Physico-chemical and Microbiological Characteristics of a River Mud as substrate for Biological Generation of Electricity in the Niger Delta, Nigeria

Aim: This study investigates the physico-chemical and microbiological characteristics of a river mud (sediments) as substrates for biological generation of electricity.

Study Design: The study employed standard microbiological and physio-chemical experimental design and data interpretation.

Place and Duration of Study: Otamiri River, Etche Local Government Area of Rivers State, April to December, 2017.

Methodology: River sediments were collected from three different sampling stations at Otamiri River in Isu (E-510627.84; N-131566.60), Odagwa (E-520087.04; N-113278.48) and Imo River in Umuebulu (E-521113.64; N-112436.74) in Etche Local Government Area of Rivers State, Nigeria. The samples from these stations were analysed using standard analytical methods.

Results: The results obtained show that the sediment had its particle size ranged from sand to silt and are porous. The pH of the sediments were acidic across the sampling points with the values ranging between 6.03 to 6.24, while conductivity values ranged from 53 to 75.4uS/cm. Nitrate content of the sediment ranged from 4.3 to 5.9mg/kg. The presence of organic content, phosphate, sulphate and total hydrocarbon were also recorded in good quantities. Microbial counts in sediment samples were carried out for both rainy and dry seasons. The results showed that the Total heterotrophic bacterial count from sediment samples from Otamiri at Isu River had more counts with 4.8x106 colony forming units per gram of the sample while Odagwa River had 2.9x106 cfu/g and Imo River had 2.2x106 cfu/g during the rainy season. Fungal count was also higher at Isu River with 6.8x105 cfu/g while Imo had the least count with 4.3x105 cfu/g. Similar trend was observed in the dry season for all stations with Isu River recording the highest with 3.8x105 cfu/g; Odagwa River had 3.2x105 cfu/g while Imo River had 2.2x105 cfu/g. Fungal count for dry season was similar with Isu River having the highest count while the Imo River at Umuebulu River recorded the least count in the sediment mud samples. The results of the microbial counts obtained shows that river mud (sediments) support microbial growth and can be used as a substrate to support microorganisms as biocatalysts for the conversion of organic and inorganic materials for alternative energy production. This is possible if the microorganisms in the sediments metabolise or convert the bio-wastes (organic and inorganic materials) to produce electrical energy. This trend can promote economic growth for domestic use and industrialisation to attain energy security and promote sustainable development.

Conclusion: It is concluded that the sediments can serve as substrates to support microorganisms as biocatalysts for the conversion of organic and inorganic materials to generate electricity if the microbial fuel cell technology is employed. This is because the results show that the physicochemical properties of the sediments and microbial populations found in the substrates can elicit adequate reactions to stimulate the production of alternative energy for electricity in this process.