19.2% in the phosphorus removal process, 16.0% during sludge treatment, and 6.1% during disinfection and discharge. In terms of equipment energy usage, feeding and decanting pumps accounted for 40% of total energy consumed following 27% for blowers. By controlling the aeration rate based on the proposed feedback control system, the DO concentration was reduced by 56% compared pre-controls and the aeration amount decreased by 28%. The overall power consumption of the plant was reduced by 6% via aeration control.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2007년도 춘계학술발표논문집
• /
• pp.287-290
• /
• 2007

We investigated the effect of ultrasound on the dewaterability of sewage sludge. Because, dewatering and disposal of waste sludge is a major economical factor in the operation of wastewater treatment plants. Capillary Suction Time(CST) and Specific Resistance to Filtration (SRF) were used to evaluate the sludge dewatering behaviors. From the results of the experiment, it was found that ultrasonic treatment can improve the dewaterability. We discovered that CST and SRF were highly related, according to the correlation coefficient($R^{2}$).

• 상하수도학회지
• /
• 제18권4호
• /
• pp.508-514
• /
• 2004

Industrial and municipal wastewater treatment plants produce large amounts of sludge cakes for final disposal. This problem is an inevitable drawback inherent to the activated sludge process. Both the reduction of the amount of sludge produced and improvement of its dewaterability are presently very important issue also in Korea. So many pre-treatment processes have been developed in order to improve sludge dewatering efficiency. In this study the effects of hydrogen peroxide and paper sludge mixing processes were considered as reasonable alternatives to enhance sludge dewaterability. The CST of sludge was significantly decreased, and dewaterability improved by hydrogen peroxide oxidation treatment. The optimum dosage of hydrogen peroxide was proved to be 10mg/g-TS (when TS of sludge was 2%) with the conditions of pH 4 and only 1~2 minutes of reaction time. The mixing of paper sludge with sewage sludge was turned out to be very effective in reduction of sludge cake; 30% of sludge cake reduction was accomplished. Optimum mixing ratio of paper sludge was about 30%(v/v). This process also could save 25% of polymer to be required. These two alternatives are somewhat realistic, but it was concluded that paper sludge mixing process will be the best choice.