• Microbiology and Biotechnology Letters
• /
• v.7 no.2
• /
• pp.91-95
• /
• 1979

Ethanol and Xylose were produced from cellulosic agricultural waste such as rice straw and corn cob by a single-step simultaneous hydrolysis-fermentation process utilizing semi-solid culture of Trithoderma as enzyme source and Saccharomyces yeast. By this process all the hexoses prduoced by the enzyme were converted to ethanol leaving pentoses which are not fermented by the yeast. By processing 50 g of rice straw, 18 ml of ethanol and 2.7 g of xylose were produced and 50 g corn cob produced 3.8 ml of ethanol and 10.8 g of xylose. Alkali-treatment of rice straw showed little effects on the productivities of ethanol and xylose. The possible reasons are discussed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.8 no.3
• /
• pp.113-118
• /
• 1988

Laboratory aerobic and anaerobic digesters were operated to determine the nonbiodegradable fractions in PS (Primary Sludge) and WAS (Waste Activated Sludge)from a municipal wastewater treatment plant in Seoul. Nonbiodegradable fractions were determined to be 45 to 47% in PS and 58 to 68% in WAS. Ultimate $CH_4$ gas production rates were estimated to be 0.76 for PS and $0.54m^3/kg$ VS removed for WAS. $CH_4$ contents were respectively 63% for PS and 65% for WAS.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.12
• /
• pp.1755-1762
• /
• 1998

In order to minimize emission of polychlorinated dibenzo dioxins and polychlorinated dibenzo furans (PCDD/PCDFs) from municipal solid waste incinerators, it is important to maintain optimized operating conditions along with the system modification/improvement. Operating conditions of MSW incinerator make very complicated influence on formation of PCDD/PCDFs in each unit apparatus. For revealing these influences, concentrations of PCDD/PCDFs are measured from the stack and from the fly ash, while monitoring the plant operating conditions. The effects are grouped into 3 main categories, combustion conditions, de Novo synthesis effects, and adsorption/destruction effects in the flue gas treatment system. Interpretation of the results showed that de Novo synthesis effect, reformation by metalic catalyst, especially Cu in fly ash in the temperature range of $250{\sim}500^{\circ}C$, is found to influence most dominantly on the concentration of PCDD/PCDFs. A plausible mathmatical model for predicting concentration of PCDD/PCDFs is proposed, and discussed.

• Membrane Journal
• /
• v.9 no.2
• /
• pp.132-139
• /
• 1999

Solid scintillation proximity membranes were prepared for measuring the amount of radioactivity in laboratories contaminated by the radionuclide of $^3H$-cortisol. The membranes, consisting of polysulfone as a polymer matrix and cerium activated yttrium silicate as a fluor, were used to monitor the amount of radioactivity without the aid of a scintillation cocktail required for the conventional wipe test. The test results of the cocktail-free wipe test showed that the prepared membranes were efficient to monitor radionuclide-contaminated areas with the good counting ability as well as with the decrease of overall production of radioactive waste. On the other hand, solvent treatment of the prepared membranes could induce a significant variation of membrane morphology, but the counting efficiency of the solvent-treated membranes was not improved than that of the untreated one.

• Journal of Korean Society of Environmental Engineers
• /
• v.39 no.11
• /
• pp.650-654
• /
• 2017

As the amount of chemicals increases, there is a global movement to reorganize the chemical management system. Korea has also reorganized its chemical management system to enact the act on Chemical Control and Registration and Evaluation etc. of chemical substance. However, it is true that there are not enough explanations in domestic workplaces. Therefore, deepening understanding of chemical control act and searched for a complementary point and future development direction. Through the proposed method, chemical control act should be widely adopted and studied both inside and outside the country as a safe chemical management system.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
• /
• v.11 no.4
• /
• pp.19-33
• /
• 1982

Briquette ashes, one of important solid wastes in Korea, have relatively high compression strength in spite of their low density, and provide sufficient surface area and some adsorption capacity. Results of this research show that a fixed-film biological process using briquette ashes as media can accomplish BOD removal efficiencies in treating organic wastewaters such as alcoholic waste, diluted nightsoil and sewage , and formula can be derived to determine the effluent BOD concentrations by superficial or volumetric organic loadings. Settling tanks may be required because effluent SS concentration is deteriorated due to the SS in influent or due to the slough-off of slime layer on the media when briquette ashes are utilized for a long period.

• Korean Journal of Soil Science and Fertilizer
• /
• v.26 no.2
• /
• pp.121-126
• /
• 1993

