Michael Fontaine is VP of project management for Falcon Project Consultants. Fontaine can be reached at 713.425.6497.
What is Biogas?
Biogas is a type of biofuel that is naturally produced from the decomposition of organic waste. When organic matter, such as dead animals and animal fecal matter, breaks down in an anaerobic environment (an environment absent of oxygen) they discharge a blend of gases, primarily methane and carbon dioxide. Because this decomposition happens in an anaerobic environment, the process of producing biogas is also known as anaerobic digestion.
Anaerobic digestion is a natural form of waste-to-energy that uses the process of fermentation to break down organic matter. Animal manure, dead animals, wastewater and sewage are all examples of organic matter that can produce biogas by anaerobic digestion. Due to the high content of methane in biogas (typically 50 to 75%) biogas is flammable, and therefore produces a deep blue flame, and can be essentially free energy.
The Science of Biogas
Biogas is celebrated as an environmentally-friendly energy source because it alleviates two major environmental difficulties simultaneously:
- Toxic methane gas released into the environment daily; and
- Dependence on fossil fuel energy to meet global energy demand.
By converting agricultural waste into energy, biogas utilizes nature’s ability to recycle substances into valuable resources. Biogas generation recovers agricultural waste materials that would otherwise pollute landfills; prevents the use of toxic chemicals in sewage treatment plants, and saves money, energy, and material by treating waste on-site. Moreover, biogas usage does not require fossil fuel extraction to produce energy.
Instead, biogas takes a problematic gas and converts it into a much safer form. More specifically, the methane content present in decomposing waste is converted into carbon dioxide. Methane gas has approximately 20 to 30 times the heat-trapping capabilities of carbon dioxide. This means that when agricultural waste converts into biogas, the environmental impact will be about 10 times less potent than if it was left to rot in a landfill.
The History of Biogas
This anaerobic process of decomposition (or fermentation) of organic matter occurs throughout nature. The bacteria that break down organic material into biogas are some of the oldest multi-celled organisms on the planet. Human use of biogas can be traced to the Assyrians in the 10th century and the Persians in the 16th century. More recently, the 20th century has brought about a renaissance of both industrial and agricultural biogas systems.
In the 18th century, it became clear to Flemish chemist Jan Baptise van Helmont that decomposing organic matter produced a combustible gas. Later on, John Dalton and Humphrey Davy clarified that this flammable gas was indeed methane. The first major anaerobic digestion plant dates back to 1859 in Bombay. Later, in 1898, the UK utilized anaerobic digestion to convert sewage into biogas, which was used to light street lamps. For the next century, anaerobic digestion was primarily used as a means to treat municipal wastewater. When the price of fossil fuels increased in the 1970’s industrial and agricultural anaerobic digestion plants increased in popularity and efficiency.
India and China developed small-scale biogas digesters for agricultural applications in the 1960s to decrease energy poverty in rural areas, and generate cleaner cooking fuels that would have accessibility in remote areas. Nearly one-third of the global population relies on firewood and other biomass for energy, leading to devastating health and environmental problems.
Farm-sized biogas units are gaining more attention and popularity as both a means of reducing agricultural waste and as a means of providing clean renewable energy to families throughout the world. Broader adoption of biogas programs to make both agricultural biogas systems and industrial-scale anaerobic digestion plants accessible, efficient and convenient. As landfills become overloaded, and as the release of methane poses more troubling problems, the benefits of using biogas systems to convert waste into energy are increasingly more relevant and important.
Uses of Biogas
Biogas can be produced with various types of organic and agricultural matter, and therefore there are several types of models for biogas digesters. Some industrial systems are designed to treat: municipal wastewater, industrial wastewater, municipal solid waste and agricultural waste. Biogas systems are used for digesting animal waste and food waste and can be used to generate gas, electricity, heat and transportation fuels.
One example of biogas is the first milk plant, one of the UK’s biggest cheesemakers is building an anaerobic digestion plant that will process dairy residues and convert them into bio-methane for the gas grid.
Need for Regular Sludge Handling
- High operating costs (Electricity and Chemical Dosing) – regular chemical dosing can increase storage costs and adversely impact safety.
- High cost of turning wastewater to recycle quality.
- High cost of capital acquisition — electro-mechanical parts increase capital costs and maintenance costs.
- Complex and high cost of equipment maintenance — maintenance and replacement of large and expensive electromechanical parts. Non-modular systems require the entire system to be shut down.
- High labor cost — Numerous workers are required in the daily operation of traditional wastewater systems.
- Large space requirements (tankage and real estate) — large space and tank requirements are needed and often new tanks are required which strain real estate and budgets.
- Fats, oil and grease are not digested — fat and oil digesting enzymes are often an added cost.
How Biological Water Treatment Can be Used in Agricultural Biogas Applications
Agricultural practitioners can reap the benefits of Biogas technology and eliminate the traditional problems of wastewater by leveraging modern biological wastewater treatment technology.
Modern biological wastewater treatment solutions use safe, patented, government-approved technologies that eliminate the traditional water treatment problems associated with agricultural water recycling.
Modern technologies have zero discharge, meaning that operators do not have to worry about emitting harmful methane gas into the atmosphere. Furthermore, modern biogas wastewater solutions can also offer low maintenance costs, no chlorination, no impacted soil, no odor and no sludge handling, which significantly decreases capital and operational expenses and leads to greater profitability.
