• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
• /
• pp.231-234
• /
• 2004

The experiments on some organic materials used in SAPS are carried out for the better sulfate reduction efficiency and the longer lifetime. Organic materials include spent mushroom compost, sewage sludge, oak chip compost and the combination of there. Reactors with mushroom compost, sewage sludge, the mixture of mushroom compost and sewage sludge, and the mixture of mushroom compost and oak chip compost maintained pH higher than 6.0. Reactors with mushroom compost, the mixture of mushroom compost and sewage sludge, and the mixture of mushroom compost and oak chip compost maintained reduction condition. Reactors with sewage sludge, oak chip compost and the mixture of sewage and oak chip compost produced COD less than 2,000ppm. Reactors with sewage and the mixture of mushroom compost, sewage sludge, oak chip compost showed about 60% of sulfate removal ratios.

• 한국환경농학회지
• /
• 제22권1호
• /
• pp.70-73
• /
• 2003

Nitrate contamination in the aquatic systems is the primary indicator of poor agricultural management. The influence of sewage sludge application rates (0, 10, 25, 50 and 100 dry Mg/ha) on distribution of nitrate originating from the sewage sludge in soil profiles was investigated. Soil profile monitoring of nitrate was carried out with a Lakeland clay soil in 1997. Irrespectively of the sewage sludge application rates up to 50 dry Mg/ha, the concentration of $NO_3$-N at the 120 cm depth was below 10 mg/kg and the difference due to the amount of sewage sludge application was negligible at this depth. There was virtually no $NO_3$-N below 120 cm depth and this was confirmed by a deep sampling up to 300 cm depth. Most of the nitrate remained in the surface 60 cm of the soil. Below 120 cm depth nitrate concentration was very low because of the denitrification even at high sewage sludge rate of 100 dry Mg/ha. The $NO_3$-N concentrations in the soil fluctuated over the growing season due to plant uptake and denitrification. The risk of groundwater contamination by nitrate from sewage sludge application up to high rate of 100 dry Mg/ha was very low in a wheat grown clay soil with high water table ( < 3 m).

• Journal of Microbiology and Biotechnology
• /
• 제26권1호
• /
• pp.110-119
• /
• 2016

High-solid anaerobic digestion of sewage sludge achieves highly efficient volatile solid reduction, and production of volatile fatty acid (VFA) and methane compared with conventional low-solid anaerobic digestion. In this study, the potential mechanisms of the better performance in high-solid anaerobic digestion of sewage sludge were investigated by using 454 high-throughput pyrosequencing and real-time PCR to analyze the microbial characteristics in sewage sludge fermentation reactors. The results obtained by 454 highthroughput pyrosequencing revealed that the phyla Chloroflexi, Bacteroidetes, and Firmicutes were the dominant functional microorganisms in high-solid and low-solid anaerobic systems. Meanwhile, the real-time PCR assays showed that high-solid anaerobic digestion significantly increased the number of total bacteria, which enhanced the hydrolysis and acidification of sewage sludge. Further study indicated that the number of total archaea (dominated by Methanosarcina) in a high-solid anaerobic fermentation reactor was also higher than that in a low-solid reactor, resulting in higher VFA consumption and methane production. Hence, the increased key bacteria and methanogenic archaea involved in sewage sludge hydrolysis, acidification, and methanogenesis resulted in the better performance of high-solid anaerobic sewage sludge fermentation.

• 한국환경과학회지
• /
• 제15권9호
• /
• pp.897-905
• /
• 2006

This study has been conducted to investigate biodegradation characteristics and optimum mixing ratio for co-digestion with thermophilic acid-fermented food waste and sewage sludge using batch anaerobic digester. As the basis operating conditions for anaerobic digestion, the reaction temperature was controlled $35{\pm}1^{\circ}C$ and stirrer was set 70rpm. Thermophilic acid-fermented food waste and sewage sludge were mixed at the ratio of 10:0, 7:3, 5:5, 3:7, 0:10 and 5;5(food waste : sewage sludge) as the influent substrates. In results of co-digestion according to mixing ratio of thermophilic fermented food wastes and sewage sludge in batch mesophilic anaerobic digestion reactor, $385mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio was more than that of any other mixing ratios. Compared with $293mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio of food wastes and sewage sludge, pretreatment of food wastes by thermophilic acid fermentation was more effective in co-digestion with sewage sludge.

• Journal of Applied Biological Chemistry
• /
• 제42권3호
• /
• pp.134-139
• /
• 1999

The distributions of Cd, Cu, and Zn concentration in soil treated with one (1988) or two (1988 and 1993) applications of sewage sludge at rates of 0, 25, 50, and $100Mg\;ha^{-1}$ (dry weight basis) were determined to assess the accumulation and mobility of the heavy metals. The heavy metals accumulated almost entirely in 0 to 15 cm soil depths. Small amounts of the metals moved out of the tillage zone (0-15 cm depth) into the subsoil, but even at the high rate of sewage sludge, little movement of heavy metals occurred below 100 cm depth. The water-extractable Cd, Cu, and Zn concentrations were very low regardless of the rate of sewage sludge application. Availability of metals as determined by DTPA extraction showed the percentage of DTPA-extractable/total concentration increased with sewage sludge application. In the 0-15 cm depth of sewage sludge treated soil, the percentage of DTPA-extractable/total concentration was higher than 46% for Cd, but the value was less than 27% and 17% for Cu and Zn, respectively. The Cd, Cu, and Zn added to this calcareous clay soil by sewage sludge application were not very mobile, and the amount of plant available form was very small.

