Source of risk substances for domestic sewage flowing into separate WWTP

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04408
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Hiroshima University
• Principal Investigator: OZAKI Noriatsu 広島大学, 先進理工系科学研究科(工), 准教授 (50294541)
• Co-Investigator(Kenkyū-buntansha): 金田一 智規 広島大学, 先進理工系科学研究科(工), 准教授 (10379901)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 下水処理場 / 生物検定 / 余剰汚泥 / コンポスト / リスク

Outline of Final Research Achievements

The purpose of this study is to know the source of the toxicity by bioassay of sewage flowing into the separate sewer. By the comparison comparison through the treatment process, it became clear that the cause of the difference was not the inflow in rainy weather, nor was it from the lifestyle. In other words, there was no big difference in the inflow toxic load of the living system at any of the treatment plants. Therefore, when the difference in the treatment process for each treatment plant was examined, it was found that there was a difference in the operation of the settling basin at the place where the toxicity was high and the place where the toxicity was low. A detailed examination showed that the toxic load of solids generated from the first settling tank may have increased the final load of excess sludge.

Free Research Field

水環境工学

Academic Significance and Societal Importance of the Research Achievements

本研究の意義は生活排水に起因する下水汚泥の緑農地還元というかたちでの再利用におけるリスク因子を特定したことである。生活排水は下水処理過程において適切に処理され再利用汚泥としてもそのリスクは大きく低減される。一方最初沈殿池において沈殿した，生物反応プロセスを経ていない固形成分はその生物検定値が低減しない結果として，重量あたりのリスクは大幅に異なる点を指摘したことがその学術的・社会的意義となる。