The purposes of this study were to evaluate the removal characteristics of COD, Ni, and P and to derive appropriate operating conditions for the plating wastewater according to NaOCl reaction time and pH operating conditions in the BPC unit process during the plating wastewater treatment process. As a results of evaluating the removal characteristics for raw wastewater by each BPC unit process, the removal efficiencies of COD, Ni and P in BPC 1-1 unit process were 72.8%, 99.1%, and 100.0%. Therefore, the proper reaction time of NaOCl was derived as 21.1 minutes. In order to maintain the +800 mV ORP and the reaction time of 20 minutes, the temporary injection and continuous injection of NaOCl in the BPC unit process were 13.7 mL and 18.7 mL, respectively. It was found that the temporary injection method of NaOCl reduced the chemical cost by 36.5% compared to the continuous injection method. Also, Ni showed the highest removal efficiency of 97.8% at pH 10.5. On the other hand, P showed a removal efficiency of 57.4% at pH 10.0.

In this research, heavy metals and T-P removal characteristics of plated wastewater are derived using BPC(Break Point Chlorination) process. AA sedimentation pond outflow(Influence) was evaluated for the removal efficiency of heavy metal(Ni) and T-P at a reaction time of 25 minutes by NaOCl input volume(9, 11, 13 and 15 mL). In the case, the higher the NaOCl input volumes, the higher the ORP values were maintained and the higher the removal efficiency tended to be. On the other hand, T-P was judged to have a low relationship between the ORP value and the removal efficiency. In addition, the efficiency of removal heavy metals and T-P in the plated wastewater by injecting 10 mL, 15 mL, 20 mL and 25 mL NaOCl, increased as the amount of NaOCl injected increased, the amount of NaOH input for pH increased. It was found that suspended solid in effluence also increased. It was also observed that the color of the plating wastewater changed from yellowish green to green to charcoal gray to black as the amount of NaOCl injected increased. Treatment characteristics of the reaction time, the longer the reaction time with the substance to be treated after the input of NaOCl, the more the heavy metal removal efficiency tended to increase. Through XRF analysis of the sludge, the constituents in the sludge such as NaCNO, CNCl, Na3PO4, CrO4, 2Na2CrO4 and 2NaNO3 will be analyzed in detail, and the mechanisms of the reaction between the plated wastewater and the complex compound will be elucidated.

Recently, an innovative method for wastewater treatment and nutrient removal was developed by combining the sequence batch reactor and membrane bioreactor to overcome pollution caused by shipboard sewage. This system is a modified form of the activated sludge process and involves repeated cycles of mixing and aeration. In the present study, the bacterial diversity and dominant microbial community in this wastewater treatment system were studied using the MACROGEN next generation sequencing technique. A high diversity of bacteria was observed in anaerobic and aerobic bioreactors, with approximately 486 species. Microbial diversity and the presence of beneficial species are crucial for an effective biological shipboard wastewater treatment system. The Arcobacter genus was dominant in the anaerobic tank, which mainly contained Arcobacter lanthieri (8.24%), followed by Acinetobacter jahnsonii (5.81%). However, the dominant bacterial species in the aerobic bioreactor were Terrimonas lutea (7.24%) and Rubrivivax gelatinosus (4.95%).

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane (CH4) from the anaerobic digestion process; and third, to promote CH4 production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), CH4 production, and biodegradability.

Soluble Cutting Fluids (SCFs) have been used in metal machining processes to improve the quality of metal processing equipment and products. Although SCFs are useful and essential material, wasted soluble cutting fluids are harmful in hydroecological systems because of the high concentration of COD and nitrogen material. If discharged to hydroecological systems without specific treatment, they may cause eutrophication in rivers and lakes. Therefore, the removal efficiency of the COD contained in the SCFs is investigated in this study using electrochemical treatment with an insoluble electrode. The electrode was made of titanium with iridium plating, made from a perforated metal sheet to agitate the sample in the reactor. Cathode and anode electrodes were inserted into acrylic reactor alternately and the reaction time was one hour. The experimental results were as follows: First, for 60 A/m2, 80 A/m2, and 100 A/m2 current densities, the COD removal efficiencies were 42.0%, 63.9%, and 78.4%, respectively.

Soluble cutting fluids (SCFs) have been used in metal machining processes to improve the quality of metal processing equipment and products in modern society. Because the characteristics among metal machining processes differ, various types of cutting fluids are manufactured to enhance the cutting efficiency of different metals. Although SCFs are useful and essential materials, particular treatment is required attributable to the high concentration of nitrogen materials and chemical oxygen demand (COD). In this study, the removal efficiency of total nitrogen (T-N) contained in SCFs was analyzed using electrochemical treatment. The electrode was made of 316 stainless steel, which had been perforated to prevent an imbalanced sample concentration in the reactor. Cathodic and anodic electrodes were alternately inserted into an acrylic reactor. The removal efficiency of T-N in SCFs using 40 A/m2, 60 A/m2, and 80 A/m2 current density, was 48.2%, 61.5% and 69.3%, respectively. The removal efficiency of T-N in SCFs with the addition of 0, 5 mM, and 10 mM NaCl was 69.3%, 74.6%, 77.6%, respectively.

