Making energy with MUD?

Pool Art with biofuel cells.

The Water Lilies are a series of pools that sit on top of the Landfill without damaging it, a contained aquatic ecosystem that prevents species from conquering the thin dirt layer at the top of the Landfill and start breaking it. The ponds are 100m² inflatable plastic pools sitting on top of a series of stainless steel foam legs 1.1m high.

Each Water Lily is a network of Biofuel Cells. Each pool is full with semi-salty water and mud from the Hudson River, with all its different natural components (plants, critters, bacteria, soil, etc) acting as the engine. Each leg is a complete new revolutionary way to harvest electrons from the natural processes that take place in the pond.

HOW IT WORKS

Biofuel cells are a kind of reactors that can harness the energy of organic compounds by oxidizing them through electrochemical reactions. Organic compounds are oxidized at the anodes, thanks to special bacteria that can take electrons from the organic compounds and transfer them to the anodes. Locally, the bacteria use the anodes as electron sinks, in addition generating hydrogen ions (H+). The electrons are transported through an electrical circuit, generating electrical energy, until they reach the cathodes, where oxygen molecules receive the electrons. Besides the electrical current, a ionic current transporting hydrogen ions (H+) from the anodes to the cathodes delivers the hydrogen ions to the reduced oxygen molecules in order to form water.

In our design, the anodes consist of graphite felt sheets modified with graphene and conductive polymers such as polyaniline and covered by an elecro-active  biofilm of specialized bacteria such as Shewanella and Geobacter species. The addition of graphene to the graphite felt increases the active area and the electron transport properties of the anode, while the biofilm catalyses the oxidation of organic compounds. The cathodes will be air-breathing cathodes, with one face exposed to the air and another face exposed to wet mud. The cathodes will consist of stainless steel or graphite foam that will serve as a kind of filter, allowing oxygen from the air to diffuse into the biofuel cells and stopping the water from the fuel cells to escape through the cathodes. Both graphite and stainless steel have proved to work well as biofilm-catalyzed cathodes in microbial fuel cells. The cathodes’ surface facing the mud could also be modified with graphene and conductive polymers. A biofilm of bacteria that can catalyse the reduction of oxygen such as Winogradskyella poriferorum and Acinetobacter johsonii will cover the cathodes’ surface facing the mud in order to increase the biofuel cell power output.

The organic compounds will be generated by living organisms living inside the ponds…(plants, microorganisms, and small aquatic creatures)

HOW MUCH IT GENERATES

Each leg is 1m deep, 1m Long and 10cm wide and it generates 2w of constant power. Each 100m2 pond is sitting on approximately 700 legs, that are tightly packed in a computer-heat-sink configuration to allow the air to flow around freely (for the oxygen)

Each pond will generate around 1200 to 1400w depending of the shape.

Our proposal is to install 850 ponds in a computer board style configuration.

The proposal will generate 1.02MW

 

ENVIRONMENTAL FOOTPRINT

The project releases Zero gases, toxins, residues or anything the like, and it only needs water, mud and bacteria, all of them natural. It is a closed ecosystem, as much as a flower pot is. It has no moving parts, it generates no noise and it is harmless to all species.

The stainless steel legs are 100% recyclable, there is some technical complexity for building them, but otherwise are pure stainless steel. The fact that they are made of stainless steel FOAM also makes them extremely light and strong, so very little of actual steel  is needed and they are very light to transport.

The plastic pond and its colors are standard plastic that is light and well known, it can be produced with modern recycled plastics that have little impact to the environment

The Graphite anode is just standard graphite just like a pencil tip (in a bit more complex configuration but still graphite)

Apart from production transport and assembly, there is no maintenance needed, except perhaps a gardener to pick up the seasonal flowers.

We say it has a POSITIVE environmental impact because it will create habitat for local species in a new extra layer one meter above the landfill cap. It requires no maintenance and reduces a lot of the maintenance needed to keep the harmful species of plants off the park.

SCALABILITY

The project is really easy to configure, reconfigure, move around, etc.. We could keep putting more Water Lilies all over  if needed or wanted. Each pond is completely independent and can be done in any shape or size. If, for example, we made the legs 2m high, the Lilies would simply generate twice as much energy.