Incineration

 

               Another popular method of waste removal that has been present since humans discovered the applications of fire, and that’s incineration. Incineration is the act of destroying trash and waste by burning. One of the first incinerators was built in Manhattan in 1905 in response to the large amount of trash that was building up in the streets. The incinerator basically consisted of a large brick chamber that was filled with trash then burned. The heat was recycled to burn more trash. Incinerators gained popularity and spread to about 200 burners around the country by 1960. Additionally, many people burned their own trash in their backyards, and this is a practice is still used today.

                Today, incinerators are more advanced and include much higher forms of technology. In municipal incinerators, waste from residential and commercial sources are brought to the plant and burned in a combustion chamber. Trash is burned at temperatures above 850˚C, and its products come in 4 forms. Some leftover solids are scrap metal and can be used as such, the rest of the solid waste is called bottom ash. Some of this ash is made of small metal fractions and can be repurposed into steel and other metals. The rest of the ash is nonhazardous and is often used for other purposes, such as an ingredient in concrete. The second byproduct is toxic gas like carbon dioxide, nitrogen oxides, and other gasses. These are “cleaned” in a variety of ways, then released. An additional solid waste of the process is fly ash which is burned material that is too light to fall to the bottom, but flies in the air. This product is considered hazardous and must be taken to a hazardous waste facility. Finally, the last byproduct of incineration is the generation of heat and energy. This expelled energy is often used to generate electricity for the plant or for the community.

                Incineration has become a very important topic of interest recently because of its many different advantages and disadvantages. Some of the advantages of incineration include space conservation and energy generation. Incinerators save space by not requiring lots of space for a landfill. Also, the generation of energy is a very important factor in today’s time when energy is becoming a prominent issue. Additionally, there are some large disadvantages to incinerators as well. First, they are rather expensive to build and to maintain, at least more expensive than a landfill. Also, the release of dangerous gasses expelled from the burning is very harmful to the environment. These gases can harm the atmosphere and contribute to global warming.

                Stay Sustainable,

                Shelby

Sources:

http://www.wrfound.org.uk/articles/incineration.html

http://www.dublinwastetoenergy.ie/uploads/archive/html/how_incinerator_works.html

http://greengarageblog.org/8-pros-and-cons-of-incineration

Landfills

                For my first post, I will be discussing one of the most common forms of waste management in the world, the collection of trash in landfills. Ever since the 1800s, people in cities had the habit of disposing of trash by throwing it out their windows. Once medical knowledge advanced, the correlation between the presence of trash in the streets and the spread of deadly diseases. By the late 1800s, many cities gathered trash in horse drawn carriages and disposed of it in dumps or even in the sea. The first modern landfill was developed in 1935 and it consisted of a hole that trash was dumped in and periodically covered in dirt. Then, by 1959, the American Society of Civil Engineers set the standards for a sanitary landfill.

                Nowadays, there are strict regulations on the composition and location of landfills. Sanitary landfills must be lined with multiple layers of organic and inorganic substances. The top layer is just a layer of soil to serve as a base for the garbage, then a geotextile layer that filters out large pieces of trash, then some filtering gravel with a plastic layer that collects all water and hazardous materials. Finally, a layer of clay lines the bottom to collect any contaminated water that has seeped through the other layers. These layers of protection are very important to the prevention of hazardous materials leaching into ground water and polluting drinking water sources. Additionally, landfills cannot be placed in areas that could allow damage to occur, such as a wetland, a floodplain, or on a fault zone. Landfills are often not placed near neighborhoods or suburbs because many people do not want the smell or the possibility of groundwater contamination.

                Like any system, there are pros and cons to sanitary landfills. Landfills are one of the cheapest options for waste management because they do not require to transport of materials to places very far away. Additionally, they are one of the safest methods when taking worker safety into consideration. There is little to no risk of harm on workers in landfills like there is in other waste management situations like incinerators. Conversely, there are many problems with landfills. They take up lots of space and change the land cover of an area. There is also the potential of ground and surface water contamination if the linings in the landfill fail. One of the largest downfalls is that they produce a lot of methane gas into the atmosphere. When wastes breakdown, they produce methane which is flammable and can cause problems if ingested. Also, methane is a very potent greenhouse gas that contributes to global warming and ozone destruction.

Stay Sustainable,
     Shelby



Sources:

http://greenrisks.blogspot.com/2011/07/landfills-history.html

https://www.teachengineering.org/lessons/view/cub_enveng_lesson05

http://earthuntouched.com/pros-cons-landfills/