안조환 Johwan Ahn , 김장호 Jangho Kim , 민성재 Sungjae Min

DOI:10.15681/KSWE.2016.32.4.343 Vol.32(No.4) 343-348, 2016

A chemical sequencing batch reactor was operated to test the feasibility of nutrient recovery from a biological livestock wastewater treatment plant. Both phosphate and ammonia could be successfully recovered as magnesium ammonium phosphate (MAP) crystals. The contents of TP and TN in the recovered MAP crystals were 26.2% and 4.0%, respectively. Zn, Cr and Ti were identified in the crystals, but the contents remained below the Korean standard for an organic fertilizer. Chemical analyses confirmed that the MAP crystals could be useful phosphate fertilizers. On the other hand, the results of physical analyses using an X-ray diffractometer and an energy dispersive X-ray spectrometer strongly suggested that crystalline materials like magnesium potassium phosphate (KMP) and hydroxyapatite (HAP) were also formed during the MAP crystallization, depending on the availability of K+ and Ca2+.

Hydroxyapatite (HAP), Livestock wastewater, Magnesium Ammonium Phosphate (MAP), Magnesium Potassium Phosphate (KMP)

정은정 Eunjeong Cheong , 김홍태 Hongtae Kim , 김용석 Yongseok Kim , 신동석 Dongseok Shin

DOI:10.15681/KSWE.2016.32.4.349 Vol.32(No.4) 349-356, 2016

Total Maximum Daily Loads (TMDLs) System has been used to improve water quality in the YoungsanㆍTamjin river basin since 2004. The Basic Policy of TMDLs sets up the standard flow based on the average dry condition or mid-range flow during the last 10 years. However, Target Water Quality (TWQ) assessment on TMDLs has been used to evaluate water quality through eight-day intervals over 36 times a year. The results for allocation evaluation and target water quality evaluation were different from each other in the same unit watershed during the first period. In order to improve the evaluation method, researchers applied Load Duration Curve (LDC) to evaluate water quality in nine unit watersheds of the Youngsan·Tamjin river basin. The results showed that achievement rates of TWQ assessment with the current method and LDC were 67~100% and 78~100%, respectively. Approximately 11% of the achievement rates with use of LDC were higher than those with use of the current method. In conclusion, it is necessary to review the application of the LDC method in all Four Major River Watersheds.

LDC (Load Duration Curve), TWQ (Target Water Quality), TMDLs (Total Maximum Daily Loads), Youngsan,Tamjin River

심재구 Jae-goo Shim , 아프잘아킬 Afzal Aqeel , 최보미 Bo-mi Choi , 이정현 Jung-hyun Lee , 곽노상 No-sang Kwak , 임호진 Ho-jin Lim

DOI:10.15681/KSWE.2016.32.4.357 Vol.32(No.4) 357-366, 2016

N-nitrosamines are a class of carcinogenic chemicals that can pose significant hazards to the human life. Ultraviolet (UV) light irradiation is considered as one of the effective methods to reduce N-nitrosamines in the aqueous phase. This study aimed to investigate the pH influence on UV photodegradation of N-nitrosamines (i.e., N-nitrosodibutylamine (NDBA) and N-nitrosopyrrolidine (NPYR)) closely related to water treatment. Photodegradation rate constants of NDBA and NPYR remained between 3.26×10-2 L/W-min to 5.08×10-3 L/W-min and 1.14×10-2 L/W-min to 2.80×10-3 L/W-min at pH2-10, respectively. This study also focused on the formation of oxidized products (i.e., primarily NO2- and NO3-). Under slightly acidic and eutral conditions, NO2- formation was more prevalent than NO3- formation, while under strong acidic conditions, NO3- was more prevalent. There was no significant change in total organic carbon (TOC) and total nitrogen (TN), suggesting negligible loss of N-nitrosamines and degradation products from the system. NDBA was easily photodegraded than NPYR. This study also demonstrated that a lower pH is a favorable condition for photolytic degradation of N-nitrosamines in water.

Nitrosamine, pH effect, Photodegradation, UV photolysis, Water treatment

김정률 Jungryun Kim , 오재일 Jeill Oh

DOI:10.15681/KSWE.2016.32.4.367 Vol.32(No.4) 367-374, 2016

In this study, the RDII impact on sewer designing in the upstream monitoring area (A site) was considered. Based on the long-term (1/1/2011~12/31/2011) rainfall and flow data consisting of 10-min interval sampling in the nearby design area (B site), the maximum RDII/DWF ratio was selected. The sewer network system at B site was evaluated by the Manning equation. Scenario 1 considering the hourly maximum flow with respect to the flow velocity showed that none of the sewer pipes satisfied the minimum flow velocity condition (0.6 m/s), and 40 pipes did not achieve half of the velocity condition. In scenario 2 considering I/I, 1 the pipes satisfied 0.6 m/s, and 35 pipes showed 0.3 m/s. Scenario 3 reflected the effect of RDII. Velocities in 26 pipes were less than 0.3 m/s, and 4 pipes satisfied the velocity condition. With respect to the allowance rate, 17 pipes were shown to have more than 99%, and none of the pipes satisfied less than 95% of the allowance rate in scenario 1. In scenario 2, 17 Ed: Per the Table pipes showed more than 99% and one pipe showed less than 95%. In scenario 3, 16 pipes showed more than 99% of the allowance rate, and 19 pipes showed less than 95%. Based on these results, it is predicted that deposition would occur due to the slow flow velocity; however, capacity would not be a problem.

Rainfall-Derived Inflow/Infiltration, Sanitary Sewer Systems (SSSs), Sewer Design Analysis, Sewer Network

황하선 Ha Sun Hwang , 이한필 Han Pil Rhee , 안기홍 Ki Hong Ahn , 박지형 Ji Hyung Park , 김용석 Yong Seok Kim , 이성준 Sung Jun Lee

DOI:10.15681/KSWE.2016.32.4.375 Vol.32(No.4) 375-383, 2016

Total Pollution Load Control (TPLC) calculates and manages the allowable pollutant load that is discharged from the watershed, which can meet the water quality target. Delivery Ratio (DR) is generally used for predicting the variation of pollutant mass balance between the pollutants discharged from the watershed and a certain point in the stream, and it is veryimportant for estimation of accurate allowable pollutant load. The concept of DR in TPLC is different from prevalent DR, because DR in TPLC includes both the discharge of pollutants from the watershed and the delivery mechanism. Therefore, DR in TPLC should be estimated by using a proper and unified methodology. The appropriate method and equation for estimation of DR in TPLC was developed through the review of various methodologies, and the applicability of the equation was evaluated in a study area (Geumho A). Determination coefficients (R2) of regression were shown to be relatively high (BOD 0.71~0.87, T-N 0.86~0.90, T-P 0.62~0.69). Applicability of the developed methodology and equations was evaluated as appropriate for TPLC, and it is suggested.

Delivery Load, Delivery Ratio, Discharge Coefficient, Total Pollution Load Control (TPLC)