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Step 4Obtaining culture media
As I mentioned in the introduction this is not truly an algae based fuel cell. This fuel cell relies upon algae to provide biomass feedstock for the production of electricity, methane and CO2. The fuel cell itself is driven by bacteria adapted to live in sediment where no oxygen is found. These anaerobic bacteria can be obtained from several sources.
One of the recommendations from the folks at Penn State was to obtain some primary affuent (waste water) from the local water purification plant. But that was just too icky.
Anaerobic bacteria are also found in the benthic zone. According to Wikipedia:
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached to the bottom. The superficial layer of the soil lining the given body of water is an integral part of the benthic zone, as it influences greatly the biological activity which takes place there. Examples of contact soil layers include sand bottoms, rock outcrops, coral, and bay mud.
Therefore much like we obtained our algae culture from natural sources we will obtain culture amples from available natural resources.
So go to a local lake or creek, a swamp is good if you're lucky enough to have one. If you fish or you are have a friend who fishes ask them where the best catfish or suckers are to be found. Tell them you're looking for bottom feeders which indicates a rich organic base.
Basically you're going to wade into the water until you're pretty deep in bottom muck, optimally the water will cover the tube when it is buried to obtain the sample. Push or drive the tube into the bottom to a depth of at least 6" inches or more. If the tube is not fully submerged when the sample is taken fill it before inserting and "top it off" with lake, pond or running water take water from near the bottom if possible.
Tilt the pipe over and place a slip cap over the mud end. Top off the pipe with ambient water and place a slip cap over the other end. Keep the pipe closed until you are ready to use it ( step 7 I think ). The bacteria of interest are anaerobic which means we want to expose it to oxygen as LITTLE as possible.
Once again wikipedia provides:
Anaerobic is a technical word which literally means without air (where "air" is generally used to mean oxygen), as opposed to aerobic.
In wastewater treatment the absence of oxygen is indicated as anoxic; and anaerobic is used to indicate the absence of a common electron acceptor such as nitrate, sulfate or oxygen. An anaerobic adhesive is a bonding agent that does not cure in the presence of air.
Take each of the mason jars and scoop down deep in the bed, possibly scooping down several times. Fill each jar with deep mud. This should generally insure that you get a good healthy sample of bacteria along with sufficient additional material to create high quaility nutrient media.
Try to disturb the water and bed as little as possible fill the Mason jars with ambient water. This will capture trace elements which may be present and beneficial to our bacteria.
Leave everything alone until we're ready to use them.
So now we're going to make a salt bridge.
One of the recommendations from the folks at Penn State was to obtain some primary affuent (waste water) from the local water purification plant. But that was just too icky.
Anaerobic bacteria are also found in the benthic zone. According to Wikipedia:
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. They generally live in close relationship with the substrate bottom; many such organisms are permanently attached to the bottom. The superficial layer of the soil lining the given body of water is an integral part of the benthic zone, as it influences greatly the biological activity which takes place there. Examples of contact soil layers include sand bottoms, rock outcrops, coral, and bay mud.
Therefore much like we obtained our algae culture from natural sources we will obtain culture amples from available natural resources.
So go to a local lake or creek, a swamp is good if you're lucky enough to have one. If you fish or you are have a friend who fishes ask them where the best catfish or suckers are to be found. Tell them you're looking for bottom feeders which indicates a rich organic base.
Basically you're going to wade into the water until you're pretty deep in bottom muck, optimally the water will cover the tube when it is buried to obtain the sample. Push or drive the tube into the bottom to a depth of at least 6" inches or more. If the tube is not fully submerged when the sample is taken fill it before inserting and "top it off" with lake, pond or running water take water from near the bottom if possible.
Tilt the pipe over and place a slip cap over the mud end. Top off the pipe with ambient water and place a slip cap over the other end. Keep the pipe closed until you are ready to use it ( step 7 I think ). The bacteria of interest are anaerobic which means we want to expose it to oxygen as LITTLE as possible.
Once again wikipedia provides:
Anaerobic is a technical word which literally means without air (where "air" is generally used to mean oxygen), as opposed to aerobic.
In wastewater treatment the absence of oxygen is indicated as anoxic; and anaerobic is used to indicate the absence of a common electron acceptor such as nitrate, sulfate or oxygen. An anaerobic adhesive is a bonding agent that does not cure in the presence of air.
Take each of the mason jars and scoop down deep in the bed, possibly scooping down several times. Fill each jar with deep mud. This should generally insure that you get a good healthy sample of bacteria along with sufficient additional material to create high quaility nutrient media.
Try to disturb the water and bed as little as possible fill the Mason jars with ambient water. This will capture trace elements which may be present and beneficial to our bacteria.
Leave everything alone until we're ready to use them.
So now we're going to make a salt bridge.
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