Solid-liquid separation is important for securing safe runoff quality in the biological treatment process. In particular, the method for determining sludge settlement characteristics using SVI, which is a parameter, evaluates the precipitation features of sludge in an aeration tank and secondary precipitation tank and is a simple and widely used method. However, in methods using SVI, the accumulation of objective data is usually not possible, since the subjective judgment of operators is mainly involved in this evaluation method. Therefore, the automation of SVI measurement is required to improve the determination method of sludge settlement using SVI. In this study, an automatic measurement system of SVI using optics was developed. To evaluate the reliability of the measurement system, a visual inspection test was performed in parallel with our suggested SV30 auto-measurement system using actual sludge and a similar tendency in the results was obtained. Using this suggested SV30 automation system, the indirect determination of MLSS (Mixed-Liquor-Suspended-Solids) activation states of the aeration tank and precipitation tank is also expected to be possible. Through the test results, it was verified that the reliability of SVI determination was increased by identifying the effect of outside light after performing a test under external light interference.

Abstract
 I. 서 론
 II. 재료 및 방법
  1. 광학을 이용한 슬러지 침강 측정장치
  2. 측정대상 슬러지
  3. 침강측정 실험
   3.1. 광학을 이용한 SV30 자동측정
    3.1.1. 공시험
    3.1.2. 생물반응조 내 슬러지의 침강특성
   3.2. 침전특성 평가
 IV. 결 론
 감사의 글
 References

• 정우진(경기대학교 일반대학원 환경에너지공학과, Department of Environmental Energy Engineering, Graduate School, Kyonggi University) | Woo Jin Chung
• 홍성민((주)아쿠아테크 R&D연구소, Aquatech Co.) | Seong Min Hong
• 김한래((주)아쿠아테크 R&D연구소, Aquatech Co.) | Han Lae Kim
• 장순웅(경기대학교 환경에너지공학과, Research & Development Cent, Department of Environmental Energy Engineering, Kyonggi University) | Soon Woong Chang Corresponding author