• 한국지반환경공학회 논문집
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• 제13권8호
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• pp.75-84
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• 2012

본 연구에서는 보강재료(폐어망, 본딩처리된 폐어망, 지오그리드)와 보강층수(1층 및 2층)에 따른 정수슬러지 혼합 경량토의 강도 및 용출 특성을 비구속압축시험과 용출시험을 통해 분석하였다. 정수슬러지가 혼합된 경량토는 정수슬러지, 시멘트, 저회를 유동성에 맞춰서 배합 제작되었다. 시험에 사용된 보강재료는 폐어망과 지오그리드이다. 흙입자와 폐어망 사이의 억물림을 증가시키기 위하여 본딩처리를 한 폐어망을 추가로 사용하였다. 정수슬러지가 혼합된 경량토에 대한 강도시험 결과 보강재료에 따른 강도증진은 폐어망, 본딩처리된 폐어망, 지오그리드 순으로 증가하였다. 또한 보강층수가 1층에서 2층으로 증가할수록 강도 역시 증가되는 경향을 나타내었다. 또한 정수슬러지를 혼합한 경량토에 대한 용출시험을 분석한 결과 환경부가 고시한 기준을 만족하는 것으로 나타났다.

• 한국환경과학회지
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• 제23권6호
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• pp.1061-1066
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• 2014

This study has cross checked the change of internal sludge-recycle in Anaerobic-Digestion, and researched about not only the improvement of Bio-gas production from the digested sludge but also the efficient method of sludge minimization. Ultimate object of the study is to reduce the amount of sludge by the improved efficiency of contact with the organic-matter and the microbes in Anaerobic-Digestion. The sludge-recycle fluidized sludge layer and raised the activity of the sludge, the optimal sludge-recycle ratio, VS and COD removal ratio were 1,000%, 28.2% and 27.7%, respectively. Through these results of this study, it may be of use to treat waste sludge by the sludge-recycle ratio in terms of minimization and circulation of resources.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.1040-1045
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• 2010

The pond sludge from golf course which is a place of business waste that recycling is necessary. But, Most pond sludge was controlled by incineration and reclamation. Also, There are no research about pond sludge from waste point of view. The purpose of this study was focusing on recycling of pond sludge to make block of vegetation. In this study, in order to recycle the pond sludge with block of vegetation from mixed additive that analyzed characteristics of strength from compaction test and shear strength test.

• 대한환경공학회지
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• 제35권1호
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• pp.64-69
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• 2013

이 연구논문의 주요 목적은 하수슬러지와 생활폐기물을 혼합소각할 경우, 소각시설의 안정적 운영을 위해 가장 중요한 변수인 하수슬러지의 정량공급 방안에 관한 것이다. 실험결과, 슬럼프테스트와 유동화테스를 통해 함수율을 약 87%로 정량공급할 경우, 하수슬러지의 표면연소를 보완하여 완전연소가 이루어 질 것으로 판단되어 향후 생활폐기물과 하수슬러지 혼합소각시 소각시설의 안정화에 기여할 것으로 판단된다.

• 유기물자원화
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• 제16권3호
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• pp.52-64
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• 2008

하수슬러지와 음식물 침출수슬러지 또는 제지슬러지를 혼합하여 부숙시킨 후 줄지렁이에게 급이하면서 지렁이의 섭식률 및 생장률을 조사하였다. 하수슬러지에 음식물쓰레기 침출수슬러지를 혼합하여 30일 부숙시킨 것에 대한 지렁이 개체군의 섭식량은 10, 20일 부숙시킨 것에 대한 섭식량보다 높았다. 그러나 부숙기간에 상관없이 먹이 급이 90일 경과 후 지렁이 개체군의 밀도는 감소하였고, 먹이급이 180일 경과 후 지렁이 개체군의 연령구성에서 성충의 비율이 현저하게 높은 것으로 보아 하수슬러지에 음식물쓰레기 침출수슬러지를 혼합하여 부숙시켜 전처리된 먹이는 지렁이 개체군의 차세대로의 성장을 저해하는 것으로 나타났다. 하수슬러지에 제지슬러지를 혼합하여 20일 부숙시킨 것에 대한 지렁이 개체군의 섭식량 및 밀도는 10, 30일 부숙시킨 것보다 높게 나타났다. 부숙기간에 상관없이 먹이급이 90일까지는 지렁이 개체군의 밀도가 증가하였으나, 먹이급이 90일 이후부터 감소하였다. 따라서 하수슬러지를 장기간 급이시 발생하는 밀도 감소에 기인하는 하수슬러지 내 독성물질의 규명 및 이를 제거하는 다른 전처리과정이 필요한 것으로 생각된다. 한편, 줄지렁이 개체군의 밀도, 유충 및 성충의 비율, 섭식량 등을 고려하였을 때, 하수슬러지와 제지슬러지를 혼합하여 20일 부숙시킨 것이 다른 전처리 먹이보다 지렁이퇴비화 가능성이 높은 것으로 판단된다.

