• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.112-127
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• 1997

The purpose of this study is to get optimum operating factors of Upflow Anaerobic Sludge Blanket (UASB) reactor by introducing methods that make it to reduce inhibition possible in each process wastewater treatment. The used substrates, concentrated corn starch liquid (CSL) wastewater, modified starch, filtering and decoloring wastewater, ion refining wastewater, and mixed wastewater including modified starch and not including modified starch, are generated from molasses process. The seeding sludge is the digested sludge that had been applied to molasses wastewater. Batch test to reduce the inhibition factors that might be existed in each wastewater was examined. Based on the this test, the optimum operating factors according to alkalinity and pH variation was studied through the continuous test using three 5.5 L UASB reactor. The first reactor added $NaHCO_3$ to control alkalinity. The hydraulic retention time (HRT) reduced to 8 hours and the organic loading rate increased gradually. The second reactor changed the pH of influent from 7.0 to 6.0 using NaOH. The third reactor was operated without changes to compare the above two reactors. As the result, the inhibition in concentrated CSL wastewater was removed by adding iron (II). When trace metals were added to mixed wastewater not including modified starch, the digestability by gas production rate increased to more fifty percentage than mixed wastewater that was not adding the trace metals. The reason that the inhibition did not decreased in spite of adding trace metals and nutrients was influenced by high concentration generated during the acid fermentation. The UASB reactors using the mixed wastewater with the most effective performance were operated as 500 mg/L as $CaCO_3$ alkalinity and 6.0 pH at steady state, and at this time, the gas production rates were 283 and 311mL gas/g $COD_{added}$. The COD removal rates were 84.7 and 86.3%, respectively.

• Journal of Soil and Groundwater Environment
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• v.16 no.2
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• pp.52-60
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• 2011

Although facilities for the passive treatment of AMD (Acid Mine Drainage) are currently operating in Korea, their removal efficiency for heavy metals is relatively low in average (only 80%). Passive treatment system is composed of oxidation tank, SAPS (Successive Alkalinity Producing System), and wetland. In the treatment system adopted in korea, SAPS (Successive Alkalinity Producing System) plays a major role to remove about 65% of heavy metals through a precipitation. However, the efficiency of SAPS is limited due to the use of mushroom compost (MC) as a organic material and of limestone as a neutralizer. Therefore, this research was performed to search for alternative organic materials through the field test. We tested two types of mixed organic materials: 1) cow manure and spent oak (herein, CO) and 2) cow manure and sawdust (herein, CS). For comparison mushroom compost (herein, MC) was also tested. The result showed that the average Fe removal efficiency was 91.38% with CO, 85.19% with CS, and 91.58% with MC. Thus, CO can be effectively used as an alternative of MC in the SAPS system for heavy metals removal.

• Journal of Environmental Science International
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• v.18 no.3
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• pp.325-331
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• 2009

This study was aimed to behaviour of organics and nitrogen on the upflow anaerobic reactor when a acid fermenter is added. Up flow anaerobic reactor (UAR) reaction will result which operates, COD removal efficiencies of reactor with nitrate loading rate 0.11, 0.66g/L/d were over 77%, but one with 1.0g/L/d was 73.5%. Especially, on NLR 0.11g/L/d, COD removal was 77% and nitrate removal efficiency was 93% simultaneously. The other side upflow anaerobic reactor and acid fermenter (UAR+AF) reaction will result witch operates, COD removal efficiencies of reactor with nitrate loading rate 0.11, 0.66g/L/d were over 85%, but one with 1.0g/L/d was 80%. Especially, on NLR 0.11g/L/d, COD removal was 85% and nitrate removal efficiency was 98% simultaneously. Also, without in reaction condition increase of influent nitrate concentration resulted in the linear decrease of nitrate removal efficiency and nitrate removal efficiency at influent nitrate-nitrogen 800mg/L was 50%. Alkalinity was increased theoretically by denitrification at low nitrate-N concentration, however, it was not increased theoretically at high nitrate-No 40% nitrate-N of UAR was denitrified until 70% height of reactor and 90% nitrate-N of UAR+AF was denitrified until 30% height of reactor Upflow anaerobic reactor was to occur accumulate acid, which TVA/Alkalinity is 0.3$\sim$0.47. Increase of NLR resulted increase of effluent alkalinity and TVA production