This study was aimed at determining the changes in heavy metal removal efficiency at different acid concentrations in a micro-nanobubble soil washing system and pickling process that is used to dispose of heavy metals. For this purpose, the initial and final heavy metal concentrations were measured to calculate the heavy metal removal efficiency 5, 10, 20, 30, 60, and 120 min into the experiment. Soil contaminated by heavy metals and extracted from 0~15 cm below the surface of a vehicle junkyard in the city of U was used in the experiment. The extracted soil was air-dried for 24 h, after which a No. 10 (2 mm) was used as a filter to remove large particles and other substances from the soil as well as to even out the samples. As for the operating conditions, the air inflow rate in the micro-nano bubble soil washing system was fixed at 2 L/min,; with the concentration of hydrogen peroxide being adjusted to 5%, 10%, or 15%. The treatment lasted 120 min. The results showed that when the concentration of hydrogen peroxide was 5%, the efficiency of Zn removal was 27.4%, whereas those of Ni and Pb were 28.7% and 22.8%, respectively. When the concentration of hydrogen peroxide was 10%, the efficiency of Zn removal was 38.7%, whereas those of Ni and Pb were 42.6% and 28.6%, respectively. When the concentration of hydrogen peroxide was 15%, the efficiency of Zn removal was 49.7%, whereas those of Ni and Pb were 57.1% and 42.6%, respectively. Therefore, the efficiency of removal of all three heavy metals was the highest when the hydrogen peroxide concentration was 15%.

Livestock manure treatments have become a more serious problem because massive environmental pollutions such as green and red tides caused by non-point pollution sources from livestock manures have emerged as a serious social issue. In addition, more food wastes are being produced due to population growth and increased income level. Since the London Convention has banned the ocean dumping of wastes, some other waste treatment methods for land disposal had to be developed and applied. At the same time, researches have been conducted to develop alternative energy sources from various types of wastes. As a result, anaerobic digestion as a waste treatment method has become an attractive solution. In this study has three objectives: first, to identify the physical properties of the mixture of livestock wastewater and food waste when combining food waste treatment with the conventional livestock manure treatment based on anaerobic mesophilic digestion; second, to find the ideal ratio of waste mixture that could maximize the collection efficiency of methane (CH4) from the anaerobic digestion process; and third, to promote CH4 production by comparing the biodegradability. As a result of comparing the reactors R1, R2, and R3, each containing a mixture of food waste and livestock manure at the ratio of 5:5, 7:3, and 3:7, respectively, R2 showed the optimum treatment efficiencies for the removal of Total Solids (TS) and Volatile Solids (VS), CH4 production, and biodegradability.

As industry continues to develop, the contents of various recalcitrant substances that are not removed by conventional wastewater treatment have increased in modern society. The metal working fluids (MWFs) used in the metal working process contain chemical substances, such as mineral oils, anticorrosive agents, extreme-pressure additives, and stabilizers, as well as high concentrations of organics and ammonia-nitrogen. Accordingly, MWFs are required to develop advanced treatments to conserve hydro-ecological resources. This study investigated the removal efficiency of ammonia nitrogen from MWFs according to operating time, applied voltage, and NaCl concentration using a Ti/IrO2 electrode in a batch-type reactor. The experimental results showed that ammonia-nitrogen removal efficiencies without NaCl were 89% and 92% when voltage was adjusted to 15 and 20 V for 60 min and removal efficiency was 90% at 25 V for 40 min. Removal efficiencies of 10 mM NaCl were 4% and 2% greater than those of not adding NaCl at 15 V for 50 min and 20 V for 30 min.

