This research selects water treatment process that suitable to use by industrial and drinking water to remove high hardness, iron and manganese (Mn) included in bankfiltrate. In hardness removal experiment by membrane, flux of UTC-20 in permeate flux and total hardness removal 0.069 m³/m²/hr that was median value and 93% of removal efficiency was shown, therefore UTC-20 was considered as optimal membrane. After adding manganese dioxide (MnO₂) slurry to bankfiltrate containing manganese 4.0 mg/L and adsorption, conclusion of Mn oxidation by potassium permanganate (KMnO₄) are as follows; Mn adsorption experiment of MnO₂ slurry at 20°C, pH 7.0, 0.28 mol-Mn⁺²/mol-MnO₂ of maximum adsorption amounts by Langmuir isotherm was shown. The reason of decreasing equivalent values after MnO₂ slurry addition and adsorption of Mn was the less consuming amounts of KMnO₄ in generated MnO₂ particle from KMnO₄ and Mn reaction and MnO₂ slurry added by autocatalytic reaction. Calcium (Ca) and magnesium (Mg) which was contained in bankfiltrate in Mn adsorption by MnO₂ slurry showed positive effect in Mn adsorption.

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This study was conducted to evaluate the ozone and UV combination (ozone/UV) process for the reuse of sewage treatment plant effluent. The ozone/UV process was compared to the ozone alone and the UV alone processes by measuring a variety of parameters, such as UV absorbance at 410 nm (A₄₁₀), COD, BOD, BOD/COD, TOC, specific UV absorbance (SUVA), and aldehydes. The organics present in sewage effluent were more effectively removed by hydroxyl radical (OH°) than by molecular ozone. The ozone/UV process was highly effective for the color removal, disinfection, mineralization of organics, and minimization of ozone by-product. It was also found that ozone/UV process equipped with high-intensity UV lamp was more efficient and economical than that with low-intensity UV lamp.

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This study was conducted to investigate the effects of hydraulic loading rate and recycle ratio on biological denitrification and nitrification for leachate containing NH₄⁺-N with high concentration about 1,500 ∼ 2,000 mg/L discharged from SUDOKWON landfill site. Pilot-scale MLE(modified ludzack ettinger) process was employed in this study. As a result of this examination, we found out that about 2.3 days in denitrification tank and 5.7 days in nitrification tank are the optimal HRT for obtaining the removal efficiency of about 80 % for T-N and 99% for NH₄⁺-N at the conditions of recycle ratio of about 600 % and BOD/NH₄⁺-N ratio of about 3.0. In addition, optimal recycle ratio for obtaining the maximum nitrogen removal efficiency while keeping proper microbes concentration in nitrification and denitrification tank was 200 % for external recycle and about 400% for internal recycle. The maximum removal rates for each load of T-N and NH₄⁺-N were 0.055kgT-N/kgVSS/d and 0.07kgNH₄⁺-N/kgVSS/d, respectively. The ratio of alkalinity consumed per T-N removed in this process (Δalkalinity/ΔT-N) was about 5.0.

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There are the improvement of standard of living and the increase of public awareness of environment. In Korea sewage treatment plant was first introduced in 1970's, and now it is constructed to small towns. Untill now sewage treatment plant has used biological treatment system to remove organics and suspended solids.
But according to the improvement of living standard and the strict restriction of effluent, secondary treatment has had a limit. Technological advances have been achieved in the sewage treatment to remove nitrogen and phosphorus simultaneously. To keep pace with this situation, POSCO E&C developed Bio-SAC BNR Process using fluidized media. In this section the result of operation will be showed at Uljin sewage treatment plant during the winter season.

