4.1 Variation of current with time
Figure 2 illustrates that the variation of voltage with duration in the
laboratory experiment. It is seen that all the three marine sediments
showed the higher value of voltage than the river sediments. Sample 3
showed the peak voltage and reached at around 300mV after 1 week. Sample
1 and sample 2 showed the similar trend of voltage generation with
sample 3. The initial rate of voltage generation was higher as the
bacteria got ample of food during the early stage of laboratory
experiments. After reaching at the peak the voltage generation reduced
and almost constant for another 2 weeks. However, voltage generation was
always lower in the case of river sediment. Though the organic content
of the river sediment was little bit higher than the marin sediment, the
grain size of river sediment was larger and consequently affect the
voltage generation. The peak voltage generation in river sediment was
140 mV which was 60% lower than the sea sediments. The high electrical
conductive saline water of sea could be another reason for the higher
value of voltage in the sea sediment (Song and Jiang, 2018). The
external resistance used in this particular research was 100 Ω both in
the lab and the field. So, the peak power output from one cell is around
28 mW/m2 . Wang et al., 2014 showed that the voltage
generation can be great influenced by the organic content present in the
sediment. However, our results showed that the power generation was
always higher in the sea sediment instead of river sediment. The
particle size and the salinity affected the results more significantly
than the organic content of the sediment.