Design Life-Cycle

 Anna Cable

Juliana Renert, Kaila Watkins

DES 040 A01 

Professor Cogdell & TA Ankit Singh

The Raw Materials for Concrete Pools

Living in the world now with all of the negative environmental impacts that humans have created throughout the centuries, including but not limited to global warming from fossil fuels, plastic and air pollution, deforestation, food waste, fast fashion and textile wear, etc., people still continue to add to the list of damaging environmental decisions by adding concrete pools to residential homes, hotels, and to public or private facilities. The addition of concrete pools are a social and common luxury seen in many places across the world. In an assessment on the design and construction errors of swimming pool facilities by a combination of structural and mechanical engineers stated that, “the POOLSAFE project conducted in the European Union in 2016, [1], there are approximately 13 million swimming pools around the world”(1). Due to this common occurrence and the eight additional years of pool construction that has most definitely occurred since the project was conducted, the need for the raw materials that are involved in the process are continuous and extensive. It is a substantial operation that includes many raw materials that have been processed and restructured then combined and formed for the result of a pool. The extraction production of these materials for these concrete pools demand significant energy consumption and result in substantial carbon emissions that not only exhaust valuable natural resources, but also exacerbates the ongoing problem on a global scale. This essay will discuss the extraction processes of each raw material, their lifecycle through processing and combination to create the secondary materials used, transportation processes, and the impact of extraction and production on the environment. 

Researching the raw materials and components that constitute concrete swimming pools, the information reveals that concrete is composed of a mixture of three products: cement, aggregate, and water. Delving deeper to understand the materials that make up cement, it becomes clear that the primary sources of cement include silica, iron ore, limestone, and alumina. These four primary raw materials of cement are typically extracted from earth at quarries or in mines by using drills and explosives. Alumina is produced from bauxite, a sedimentary rock with high concentrates of aluminum. Iron ore and limestone are both sedimentary rocks that are also extracted similarly. Silica is sourced from the earth's crust and upper mantle, found in both igneous and sedimentary rocks. After explosives and drillings, the extracted raw materials are then loaded onto belt conveyors or trucks where they then are taken to a processing plant. Once the materials arrive at the processing plant, the sequence of events begins. The first step in the cement production process is to crush each primary source into manageable sizes for the machine. After crushing these materials, they undergo a grinding process which reduces them to a fine powder. This facilitates the next crucial step of mixing and blending the dried ingredients. This combined mixture is then placed in a preheater where the processing of melting the materials together starts. Once this mixture reaches its desired temperature of about 1300-1450°C , the mixture is transferred to the rotary kiln, a large rotating furnace, where it spends a significant amount of time undergoing a chemical change that results in the formation of a secondary material, a new substance, called clinker. The clinker is then rapidly cooled in the clinker cooler to stabilize its properties. After the cooling is completed in the clinker, a small amount of gypsum is added. Gypsum is a natural occurring mineral found in sedimentary rocks in lagoons connected to the ocean with high calcium and sulfate levels. It is extracted using the same process for the other sources: drilling and blasting. The addition of gypsum to the mixture helps to control the setting time of the cement for later use. The final step of this process involves the clinker and the gypsum being grinded together to produce the fine powder known as cement. This final product is stored in silos then packaged in bags or large containers for distribution. After learning about the extensive process of cement production, it is evident that it generates significant heat, energy, and carbon emissions resulting in a substantial negative environmental impact. The Journal of Cleaner Production, in the article “A Life-Cycle Assessment of Portland Cement Manufacturing: Comparing Traditional Processes with Alternative Technologies,” it clearly addresses the fundamental issues with the production of cement by stating, “Approximately 5% of global carbon emissions originate from the manufacturing of cement”(2). With cement only being one in three of the materials needed to create concrete for pools, we now transition into the next steps of combining this secondary material with the primary materials of sand and water.

