In the US, most of the human waste that is flushed down is generated in the form of sludge is utilized as fertilizers on farmlands and vegetable gardens. When you think of it, recycling human waste is the best method of obtaining renewable energy, human waste being an inevitable byproduct of the society. However, the problem with using sludge as fertilizer is that sludge may be composed of everything that probably goes down the drain, ranging from medicines that are flushed down to the oil released from factory outlets. This explains why many cities have started looking for a substitute to discard sludge, and they have come up with complex poop-to-power plants. According to statistics, the daily sludge output of one American is sufficient to generate electricity to light a 60-watt bulb for more than 9 hours. Given below is a list of 5 innovative ways to convert human waste to watts:
- Turd Cell Smashers
When the cell walls in sludge are destroyed, its capacity to produce methane is increased by 50% or even more in case of anaerobic digesters. The cell walls can be destroyed either by heating the sludge under pressure, pulsing it with electric fields, or zapping it with ultrasonic waves. The disadvantage of this method is that it has been found by the scientists that many of such processes can set free horrible stench and even release a “chemical attack” on the sewage machinery.
- Poop-Eating Bacteria
Digesters like brewery casks accommodate anaerobic bacteria that consume sludge and give out methane in return. This is the cheapest, oldest and the most efficient poop-to-power method of technology as of now. However, despite its efficiency, less than 10% of the 6,000 public wastewater plants in the U.S. have these digesters. Moreover, out of these 10%, only about 20% burn and utilize the methane gas for energy. Several cities make use of methane gas to run most of the city buses. The demerit of the anaerobic digesters is that they can only decrease the volume of the sludge by half and only confine a part of its implanted energy.
- Geological Toilets
A few summers ago, Los Angeles started an initiative to convert sludge into power. They poured sludge into a deep well, where the pressure and heat in the well would make it release adequate methane to power up around 1,000 homes. Furthermore, the well also suspends and confiscates carbon dioxide that the sludge usually releases, thus removing the comparable exhaust of about 1,000 cars per annum. This project, among other renewable energy projects implemented that year was suggested to save money as well as to make money.
- Feces Ponds
Around fifty waste plants in twenty nations have chosen a cheaper green alternative by installing different versions of Advanced Integrated Wastewater Pond Systems Technology introduced by a professor from UC Berkeley, Prof. William J. Oswald. These are huge open-air ponds that principally depend on photosynthesis and anaerobic digestion to collapse sludge and change it into a fertilizer or even as food for the nitrogen-rich algae. These algae can also be used as a feedstock for biofuels in return. But the disadvantage of this system, as discovered by the environmental scientist Mr. Rich Brown, is that while it may work in the rural areas, but it will not be a feasible option in the big cities like San Francisco.
Throughout Germany and Europe, sludge gasification plants are not news; they are quite popular in these areas, particularly in Germany. A reaction of low-oxygen alters the solid matter in sludge into a carbon-rich material called “char”, which is comparable to BBQ briquettes. After this, the char is gasified in the presence of air to produce a syngas which can be burned to get energy.