Utilization of wastewater for corrosion prevention of carbon steel pipe using single chamber microbial fuel cells

Abstract

This study applies a concept Microbial Fuel Cells (MFCs) in a biological cathodic protection (CP) system. The biological CP uses the microbial properties of living microorganisms which are able to produce electrons and suffice the requirement for CP in corrosion prevention system. The electrons produce by the bacteria will be diffuse and transfer to the surface area of graphite which is use as anode. The objective of MFCs for CP is to achieve an optimum value of electro potential produce by bacteria inoculated in MFCs system as preventive measures against corrosion occurred in commonly used carbon steel pipeline. The purpose of the study is to identify the wastewater derived from industry, estuary and dairy farm animal that can give the nearest optimum value of -850 mV for CP. Prior to the objective, three different types of waste is choose as samples in this study which are palm oil mill effluent (POME), estuary water and goat’s feces. Wastewater such as POME and estuary water is stored in a freezer at the temperature below 4oC. Meanwhile goat’s feces is soak in distill water for 24 hours before it is place in a freezer. After the collection of wastewater, a proximity analysis such as pH, conductivity, salinity, COD and TSS is conducted to determine the quality of the wastewater. The 4 liter of wastewater is place in a rig and 40g of sodium acetate as substrate is mix so that it will act as medium for bacteria growth in a single chamber MFCs. The backfilling for the experiment is sand with sand to wastewater is 2L and 4L respectively. The anode (graphite) will undergoes treatment to remove contamination by soaking it in a 100% ethanol for 30 minutes and then soak in 1.0 M HCl for one hour. The electro potential reading is record periodically in hourly basis using electrical multi meter for each source of wastewater and correspondent current density and power density will be determined. In the experiment, three samples is used to represents the population of each type of wastewater in order to have accurate reading and more reliable results during analysis. A statistical analysis is use for the purpose of fulfilling the objective of the study. The result of study shows that wastewater from goat’s feces gives the lowest rate of corrosion which is 1.18 x 10-6 kg/h and followed by estuary water and palm oil mill effluent of 4 x 10-6 kg/h and 7.18 x 10-6 kg/h respectively. It is also found that the wastewater from goat’s feces achieved the highest mean negative potential of -578.07 mV while standard cathodic protection is -850 mV.