• 상하수도학회지
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• 제19권4호
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• pp.497-505
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• 2005

Domestic Sewage Treatment Plants are mostly based on biological treatment, in which large amounts of excess sludge are generated and occupy about 40 ~ 60% of the total sewage treatment costs. Several methods for sludge treatment has been so far reported as upgrading biodegradation of sludge; heat treatment, chemical treatment, including thermo-alkali and ozone, mechanical treatment including ultrasonic pulverization. But, it has a limitation in case of reducing the amount of excess sludge which are already producted. In this study, application of excess sludge reduction process using thermophilic aerobic bacteria for activated sludge was examined. The research was carried out two different stage. one for a biological wastewater treatment and the other for a thermophilic aerobic solubilization of the waste sludge. A portion of excess sludge from the wastewater treatment step was into the thermophilic aerobic sludge solubilization reactor, in which the injected sludge was solubilized by thermophilic aerobic bacteria. The solubilized sludge was returned to the aeration tank in the wastewater treatment step for its further degradation. Sludge solubilization reactor was operated at $63{\pm}2^{\circ}C$ with hydraulic retention time(HRT) of 1.5 ~ 1.7 day. Control group was operated with activated sludge process(AS) and experiment group was operated with three conditions(RUN 1, RUN 2, RUN3). RUN 1 was operated with AS without sludge solubilization reactor. RUN 2 were operated with AS with sludge solubilization reactor to examine correlation between sludge circulation ratio and sludge reduction ratio by setting up sludge circulation ratio to 3. RUN 3 was operated with sludge circulation ratio of 3 and MLSS concentration of 1,700~2,000mg/L to examine optimum operation condition. The quantity of excess sludge production was reduced sharply and in operation of RUN 3, sludge The quantity of excess sludge production was reduced sharply and in operation of RUN 3, sludge solubilization ratio and sludge reduction ratio were 53. 7%, 95.2% respectively. After steady state operation, average concentration of TBOD, SBOD, $TCOD_{Cr}$, $SCOD_{Cr}$, TSS, VSS, T-N, T-P of effluent were 4.5, 1.7, 27 .8, 13.8, 8.1, 6.2, 15.1, 1.8mg/L in the control group and were 5.6, 2.0, 28.6, 19.1, 9.7, 7.2, 16.1, 2.0mg/L in the experimental group respectively. They were appropriate to effluent standard of Sewage Treatment Plants.

• 한국환경과학회지
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• 제15권11호
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• pp.1053-1059
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• 2006

This study was performed to investigate the possible uses of waste sludge for the removal of heavy metal ions. The adsorption experiments were conducted with wastes such as sewage treatment sludge, water treatment sludge and oyster shell to evaluate their sorption characteristics. Heavy metals selected were cadmium, copper and lead. in the sorption experiments on the sewage treatment sludge, water treatment sludge, oyster shell and soil, sorption occurred in the beginning and it reached equilibrium after 40 minutes on the oyster shell and 4 hour on the sewage treatment sludge and water treatment sludge. Results of Freundlich isotherms indicated that sewage treatment sludge could be properly used as an adsorbent for heavy metals and sorption strength of heavy metals was in the order of Pb > Cu > Cd. In the influence of pH on the adsorbents, sorption rate was more than 80% in pH 4 and most of heavy metals were adsorbed in pH 9. Adsorption rate of Cd decreased with decreasing pH and then adsorption rate of Cu was lower in soil.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1542-1550
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• 2014