Concrete is one of the most widely used and mass produced products in the world, fulfilling an array of purposes from sidewalks and roads to floors, support beams in buildings,  and the bases of various structures, among other things. When combining the three materials: cement, aggregates and water through a chemical process called hydration the result is concrete. Aggregates are a coarse to medium grained particular material that includes sand, gravel, crushed stone, slag, and or recycled concrete. This process begins with the gauging of the materials, meaning that there needs to be measuring for the exact parts of each material for the process. After gauging distributions, the mixing of water with the cement powder begins which forms a paste that binds together the aggregates located in the cement powder. The next step includes coarse aggregates and fine aggregates, such as sand, which are then added to the cement paste. This bulks up the concrete mixture and provides strength and durability for the finished product. From there, the cement paste and aggregates are thoroughly mixed together to ensure complete distribution of the paste. This process is usually completed through mechanical mixers but can also be done manually, it’s just very strenuous. After this step, water is added to the mixture to activate the cement and start the hydration process. An amount of water is added carefully so that the desired consistency and strength of the concrete can be achieved. The mixing continues until the concrete mixture is consistent with all of the aggregates evenly coated in the cement paste. Once this mixture is at its desired texture, there is a slump and cube test to ensure that the consistency and curing processes are successful. This combination of materials to create concrete can be achieved at a mixing plant near the worksite and then can be transported within wheelbarrow or dumper trucks. It can also be distributed through chutes, a belt conveyor, and a mortar pan. However, this transportation system must continue to mix the concrete to prevent premature curing. To fully understand the environmental impacts of concrete production, civil and environmental engineers collaborate with environmental science academics to evaluate its life cycle. The assessment of this topic includes examining the volume of concrete manufactured every year with statistics that indicate approximately 1 ton of concrete is produced each year for every human being on earth. Now doing the math with today’s current increasing population number, you get almost 7.9 billion tons of concrete produced yearly, which is an atrocious amount of concrete being produced. Imagine how much of that concrete is being produced for pools; the answer is too much. 

Another crucial aspect of constructing a concrete pool, following the examination of its composition, is the steel rebar frame, which serves as the skeleton for the physical design of the pool. Steel is made out of the primary raw materials iron ore and metallurgical coal, as well as the secondary scrap material of steel. The production process includes the iron ore being placed into a blast furnace with coke, which is residue left after heating coal which is usually 90% carbon, recycled steel and limestone where it is added to the blast furnace in intervals. After some time melting in the blasting furnace, the iron has melted, producing molten iron known as pig iron that contains a lot of the carbon residue. Then scraps of steel and air are added to adjust the composition and remove purities resulting in steel. While the refinement of the steel is beginning, casting molds are prepared, which are typically made from sand or other materials and shaped into the desired form of reinforcement bars. Once the steel has solidified, the molds have been removed then the castings are extracted. They undergo the finishing processes, such as machining, grinding, or heat treatment to achieve the desired properties and dimensions. When the steel reinforcement bars have been manufactured and transported through semi-trucks, trains, airplanes, or cargo ships to the destination, they are then re-shaped according to the client specifications for their concrete pool. Once the skeleton of the pool is created from the steel rebar, then the construction workers will pour the concrete mixture on top and shape it to the desired look. They pour as many layers as needed of concrete on top of one another so that they are able to build the client's design. A positive aspect about the steel production is that any unused material from the casting process can be reclaimed and recycled for future production. In an article discussing maximizing scrap usage of steel production, it states, that. “Almost every single plant uses scrap as a part of its raw materials mix, and therefore almost every steel plant is also a recycling plant”(3). In the production of concrete pools, the need of steel reinforcement bars for the skeleton of the pool, this information represents the most environmentally friendly aspect of this project, which has been dictated through research. With the production of steel stepping in the right direction for our future, it gives hope that the production of cement and concrete could also develop a positive step.

