DEVELOPMENT OF WASTEWTER TREATMENT TECHNOLOGY WITH POWER GENERATION IN SEWER PIPELINE FOR AN APPLICATION TO THE PACIFIC ATOLL NATIONS

Abstract

 In low-lying Pacific atoll nations, the fundamental processes of formation and maintenance of coral reef islands are being destroyed due to anthropogenic factors such as domestic wastewater discharge as well as global ones. The aim of the present study was to develop wastewater treatment technology with power generation in sewer pipeline. The sewer-typed microbial fuel cell (MFC) had two stractual features: i) an anode was placed along with inside of the pipeline; ii) a cathode was able to receive H+ provided from HCl to avoid rate-determining cathodic reactions. A lab-scale sewer-typed MFC demonstrated an organic matter removal rate of 8.0 mg-C L⁻¹ d⁻¹ and a maximum power density of 94 mW m⁻². However, the total internal resistance was 1.7 kΩ and the major contributors were identified as wastewater and anode. Thus, the improvement of these internal resistances will be key to enhance power generation in the sewer-typed MFC. A rough estimation showed that organic matter of ~25 % in domestic wastewater can be removed with a power generation of 4.7 kWh d⁻¹, when this MFC technique is applied to sewer pipe with ~14 km distributed in the urban area of Majuro atoll, the Marshall Islands.