The behaviors of inorganic nitrogen derived from solid animal waste in soil has been received too much concern partly because nitrate which occurred from nitrification can act as a pollutant to soil and groundwater and partly because the loss of nitrogen from surface soil by downward movement of water is disadvantageous in the view of plant nutrient. This present study was conducted to get fundamental imformations on nitrogen behavior and to provide improved basical concepts on the management of animal waste. Fresh or fermented pig manure was mixed with a sandy loam soil in the ratio of 2:1(soil:pig manure), packed into test tube and incubated at $30^+/-1^{\circ}C$ for 8 weeks under aerobic- or anaerobic condition. Sample tubes were taken at the one week interval and analyzed on pH, the amount of $CH_4$ produced under anaerobic condition and inorganic nitrogen. The pH of soil treated with fresh pig manure under anaerobic condition was lowered by 1.87 unit compared to that of under aerobic condition, but at the treatment with fermented pig manure, pH change was very little between aerobic and anaerobic condition. The coefficients of regressional equations which were obtained from pH and incubation time were -0.114 in fresh pig manure and -0.089 in fermented pig manure, and the extent of pH decrease due to incubation was greater in fresh pig manure than that of fermented pig waste. No differences in the amounts of $CH_4$ produced under anaerobic condition between fresh and fermented pig manure was observed until 3 weeks of incubation, however, after that the amount of $CH_4$ produced in fresh pig manure was abruptly increased and cumulative amont of $CH_4$ was reached 8.6 mole/g. K values on $CH_4$ production in fresh and fermented pig manure was 0.211 mole/g/day and 0.046 mole/g/day, respectively, for 5 weeks from the 3rd to the 8th week. $NH_4-N$ concentration at aerobic condition with fresh pig manure treatment was lowered by passing time of incubation, but $NO_3-N$ concentration was elevated from 11.2 ppm at initial state to 67.3 ppm after incubation and this trend on $NH_4-N$, $NO_3-N$ concentration was very similar to the treatment of fermented pig manure. While $NH_4-N$ concentration under anaerobic condition was greatly increased. $NO_3-N$ concentartion was not only very low but also no great changes, that was ranged from 4 to 8 ppm.

• Resources Recycling
• /
• v.19 no.1
• /
• pp.40-48
• /
• 2010

It was investigated that effects of NaOH concentration on synthesis of mesoporous materials using municipal solid waste incinerator ash slag (MSWI-ash slag). In order to increase the purity and maximize the amount of extracted Si content the raw MSWI-ash slag was mechanically activated. Extraction of Si from the MSWI-ash slag was carried out by alkali treatment using concentrated NaOH solution, which varied from 1M to 4M. Physical properties (i.e., pore size, specific surface area and total pore volume) of the synthesized mesoporous silica were also evaluated as a function of NaOH concentration via BET, SEM, TEM and small-angle X-ray scattering analyses. Over the entire range of NaOH concentration investigated (i.e., 1-4M), the synthesized mesoporous materials were determined to be SBA-15, which exhibited a hexagonal structure with the pore size of approximately 7 nm. On the other hand, specific surface area and total pore volume increased with NaOH concentration up to 3M while the values decreased at 4M, indicating that the optimal NaOH concentration for the synthesized mesoporous silica was approximately 3M. Further comparison analysis between two conditions (3M versus 4M) showed that the decrease in two physical properties at 4M NaOH concentration was likely due to the potential inhibition by excess Na ions on the formation of mesophase and the consequent increase of pore wall thickness by remaining Si ions.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 1996.06c
• /
• pp.692-700
• /
• 1996

The objective of this study is to develop a systematic purification plant using the metabolism of aerobic microorganisms. This system is subsequently aerated and continuously removes suspended solids and settling sludges caused by aerating pressure at the bottom of a lower pipe (i.e., Continuous Removal of Suspended solids and Settling sludges, CRSS). The CRSS plants are brought out by introducing fine air bubbles into the liquid phase of a lower pipe in the bio-reactor. These plant uses aeration pipe, with multiple inlets to sweep the floor of bio-reactor tank, instead of the conventional scraper mechanisms. The principal advantage of this system is that it can continuously remove very small or light particles that settles completely within a short time. Once the particles have been floated to the surface, they can be moved into the pipe and collected in the settling tank by sequently aerated pressure. The experimental results shows that about 99.0% of the biochemical oxygen demand(BOD), 99.3% of the suspended solid(SS), 92.3% of the total nitrogen(T-N), 99.0% of the turbidity(TU), 100% of the total coliform(TC)and ammonia was respectively removed during aerobic digestion for 9 days. These result indicates that the CRS S plants are very effective for reduction and deodorization of swine wastewater contaminants, and the efflux from CRS S can either be discharged in the river or used as nutrient solution of formulation for plant growth factories. The developed CRSS plant proved to be flexible and it can simply be adapted to any type of biological waste treatment problem.roblem.

• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.7
• /
• pp.523-529
• /
• 2011

This study has been performed to examine the influence of the size of particles on the stabilization in the aerobic stabilization equipment connected with MBT system. The biodegradable waste inside the reactor (60% of food waste, 25% of paper waste, 2% of wood waste and 5% of compost) has been charged in same composition. The degree of stabilization was compared and analyzed after charging with adjustment of particle size in 5 mm, 10 mm, 20 mm, 50 mm, 100 mm and state of no separation. The experiment revealed that highest temperature beyond $65^{\circ}C$ was shown in the particle size of less than 50 mm in change of temperature and the highest temperature was about $50^{\circ}C$ in reactor of 100 mm and no separation. The proportionality between generated quantity of $CO_2$ and particle size was not observed, even the highest in generated quantity was shown in over 100 mm. The weight changes based on wet and dry conditions in the reaction process showed the 30% and 46% of reduction in the smallest particle size of 5 mm and it showed the trend of the lower reduction rate at the bigger particle size. The water soluble $COD_{Cr}$ and TOC showed the reduction rate of 60% in reactor of particle size in 100 mm and no separation while the reduction rate comparing to the initial stage of reaction in the reactor of less than 50 mm was 80%. Such result derived the conclusion of acceleration in the decomposing stabilization of biodegradable material due to the decomposing rate of organic substance as the particle size of biodegradable waste gets smaller. It is concluded as necessary to react in adjustment under 50 mm of particle size as much as possible.