Steel reinforcement bars provide for the skeleton of the concrete pool and the concrete provides its physical structure, the subsequent step involves applying one to three coats of plaster on top of the concrete surface. This application of plaster serves to enhance the pool's aesthetic appeal, while also providing a protective surface by smoothing the finish. The primary materials that are composed of plaster include gypsum, lime, or cement material, which are ground into a powder and are blended with fine aggregates such as sand to form the secondary material. This process is almost identical to the process of cement. After the process of refining the materials is complete into a powder, adding water to it creates the paste that is used for the final product. The plaster is applied while wet and when dried it hardens for a smooth finish. There isn’t a replacement of positive environmental materials that could be applied to this process due to the necessary materials to create this hardened cure. Following the plastering process, the addition of ceramic pool tiles is added for both aesthetic and safety. These tiles are derived from natural clay sourced from sedimentary rock found in streams or rivers. The clay is molded into the desired shape, dried and then fired at a high temperature in a kiln. After firing, the ceramic tile is glazed to enhance water resistance and protect the material from chemical deterioration. Ceramic tiles are a cheaper and popular option due to the abundant amount of clay that is accessible for production and also for the ability to have any color the client wants. However, they are not the most durable option due to it being a high absorption material and typically have a lifespan of up to ten years when properly cared for until it needs replacement. Once the ceramic tiles are added, the concrete pool’s physical structure is complete. The final steps involve adding water and the chemical aspect, chlorine, to ensure its completion.

The remaining aspects for the entirety of concrete pools are the additions of water and chlorine. The water sources typically used in pools are municipal water and well water. Municipal water is water that has been cleaned and treated at a treatment facility so that it does not contain high concentrations of impurities such as heavy metals, phosphates, and nitrates that could potentially create issues in the pool. This water is also supplied by the local government to homes, businesses, and other establishments. This water may come from very sources, such as rivers, lakes, reservoirs, groundwater, or surface water treatment plants where it undergoes treatment processes to ensure it meets the safety and quality standards before reaching the consumers. Once this water is accessed by the construction company doing the concrete pools, the water is placed into the pool where it will fill it to its specified depth. The next steps of adding chlorine to the water of the pool are extremely crucial. Chlorine is a highly volatile chemical that is a sanitizer and disinfectant used to keep the quality of the concrete pool and the quality of the water. Chlorine is a naturally occurring chemical element that is bound to other compounds such as sodium. Chlorine is very abundant because of its natural source being sodium chloride, also known as table salts. The dry chlorine salt is mined and transported to industrial chlorine manufacturing facilities commonly called a chlor-alkali manufacturing facility. Next, the chlorine is dissolved in water to create a brine. Electricity is applied to the brine to produce chlorine gas. However, the chlorine gas may be contaminated with oxygen, which needs to be removed. This is achieved by cooling the gas, causing it to undergo a chemical process and transformation into a liquid state. This process is known as liquefaction. With this process completed in various industrial facilities or water treatment plants it is then transported to consumers who then use it to add it to their specific plans. In this case, the chlorine would be added to the water in the concrete pools. The use of chlorine is continuous, and needs to be combined with the water repetitively for the best results. Chlorine is a natural substance that has not been researched for a replacement and because it’s an abundant product, there really isn’t a need to find a replacement. 

Throughout this research paper the process of acquisition for the raw materials, the multiple transportation adventures, the manufacturing, treatment, and mixing facilities, as well as the distribution, combination, and possible recycle methods. The creation of concrete pools is an extensive process that requires a significant amount of materials for the result. The materials are cement, concrete, steel rebar, plaster, ceramic tile, water and chlorine. The extraction and acquisition of these materials consume large amounts of energy, which is compounded by the energy needed through transportation, processing and distribution. With expending large amounts of energy there is also the significant release of carbon emissions throughout the manufacturing process. With this release during the process, it puts the production of these materials at about 5% of the carbon emissions in the world. From this process, concrete pools have a negative global environmental impact even though it may have a positive impact for social and selfish reasons. 

