In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.

In this study, the International Maritime Organization (IMO)’s guideline MEPC. 277 (64) was developed and evaluated for the removal efficiency of T-N in a SBR and MBR combined process. This combined process of resized equipment based on large capacity water treatment device for a protection of marine aquatic life. In this experiment, T-N concentration of influent and effluent was measured through with the artificial wastewater. The SBR reactor operation time was varied according to the C : N : P ratios so that different conditions for mixing and aeration period in mins (90 : 60, 80 : 40, 70 : 50) and two C: N: P ratios (10 : 5 : 3, 10 : 3 : 1) were used. During experiment in the reactor’s aeration and anoxic tank DO concentrations were 3 mg/L and 0.2 mg/L respectively. Furthermore, in the reactor MLSS concentration was 2000 mg/L and flowrate was 2 L/hr. Experiment results showed that C : N : P, 10 : 3 : 1 ratio with 90 mins mixing and 60 mins aeration maximized removal efficiency at 97.3% T-N as compared to other conditions. The application of the SBR and MBR combined process showed efficient results.

The mother machine makes the necessary shape by processing materials such as metal. The SCFs are applied to the processing surface when the mother machine processes the material, thereby improving the cutting conditions. SCFs contain high concentrations of organic components and nitrogen compounds, which can cause problems such as eutrophication and algae bloom. Therefore, proper treatment is required. Electrochemical treatment is expected to be an alternative to conventional processes, and to be useful in various wastewater treatments. Moreover, it is an efficient elimination technique for contaminants and has a simple equipment composition. In this study, the removal efficiency of the T-N contained in the waste SCF using electrochemical treatment is analyzed. The electrode was made of titanium and iridium, made into a perforated metal sheet to prevent an imbalance of the sample concentration in the reactor. Experiments were conducted to examine the effects of current density and the concentration of the supporting electrolyte (NaCl, Na2SO4) on removal efficiency. In the cases with 60 A/m2, 80 A/m2, and 100 A/m2 current densities, the removal efficiencies of the T-N contained in the waste SCF were 51.03%, 68.83%, and 79.58%. Comparing between the addition and non-addition of NaCl, the removal efficiency with the addition of NaCl (5 ~ 10 mM) was higher than for no addition at 60 min for all current densities. The addition of Na2SO4 increased the removal rate of the T-N, but it was less effective than NaCl addition.