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This study was conducted for microbial hydrogen production from food waste and sewage sludge. Thirty three batch tests with different VS concentration (from 0.5 to 5.0 %, w/v) and mixing ratio of food waste to sewage sludge (from 0:100 to 100:0) were performed at 35°C. Heat-treated anaerobic sludge was used to seed the serum bottles. In all the tests, cumulative hydrogen production reached the maximum values within 2.5 days. n-Butyrate was produced simultaneously with hydrogen production, of which the amount was proportional to that of n-butyrate. Clostridium sp. are, therefore, considered to be the dominant microorganisms in this study because these microorganisms are responsible for n-butyrate fermentation. The hydrogen production potential of food waste was found over 34.0 mL/g VS at all the VS concentration. The maximum potential of 59.2 mL/g VS was found at 3.0 % of VS concentration. The potential decreased as sewage sludge composition increased due to the methanogens contained in sewage sludge and low carbohydrate concentration; however, the addition of sewage sludge to food waste enhanced hydrogen yield because of sufficient protein. The maximum hydrogen yield of 1.01 mole H₂/mole hexose_added was achieved at the food waste to sewage sludge ratio of 80:20 at the VS concentration of 3.0 %. The specific hydrogen production rate increased up to 22.6 mL H₂/g VSS/h as both food waste composition and VS concentration increased.

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For applying the optimum backwash method to activated carbon absorption process, this study had performed an efficiency test of backwash method and a test for determination of backwash period at the M water purification plant in Daegu metropolitan city.
The minimum fluidization velocity was different according to kinds of carbon like spent carbon and reactivated carbon. Changing water position before backwashing was more efficient in backwashing than controlling backwash time. In the case of water position LL(a height of 60cm over the outer layer of activated carbon) before backwashing, the most efficient backwash method has turned out to be 10 min. of air wash and 18 min. of water wash.
The turbidity of activated carbon filter outflow water and organic matter change have no big difference according to the days of seasonal operation after backwashing. As backwash period is very related to microbiological growth and is influenced by outflow water change, the study has found that it's desirable to operate in consideration of HPC(Heterotrophic plate counter) distribution of filtered outflow water, water quality, the condition of a filter basin and the years of activated carbon use.

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During the past several years, concern has risen over potential pollution of waterways with estrogenic compounds, including steroidal hormones from human and animal sources. However, it is unclear whether the concentrations of estrogenic substances present in the environment are sufficient to cause adverse physiological effects. In spite of the fact that it is the receiving body for the sewage coming from a big city and an industrial area, Nakdong River water is used as a source for waterworks from the upstream to the downstream of the river. As such, it poses a threat as having potential to cause adverse health effects in humans and wildlife. The aim of this research is to evaluate estrogenic activity and concentrations of endocrine disruptors in this water environment. Examination of Nakdong River basin revealed that estrogenic substances and activity are distributed over the entire middle and downstream area but excluding the upstream. Estrogenic activity cannot be sufficiently removed by conventional activated sludge treatment, but can be reduced entirely by oxidation processes such as prechlorination and the combination of sand filtration and ozonation in sewage treatment plants (STPs) or water treatment plants (WTPs). During water-purifying processing, estrogenic activity decreased significantly with prechlorination followed by coagulation and sedimentation treatment.

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Hydroxyl (OH) radical is one of the important reactive species in the advanced oxidation process. The objective of this study is to present the quantitative analysis of hydroxyl radical generation by using the electron spin resonance (ESR)/spin-trapping technique and to apply this method to evaluation of the enhancement of OH radical generation by several humic substances during ozonation in water. OH radical was trapped with a 5,5-dimethyl-1- pyrroline-N-oxide (DMPO) as a stable adduct, DMPO-OH. The generation of OH radical was demonstrated with mathematical equation of the initial velocity of DMPO-OH generation, and the effect of the compounds, 3-chlorophenol and resorcinol, on OH radical generation expressed with ν0 (10^-6 M/s) = {9.7 ∼ 10.5 × [compound (10^-9 M)] + 0.0005} exp(57 × [ozone (10^-9 M)]). The effect of humic substances on OH generation was evaluated with the amount of DMPO-OH with batch system because of high viscosity of humic acid solution. The amount of DMPO-OH reached almost maximum level within 2 min and kept the level till 60 min in most cases. The amount of DMPO-OH depended both of the amounts of ozone and humic acid. The origin of humic acid also affected the amount of DMPO-OH.