The objectives of this study are to examine the processing of oils contamination soil by means of using a micronano-bubble soil washing system, to investigate the various factors such as washing periods, the amount of micro-nano bubbles generated depending on the quantity of acid injection and quantity of air injection, to examine the features involved in the elimination of total petroleum hydrocarbons (TPHs) contained in the soil, and thus to evaluate the possibility of practical application on the field for the economic feasibility. The oils contaminated soil used in this study was collected from the 0~15 cm surface layer of an automobile junkyard located in U City. The collected soil was air-dried for 24 hours, and then the large particles and other substances contained in the soil were eliminated and filtered through sieve No.10 (2 mm) to secure consistency in the samples. The TPH concentration of the contaminated soil was found to be 4,914～5,998 mg/kg. The micronano-bubble soil washing system consists of the reactor, the flow equalization tank, the micronano- bubble generator, the pump and the strainer, and was manufactured with stainless material for withstanding acidic phase. When the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 30 minutes were respectively identified as 4,931 mg/kg (18.9%), 4,678 mg/kg (18.9%) and, 4,513 mg/kg (17.7%). And when the injected air flow rate was fixed at 2 L/min, for each hydrogen peroxide concentrations (5, 10, 15%) the removal percents for TPH within the contaminated soil with retention times of 120 minutes were respectively identified as4,256 mg/kg (22.3%), 4,621 mg/kg (19.7%) and 4,268 mg/kg (25.9%).

The main objectives of this research are to investigate characteristics of ozone solubility due to low solubility of conventional bubbles-ozone generators, evaluate the treatment characteristics of reclaiming textile wastewater for industrial water by means of micro/nano bubbles-dissolved ozone flotation(MNB-DOF) process. The textile wastewater used in this research was obtained from final effluent of the textile wastewater in B city. There is a 400L reactor which consists of a micro-nano bubble system and a ozone generator for experiments. As a result of generating micro-nano bubbles (below 0.5 ㎛) by using of MNB-DOF process, it improved ozone solubility due to higher ozone transfer rates. Consequently, the shorter ozonation time clearly indicates the lower power costs. The reported results clearly indicated that MNB-DOF process can be effectively and inexpensively. Results of the experiments through MNB-DOF process in this study satisfy all reclaiming standards as industrial water: pH 6.5～8.5, SS 10 mg/L or below, BOD_5 6 mg/L or below, turbidity 10 NTU or below, Coliforms 1,000/100 mL or below. Therefore there is a possibility of the reclaiming of the textile wastewater as industrial water.

The Raw water from Deer Creek (DC) reservoir and Little Cottonwood Creek (LCC) reservoir in the Utah, USA were collected for jar test experiments. This study examined the removal of arsenic and turbidity by means of coagulation and flocculation processes using of aluminum sulfate and ferric chloride as coagulants for 13 jar tests. The jar tests were performed to determine the optimal pH range, alum concentration, ferric chloride concentration and polymer concentration for arsenic and turbidity removal. The results showed that a comparison was made between alum and ferric chloride as coagulant. Removal efficiency of arsenic and turbidity for alum (16 mg/L) of up to 79.6% and 90.3% at pH 6.5 respectively were observed. Removal efficiency of arsenic and turbidity for ferric chloride (8 mg/L) of up to 59.5% at pH 8 and 90.6% at pH 8 respectively were observed. Optimum arsenic and turbidity removal for alum dosages were achieved with a 25 mg/L and 16 mg/L respectively. Optimum arsenic and turbidity removal for ferric chloride dosages were achieved with a 20 mg/Land 8 mg/L respectively. In terms of minimizing the arsenic and turbidity levels, the optimum pH ranges were 6.5 and 8for alum and ferric chloride respectively. When a dosage of 2 mg/L of potassium permanganate and 8 mg/L of ferric chloride were employed, potassium permanganate can improve arsenic removal, but not turbidity removal.

The objectives of this research are to evaluate and compare the oxygen transfer coefficients(KLa) in both a general bubbles reactor and a micro-nano bubbles reactor for effective operation in sewage treatment plants, and to understand the effect on microbial kinetic parameters of biomass growth for optimal biological treatment in sewage treatment plants when the micro-nano bubbles reactor is applied. Oxygen transfer coefficients(KLa) of tap water and effluent of primary clarifier were determined. The oxygen transfer coefficients of the tap water for the general bubbles reactor and micro-nano bubbles reactor were found to be 0.28 hr -1 and 2.50 hr -1 , respectively. The oxygen transfer coefficients of the effluent of the primary clarifier for the general bubbles reactor and micro-nano bubbles reactor were found be to 0.15 hr -1 and 0.91 hr -1 , respectively. In order to figure out kinetic parameters of biomass growth for the general bubbles reactor and micro-nano bubbles reactor, oxygen uptake rates(OURs) in the saturated effluent of the primary clarifier were measured with the general bubbles reactor and micro-nano bubbles reactor. The OURs of in the saturated effluent of the primary clarifier with the general bubbles reactor and micro-nano bubbles reactor were 0.0294 mg O2/L․hr and 0.0465 mg O2/L․hr, respectively. The higher micro-nano bubbles reactor's oxygen transfer coefficient increases the OURs. In addition, the maximum readily biodegradable substrate utilization rates(Kms) for the general bubbles reactor and micro-nano bubbles reactor were 3.41 mg COD utilized/mg active VSS․day and 7.07 mg COD utilized/mg active VSS․day, respectively. The maximum specific biomass growth rates for heterotrophic biomass(μmax) were calculated by both values of yield for heterotrophic biomass(YH) and the maximum readily biodegradable substrate utilization rates(Kms). The values of μmax for the general bubbles reactor and micro-nano bubbles reactor were 1.62 day -1 and 3.36 day -1 , respectively. The reported results show that the micro-nano bubbles reactor increased air-liquid contact area. This method could remove dissolved organic matters and nutrients efficiently and effectively.

