파일럿 규모 하이브리드 비점오염저감시설을 이용한 계성천 총인 제거 성능 평가 = Performance Evaluation of a Pilot-Scale Hybrid System for Total Phosphorus Removal in the Gyeseong Stream

다국어 초록 (Multilingual Abstract)

This study was conducted to address the recurring eutrophication problems in the Gyeseongcheon watershed, where residential areas, farmland, and livestock facilities lie in close proximity and continually contribute to non-point source pollution. Because these pollutant inputs occur irregularly and often unpredictably, a pilot-scale hybrid treatment system integrating coagulation sedimentation with a constructed wetland was evaluated to determine whether more stable total phosphorus (T-P) reduction could be achieved under realistic field conditions. A further aim of the study, directed toward the practical use of a statistical model, was to establish feasible operating conditions and develop a model that can reasonably represent the behavior of the treatment system without relying on excessive simplification.
Among the four operating modes tested, the serial configurations generally showed the most consistent performance. In serial mode 1, Alum dosing at an average of 16.3mg/L resulted in 82.4% T-P removal, while PAC, applied at 10.3mg/L in serial mode 2, achieved 86.4%. Although both coagulants produced comparable efficiencies, Alum offered an estimated 20% economic advantage an important consideration for long-term operation. Under influent
concentrations ranging from 0.082 to 0.605mg/L for T-P and 0.003 to 0.331 mg/L for PO4-P, serial mode 1 again yielded the highest removal efficiency (82.0%). However, its performance dropped sharply to 42.25% during rainfall events, whereas the other modes maintained efficiencies above 70%, indicating that single or parallel operation may respond more effectively to sudden hydraulic surges.concentrations ranging from 0.082 to 0.605mg/L for T-P and 0.003 to 0.331 mg/L for PO4-P, serial mode 1 again yielded the highest removal efficiency (82.0%). However, its performance dropped sharply to 42.25% during rainfall events, whereas the other modes maintained efficiencies above 70%, indicating that single or parallel operation may respond more effectively to sudden hydraulic surges.
To support the practical application of the statistical model, seven water quality variables including BOD, TOC, SS, and T-P were incorporated into a multiple regression framework. The resulting model demonstrated strong explanatory power, with R2 values ranging from 0.626 to 0.950. Coagulant dose, TOC, and T-P emerged as statistically significant predictors (p<0.05). Analysis of the Al/P molar ratio further revealed that the influent ratios observed in this study (T-P:1.0-18.7, PO4-P:1.3-44.0) were higher than those commonly reported in earlier physicochemical studies, suggesting that particulate phosphorus in natural stream environments may increase coagulant demand.
SEM-EDS observations corroborated the quantitative results Alum facilitated the transformation of fine suspended particles into larger, more porous flocs and increased aluminum content on particle surfaces. These findings provide visual evidence of the mechanisms responsible for phosphorus removal in the hybrid system. Overall, the combined process exhibited greater stability and cost effectiveness than the single process configurations evaluated. The operational insights and the practically applicable statistical model developed in this study may contribute to improved phosphorus load management in similar stream environments. Further investigation is recommended to assess full-scale performance under broader hydrological and seasonal conditions.

목차 (Table of Contents)

• 1. 서 론 1
• 1.1 연구배경과 목적 1
• 1.2 연구내용 및 범위 4
• 2. 문헌 연구 8
• 2.1 pH에 따른 인산의 이온화 및 형태변화 8
• 2.2 물리·화학적 인(P) 처리 원리 10
• 2.3 응집의 영향 인자 13
• 2.4 인공습지를 이용한 총인(T-P) 처리 18
• 2.5 인공습지에서의 총인(T-P) 처리 영향 인자 19
• 3. 연구내용 및 실험방법 22
• 3.1 인처리를 위한 파일럿 시스템 22
• 3.1.1 위치 및 시설구성 22
• 3.1.2 연구내용 26
• 3.1.3 운전방안 설정 27
• 3.2 시료채수 및 분석 29
• 3.2.1 수질측정 모니터링 주기 및 항목 29
• 3.2.2 시료의 채수 및 분석 30
• 3.3 다중회귀분석 31
• 4. 수질특성 및 응집제 선정 34
• 4.1 하천 유입수 특성별 처리효율 분석 34
• 4.1.1 하천수의 년간 수질현황 34
• 4.1.2 수온 및 강수량 35
• 4.1.3 pH 및 알칼리도 38
• 4.2 응집제의 선정 40
• 4.2.1 운전 MODE별 응집제 영향 검토 40
• 4.2.2 최적 응집제의 선정 49
• 5. 운전 MODE별 처리효율 및 특성 50
• 5.1 선정된 응집제를 활용한 운전 MODE별 처리효율 50
• 5.1.1 청천 시 처리효율 50
• 5.1.2 강우 시 처리효율 56
• 5.2 응집플럭의 물리·화학적 특성분석(입도, SEM/EDS) 61
• 5.2.1 입도분석 61
• 5.2.2 SEM 분석 결과 64
• 5.2.3 EDS 분석 결과 66
• 5.3 최적 운전MODE 선정 70
• 6. 예측모델 도출 및 분석 72
• 6.1 다중회귀분석 예측모델 72
• 6.1.1 다중회귀분석 72
• 6.1.2 다중회귀분석 보정 75
• 6.1.3 상관관계도 분석 78
• 6.2 처리농도 예측식 도출 80
• 6.2.1 처리농도 예측식 산정 80
• 6.2.2 적정 약품주입량 검토 86
• 6.2.3 처리수질 검증 및 수질개선 효과 90
• 7. 결론 94
• 7.1 연구결과 요약 94
• 7.2 종합결론 95
• 참고문헌 97
• ABSTRACT 103