Bibliography

3.2 Manufacturing Process of Concrete, www.rcet.org.in/uploads/academics/rohini_21571433621.pdf. Accessed 5 June 2024. 

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(1)Author links open overlay panelA. Skotnicka-Siepsiak a, et al. “Research and Numerical Assessment of Design and Construction Errors in the Swimming Pool Facility Structures.” Engineering Failure Analysis, Pergamon, 28 Apr. 2024, www.sciencedirect.com/science/article/abs/pii/S135063072400390X?casa_token=JzIMkoPq4a8AAAAA%3Ajf2WebJTyUFY7mocobKNz-_PnP03p_ec_RaRf7yubQ7l1oXHZ5LPT-lkiPvUNo_lfO2IRCFJ. 

(2)Author links open overlay panelDeborah N. Huntzinger a, et al. “A Life-Cycle Assessment of Portland Cement Manufacturing: Comparing the Traditional Process with Alternative Technologies.” Journal of Cleaner Production, Elsevier, 2 July 2008, www.sciencedirect.com/science/article/pii/S0959652608000826?casa_token=XR4su75_Tz8AAAAA%3AyKma8u762WKzZzsL1ox5Xb1AqynJ7lORboIQPGP0gBmGsJJnw9dlE0aBUT_7yK3bfw2k5eJK. 

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Kaila Watkins

Professor Cogdell

DES 040

June 2, 2024

Embodied Energy in Concrete Pools

What is one of the best ways to cool off during a hot summer day? Going to school in California, many of us are all familiar with swimming pools. People all over the world use them to cool off, entertain, exercise, and relax next to. RubyHome found pool statistics that stated that there are 10.7 million pools in the United States. Many of these pools are concrete pools. Concrete is one of the most commonly used materials for swimming pools, however there are also fiberglass and vinyl pools as well. Pools are a very desirable aspect for homes, as well as hotels, especially in areas like California where it can get very hot. The United States is the country with the most swimming pools, however other countries also have many swimming pools too. Swimming pools are also quite expensive to build. RubyHome also found a statistic that showed the average inground swimming pool costs around $35,000. This is because the process to build an inground concrete swimming pool, and maintaining it, takes a lot of labor and energy. It also takes a lot of energy to demolish and dispose of a concrete swimming pool properly. This all in turn makes the construction, maintenance, and demolition of concrete swimming pools not very eco friendly since it takes so much energy.  This paper will inform the reader about the life cycle of a typical concrete swimming pool, how to build and demolish a concrete pool, the maintenance it takes while it is in use, and the overall embodied energy that goes into each part of those processes.

Energy is defined as the capacity to perform work. There is lots of work that goes into building a concrete pool, as well as the work it takes to collect, and create the materials needed. To fully understand the energy it takes to build, maintain, and demolish a concrete pool, we must first understand the process it takes for each of these steps of a pool's life cycle. First we need to take a look at the raw materials that are needed to build a concrete swimming pool. The concrete that is needed for the pool is made out of water, cement, and sand. Concrete as a building material itself, has “...contributed 14% to total embodied energy and 22% to GHG emissions, respectively” (Science Direct). The machinery used to create concrete such as batchers, mortar mixers, concrete mixers, concrete haulers, concrete pumps, and more all use a good amount of energy. The engines of these machines can range in their fuel power. For instance for concrete pumps, the two main types of engines are diesel and electric. The cement in concrete is made from iron ore, silica, limestone, and alumina. Strine says that “Of all the material used to make concrete, cement has the highest EE of 5.6 MJ/kg” (Strine). There is also something called rebar that is made from steel. Steel is made from iron ore and metallurgical coal. The typical embodied energy of steel is 38.8 MJ/kg according to YourHome. There is also plaster that is used for the shell of the pool, which is made of cement, sand, marble dust, pigment and water. There is water, and often chlorine which is a chemical that helps keep pools clean. The PVC pipes used to circulate the water are made of a mix of chlorine and ethylene to create a plastic. These pipes are often used for the pool pump which can take lots of electricity to run. “In fact, a pool pump will consume between 3,000 and 5,000 KWh per year” (Angi). There are also often ceramic tiles made of clay minerals and feldspar, as well as pool lights made of stainless steel, plastic, glass, brass or aluminum. The most common light bulbs that are used for pool lights are halogen, incandescent, and LED. Eco Outdoor says that “Incandescent lights typically run from 300 to 500 watts, whereas LED bulbs use as little as 42 watts” (Eco Outdoor). The extraction of all of these materials, and the assembling of them takes lots of manpower, and machine power. 

