• Applied Chemistry for Engineering
• /
• v.19 no.1
• /
• pp.122-128
• /
• 2008

We evaluated the relationship between the multiplication of heterotrophic microorganisms and physicochemical factors in the final discharged sewage water from J municipal waste water treatment plants. Dissolved organic carbon (DOC) was the most crucial factor influencing multiplication of heterotrophic plate counts (HPC) among the water quality variables selected. Degrading bacteria, such as proteolytic bacteria, lipholytic bacteria, starch degrading bacteria, cellulolytic bacteria, and pectinolytic bacteria, were monitored to understand the condition of nutrients in finished sewage effluent. The percentages of lipid and protein combined occupied 81% in finished sewage water. The multiplication of HPC showed the highest value in August. The formation of trihalomethane (THM) was low in the finished discharge water during chlorine disinfection, which was $71{\mu}/L$ (which was less than $100{\mu}/L$- the standard of drinking water quality) with 10 mg/L of chlorine during 15 min.

• Journal of Korean Society on Water Environment
• /
• v.27 no.1
• /
• pp.36-43
• /
• 2011

This study is selected two points of combined sewer that occurred Fish Kill after first flush, that analyzed generation of pollutants and stream runoff generation of combined sewer overflows (CSOs) as fine weather and rainfall. In addition, this study was to analyze the relationship between CSOs and sediments, to propose measures to reduce the sediment relevant with CSOs and rainfall runoff from entering sewage treatment plants and measures for discharged directly into streams when indicate relatively good water quality after overflow. Sediments in combined sewer system was discharged about 50~80% as overflows during rainfall and we can reduce the amount of the CSOs at least 50% or more if the sewer does not exist in the sediments because of the amount of discharge about the amount of intercept has been investigated by 3~5 times. Because of velocity at sediment interval in sewer is very low, sewage velocity of about 3~5 times as much as it can increase the amount of sediment can be reduced if the separation wall is installed. Effective control of BOD overflow load is respectively 77.5%, 75.8% at first point, second point by the separation wall is installed. Drainage area greater than area in this study or many combined sewer overflows region is increased the more effective control of separation wall. Turbidity to measure changes in water quality of overflows can be used as an factor to control the intercept flows because the intercept flows(3Q) after the first flush has lowered removal efficiency and increases the operational load of sewage treatment plants. Sewage water quality after a overflow when the reasonable turbidity was measured at this point flows to excluded intercept flow(1Q) can be discharged to stream.

• Journal of Korean Society on Water Environment
• /
• v.37 no.2
• /
• pp.128-136
• /
• 2021

It is generally known that a wastewater treatment plant (WWTP) consumes immense energy even if it can produce energy. With an aim to increase the energy independence rate of WWTP from 3.5% in 2010 to 50% in 2030, the Korean government has invested enormous research funds. In this study, cost-effective operating alternatives were investigated by analyzing the energy efficiency and economic feasibility for biogas and power generation using new and renewable energy. Based on the US EPA Energy Conservation Measures and Korea ESCO projects, energy production and independence rate were also analyzed. The main energy consumption equipment in WWTP is the blower for aeration, discharge pump for effluent, and pump for influent. Considering the processes of WWTP, the specific energy consumption rate of the process using media and MBR was the lowest (0.549 kWh/㎥) and the highest (1.427 kWh/㎥), respectively. Energy-saving by enhancing anaerobic digester efficiency was turned out to be efficient when in conjunction with stable wastewater treatment. The result of economic analysis (B/C ratio) was 2.5 for digestive gas power generation, 0.86 for small hydropower, 0.49 for solar energy, and 0.15 for wind energy, respectively. Furthermore, it was observed that the energy independence rate could be enhanced by installing energy production facilities such as solar and small hydropower and reducing energy consumption via the replacement of high-efficiency operating.

• Journal of Environmental Health Sciences
• /
• v.26 no.3
• /
• pp.61-68
• /
• 2000

The use of photo-catalytic processes in pollution abatement and resource has a significant economic importance. Therefore, the applications of photochemical oxidation of secondary effluent driven by UV, TiO2, TiO2/UV, H2O2/UV and TiO2/H2O2/UV, have been investigated in order to treat the secondary effluent from municipal sewage. Various experimental parameters such as BOD, CODcr, Nurbidity, total P, and SPC were examined in each photo-catalytic reaction system. The results showed that the application of single oxidant such as UV, TiO2 only has a minor effect on parameters reduction (CODcr, BOD, etc) to treat the secondary effluent, whereas the combinations of oxidants increase the removal efficiency. The best removal efficiency in every parameters was achieved by the combination of TiO2, H2O2 and UV. It was also found that the optimum amount of TiO2 for the treatment was 1g/ι to achieve water reuse standard. From the results, the photocatalytic reaction system can be an alternative as a post-treatment to treat the secondary effluent from municipal sewage.

• Journal of Environmental Science International
• /
• v.23 no.5
• /
• pp.853-859
• /
• 2014

The purpose of this study was to improve low digestibility in anaerobic digestion facility of the sewage treatment plant. To perform this research, sludge digestion and digestion gas purification facilities in sewage treatment plant was applied. In the result of this study, it was very effective for sludge reduction from the improvement of digestive efficiency. In addition, it was confirmed that high purity $CH_4$ (methane) was produced. This results can be useful as basic data to improve the low digestibility in anaerobic digestion processes.