• Geomechanics and Engineering
• /
• 제10권5호
• /
• pp.689-707
• /
• 2016

Soil stabilization is one of the useful method of ground improvement for soil with low bearing capacity and high settlement and unrequired swelling potential. Generally, the stabilization is carried out by adding some solid materials. The main objective of this research was to investigate the feasibility of stabilization of organic soils and sewage sludge to obtain low cost alternative embankment material by the addition of two different slags. Slags were used as a replacement for weak soil at ratios of 0%, 25%, 50%, 75% and 100%, where sewage sludge and organic soil were blended with slags separately. The maximum dry unit weights and the optimum water contents for all soil mixtures were determined. In order to investigate the influence of the slags on the strength of sewage sludge and organic soil, and to obtain the optimal mix design; compaction tests, the California bearing ratio (CBR) test, unconfined compressive strength (UCS) test, hydraulic conductivity test (HCT) and pH tests were carried out on slag-soil specimens. Unconfined compressive tests were performed on non-cured samples and those cured at 7 days. The test results obtained from untreated specimens were compared to tests results obtained from soil samples treated with slag. Laboratory tests results indicated that blending slags with organic soil or sewage sludge improved the engineering properties of organic or sewage sludge. Therefore, it is concluded that slag can be potentially used as a stabilizer to improve the properties of organic soils and sewage sludge.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_2호
• /
• pp.73-77
• /
• 2001

The disposal of sewage sludge using landfills and ocean dumping is no longer a viable option due to land scarcity and increasingly stringent environmental control regulations. As such, various efforts have been made to develop new sewage sludge recycling technologies. This work investigates the fundamental physical and chemical characteristics of rural type sewage sludge from Chungnam province in South Korea. The average moisture content, ignition loss, elementary analysis, and average heating value of the sewage sludge samples were examined. The average moisture content of the dewatered sludge was about 80%, while the organic matter was about 50% of the total solid sludge weight. The average heating value of a sewage sludge and petroleum coke waste mixture(1:1 weight ratio) was about 5,000 ㎉/kg, thereby indicating a high potential for energy recycling.

• Environmental Engineering Research
• /
• 제24권2호
• /
• pp.202-210
• /
• 2019

In order to maximize the utilization of sewage sludge, a waste from wastewater treatment facility, the residual sewage sludge generated after lipid and carbohydrate extraction for biodiesel and bioethanol production was used to produce bio-oil by pyrolysis. Thermogravimetric analysis showed that sludge pyrolysis mainly occurred between 200 and $550^{\circ}C$ (with peaks formed around 337.0 and $379.3^{\circ}C$) with the decomposition of the main components (carbohydrate, lipid, and protein). Bio-oil was produced using a micro-tubing reactor, and its yield (wt%, g-bio-oil/g-residual sewage sludge) increased with an increase in the reaction temperature and time. The maximum bio-oil yield of 33.3% was obtained after pyrolysis at $390^{\circ}C$ for 5 min, where the largest amount of energy was introduced into the reactor to break the bonds of organic compounds in the sludge. The main components of bio-oil were found to be trans-2-pentenoic acid and 2-methyl-2-pentenoic acid with the highest selectivity of 28.4% and 12.3%, respectively. The kinetic rate constants indicated that the predominant reaction pathway was sewage sludge to bio-oil ($0.1054min^{-1}$), and subsequently to gas ($0.0541min^{-1}$), rather than the direct conversion of sewage sludge to gas ($0.0318min^{-1}$).

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제4권4호
• /
• pp.215-220
• /
• 2000

This study on the incineration ash and sintering pellet from sewage sludge was carried out to evaluate the possibility of recycling in sewage sludge disposal. The samples used in this experiment were raw sewage sludge, its incineration ash, and sintering pellet. The characteristics of the three sample types were identified using X-ray diffraction(XRD), X-ray fluorescence(XRF), atomic absorption spectroscopy(AAS), and inductively coupled plasma spectroscopy(ICP). The chemical compositions of all three sample types were similar in their clay component, however, the sewage sludge had a high content of organic materials. From an analysis of the mineral content of the three sample types, the conversion of their compositions was found to be relative to temperature. Accordingly, incineration ash and sintering pellet both have potential for use as a functional construction material.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
• /
• pp.477-480
• /
• 2005

The discharge of sewage sludge is rapidly increasing in Korea. But the most common sewage sludge disposal alternative is to incinerate and to deposit it in controlled landfills. However, space limitations on existing landfill sites, and increasing environmental concerns have prompted the investigation of alternative ash disposal routes. The utilization of sewage sludge ash would contribute to the elimination of an environmental problem and to the development of new high-performance materials. The purpose of this study is to apply to Alkali Activation into solidification of sewage sludge ash. It achieves leaching test, chemical composition and compressive strength test. As a result of tests, the sewage sludge ash has sufficient potential for use of pozzolanic raw material. However, it is judge to be available to construction material if research is continuously gone.