The manufacturing process and the formation takes lots of labor to build, which in turn means lots of energy being used. Science Direct found that “The construction industry used about 40% of the total energy consumed in the world (Economy Watch, 2010)” (Science Direct). One typical construction job is creating concrete pools. What is first done when constructing a concrete pool is the excavation of the Earth. This is usually done with heavy machinery like an excavator. This dirt often has to be transported off site somewhere. For a typical excavation and transportation of soil jobs, Science Direct says the energy use “...is in the range of 14-89 MJ/cu.m. and 19-135 MJ/cu.m. respectively” (Science Direct). Then there is the placement of the rebar, which is like a metal cage around the outside of the pool to prevent the concrete from cracking. Next, the plumbing is installed and the PVC pipes to circulate the pool water. Then the concrete is poured into the shell and smoothed to create flat edges. The pouring of the concrete is usually done through a concrete pump which is powered by diesel or electric motors. The smoothing of the concrete is done by hand through manual labor. The concrete then needs around 28 days to cure. After it has had time to cure, plaster is applied as a waterproofing shell. Then it is time to fill the pool with water. After the pool has been filled with water, the owners of the pool need to make sure they brush the bottom of the pool twice a day for 10 days, in order to remove the plaster dust. According to FSPS, “The minimum energy output during a routine daily activity is about 1.800-3.000 kcal/24 hours which is roughly equivalent to 7.600-12.600 kJ/24 hours” (FSPS). After two days have gone by, chlorine can be added to the pool. This process involves lots of energy exerted from human labor, as well as machine powered labor.

The distribution and transportation part of the life cycle involves lots of energy as well. Vehicles are having to constantly transport the materials to the job site. To transport one shipment of concrete to a jobsite that is about 164.6 km round trip, it would take 689.6 MJ of embodied energy. To transport one shipment of steel for the rebar about a 32.8 km round trip, it would take 177.7 MJ of embodied energy. There is also a need to transport things off of the jobsite as well such as all that excavated dirt. As stated above, it takes around 14-89 MJ/cu.m. and 19-135 MJ/cu.m. to excavate and transport soil off of the jobsites grounds. Vehicles use up lots of energy to drive two and from places. 

The usage, and maintenance part of having a concrete pool involves lots of money, labor, and time. Concrete pools develop algae easily so owners need to brush the pool at least once a week, or hire a pool cleaning service. This would be around 7.600-12.600 kJ/24 hours of energy exerted by whoever is completing the task. Concrete is also alkaline based so it messes up the pH of the water, so it is important to check the pH balance regularly and add acid when needed. Concrete pools need to be replastered every 10-15 years too which is a whole process.  There are also some pools that are heated and have pool lights which involve lots of electrical energy. For heating a pool with a heat pump, Hawkins Service Co. found that they “...will use around 5,000 watts or 5 kilowatts per hour per 100,000 BTU's” (Hawkins Service Co.). However there are other ways to heat pools such as solar. To run pool lights there are a variety of different bulbs that will take different amounts of energy to run. The cheapest lightbulb to use for cement pools would be LEDs because they only use as little as 42 watts. There are many different routes to choose from when heating and lighting a pool, but they all end up using up some ammount of energy. 

