Cause investigation of functional disorder for sewage treatment DHS reactor in developing country

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H07318
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Environmental engineering and reduction of environmental burden
• Research Institution: Ube National College of Technology
• Principal Investigator: Nomoto Naoki 宇部工業高等専門学校, 物質工学科, 助教 (70802916)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 下水処理 / DHS / 開発途上国

Outline of Final Research Achievements

It is investigated cause of functional disorder for sewage treatment DHS reactor in India. Experimental validations were carried out for two possibilities, first, deterioration of hydraulic retention time for clogging of sponge media since clayey (kaolin) in sewage, second, decline of microbial activity since accumulation of heavy metal from sewage. For first, two systems which are sewage in kaolin 200 mg/L and just sewage were prepared and examined for sewage treatment with DHS reactor. As a result, each BOD removal ratios were 56.9% and 62.6%, hence, it decreased for kaolin addition system. For second, biodegradability tests were conducted to evaluate effect of heavy metal for microbial activity. Consequently, COD removal ratios of heavy metal addition system and control systems were 91% and 51%, respectively. Therefore, added heavy metal caused decline of organic removal performance.

Free Research Field

環境

Academic Significance and Societal Importance of the Research Achievements

インドの試験において、粘土質が流入した要因は、前処理設備の整備不良である。本研究の成果より、前処理設備を定期的に整備し、蓄積した汚泥を除去することの重要性が示された。重金属については、恒常的に高濃度で流入していたわけではないものの、一時的な高濃度の流入、または低濃度の連続的な流入により保持汚泥内に蓄積したと考えられる。開発途上国では、産業排水処理が十分に行われておらす、下水中に重金属が流入する可能性がある。本研究の成果より、開発途上国において下水処理設備を設計する際は、最大3割程度の有機物除去性能の低下が生じる可能性を考慮する必要があることが示唆された。