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Biodegradability improvement of refractory pollutants by hydrothermal reaction was investigated based on their structural conversion. Di- and Trichloroacetic acid were used as test sample, representing linear hydrocarbon structured refractory pollutants. At 250 °C and 4 MPa, attached recalcitrant chlorine atoms were eliminated by hydrolysis at the beginning of hydrothermal reaction. Biodegradable organic acids were yielded from hydrolyzed intermediates by dehydration and thermal decomposition. The decomposition rates of chloroacetic acids increased with increasing the number of attached chlorine atoms. During the initial structural conversion by hydrothermal reaction, the reduction of carbon contents of dichloroacetic acid did not exceed 6 % under the tested conditions. The similar results, however, were not observed in case of trichloroacetic acid. Biodegradable products were reduced by thermal decomposition as reaction time increased. The biodegradability of reaction products was not fatally retarded despite the presence of chlorine ions under the tested conditions. Hydrothermal reaction was proved as suitable pretreatment method to obtain biodegradable products from the structural conversion of refractory pollutants such as chloroacetic acids for the following biological treatment methods.

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The purpose of this experimental study was to clarify the effect of the number of the vertical perforated pipes on the composting rate and the extent of organic matter degradation. To achieve this target, composting was performed on the simulated organic solid waste, blended with wood chips and inoculums using a laboratory-scale composting reactor equipped with the vertical pipes as air suppliers for the passive aeration. The dog food (DF) was used as a simulated organic waste to be composted. For the aeration purposes, two, four and six vertical perforated pipes, which top wall was heated at the initiation phase, were embedded in the reactor at Runs A, B and C, respectively. The composting was monitored by regularly measuring the bed temperature at different points during the composting process. Thermophilic temperatures, about 55°C, were observed within the bed during each of the composting runs. The final conversions of carbon were, approximately, 86 to 96%. On the basis of a simple heat balance obtained under a steady reaction proceeding, the composting rate was analyzed. The composting reaction rate increased in increasing in the number of the vertical pipes during the composting process. The reaction rate was expressed as a first order equation and the reaction rate constant was calculated.

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In Japan, Kasumigaura Lake, Biawako Lake and many other closed water bodies are very serious in water quality. We attribute the water pollution to that the suspended solids flow into closed water body from surrounding environment. Floatation and supply of oxygen by micro-bubble, mild flow up of water by screw pump and biological filtration/oxidation were applied. These technologies were combined in developing a novel system for the purification of lake water. HRT was 10 minute, and 40 ton/d of lake water was treated. Thirsty percent of suspended solids (SS), equivalent to 3.53 mg-SS/L-lake water, was removed. COD decreased from 4.5 mg/L to 2.5 mg/L. The transparency was improved 36%. This system is in self-completion.

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In this study, GIS-based system analysis has been performed for the aim of monitoring and managing the sewerage lines. The model has been designed for a proper and efficient application, which have several objectives such as integrating data processing, modeling, analyzing and reporting. Spatial data have been collected from different sources and several different data layers and their related tabular data have been used in this study. Possible usage of GIS for analyzing sewerage system has also been described in the study. Old and newly planned wastewater lines of the study area and, stream channel, maps and basins were also added to the system. Population estimation and drainage water flow of the year 2033 have been calculated. Obtained drainage water flow rate and population were added to the system and used as a new attribute for the analysis. Additionally, appropriateness of the methods for flow calculation and population estimation were also examined in this study. Comparing present and future population as well as flow estimation, feasibility of the system for further thirty years was also discussed.

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The objective of this study is to clarify the effect of DOM and biofilm on the adsorption capacity of PAC in the aeration tank of PACT process. The adsorption capacity of PAC for 3,5-DCP was significantly decreased by the addition into the aeration tank. The decrease in the adsorption capacity significantly deteriorated the performance of PACT process. The adsorption of DOM with molecular weight ranged from 50,000 to 300,000 Da decreased the adsorption capacity of PAC in the aeration tank for 3,5-DCP. However, DOM with molecular weight less than 50,000 Da and more than 300,000 Da had little effect on the adsorption capacity of PAC in the aeration tank.

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