• Journal of the Korea Institute of Building Construction
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• v.17 no.6
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• pp.517-525
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• 2017

Red mud is an industrial by-product produced during the manufacturing aluminum hydroxide ($Al(OH)_3$) and aluminum oxide($Al_2O_3$) from Bauxite ores. In Korea, approximately 2 tons of red mud in a sludge form with 50% moisture content is produced when 1ton of $Al_2O_3$ is produced through the Bayer process. In the paper, dispersion characteristics of liquefied red mud that does not require heating and grinding process for recycling were investigated through viscosity and sediment index. The results showed that the sediment index of liquefied red mud increased but viscosity of that decreased with a higher W/R ratio. Also we proposed the range of initial viscosity from 2000cP to 8000cP and target sedimentation index below 20% at elapsed time 180days for stable dispersion of liquefied red mud.

• Journal of Korean Society on Water Environment
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• v.28 no.4
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• pp.608-614
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• 2012

The effluent limitation of industrial wastewater is based on uniform regulatory criteria for effluent discharge facilities of all in Korea. But, an individual effluent limitation on each effluent discharge facility is widely applicable for regulation of industrial wastewater in US.EPA. To decide an individual effluent limitation, TBEL (Technology-based effluent limitation) and WQBEL (Water quality-based effluent limitation) are used. TBEL is based on the capability of a treatment technology to reduce the pollutants. WQBEL is based on ambient water quality standards. In this study, TBEL were derived for the pulp, paper and paper board manufacturing based on best practicable control technology currently available. It was suggested that effluent limitations were $BOD_5$ 4.7 mg/L, $COD_{Mn}$ 44.3 mg/L, SS 13.2 mg/L, TN 1.4 mg/L, TP 0.15 mg/L and best practicable control technology currently available (BPT) was neutralization, activated sludge treatment and coagulation and sedimentation for the pulp, paper and paper board manufacturing.

• Applied Biological Chemistry
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• v.25 no.2
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• pp.99-104
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• 1982

Natural zeolite rock was pulverized and dispersed in water. Clay fraction was collected by sedimentation method. The dominant clay mineral was Clinoptiolite with some Mordenite and Smectite. $P^{32}$ adsorption on Na-zeolite was determined in different ionic strengths using $P^{32}$ isotope by sludge method. The lower the pH of suspension, the longer the contact time, and the more the amount of zeolite, the more inorganic P was adsorbed by Na-zeolite, whereas the more P adsorption per unit gram of zeolite was observed at a 100mg addition than a 200mg in same volume of P-NaCl solution (20ml), indicating that the whole positively charged surface of Na-zeolite was not occupied by inorganic P. Furthermore, the more P adsorption on Na-zeolite was observed in higher ionic strength than in the lower. The maximum P adsorption on Na-zeolite was about 1me/g, and the zero point charge (ZPC) is assumed to be below pH 3.7.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.2
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• pp.261-272
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• 2013

Algae boom (Red tide) in south coastal area of Korea has been appeared several times during a decade. If algae boom appears in the desalination plant, media filter and UF filter are clogged quickly, and the plant should be shutdown. In general, Algae can be removed from water by flotation better than by sedimentation, because of the low density of algal cell. The purpose of this study conducts the CFD simulation of DAF flotation basin to apply the design of the dissolved air flotation with ball filter in the Test Bed for SWRO desalination plant. In this study, Eulerian-Eulerian multiphase model was applied to simulate the behavior of air bubbles and seawater. Density difference model and gravity were used. But de-sludge process and mass transfer between air bubbles and seawater were ignored. Main parameter is hydraulic loading rate which is varied from 20 m/hr to 27.5 m/hr. Geometry of flotation basin were changed to improve the DAF performance. According to the result of this study, the increase of hydraulic loading rate causes that the flow in the separation basin is widely affected and the concentration of air is increased. The flow pattern in the contact zone of flotation basin is greatly affected by the location of nozzle header. When the nozzle header was installed not the bottom of the contact zone but the above, the opportunity of contact between influent and recycle flow was increased.

• Analytical Science and Technology
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• v.18 no.3
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• pp.216-223
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• 2005

In this study, several kinds of volatile amines in ambiant air were collected and their concentrations were expected from the calibration curves prepared by standard solutions of 7 amines by the official measuring method prescribed in Japanese Offensive Odor Law. The obtained calibration curves showed a good linearity and the detection limit of trimethyl amine was found to be about 0.033 ppb (0.040 ng) in case of 50 liters air. It means that trimethyl amine could be detected with the concentration of lower than its permitting level at the border line of companies. As typical examples of measuring amines in air, results of investigation of two sewage works and one rendering plant around the capital area indicated that 4 kinds of amines, i.e. methyl amine, dimethyl amine, trimethyl amine and isopropyl amine were detectable and concentrations of trimethyl amine at the primary sedimentation pond and sludge dewatering building of the sewage plant A showed 9.07 ppb and 7.79 ppb respectively, being over the concentration of odor strength 2.5, And the aeration tank, excrement input facility and indoor of maintenance room of excrement process building in the sewage plant B showed 70.0 ppb of dimethyl amine and 2.44 ppb of trimethyl amine.