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.E4
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• pp.157-162
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• 2001

Jet Bubbling Reactors(JBRs) were operated for the removal of SO$_{x}$ in flue gases produced from many electric power plants. However, many JBR flue gas desulfurization (FGD) facility faced a decrease of SO$_{x}$ removal efficiency and an increase of scale problems with continuous operations. We increased alkalinity of the SO$_{2}$ absorbing medium by adding the dibasic acids (DBAs) to solve these problems more effectively. The SO$_{2}$ removal efficiency, the purity of CaCO$_{3}$ and COD of the wastewater was measured to identify the addition effects of DBAs (150, 200, 250, and 400 ppm) for 2hr in a day into the JBR attached to the large-scale power plants (400 MW$\times$3). Addition of the DBAs resulted in the improvement of the SO$_{2}$ removal efficiency from 2 to 5% and the purity of the gypsum from 1 to 2%; these improvement were due to the alkalinity increase of the absorbing medium and the reduction of a proportion of un-reacted CaCO$_{3}$, respectively. Also, the scale problems formed by un-reacted CaCO$_{3}$ inside the reaction zone of the JBR were substantially reduced. Even though the effluent COD of the wastewater slightly increased from 10~15 to 18~36 mg/l and the erosion problems in the injection pump and duct occurred, this method of increasing SO$_{2}$ removal efficiency by adding the DBAs could be considered as a profitable approach.ach.

• The Journal of Engineering Geology
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• v.12 no.4
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• pp.439-457
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• 2002

Sping waters at 60 sites and groundwaters at 6 wells in Mts. Geumjeong and Baekyang area were investigated for measuring nine physicochemical components (temperature, pH, Eh, EC, TDS, DO, salinity, alkalinity and discharge rate). The pH of spring waters ranges from 5.06 to 8.38, alkalinity from 7.93 to 102.21 mg/ㅣ, electrical conductance from 9.5 to $270{\;}\mu\textrm{s}/cm$, Eh from 64.2 to 685.9 mV, DO from 4.57 to 12.13 mg/l, and the discharge rate from 4.26 to 182.2 ml/s. General statistics was carried out to analyze statistical characteristics of those components. To compare the components with one another, regression analyses were carried out. And the components of spring waters were compared to those of groundwaters. Kriging was used to estimate the spatial variation of DO, pH, Eh, EC, alkalinity and discharge rate in the study area. The kriged isopleth maps were made using normalized kriged values to find anomalies of the physicochemical components and to compare anomalies of different components.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.499-506
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• 2005

This study was performed to investigate the effects of influent C/N ratio on the removal of organic and nitrogenous compounds by two nonwoven fabric filter bioreactors. The reactors were alternately aerated at an aeration/nonaeration period ratio of 60 min/60 min, and fed with wastewater only during nonaeration period. The influent C/N ratio (COD/TKN) was gradually reduced from 10 to 2. The influent was prepared by diluting the leachate from a foodwaste treatment facility in I city so that the COD concentration could be about 2,500 mg/L. The C/N ratio of the wastewater was adjusted by adding ammonium chloride. The results of the experiment showed that the COD and BOD concentration of the effluent was $40{\sim}54\;mg/L$ and $1{\sim}4\;mg/L$, respectively at the C/N ratios of $10{\sim}3$, and the effluent SS concentration was always below 2.0 mg/L. The T-N removal efficiencies were 96% or higher at C/N ratios of $10{\sim}5$, but decreased to 83% and 81%, respectively at the C/N ratios of 3 and 2.8. At the C/N ratios of 2.6 and 2, the effluent quality deteriorated due to ammonia toxicity. The fraction of nitrifying microorganism in the reactors increased from 10% to 20% as the C/N ratio decreased from 5 to 2.6. Alkalinity consumed were $3.12{\sim}3.49\;g$ alkalinity/g T-N removed at the C/N ratios of $10{\sim}5$, which are lower than the theoretical value of 3.57. However, the ratio increased to 4.63 and 4.87 g alkalinity/g T-N removed, respectively at the C/N ratios of 3 and 2.8.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.231-239
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• 2000

