• Journal of Microbiology and Biotechnology
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• v.3 no.1
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• pp.19-23
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• 1993

Spirulina platensis NIES 39 was grown in effluents from a wastewater treatment plant utilizing activated sludge process at a pig farm to reduce pollutants and to produce feed resources. The addition of 2 g/l NaCl was required for the growth of S. platensis in the effluents with about 100 mg/l ammonia nitrogen concentration. The growth was stimulated by the addition of 2 g/l sodium bicarbonate and 4 mg/l ferrous sulfate. The microorganism grew well at pH 8~11, and the optimum pH for the growth was 10. The algal concentration of 1.1 g/l was attained after 8 days of growth at the optimum condition with the removal of 95% ammonia nitrogen and 34% phosphorus.

• Journal of Korean Society on Water Environment
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• v.21 no.2
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• pp.190-195
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• 2005

The laboratory and pilot scale BAFs (biological aerated filters) were operated with 0.3 hr to 1.1 hr EBCT(empty bed contact time) at a maximum filtration rate of $472m^3/m^2/day$ as a treatment method for reuse of secondary effluent and by-pass flow in this study. The effluent BOD and SS were generally 3.5 to 5 mg/L and 2 to 3 mg/L, respectively with 2ndary effluent, but the SS concentrations increased to 4 to 8 mg/L with the increased flow rates of by-pass flow. Potential nitrification rates were very high, but the nitrogen removal efficiencies were low due to the limited carbon sources. Bypass of a part of primary effluent seemed to be desirable to increase the nitrogen removal. Disinfection must be furnished for the reuse of BAF effluent.

• Journal of the Korean Ceramic Society
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• v.55 no.5
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• pp.473-479
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• 2018

Highly toxic gases such as hydrogen sulfide ($H_2S$), carbon dioxide ($CO_2$), and ammonia ($NH_3$) are generated by both nature and human activities and affect human health. In this research, activated carbon combined with $Ca(OH)_2$ and $CaCO_3$ (AC-CO and AC-CC, respectively) were fabricated and applied in absorbing toxic gases from air pollutants. Activated charcoal powder was compressed in the form of pellets and used in the designated conditions. The optimum operating conditions and material properties, such as adsorption capacity, effect of weight ratio of the mixture, and hardness, have been investigated after combining with the calcium derivative. The good performance exhibited in this study suggests that this material is expected to be an effective and economically viable adsorbent for $NH_3$, $CO_2$, and $H_2S$ removal from the air system.

• Journal of Soil and Groundwater Environment
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• v.22 no.2
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• pp.33-40
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• 2017

In typical remediation practices, separate washing systems have to be applied to clean up the soils contaminated with both oil and heavy metals. In this study, we evaluated the efficiency of successive two-stage soil washing in removal of mixed-contaminants from soil matrix. Two-stage soil washing experiments were conducted using different combinations of chemical agent: 1) persulfate oxidation, followed by organic acid washing, and 2) Fenton oxidation, followed by inorganic acid washing. Persulfate oxidation-organic acid washing efficiently removed both organic and inorganic contaminants to meet the regulatory soil quality standard. The average removal rates of total petroleum hydrocarbons (TPH), Cu, Pb, and Zn were 88.9%, 82.2%, 77.5%, and 66.3% respectively, (S/L 1:10, reaction time 1 h, persulfate 0.5 M, persulfate:activator 3:1, citric acid 2 M). Fenton oxidation-inorganic acid washing also gave satisfactory performances to give 89%, 80.9%, 87.1%, and 67.7% removal of TPH, Cu, Pb, and Zn, respectively (S/L 1:10, reaction time 1 hr, hydrogen peroxide 0.3 M, hydrogen peroxide:activator 5:1, inorganic acid 1 M).

• Journal of environmental and Sanitary engineering
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• v.15 no.1
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• pp.54-61
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• 2000

We studied the adsorption characteristics on the treatment process of heavy metal wastewater by using cuttle fish bones powder. When adding the 0.25% cuttle fish born powder in the heavy metal solution, $Fe^{3+}$ and $Pb^{2+}$ were high removed than other heavy metals as above 95%. In the solution which was adjusted to pH 5, 7 and 9, there was not observed the difference thing on the heavy metal removal rate. At test using plating wastewater treatment, adding 1%, 1.5% and 2% of the cuttle fish born powder, the heavy metal removal rate were as follows; Zn 12.5 - 37.5%, Mn 18.0 - 62.2%, Cd 36.8 -93.0%, Cu 51.4 - 97.4%, Cr 70.8 - 99.1%, Fe 87.2 - 99.3% and Pb 92.8 - 99.9%. When adding the 0.15% cuttle fish born powder and mixing for 20 minutes, the solution was happened the adsorption equability. Applied this results to the Freundlich＇s iso-thermal equation, we found the cuttle fish born＇s probability as a good adsorbent.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.247-251
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• 2005