• Journal of Korean Society of Disaster and Security
• /
• v.12 no.2
• /
• pp.25-34
• /
• 2019

The efficiency of sewage treatment was analyzed by statistical method based on the water quality and operation data of the sewage treatment plant applying the oxidation method. The obtained water quality data were pH, temperature, BOD, SS, T-N, ${NH_4}^+-N$, and T-P of influent and discharge water. Data analysis was performed by correlation analysis, ANOVA analysis, and cluster analysis. As a result of the statistical analysis, the influent flow rate in the sewage treatment plant was the highest in summer. The average inflow flow rate was $3.000m^3/s$. According to Box plot results, COD, and T-P concentrations of effluents were not significantly different from season to season. The Pearson correlation analysis showed strong positive correlation between BOD, COD, T-N, and T-P in influent flow. Seasonal BOD and T-N concentrations were highest in winter and COD and T-P in seasonal influences. BOD showed a strong negative correlation with the water temperature, but showed a positive correlation with other operating factors such as HRT, SRT and C/N. The higher the influent temperature, the lower the BOD concentration. Therefore, retention time was shortened and BOD treatment efficiency was lowered. It was found that T-N had a higher retention time and a higher concentration than DO concentration. On the other hand, T-P did not show a significant correlation with operating factors.

• Korean Journal of Environmental Agriculture
• /
• v.4 no.1
• /
• pp.37-42
• /
• 1985

Recently the method using fixing biological contactor in treatment of sewage and wastewater has been propelling on the ground that it has advantages of reducing both motive and man power and applied treatment plants of this method are increasing gradually in Korea. After analysing the results from which real structure pilot plant had operated in the field with RBC sewage wastewater system-one of the fixing biological contact methods-for five months, this study was performed to investigate how to apply the standard of establishment that provided in article of sewage disposal facilities notified (act 8 of art 84) by the office of environment on May 16, 1984, to real treatment plant. The rotating velocity and the staying time of rotating disc have interrelation on removal efficiency of BOD. When circumferential velocity of rotating disc was ranged from 18 to 20 m per minute, economical price was the best. When the staying time was even about 120 minutes for that of home RBC facilities showed 90% or above of BOD removal efficiency of high concentration sewage also showed excellent efficiency ranged from about 85% to 90%.

• Journal of Wetlands Research
• /
• v.17 no.1
• /
• pp.11-18
• /
• 2015

As the seriousness of water pollution resulted from nitrogen is being magnified, research has been conducted to reduce nitrogen in sewage as well as wastewater. Particularly research on innovative nitrogen removal methods that are based on the reaction of nitritation and are economically feasible and eco-friendly has been receiving attention. However, research on the applicability and efficiency of the methods based on the reaction of nitritation has not been completely done yet. Accordingly, the current study has analyzed the characteristics of sewage flowing into municipal wastewater treatment plants, primary clarifier supernatant, recycled water, and livestock wastewater and also operated a laboratory-level reactor. The result shows that recycled water and livestock wastewater contain higher-concentration nitrogen than other kinds of sewage, so they increase nitrogen loading in the water treatment line. And the result of operating a reactor shows that because of ammonium nitrogen low concentration, sewage and primary clarifier supernatant do not induce the reaction of nitritation. Also, there exist differences in the conditions of retention time inducing the reaction of nitritation by the types of sewage, and this seems to be attributed to organic compound and ammonium nitrogen concentration. Among the kinds of sewage inducing the reaction of nitritation, anaerobic digester supernatant indicates the highest efficiency.

• Journal of Korean Society of Water and Wastewater
• /
• v.26 no.6
• /
• pp.825-831
• /
• 2012

The retrofitting of a thickening unit process is widely considered in municipal wastewater treatment plants in Korea to enhance the anaerobic digestion efficiency. The authors examined the effect of feed concentration (2-34.1 g VS/L) and feed to microorganism (F/M) ratio (0.50-1.35 g VS/g VS) on anaerobic batch digestion of sewage sludge. Methane yield over 90 mL $CH_4/g$ $VS_{feed}$ was found at a feed concentration in the range of 12-26 g VS/L and a F/M ratio below 0.6 g VS/g VS. A high F/M ratio decreased methane yield and rate with oragnic acid accumulation. As sudden increase of sewage sludge concentration prior to anaerobic digestion would jeopardize the digester performance due to the rasied F/M ratio, gradual increase of the sludge feed concentration or an additional biomass retention in the digester is recommended.

• Journal of Korean Society of Water and Wastewater
• /
• v.21 no.4
• /
• pp.453-465
• /
• 2007

With rapid expansion of the water market and growth of water companies, the recent trends in international water industry show that standardization of service activities concerning management of water and wastewater system (ISO/TC 224, to be issued in the second half year of 2007) is expected to have a large influence on the global water market including liberalization of water service market. In the Draft International Standard(DIS) of ISO/TC224, Performance Indicators(PIs) are suggested to estimate the service activities relating to water and wastewater treatment facilities. PIs have been developed in many countries including some international organization(World Bank, IWA and etc.) for service benchmarking. To evaluate public service level and establish plans to improve service level of wastewater utilities, we developed PIs for 120 items and applied them to 10 sewage utilities in the consideration of their scales, circumstances and conditions. In this study, we verified the applicability of the developed performance indicators(PIs). So, we concluded that PIs developed for the purpose of this study can be a useful tool applicable to objective evaluation of the service level of sewage utilities. Using the evaluation tool of PIs developed, it can also be used as a benchmarking tool in this industry as well as for enhancing the efficiency of operation and management of the sewage system. It will also contribute to the water resource management through determination of investment priorities based on the evaluation results and to raising international competitiveness of the domestic sewage utilities to meet the future opening of the water market.