The conversion of raw materials into finished products takes a lot of energy. The US is on a quest to become energy independent. Part of making this possible lies in using the resources we have to the highest efficiency. Recycling is one of the major opportunities. The City of Columbus is making recycling a lot easier as the separate pickup on recyclables is now underway.
The major products to be recycled are aluminum, steel, glass, paper, and plastics. These products make up about 2/3 of the potential for recycling. Food wastes and sewage are not normally considered to be in the recyclable stream, but there is major potential in this area as well. The city is converting sewage and food wastes in the sewage stream into biogas, but the gas is not being used very effectively.
The energy required to turn bauxite into aluminum is a major part of the cost if making aluminum containers and other aluminum products. One of the reasons that Alcoa was sited in Tennessee and Kaiser Aluminum was sited in Washington State was that there is an abundance of relatively cheap hydroelectric power available. Using recycled cans and aluminum tubing instead of bauxite saves about 95% of the energy used to produce aluminum. Approximately two out of every three aluminum cans in the US gets recycled.
Common glass is produced by melting silica sand and borax at very high temperatures. Recycled glass melts at lower temperatures, which saves about 30% of the energy required to melt virgin raw materials. There is also a major reduction in emissions, which includes boron that is toxic to the environment. Glass is not achieving the same high rate of recycling found in aluminum. Using glass containers to store food and for use in microwaves is a lot healthier than using plastic if you aren’t recycling the glass containers.
Paper is another major opportunity for recycling. The common myth was that buried paper decomposes over time in landfills. This is not the case because the buried paper does not have the water and bacteria necessary to break down the paper. Paper as newsprint, corrugated boxes, office waste and food containers make up about 40% of the waste going to landfills. The overall average saving in energy from recycling all forms of paper is in the range of 35 to 40%. This does not count the energy used to bring the wood to the mills for pulping.
One of the largest potential areas for savings from increased recycling is in iron and steel. There was a time when garbage went through processing plants where the garbage was shredded and the iron and steel was extracted using magnets. The tendency today is to take the garbage directly to landfills. Using recycled steel to make up a significant part of steel batch materials saves nearly 75% of the energy of using iron ore, and cuts air pollution by 85%, water pollution by 75% and mining wastes by over 95% versus using raw iron ore.
Plastic materials used in packaging are now labeled as to the type of materials, e.g. polyethylene, polystyrene and PET have number designations for sorting. The savings in energy from using recycled plastics instead of plastics derived from oil and natural gas is 85%. The quantity of plastic being recycled versus thrown into trashcans and garbage bins is very low. The opportunity to reuse the plastic is great. Recycled plastics can be used for everything from pipe, carpet and construction.
Recycling programs like those in Columbus make it easy to separate the paper, plastic, glass, and steel from the food waste. The savings in energy, landfill space, and air and water pollution make this a civic duty.
It was mentioned above that recycling sewage and food waste is also available for recycling. Jackson Pike and Southerly are the two major sewage treatment plants for Columbus and the surrounding communities. Each day anaerobic digesters at these plants process human sewage and food waste run through garbage disposals into millions of cubic feet of biogas. This gas is used to incinerate the sludge that remains after the waste water is extracted. Using biogas is better than buying gas for incineration from Columbia Gas, but it could be put to better use.
There was a time when electricity was produced at Jackson Pike using the biogas. The electric plant was allowed to go into disrepair. It is still possible to rebuild this plant, and to add an electric plant at the larger Southerly facility. There are major cities in the US and abroad that use biogas to power the municipal transportation systems.
Overall, recycling is a win-win solution to reducing energy usage, reducing air and water pollution, saving landfill space, and ultimately contributing to our energy independence in a responsible way. Recycle and help save the planet.
Note: The author wants to thank the Mississippi Department of Environmental Quality for many of the items of statistical data used in this article.