Co-digesting molasses wastewater and sewage sludge was evaluated for hydrogen production by response surface methodology (RSM). Batch experiments in accordance with various dilution ratios (40- to 5-fold) and waste mixing composition ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100, on a volume basis) were conducted. Volatile solid (VS) concentration strongly affected the hydrogen production rate and yield compared with the waste mixing ratio. The specific hydrogen production rate was predicted to be optimal when the VS concentration ranged from 10 to 12 g/l at all the mixing ratios of molasses wastewater and sewage sludge. A hydrogen yield of over 50 ml $H_2/gVS_{removed}$ was obtained from mixed waste of 10% sewage sludge and 10 g/l VS (about 10-fold dilution ratio). The optimal chemical oxygen demand/total nitrogen ratio for co-digesting molasses wastewater and sewage sludge was between 250 and 300 with a hydrogen yield above 20 ml $H_2/gVS_{removed}$.

• 신재생에너지
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• 제10권1호
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• pp.20-29
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• 2014

The present study investigated the effects of thermal pre-treatment on the enhancement of anaerobic biodegradability of waste activated sludge at varied TS concentration levels. The activated sludges were thermally oxidized for 30 minutes at $80{\sim}200^{\circ}C$ with varied TS concentrations (2%, 4% and 6%). and then, sludge characteristics, solubilization efficiency and methane production yield of thermally pre-treated sludges were analyzed. The higher the temperature in the thermal pre-treatment, the higher the concentration levels of dissolved matters such as $SCOD_{Cr}$, $NH_4{^+}$ and VFAs, which indicates that the thermal pre-treatment facilitates the hydrolysis and acid fermentation. Furthermore, the solubilization efficiency was increased in proportion to the temperature rise at all TS concentrations and was reached at 68.9%, 55.6% and 53.1%, respectively, at $200^{\circ}C$. In the BMP test of the pre-treated sludges, higher methane production yields were observed as 0.313. 0.314 and $0.299m^3\;CH_4/kg\;VS_{add}$ at the condition of TS 2% ($160^{\circ}C$), 4% ($160^{\circ}C$) and 6% ($180^{\circ}C$), respectively, and degradation rate was increased by 84%, 79% and 65% compared with non-pretreated waste activated sludge. These findings suggest the effectiveness of thermal pre-treatment of waste activated sludge for anaerobic biodegradable process.

• 상하수도학회지
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• 제10권2호
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• pp.104-116
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• 1996

Anaerobic digestion is generally used for the treatment of volatile organic solids such as manure and sludge from waste water treatment plants. However, the reaction rate of anaerobic process is slow, and thus it requires a large reactor volume. To minimize such a disadvantage, physical and chemical pre-treatment is generally considered. Another method to reduce the reactor size is to adopt different reactor system other than CSTR. In this paper, the effects of heat pre-treatment and reactor configurations on the anaerobic treatability of volatile solids was studied. Carrot, kale, primary sludge, and waste activated sludge was chosen as the test materials, and the BMP method was used to evaluate the maximum methane production and first order rate constants from each sample. After the heat treatment at $130^{\circ}C$ for 30min., the measured increase in SCOD per gram VS was up to 394 mg/L for the waste activated sludge. However, the methane production potential per gram VS was increased for only primary and waste activated sludge by 17-23%, remaining the same for carrot and kale. The overall methane production process for the tested solids can be described by first order reactions. The increased in reaction constant after heat pre-treatment was also more significant for the primary and waste activated sludge than that for carrot and kale. therefore, the heat pre-treatment appeared to be effective for the solids with high protein contents rather than for the solids with high carbohydrate contents. Among the four reactor systems studied, CSTR, PFR, CSTR followed by PFR, and PFR with recycle, CSTR followed by PFR appeared to be the best choice considering methane conversion rate and the operational stability.