This study was investigated to estimate optimal conditions and biological oxic denitrification to treat wastewater with low C/N ratio and high strength total inorganic nitrogen (TIN) concentration by using $A_2O$ fixed biofilm system. The lab-scale experimental system packed with media, which were composed of polyvinylidene chloride fiber (oxic basin) and ceramic ball (anaerobic and anoxic basin), was used. This system was operated with various influent alkalinities at the C/N(TOC/TIN) ratio of 0.5. The study results showed that TOC were removed over 96.0% at all operation conditions. The removal efficiencies over 93.5% for $NH_4{^+}-N$ and 81.8% for TIN were obtained at the alkalinity of about 1210mg/L(Run 5). Among the removal of TIN, 64.9% was occurred by biological denitrification at an oxic basin. It was confirmed through mass balance of alkalinity and nitrogen that the amount of alkalinity produced during biological denitrification at oxic basin was 2.49~3.46 mg Alkalinity/mg $NO_2{^-}-N$, ${\Delta}TOC/{\Delta}DEN$ of 0.34 (Run 5) was obtained at an oxic basin, which was less than the theoretical value of 1.22.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.3
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• pp.61-68
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• 2011

The pH of recycled aggregate is over 12 because of high alkalinity of cement. This high alkalinity give circumstance harmful effect. The high alkalinity of recycled aggregate can appear variously according to aggregate properties, elution time of alkalinity, aggregate size, and so on. This study analyzed recycled aggregate properties according to wet and dry type manufacture process; different test methods: waste official test, soil contamination official test, BS EN 1744-3 standard; elution time and different size to test effects of various condition. These test results can contribute to solving environmental problems by recycled aggregate. In the test results, pH of recycled aggregate was as higher as smaller particle size and as time elapsed. There was no difference between dry and wet type recycled aggregate except for difference according to elapsed time. Waste official test method got the highest pH value between pH test methods. So unified pH test method need to test recycled aggregate pH.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.362-368
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• 2005

The pH, alkalinity and calcium hardness could be adjusted by $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ addition in the water treatment process for corrosion protection of the water pipes. This research was performed to investigate the effect on the variation of water quality on the unit process by addition $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ in water treatment process. Carbon dioxide and lime were added before the coagulation basin and soda ash was added after the BAC process. pH and aklainity were increased at coagulation basin then after the water qualities had sustained similiarly to BAC process. There was no effect on turbidity and DOC removal efficiency during experimental period by addition\ $CO_2$, $Ca(OH)_2$, and $Na_2CO_3$ solution was added into clear well, the last process for optimum control of CCPP and is used mainly to control pH and alkalinity. In this research, average pH, alkalinity, and calcium hardness in treated water were 8.39, 61.4 mg/L as $CaCO_3$, 59.4 mg/L as $CaCO_3$, respectively and CCPP of treated water was higher than 29.5 mg/L to BAC process water, so adjusted water was expected to prevent internal corrosion of water pipe.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.205-211
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• 2011

On board comparison of pH and total alkalinity measurement in seawater was carried out during the JES expedition on R/V Roger Revelle in the East Sea using 550 real seawater samples from the surface to the bottom. Spectrophotometry and potentiometry without liquid junction were compared for pH measurement. The pH values of two methods are generally in a good agreement. Spectrophotometry with a pipette provides higher value compare with the potentiometry in the deep layer, where pH values are lower. However, spectrophotometry without a pipette shows same values with potentiometry within their precision range. The pipetting procedure may remove of $CO_2$ in the sample, which causes increase of pH. Potentiometric titration methods using a closed-cell and an open-cell were compared for the total alkalinity measurement. Values from open cell method are smaller by about 5~10 ${\mu}mol\;kg^{-1}$ than those from closed cell method. This may be caused by the bubble formed in the closed cell during the experiment. Although any analytical method compared in this study for the pH or TA measurement can be applied, special attentions should be paid for satisfactory results.