• Advances in concrete construction
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• v.14 no.1
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• pp.1-13
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• 2022

Due to the physical-chemical characteristics of some bottom ash (BA), there are technical, economic and environmental limitations to find a destination that will add value to it. In Brazil, this residue is eventually used for filling coal extraction pits or remains in sedimentation ponds, creating a susceptible panorama to environmental issues. The geopolymers binders are one of the alternatives to the proper use high amounts of these materials. In this work, geopolymeric binder pastes were produced with BA mixed to activators with different alkali contents (expressed as %Na₂O), as well as the incorporation of soluble silicates (Ms content). The production of binary geopolymeric pastes based on the use of two industrial wastes: fluid catalytic cracking (FCC) and aluminum anodizing sludge (AAS), was also assessed. The content in mass of BA/FCC and BA/AAS ranged from 100/0, 90/10; 80/20 and 70/30. Systems with soluble silicates as activator in a molar ratio SiO₂/Na₂O of 1.0 (Ms = 1.0) and Na₂O content of 15%, showed the best results of mechanical strength (42 MPa at day 28^th). The improvement is up to 5X when compared to NaOH based systems. For systems with partial replacement of BA of 10% of AAS and 20% of FCC (80/20), the presence of soluble silicates was also effective to increase compressive strength.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.191-195
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• 1999

An integrated wastewater treatment pond system is developed for treatment and recycling of excreta from dairy cattle. It is composed of three ponds in series. A pit with a capacity of $10m^3$, 2-day hydraulic residence time, and overflow velocity of $1.5m^3m^{-2}day^{-1}$ is located internally in primary pond. It is designed for efficient sludge sedimentation and effective methane fermentation. It receives $5m^3/day$ of diluted cattle excreta by the water used for clearing stalls. A submerged gays collector for the recovery of methane is installed on the top of the pit. The average BOD_5 concentration of influent is 398.7mg/l. That of the effluent from primary pond is 49.2mg/l. About 88% of BOD_5 are removed in primary pond. It is assumed that about 60% of the influent BOD_5 is removed in the pit and that almost all of the carbon of the removed BOD_5 in the pit is converted to methane and carbon dioxide. Methane fermentation of the pit is well established at $16^{\circ}C$. This phenomena results from temperature stability, complete anaerobic condition, and neutral pH of the pit. Gas from the collector is almost 90% methane, less than 9% nitrogen, and less than 1% carbon dioxide. Thus a purified methane is produced, which can be used as energy source.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.177-183
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• 2005

The effluent quality is directly affected by the separation of biological solids in a final clarifier because the majority of discharged $BOD_5$ and SS are virtually dependent on the results of biological solids in the sedimentation tank effluent. If a final clarifier is effectively designed and operated, the desired goal of clarification for wastewater can be achieved together with the cost reduction in the treatment of wastewater. To this end flow characteristics and the removal efficiency of SS are numerically investigated especially by the change of the inlet position and the installation of baffle to improve the performance of a rectangular final clarifier. The 2-D computer program developed in a rectangular coordinates has been successfully validated against experimental residence time distribution(RTD) curves obtained by tracing radio-isotope. The lowering of the inlet position weakens the density current and induces the settling of SS in the front zone of a clarifier. Thus the decreased traveling distance of the sludge increases the removal efficiency of SS in the effluent. The inlet baffle installed in the front region of clarifier prevents the short circuiting flow and induces to flow into the dense underflow, which eventually improves the effluent quality. In the case of lower inlet position, however, installation of baffle results in degradation of effluent quality. Consequently it is strongly recommended that in-depth numerical study be performed in advance for optimizing a clarifier design and retrofitting to improve effluent quality in a final clarifier.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.7
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• pp.3341-3352
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• 2011

In this study, characteristics of wastewater treatment of sewage intermittently mixed with industrial wastewater is examined by investigating the operational status of each unit operation and measuring water quality. The bioreactor operating condition was measured for MLSS concentration 2,000~3,000 mg/L, HRT 5.3~16.3 hour, SRT 2.8~66.6 day, and SVI frequently showed the value above 200 which was higher than the optimal range of 50~150. It is thought that the sludge is not in suitable condition for sedimentation caused by the incoming industrial wastewater. When industrial wastewater is come into the system, MLDO inside of bioreactor rapidly increased, rate of nitrification is steeply decreased, and Pin floc. is spilled in the secondary clarifier. In the observance of microorganism showed that various bacterial floc. and ciliata were found as well as actinomycetes and filamentous bacteria(Sphaeotilus) which is known to cause bulking. Efficiency of each unit operation was fairly good in average. However, efficiency of the bioreactor treatment showed high fluctuation by unstable operating condition by intermittently incoming industrial wastewater.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.113-125
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• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.