Development of a nitrogen removal process using simultaneous anammox and denitrification from domestic wastewater

2020 Fiscal Year Final Research Report

• Project/Area Number: 17H01897
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Ritsumeikan University
• Principal Investigator: Soda Satoshi 立命館大学, 理工学部, 教授 (30322176)
• Co-Investigator(Kenkyū-buntansha): 井坂 和一 東洋大学, 理工学部, 准教授 (40543939) ; 黒田 真史 大阪大学, 工学研究科, 助教 (20511786) ; 池 道彦 大阪大学, 工学研究科, 教授 (40222856)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 窒素除去 / アナモックス / 従属栄養脱窒 / C/N比 / 常温

Outline of Final Research Achievements

This study investigated nitrogen removal by the simultaneous anaerobic ammonium oxidation (anammox) and heterotrophic denitrification (SAD) process in a lab-scale continuous reactor inoculated with immobilized activated sludge and immobilized anammox sludge at various organic carbon/nitrate (C/N) ratios. Synthetic wastewater containing nitrate 40 mg-N/L, ammonium 30 mg-N/L was fed to the reactor operated at 20 degree and at hydraulic retention time of 24h. Nitrite reduced from nitrate by heterotrophic denitrification was accumulated and removed with ammonium. The SAD process removed nitrate and ammonium effectively (T-N removal, 40-60%) by the high anammox contribution under low C/N ratios (0.5-1.0). At high C/N ratios of 1.0-1.75, the SAD process maintained T-N removal 40-90% with predominance of heterotrophic denitrification. Results demonstrated that the SAD process performs high nitrogen removal effectively from wastewater at ambient temperature with widely different C/N ratios.

Free Research Field

環境工学

Academic Significance and Societal Importance of the Research Achievements

日本には、都市下水処理場が既に2100ヶ所以上あるものの、大半が窒素除去能力は不十分であり、建設費からしても、新設は容易ではない。SADプロセスは、循環式硝化脱窒プロセス（約30）、嫌気無酸素好気プロセス（約40）、ステップ流入式多段硝化脱窒プロセス（約25）に加え回分式プロセス（約70）を経済的で高性能な窒素除去プロセスにアップグレーディングできる可能性がある。標準活性汚泥プロセス（約600）も窒素除去型に更新する必要がある。本研究成果より、脱窒槽に必要なAnammox汚泥量、冬季における無加温の限界温度、ステップ流入比の運転条件などが推測できる。