Reduce, Reuse, Recycle

“Reading, wRiting and aRithmatic” used to be considered the three “R’s” of school. The three “R’s” our generation will remember will be “Reduce, Reuse, Recycle.”  Reduce, Reuse, Recycle. In elementary school we practically marched in place to these words.  Well the repetition has made this phrase stick, giving me an idea for this month’s post.  

Civil Engineers have some pretty savvy ways to Reduce, Reuse, and Recycle. I’m only going to talk about a few in this post, but be sure to comment if you have some other great examples. Let’s start with Reduce.

A popular civil engineering material, and for good reason, is cement concrete. Cement, as you may or may not know, is a fine powder that when mixed with water becomes a glue that will hold aggregates together in the concrete. Cement has two basic raw ingredients: Calcium Oxide (limestone) and Silica and Alumina (clay). These ingredients must be crushed, mixed and burned to produce clinker. Because heating is needed, the cement making process is expensive. It takes a lot of energy to make cement. So engineers have developed a green solution to cut costs. Fly ash, a byproduct of coal fired power plants, can be used to replace some of the cement. Problems with this substitution can arise because fly ash is not optimized for the cement concrete process. However, this is an excellent way to reduce the amount of cement needed in a mix by maybe 20%. Looking at this process from the fly ash side, will look more like reusing or recycling wasted material. But, I have even better examples of Reuse and Recycle. Reuse is up next.

This year, my environmental engineering lab took a tour of the Fargo Wastewater Treatment Plant. A brief explanation of the process that we were shown in class is here. The sludge that is produced in the wastewater treatment process warrants further treatment.  Fargo’s wastewater treatment plant process produces methane during its anaerobic sludge treatment process. They use this methane to heat the plant’s many structures which keeps their ‘worker microbes’ alive during the winter months. This is an excellent way to be green, take what used to be a waste product, and turn it into a product you needed anyway like a heat source.

Finally, we have my recycling example. North Dakota State University is doing research on using recycled materials in asphalt production. This semester I am also taking a Civil Engineering Materials class, and my professor, Dr. Magdy Abdelrahman, is the researcher for recycled materials in civil and construction engineering applications.  The NDSU CE research site probably describes it best:

“This area includes characterization of recycled materials, from old civil engineering structures and/or other sources such as industrial waste, as used in new construction projects. Current research areas include the use of recycled tires in asphalt pavement and the use of recycled pavement materials in civil/construction applications. This area also includes enhancing the qualities of recycled materials through the addition of new and virgin modifiers.” 

Well, there you have it. Reduce, Reuse, and Recycle are all intertwined. Reusing is recycling, and this reduces what we use.  But this isn’t a lecture on how we need to recycle, I want you to notice that each of these examples SAVED MONEY. Fly ash is much cheaper than cement, using something you produce as a byproduct as a heating source means you get free heat, and using industrial wastes in asphalt means people will pay you to get your wastes, you don’t have to pay someone to come and collect your wastes.

*picture from conservationhawaii.org*