Activated sludge sewage treatment processes are difficult to be controlled because of their complex and nonlinear behaviour, however, the control of the dissolved oxygen level in the reactors plays an important role in the operation of the facility. For this reason, this study is designed to present a system which accurately measures DO, MLSS, pH and ORP in the aeration tank to alleviate situations above and provide the automatization of a sewage treatment plant (STP) using new DO control system. The automatic control systems must be guaranteed the accuracy. Therefore, the proposed automatic DO control system in this study could be commercial applications in the aeration tanks by means of operating cost analysis and user-friendly for operation and maintenance. We could get accurate data from the lab tank which has water quality checker because there was no vortex and air bubble during the measurement process. Improvement of confidence in the lab tank enabled effective and automatic operation of sewage treatment plants so that operation costs and manpower could be saved. If this result is put in place in every sewage treatment plant nationwide for practical purposes, it is estimated to cost 18.5 million dollars in installing the lab tank and to save 9.8 million dollars in management cost a year, except for cost saved by automation.

The removal characteristics of total petroleum hydrocarbons (TPHs) and heavy metals in contaminated soils with ultrasonic washing have been studied. The ultrasonic washing was evaluated on a laboratory scale. In this investigation, the effects of factors such as ultrasonic frequency, power intensity, duration of irradiation, contents of the TPHs and heavy metals and mixing ratios between the contaminated soils and water, were considered. Experimental results suggested that the rates for contaminant extraction of the TPHs and heavy metals in the contaminated soil increased considerably with the ultrasonic washing. Therefore, the ultrasonic washing has previously been to be an effective method to remediate the contaminated soils with the TPHs and heavy metals.

The application of microwave technology has been investigated in the remediation of diesel-contaminated soil. The paper deals with economic assessment by means of cost analysis and degradation characteristics at different microwave powers for total petroleum hydrocarbon (TPH) in diesel contaminated soils. The soils from S Mountain around the D University were sampled. The samples were screened with 2.0 mm mesh and dried for 6 hours before the diesel was added into the dried soils. The diesel-contaminated soil (3,300 mg THP/kg soil) was prepared with diesel (S Co.). The drying process was carried out in a microwave oven, a standard household appliance with a 2,450 MHz frequency and 700 W of power. The experiments were conducted from 0 to 20 minutes as the microwave powers increased from 350W to 500W to 700W. The concentrations of TPH were analysed using a gas chromatography/mass spectrometer (GC/MS). The initial concentration of TPH was 3,300 mg TPH/kg soil. The weight of contaminated soil was 200g. The concentration of TPH was decreased to 1,828 mg TPH/kg soil (44.7%), 1,347 mg TPH/kg soil (59.2%) and 1,014 mg TPH/kg soil (69.3%) at 350W, 500W and 700W for 15 minutes respectively. In addition, the curve was best fit with first order kinetics using the least-square method. The ranges of a first order rate constant k and r-square were 0.0298～0.0375min-1 and 0.9373～0.9541 respectively.

The purpose of this study is to investigate weighted compaction density according to a loading density in truck, a compaction density of solid waste and composition ratios of solid waste for calculation of a capacity of the landfill sites. The experiments for calculations of in-place density at landfill site have been conducted in S landfill site at B City. The size of vessel for measuring the compaction density was 1m3(1m×1m×1m). The experiment tests have been carried out methods (1 time for bulldozer and 4 times for compactor) that do contain all of specification at the landfill site. Average of the loading density at the landfill site was 0.264 ton/m3 (0.113～0.487 ton/m³). When the loading density for each compositions was compared, the composition of the highest average loading density (0.474 ton/m³) was miscellaneous wastes. The composition of the lowest average loading density (0.120 ton/m³) was general solid waste. The reported results indicated that the compaction density at the landfill site was 0.538 ton/m³, which was calculated with weighted incoming ratios of compositions. The ranges of the density for each composition were from 0.021 ton/m³ to 0.221 ton/m³. When the compaction density for each composition was compared, the composition with the highest average compaction density (0.221 ton/m³) was miscellaneous wastes. The composition with the lowest average compaction density (0.021 ton/m³) was general solid wastes.