• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.43 no.3
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• pp.212-221
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• 2007

This paper describes on the evaluation and management of work process in suction hopper dredger and grab bucket dredger as an application of a PC-based ECDIS system. The dynamic tracking of dredging bucket and the data logging of grab dredging information were performed by using the grab dredging vessel "Kunwoong G-18". The position and route tracking of the dredger moving toward the ocean dumping site of dredged material was performed by using the hopper dredging vessel "Samyang-7". The evaluation of wok process in the dredging field, for grab dredger, was continuously carried out on January to May, 2006, in Incheon Hang and for hopper dredger, on July to December, 2003, in Busan Hang, Korea. The dredging information, such as dredger's position, heading, dredging depth and route track which was individually time stamped during the dredging operation, was automatically processed in real-time on the ECDIS and displayed simultaneously on the S-57 ENC chart. From these results, we conclude that the ECDIS system can be applied as a tool in order to manage the work process during the dredging operation, and also in order to generate the factual record of the dredging activities that is sufficient for dredging inspector to accurately evaluate the contract performance even in the absence of a full-time onboard inspector.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.2 s.25
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• pp.107-113
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• 2006

Water treatment plant sludge occurred in sedimentation and inverse wash process is generally disposed by ocean dumping or reclamation after dehydration processing using mechanical or natural dry method. Recently, ocean dumping of sludge is limited actually by London Convention. Physical, chemical, and geotechnical characteristics of water treatment plant sludge were analyzed by experiments. The possibilities for recycling of the dehydration sludges as materials for covering sanitary landfill were examined. Experiments performed with sludges mixed with general soil to improved the sludge properties are the hydrometer analysis, the liquid and plastic limit test, the specific gravity test, the compaction test, and the unconfined compression test. The value of ${\gamma}_{dmax}$ is increased and OMC(Optimum Moisture Content) is lessened with mixed sludge. The value of maximum compressive strength and friction angle are increased and the cohesion is decreased with mixed sludge. The ratio between sludge and soil in mixed sludge was 3:7 and the strength of mixed sludge showed $3.6kg/cm^2$. These results satisfy the regulation of U.S. E.P.A regarding materials for covering sanitary landfill.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.1
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• pp.1-9
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• 2022

The effect of sediments in a waste dumping area on marine organisms was evaluated using sediment toxicity tests with a benthic amphipod (Monocorophium acherusicum) and bioluminescent bacterium (Vibrio fischeri) in accordance with the Korean Standard Method for Marine Wastes (KSMMW). Nine sites in the East Sea-Byeong, East Sea-Jeong, and Yellow Sea-Byeong areas were sampled from 2016 to 2019. The test results showed that the relative average survival rate (benthic amphipods) and relative luminescence inhibition rate (luminescent bacteria) were below 30%, which were judged to be "non-toxic." However, in the t-test, a total of 12 benthic amphipod samples (6, 1, 1, and 4 in 2016, 2017, 2018, and 2019, respectively) were significantly different (p<0.05) from the control samples. To identify the source of toxicity on benthic amphipods, a simple linear regression analysis was performed between the levels of eight heavy metals (Cr, As, Ni, Cd, Cu, Pb, Zn, and Hg) in sediments and the relative average survival rate. The results indicated that Cr had the highest contribution to the toxicity of benthic amphipods (p = 0.000, R2 = 0.355). In addition, Cr was detected at the highest concentration at the DB-85 station and exceeded the Marine Environment Standards every year. Although the sediments were determined as "not toxic" according to the ecotoxicity criteria of the KSMMW, the results of the statistical significance tests and toxicity identification evaluation indicated that the toxic effect was not acceptable. Therefore, revising the criteria for determining the toxic effect by deriving a reference value through quantitative risk assessment using species sensitivity distribution curves is necessary in the future.

• Ocean and Polar Research
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• v.24 no.4
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• pp.391-398
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• 2002

Trace organic contaminants in deep-sea sediments near Dokdo were analyzed. Total PAMs concentration ranged 14.8-314 ng/g dry weight and high molecular weight PAHs were dominant. The highest PAHs concentration was detected at A19 which located at Ulleung Basin. Most of organochlorines were under detection limit. Among the detected organochlorines, DDT compounds were dominant and followed by HCHs and HCB. Butyltin compounds and most of organophosphorus pesticides were not detected. Vertical distribution of PAHs showed typical sub-surface maximum and decreasing trends depending on depth. The highest PAHs concentration reached 454ng/g. Some organochlorines, DDT, HCH was detected and also showed decreasing trends. Other target organic pollutants were not detected in core sediments. Abnormally high level of PAHs concentration in A19 was discussed and the input sources were inferred to be the transport of sludge derived pollutant dumped at dumping site 'Byung' by deep current.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.3
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• pp.257-262
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• 2017

