Some bacteria form projections or 'fingers' when subjected to certain conditions and these bacteria are routinely used in waste water treatment to help form sludge blankets. What is the relationship between sediment particle size / constituency and bacterial i.d. and presence? Some sediment constituents, because of their structure, have electrostatic charges that can attract microbes with opposite cell surface charges. Is what you are documenting a symbiotic relationship? If so, it would seem that the limiting factor for 'bacterial electrical generation' is still the type and quantity of their food source. Tapping into their ability to create electrical charge may deplete their food source, kill them, and disrupt the ecosystem from which they originate. Any pragmatic thoughts on remediation?