The concept of using waste to generate energy is not new. Incineration, which generally entails burning municipal and industrial waste to produce heat, and power generators that produce electricity for distribution, has been around for years. Traditional methods are, however, extremely inefficient and typically emit high concentrations of harmful emissions and toxins into the atmosphere.
There are a number of new and exciting Waste-to-Energy technologies and solutions that make energy generation more efficient while lowering associated emissions. This means that we become less reliant on other waste management techniques that do considerable harm to the environment such as landfill and incineration while producing climate-friendly energy fuel sources.
The Environmental Impact of Waste Disposal
As our societies modernized through industrialization and as our populations have grown, the amount of waste we produce creates a large-scale impact on our environment. Poor waste management can result in the air, soils, and waters being polluted, along with litter issues, losses in biodiversity and explosions in weed and pest populations. Rain and wind can cause light waste materials to escape from landfills into to surrounding areas and interfere with the food chain with devastating effects on wildlife and even human health.
Industrial waste involves larger scale chemical and toxic material disposal which further adds to the complexities of waste management. As plastics and other materials break down, usually over vast amounts of time, they release chemicals and gasses into the surrounding soils and into the atmosphere, with some chemicals even making their way into water tables. The effects of unchecked industrial waste pollution are lasting and often irreversible.
New Approaches to Waste Management
Lifecycle thinking and analysis is a new approach to waste management. It involves evaluating how a product is consumed and what impact this has on the environment. When looking at any particular product’s lifecycle, you evaluate every step of its lifecycle from raw material extraction to processing, transportation, distribution, consumption, recycling, and right up to its eventual disposal. You would then look at the parts of the process where you can make environmental impact gains, particularly, re-use, recycling, and disposal. You then pick the most appropriate waste disposal methods that apply to the different types of waste.
Waste Processing Practices
The most common methods for waste disposal are dump sites, landfill, recycling and incineration, and each of these methods comes with its own set of challenges and shortcomings when meeting environmentally sustainable targets and goals:
- Landfill and dump sites need to be designed in such a way so as to minimize chemicals, gasses, and litter leaching into the surrounding environment.
- Recycling involves large-scale waste separation operations, be they urban or industrial. Storage and distributions of recyclable materials can be difficult to manage as there is often no consistency in the quality and quantity of each material you separate.
- As mentioned above, incineration is great for reducing the mass of materials, however, the process can be extremely toxic, particularly when plastics, paints and other synthetic materials are burned. Incineration can be used for energy production and heat distribution, but the efficiency of this technique generally varies from poor to insufficient and it involves unchecked pollutants entering the atmosphere.
Turning Waste into Energy
Waste-to-Energy solutions are seen as the most promising way to ease the use of landfills and incineration. Waste-to-Energy involves techniques that convert waste into a cleaner energy fuel sources. Various energy recovery techniques have evolved:
- Anaerobic Digestion — a biochemical conversion of organic material that goes through a fermentation process where enzymes break down and decompose organic materials. Depending on the organic matter, methane and alcohol can be captured during the decomposition process.
- Landfill Gas Recovery — various techniques that capture gases that are released from the slow decomposition of landfill. The main gas released is methane which can be used as a cooking gas or even in some types of engines and turbines.
- Gasification — a process of chemical decomposition of organic matter, such as coal waste and animal waste, that is exposed to heat and reduced oxygen. The molecules of the waste are broken down into gas which is known as producer gas, Biogas or Syngas. These gases can be readily used in turbine engines that produce electricity. The resultant clean gases can also be further processed for multiple other uses such as liquefaction into common liquid fuels for transport, electricity production, chemical conversion into hydrogen, methane and other chemicals used in industry.
Of all the techniques, gasification is proving to be one of the most promising for disposing of waste materials and capturing gases that can be used as fuel. It can make use of various types of waste material, also known as feedstock, such as municipal solid waste, oil residue and waste, petroleum coke, general biomass, refuse-derived fuel and coal waste.
The ability to use coal waste in the gasification process is creating a lot of enthusiasm for electricity generation projects in Africa where coal waste is abundant.
The Role of Carbon Mitigation
To produce Syngas and other clean-burning gases you will get CO2 as a byproduct, so a emissions mitigation solution is necessary for the technique to be 100% environmentally sustainable. Together, these solutions will play a significant role in the renewable energy economy.
Blockchain technology can be applied to create efficiency in markets where the exchange of Waste-to-Energy and other types of natural assets can flourish. This has a democratizing effect on the market and means that individuals and communities will no longer have to rely on industry giants to provide the solutions described above.