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EEtWaste streams such as wet waste, solid waste, and gaseous waste have the potential to be valuable resources for the production of biofuels, bioproducts, heat, and electricity in the domestic market. These waste streams can be used as feedstocks for the creation of renewable fuels and products, and utilizing them can help solve waste disposal problems.

As these resources are not likely to decrease in volume shortly, they may provide a low-cost option for feedstocks that can justify the wider investment. The U.S. Department of Energy’s Bioenergy Technologies is interested in the transformation of waste into energy for certain waste streams including:

  • The excess food that is generated by commercial, institutional, and residential sources, particularly those that are typically disposed of in landfills.
  • The organic-rich liquid streams and sludges are produced as a result of municipal wastewater treatment processes, such as biosolids.
  • The slurry of manure that is produced by concentrated livestock operations.
  • The organic materials that are generated as a result of industrial processes, such as food and beverage manufacturing, biodiesel production, and integrated biorefineries, as well as industries like pulp and paper, forest products, and pharmaceuticals.
  • Biogas is produced by utilizing any of the previously mentioned feedstock streams, such as landfill gas.

What Is Waste to Energy?


Photo Credit IASGyan

Waste to Energy (WTE) is a growing phenomenon which involves the conversion of non-recyclable waste into energy. This process is used around the world to create electricity, heat and biogas from waste materials. It’s an important part of our global energy mix, as it allows us to reduce emissions and produce energy from resources that may otherwise be wasted.

In its simplest form, WtE is a process where trash is used as a fuel source. During this process, trash such as paper, cardboard, plastic bottles and food scraps are combusted into electricity or heat. The heat from combustion can then be used to generate steam to drive turbines which produce electricity.

This electricity can then be fed into the electrical grid and used by consumers for their daily needs. Not only does it provide an alternative power source but it also cuts down on landfill waste by using up materials that would otherwise just sit around taking up space in landfills or worse – pollute our environment.

How to Turn Waste Into Energy?


Video by Studentenergy.org

The waste-to-energy process collects the heat from combustion, which can be used to heat water, produce steam, or turn a steam-powered turbine to produce electricity. The energy produced can be exported to surrounding enterprises or the local utility, or it can be used directly by the plant itself.

Waste to Energy Pros and Cons

Pros:

Pros  Explanation
Better than traditional incineration WTE technology has improved over time and is now considered a more environmentally friendly option than traditional incineration.
Avoids Landfilling WTE reduces the amount of waste that is sent to landfills, which can help to reduce greenhouse gas emissions and minimize the negative impacts of landfills on the environment.
Resource Recovery WTE can recover valuable resources from waste, such as metals and other materials that can be recycled. This can help to conserve natural resources and reduce the demand for new materials.

Cons:

Cons  Explanation
High CO2 emissions WTE facilities can produce high levels of CO2 emissions, which can contribute to climate change.
Potential to Destroy Recoverable Materials WTE processes can destroy some materials that could be recovered through recycling, such as glass or certain types of plastics.
Could Disincentivize Recycling If Waste-to-energy is used as an alternative to recycling, it could reduce the incentive to recycle and conserve natural resources.
Fuels an Unregulated Waste Trade WTE facilities often rely on importing waste from other countries, which can fuel an unregulated and potentially harmful waste trade.

Waste-to-energy Systems

Thermal Technologies for Waste-to-Energy

  1. Incineration

    The utilization of waste incineration as a means of disposal can be traced back to 1885 when the first such facility was established on Governors Island in New York City. By the mid-20th century, a significant number of these types of incinerators were in operation across the United States, however, at that time, little was known about their impact on the environment.

    The Clean Air Act of 1970 mandated that these incinerators either implement technology to address concerns such as particulate matter emissions or shut down. Additionally, the EPA’s Maximum Achievable Control Technology regulations in the 1990s mandated further control of emissions such as mercury and dioxin.

    Incineration as a method of waste disposal has several significant environmental drawbacks. Combustion of waste generates greenhouse gas emissions and particulate matter, and the ash residue can contain harmful toxins. Due to these issues, companies proposing to build new incineration facilities will likely face significant opposition.

    Fortunately, there are many more sustainable options available. One drawback of incineration is that it precludes the possibility of recycling, as the materials are destroyed in the process. However, a newer approach called refuse-derived fuel addresses this issue by sorting recyclable materials and non-combustible materials before burning the remaining waste.

  2. Gasification

    Waste-to-energy technology utilizes waste as a raw material, rather than as a source of fuel. Any gases produced through this process are considered valuable byproducts rather than emissions. These gases can be harnessed to power the system itself.