This research was performed for developing of biological treatment process of odor gas such as MEK, $H_{2}S$, and toluene, which is generated from the food waste recycling process. To establish the operational conditions of odor gas removal by small-scale biofiltration equipment, it was continuously operated by using toluene as a treating odor object. When the odor treating microorganisms were adhered to fibril form biofilter, high removal efficiency over 93% was obtained by biofilm formation. At 400 ppm of inlet odor gas concentration and 10 sec of retention time, the removal efficiency was 76% and 93% in 1st stage reactor and 2nd stage reactor, respectively. However, the removal efficiency remained over 97% at the operational conditions above 15 sec of retention time.

• Clean Technology
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• v.26 no.4
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• pp.263-269
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• 2020

Zeolite was synthesized hydrothermally using the water-treatment sludge, and the effects of various synthesis parameters like reaction temperature, reaction time, and Na2O/SiO2 molar ratio on the crystallization of zeolite were investigated. Crystal structure, physical property, and thermal stability of zeolite crystals were characterized by X-ray powder diffraction, FTIR spectroscopy, BET nitrogen adsorption, and TGA measurements. The removal efficiencies of nitrogen in ammonia, heavy metal ions, and TOC were calculated to evaluate zeolite's adsorption capacity. The primary chemical composition of water-treatment sludge was 28.79% Al2O3 and 27.06% SiO2. The zeolites were synthesized by merely employing the water-treatment sludge as silica and alumina sources without additional chemicals. Zeolite crystals synthesized through the water-treatment sludge were confirmed as an A-type zeolite structure. Zeolite A had the highest crystallinity obtained from a gel with the molar composition 2.1Na2O-Al2O3-1.6SiO2-65H2O after 5 h at a temperature of 90 ℃. The specific surface area of zeolite obtained was 55 ㎡ g-1, which was higher than commercial zeolite A. The removal efficiency of nitrogen in ammonia was 68% after 3 h of reaction time, while the removal efficiencies of Pb2+ and Cd2+ ions were 99.1% and 99.3%, respectively. These results indicate active ion exchange between Pb2+ or Cd2+ ion and Na+ ion in the zeolite framework. The adsorption experiments on the different zeolite addition conditions were performed for 3 h with 300 ppm humic acid. Based on the results, TOC's highest efficiency was 83% when 5 g of zeolite was added.

• Korean Chemical Engineering Research
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• v.53 no.5
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• pp.576-583
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• 2015

This paper aims to investigate the potential use of cempedak durian peel (CDP) from Negara Brunei Darussalam, which is low-cost, locally available, eco-friendly and highly efficient to remove methyl violet (MV) dye from aqueous solutions. The time required for equilibrium to be reached is 2.0 h with no adjustment of pH necessary. FTIR analysis was indicative of the involvement of -COOH and C=O functional groups in adsorption process. The Langmuir model provided the best fit with maximum adsorption capacity of $0.606mmol\;g^{-1}$. Thermodynamics data indicate that the adsorption is spontaneous, feasible and endothermic in nature. Best regeneration of CDP's adsorption ability is achieved by base solution, showing about 95% removal efficiency of MV even after 5 cycles, indicating that CDP can be regenerated and reused. This, together with its high adsorption capacity, makes CDP a potential adsorbent for the removal of MV in wastewater.

• Journal of Wetlands Research
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• v.17 no.1
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• pp.75-79
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• 2015

DIWS system was introduced to treat HCl gas from the scrubber of iron and steel industry according as the regulation of air quality is expected to be changed to 2ppm. pH of condensed water at stack was increased to 6.0. While 13.3ppm of inflow HCl was introduced to DIWS system, the average exhaust gas was 0.43ppm with 96.9% of removal efficiency. Compared with HCl data of TMS, the stable removal efficiency was shown in DIWS system, but the phenomenon of data hunting was also observed with different types of TMS apparatus.

• Solar Energy
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• v.7 no.2
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• pp.30-36
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• 1987

A shelf type solar dryer of simple design has been constructed and its performance evaluated by KIER (Korea Institute of Energy and Resources). Experimental result, the rate of moisture removal of the dried sguid in dryer is higher to that obtained by conventional sun drying. Design modification are suggest to improve its performance.