Once it is time to demolish and recycle the materials within the concrete pool, there is lots more labor that needs to be done and involves more energy usage. There are two ways of demolishing a concrete pool: completely removing it, or filling it in. When completely removing it, first the water from the pool must be drained. The most energy efficient way of doing this would be to siphon the water with a hose. Then the concrete needs to be removed using a jackhammer. Bluetti found that “A typical electric jackhammer requires a power source of about 120 volts and 15 amps. This translates to a power requirement of 1800 watts” (Bluetti). Then, when the rebar is exposed again, it needs to be cut and removed using rebar cutters. Next, the debris needs to be sorted into separate piles depending on materials to be disposed of. For the fill method, first the pool needs to be drained. Once again, siphoning will be the most energy efficient way to drain the pool. Then holes need to be drilled into the bottom of the concrete for drainage purposes. To drill holes in the bottom, usually an electric drill or hammer drill is used. SlashPlan mentions that “Electric drills use up to 600 watts of power, which is equivalent to 0.6 kilowatts (kW) of energy” (SlashPlan). Then, at least the first foot and a half of the pool's concrete needs to be removed. This can be done most likely by a jackhammer and would be around 1800 watts. Then the pool can be filled with dirt. Both of these methods are not the most eco friendly, however the complete removal will make it easier for the landscape to return to its natural state.

In order to dispose of all of the debris from the demolition of the concrete swimming pool, the excess materials need to be hauled to a landfill or transfer company. There are many companies that will rent out dumpsters, or provide junk hauling services. The equipment that is used at landfills is usually large trucks, bulldozers, excavators, and tractors. These are all run off of fossil fuels. The other option could be to recycle the materials, for instance the steel could be sent to a construction and demolition waste recycling facility to be reused. However the machinery used at these facilities is also going to be most likely running off fossil fuels as well. 

The creation of a concrete pool, it’s maintenance, and its demolition all involve lots of labor and energy. There are primary sources of energy being used such as all the hands on labor that the people who are working at the site are exerting. There is also lots of secondary energy being used, such as the electricity that runs some of the heavy duty machinery that is needed to transport, build, and demolish the concrete pool. The machines are also used to extract lots of the materials that are used to build the concrete pool. All adding up in total, (and accounting for how many concrete swimming pools there are in the entire world), it shows how much energy is being used up to build, maintain, and demolish these pools. 

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Juliana Renert

Kaila Watkins, Anna Cable

DES 040 A01 

Professor Cogdell & TA Ankit Singh

Waste and Emissions of Concrete Pools

Every time a residential concrete swimming pool is built,  pollutants like CO2 emissions and the chemicals in chlorine are released into the atmosphere, land, and water. Concrete swimming pools don’t only pollute the environment while they are being used, but also before it’s even built. Through every step of the building and use of a concrete pool- extraction of materials, processing and production, transportation, use, maintenance, and recycling, there are large amounts of waste in a variety of forms that harm the environment. Emissions from extracting, processing, and manufacturing materials, CO2 from transportation, water waste from excess water and chemicals, and solid waste of decomposing steel and concrete. This research paper goes over the life cycle of a concrete pool and highlights the waste and emissions starting with the extraction of materials, processing and manufacturing of said materials, transportation, construction, use, side effects, and after-effects that occurs in the development of a pool.

The environmental impact of a swimming pool is multifaceted, and largely untalked about. The most recent statistic in October of 2023 according to Justin Wiley, the vice president of government relations for the Pool & Hot Tub Alliance, shows that, “California has over 1.3 million in-ground pools that have already been installed and they are on pace to do… over 15,000 new pools each year” (Secaira). This seemingly minor recreational addition to the picture perfect “American Dream” house, complete with a white picket fence and a front porch, done on such a scale can have detrimental effects on the environment. In a society striving to have a more sustainable way of life, one of the first ways to start that process as an individual or family is to consider the impacts of choices like this, and understand the cost of building a pool. When homeowners consider the cost of adding a pool to their backyard, the only number they consider is the cost. However, there are other numbers not to be ignored: the real cost of building a pool starts with material extraction. The materials that are the most common are: cement, steel, plaster, water, chlorine, concrete, and ceramic tiles. The typical concrete swimming pool has a simple design, starting with the frame of steel rebars, concrete then shot to make the frame, and then a sealant of plaster and tiles to finish it off. These primary raw materials largely originate from within our Earth- quarries, mines, and valleys are extracted through mining, drilling, or explosives. Sedimentary rocks are the basis of concrete, tiles, plaster, and iron for steel, for example. Besides this, the water used for pools is purified fresh water from lakes, rivers, or dams. The cost of extracting these materials mostly comes in the form of greenhouse gas emissions- from the CO2 of the diesel engines in excavators, to the methane released from drills, the surface of Earth has begun to heat with all the greenhouse gasses in our atmosphere. These gasses, “absorb the sun's heat that radiates from the Earth's surface, trap it in the atmosphere and prevent it from escaping into space,” (European Parliament). The true cost of constructing a pool is the damage to our environment, and this is only the beginning of the life cycle. The greenhouse gas emissions don’t stop there- the next phase of the life cycle is the transportation of these goods. 