Several disposal processes for waste sludge from wastewater treatment plants such as landfill, ocean dump, incineration, reuse as fuels or fertilizers are practiced. However, ocean dumping is prohibited by international treat. New constructions of landfill sites or incineration facilities are limited by NIMBY and reuse processes are still suffering from low energy yield. Therefore, development of alternative processes for sludge disposal are currently needed. In this study, alternative technique for sludge solubilization using HVI (high voltage impulse) was suggested and verified experimentally. Sludge solubilization was carried out for 90 minutes using HVI discharge with peak voltage of 16 kV and pulse duration for 40 microsecond. About 3~9 % of MLSS and MLVSS concentration were reduced, but the soluble COD, TN, TP of the sludge increased to 372 %, 56 % and 102 % respectively. It indicates that the flocs and/or cells of the sludge were damaged by HVI. These resulted in flocs-disintegration and cells-lysis, which means the internal matters were bursted out of the flocs as well as the cells. Thus, electrical conductivity in bulk solution was increased. All of the results verified that the HVI could be used as an alternative technique for sludge solubilization processes.

• 한국연소학회:학술대회논문집
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• 2014.11a
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• pp.29-32
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• 2014

The practical route for disposal of sewage sludge becomes energy recovery by combustion after its ocean dumping is banned in 2012 in Korea. Due to the high moisture content, however, sewage sludge is required to be dried before transport and combustion. In this study, pyrolysis and combustion characteristics of dried sewage sludge was investigated in a small-scale fixed bed reactor in order to provide fundamental data for energy recovery of the fuel. As the first step of combustion, the primary products of pyrolysis were analyzed in a fixed bed reactor for the condensable volatiles (tar), non-condensable gases, and char. For the combustion characteristics, another fixed bed reactor was constructed to monitor the weight and temperature of the fuel particles during ignition and combustion under different air flow rates. The test results were used to derive the ignition and burning rates.

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.165-165
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• 2009

• 한국해양학회지
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• v.28 no.2
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• pp.132-136
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• 1993

Attempt was made to identify potential pollutants in Korean Sean and to assess their environmental qualities. Existing pollution data for these Seas so scarce that environmental quality assessment was not possible. However, numerous pollutants were identified. Among them, heat and radioactivity from electric power plants, organic wastes from ocean dumping and land based sources, and accidentally spilled oils are suspected to be of most concern.

• Journal of Wetlands Research
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• v.2 no.2
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• pp.109-116
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• 2000

The equipment of a landfill need whole cut off facilities so that leachate generated from the landfill primarily do not leak to the ocean. Also, the whole collected leachate need a consecutive clarification treatment to discharge. A method is considered the best among the three alternatives. The merits of this method are as follows; have no secondary pollution. can cut down the expense of treatment, have good effects on preventing external leakage, don't need a leachate well, reliable quality control and easy post management. The weaknesses of this method are as follows; need a thorough survey about underground water and quality of the soil, need a special process to use as the land.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.3
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• pp.132-137
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• 2008

The average concentrations of COD and copper in the livestock sludge are $930,726{\pm}380.801$ mg/kg and $679{\pm}341$ mg/kg, respectively. Due to the high concentrations, dumping to the sea of the sludge could pose potential adverse effects to the marine environment. On the contrary, it could have economic advantages on land as the energy of biogas generated by decomposition of organisms and the compost in case of the sludge of good quality with the abundant nitrogen and phosphorus. Nevertheless, the amount of livestock sludge dumped to the sea in Korea increased sharply from 51,000 $m^3$ in 1997 to 2,745,000 $m^3$ in 2005. And also it had the high proportion of 27% in total amount of waste dumped into the sea (7,451,000 $m^3$) in 2007. It might cost between 20,000 won and 33,000 won to dump to the sea of the sludge. In comparison, it might cost 20,000 won to com- post the sludge. And its purification treatment even might cost just 10,000 won. It means that the disposal of the sludge at sea is the most expensive method to deal with the sludge, but ranchers, who engage in the livestock industry, still prefer the disposal at sea to the other methods on land such as the compost and purification treatment. In this article, therefore, we would analyze various factors in the ranchers' preference for the disposal of the sludge at sea, and then we could suggest some legal improvements to prevent and reduce pollution of the sea.