Phosphorus recovery and biogas production from sewage sludge using phosphorus adsorption membrane

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K13860
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22060:Environmental systems for civil engineering-related
• Research Institution: Hokkaido University (2019-2020); National Institute for Environmental Studies (2018)
• Principal Investigator: Hafuka Akira 北海道大学, 工学研究院, 助教 (30735353)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 資源回収 / 嫌気性消化 / メタン発酵 / 嫌気性膜分離 / 吸着剤 / 分離膜

Outline of Final Research Achievements

We developed a process which can produce biogas through anaerobic digestion and can recover phosphorus from sewage sludge by using phosphorus adsorbent or adsorbent-embedded membranes. The adsorbent-embedded membrane provided simultaneous solid-liquid separation and phosphorus recovery during continuous membrane filtration of digested sludge for 50 hours. Cross-flow filtration lead to mitigation of membrane fouling. The phosphorus-adsorption column was connected to an anaerobic membrane bioreactor and the reactor was continuously operated for three months. As a result, 14% of total phosphorus was dissolved to phosphate ion and 80% of the phosphate ion was recovered by the column.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

下水汚泥は国内において年間220万トン以上発生しており，産業廃棄物の約20％を占める．また，日本はリン資源のほぼ全量を輸入に頼っており，下水汚泥には輸入されたリン資源量の約20%が移行している．したがって下水汚泥の有効利用と汚泥からのリン回収は非常に重要である．本研究では下水汚泥を嫌気性消化することでメタンを含むバイオガスを得ると同時に，リン吸着膜またはリン吸着剤を用いてリン回収を行うプロセスを構築した．プロセスにおけるリン溶出率と回収率を明らかにし，長期間の連続運転を達成した．