In this study, an operational data set was analysed by establishing a path model to figure out the actual cause-effect relationship of a wastewater treatment plant (WWTP); in particular, for the effluent concentrations of T-N and T-P. To develop the path models, data sets of operational records including effluent concentrations and operational factors were obtained from a field scale WWTP of 680,000 m3 of treatment capacity. The models showed that the relationship networks with the correlation coefficients between variables for objective expressions indicated the strength of each relationship. The suggested path models were verified according to whether the analyzation results matched known theories well, but sophisticated minute theoric relationships could not be cropped out distinctly. This indicates that only a few paths with strong theoric casual relationships were represented as measured data due to the high non-linearity of the mechanism of the removal process in a biological wastewater treatment.

Abstract
 1. 서 론
 2. 재료 및 방법
  2.1. 연구대상 하수처리장 및 데이터구성
  2.2. 경로모델 구축
 3. 결과 및 고찰
  3.1. 유출수 T-N의 경로도형
  3.2 유출수 T-P의 경로도형
 4. 결 론
 REFERENCES

• 조영대(부산가톨릭대학교 환경공학과) | Yeongdae Cho
• 김민수(부산가톨릭대학교 환경공학과) | Minsoo Kim
• 이슬아(부산대학교 환경공학과) | Seul-ah Lee
• 김효수((주)엔바이론소프트) | Hyosoo Kim
• 최명원((주)엔바이론소프트) | Myungwon Choi
• 김예진(부산가톨릭대학교 환경공학과) | Yejin Kim Corresponding author