Development of Anaerobic Co-digestion of Rural Sewage Sludge and Food Waste Considering Environmental Risk of Pharmaceuticals and Personal Care Products (PPCPs)

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06305
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 41030:Rural environmental engineering and planning-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: NAKAMURA MASATO 国立研究開発法人農業・食品産業技術総合研究機構, 農村工学研究部門, 上級研究員 (60414463)
• Co-Investigator(Kenkyū-buntansha): 治多 伸介 愛媛大学, 農学研究科, 教授 (60218659)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 農業集落排水施設 / 汚泥 / 作物残渣 / C/N比 / 医薬品

Outline of Final Research Achievements

In this study, stable condition of anaerobic co-digestion of rural sewage sludge and food wastes and the degradation characteristics of pharmaceuticals and personal care products (PPCPs) during anaerobic digestion and the use of digestate as fertilizer were investigated. The results indicated that the pH and gas production rate gradually dropped, indicating process failure when co-digestion of rural sewage sludge and food waste with a C/N ratio higher than that of kitchen garbage. When urea was added to the feedstock material as nitrogen source, digestion proceeded stably. The addition of urea not only improves the stability of digestion, but also improves the fertilizer value of the digestate. Regarding the decomposition characteristics of PPCPs, it was clarified that the decomposition of PPCPs is likely to proceed under thermophilic digestion condition and in the process of storing digestate.

Free Research Field

地域環境工学

Academic Significance and Societal Importance of the Research Achievements

集排汚泥と食品廃棄物等の混合メタン発酵は、廃棄物から再生可能エネルギー源であるメタンを取り出せ、消化液（発酵残渣）を肥料として利用できる、農村地域に適した技術である。農村で発生する廃棄物を幅広く活用することが望ましいが、C/N比の高い食品廃棄物を原料とすると、発酵不良を引き起こす可能性があった。それに対して、本研究では、原料に尿素を添加することにより、発酵不良を起こさず、肥料利用に適する消化液が得られる条件を明らかにできた。また、メタン発酵及び消化液の液肥利用過程での医薬品の分解特性を把握できたことは、より安全・安心な消化液の肥料利用の推進につながる。