    Gasification is a method of converting waste materials, such as non-recyclable plastics, into syngas through the application of high temperatures (between 1,000-2,800º Fahrenheit). It results in significantly less pollution than traditional incineration methods. The resulting syngas can be utilized as fuel for transportation or as an alternative to natural gas, and also for producing fertilizers.

    Similar to refuse-derived fuel, it is important to take care with the sorting and pre-processing of materials before gasification in order to remove any items that would not be suitable for the process.

  3. Plasma Gasification

    A newer Waste-to-energy technique, known as plasma gasification, employs even higher temperatures to convert waste into useful materials. In this process, an inert gas is passed through an electrical arc, vaporizing all organic waste and forming hydrogen, carbon monoxide, and other useful gases, without producing any air pollution. The remaining inorganic waste, including heavy metals, cools and solidifies into a glass-like material which can be used as a construction aggregate or other building material.

    Plasma gasification has been utilized to safely destroy chemical weapons and other hazardous materials, and it leaves behind no toxic residue. However, it is currently too costly to be widely implemented for the treatment of regular waste on a large scale.

  4. Pyrolysis

    Pyrolysis, a process that subjects organic material to high heat in the absence of oxygen, has been widely used in the chemical industry. However, it is only recently that it has been gaining recognition as a Waste-to-energy technology. By utilizing various feedstocks such as biomass, plastics, and old tires, the process converts complex molecules into smaller ones. Utilizing various catalysts can improve the efficiency of pyrolysis.

    The end product of this process includes a solid residue called biochar, a liquid similar to crude oil. Biochar has a number of uses, including serving as a compost feedstock, a water filtration medium, and for the sanitation of biowastes. The pyrolysis oil, after undergoing additional treatment, can even serve as a replacement for crude oil. The gases remain in the chamber until they are removed for use, preventing the release of potent greenhouse gases into the atmosphere.

  5. Hydrothermal Carbonization

    Thermal technologies have become increasingly popular for efficient Waste-to-energy conversion, and one of the most promising options is hydrothermal carbonization (HTC). The process utilizes a significantly lower temperature, around 400º Fahrenheit, in comparison to other gasification techniques.

    Additionally, it necessitates feedstock with a high moisture content, making food waste an ideal candidate. The outcome of the process is solid resembling coal, called hydrochar, which can be used as a fuel source or left untouched to sequester carbon. The only byproduct of this method is non-toxic water, and it also boasts the lowest emissions of greenhouse gases among similar Waste-to-energy technologies.

Biochemical Technologies for Waste-to-Energy

  1. Anaerobic Digestion

    Anaerobic digestion is a powerful biological process that harnesses the natural abilities of microorganisms to convert biomass into a usable energy source. By breaking down organic materials in an oxygen-free environment, these microorganisms produce biogas that is rich in methane.

    This biogas can then be captured and used as a fuel for a variety of applications, including the generation of electricity and heat, or even as a fuel for transportation. This process not only provides a sustainable source of energy but also helps to reduce waste and environmental impact by repurposing it into a valuable resource.

  2. Dendro Liquid Energy

    Dendro Liquid Energy is a biotechnology that converts wood waste into liquid biofuels. The process begins by breaking down the wood into a pulp, which is then fermented using microorganisms to produce ethanol, a liquid biofuel. Ethanol can be used as fuel for vehicles, industrial boilers and power generators.

    This technology has the potential to significantly reduce greenhouse gas emissions and dependence on fossil fuels by using renewable resources. Additionally, it can also help to reduce the amount of wood waste that ends up in landfills and decrease the cost of waste disposal. It is worth noting that the specific details of Dendro Liquid Energy would vary based on the company or research group implementing the technology.

Is Waste to Energy Renewable?

The energy produced by waste-to-energy is considered to be somewhat renewable because the garbage handled in WtE plants is partially biogenic, or simply biomass.

Are Waste-to-energy Plants Good?

It is evident that Waste-to-energy only has advantages when compared to traditional waste disposal methods such as landfilling or burning. However, when evaluated on its own merits, WtE poses several fundamental issues that make it a questionable solution for a sustainable, circular economy. In a time when the focus is on achieving zero waste, Waste-to-energy is not a viable option. Alternatives do exist that address some of the concerns associated with Waste-to-energy, but these options still fall short of the ultimate goal of reducing, reusing, and recycling materials.

Conclusion

In every business, waste management is quickly becoming a necessary component. Additionally, all businesses—especially those in the manufacturing industry—should implement a proactive strategy for waste reduction. The measures mentioned above can assist you in following the law as best you can because industrial waste management is subject to a number of regulations and limitations.