Cement, for example, begins with the extraction of iron ore, silica, limestone, and alumina from quarries. From there, these raw materials are, “transported to the crushing plant by trucks, railway freight cars, conveyor belts, or ropeways,” (Britannica). Each individual raw material has to be transported from each individual site, to the manufacturing plant, to the independent businesses or contractor, and finally to the home itself. As mentioned above, these seven materials come from different locations, from mines, to lakes, to quarries, and vary in distance from each other.  Once at the factory and have completed the processing steps, they are then transported by individual company transportation methods that range from trucks to freight trains, each with their fair share of CO2 emissions to reach the independent businesses, suppliers, and/or contractors. Because there are so many steps and different locations in the transportation process, lots of energy is used and waste is produced. As an example, the water supply in SoCal is, “...known to be particularly energy intensive due to the reliance on two long distance transport systems” (Forrest and Williams S22). Even after all that moving around, the materials then have to be transported by car, or in some cases truck (like a cement truck) to reach the client, where the construction can begin. According to AMCS Group,“Construction accounts for 1% of transport emissions, which in turn accounts for 0.1 gigatons of carbon dioxide”. Although 1% seems like a low number, 0.1 gigatons of CO2 doesn’t sound so harmless. So the materials were transported from site to processing plant to manufacturing to contractor to construction company to client. So much waste already accrued and carbon dioxide in the air, and the cost of manufacturing and constructing the materials hasn’t even been touched on yet.

The construction sector is the largest sector of CO2 emissions, with it accounting for 37% of greenhouse gas emissions globally (Environment Programme). While this statistic is clearly meant for the construction of all buildings and structures, companies and independent contractors are usually hired to construct a pool, which means that pool construction does in fact leave a carbon footprint. The materials that these construction workers are using come prepackaged, already manufactured. What was the cost of manufacturing them? According to Princeton University, the processing and manufacturing of cement “makes up to 8% of overall global emissions” and “12% of emissions in New Jersey” (Ramsden).  To make cement, for example, the materials have to go through these steps: be crushed and ground, blended, burned in the kiln, and then grinded again with gypsum, (Britannica). Turning the primary raw materials of iron ore, silica, limestone, and alumina into the secondary raw material of concrete takes time and as seen above has detrimental effects in the atmosphere. If we continue on this path in the future the carbon footprint left behind and the destruction in its wake might be irreversible. However, thanks to modern research and the growth of the sustainable design and biotech industries, there are many alternatives to materials such as concrete and cement which have a long and expensive manufacturing process. Biotechnology is a budding field which tries to come up with more sustainable solutions in all industries from fashion to construction. For example, the first house was built in Africa using solely mushroom mycelium brick, or turning to bamboo as a biodegradable material for the structure of a home. Instead of using the toxic chemical chlorine to purify the water, salt water can be used as a disinfectant along with UV (NIP group). As of now, however, society is still majorly using methods of construction that cause a lot of harm to the environment and aren’t as biodegradable or organic. Excavators used to dig the hole have “emissions, soil disruption, noise pollution, and water quality” (Qilu Machinery). The diesel engines emit nitrogen oxide, the soil can become compacted, the noise and land taken up can cause displacement and habitat disruption, to name a few. After all of this construction and destruction, the pool is finally constructed. Now what?

The pool is constructed, the water is just filled, the sun is out, and the kids are waiting to jump in. The end goal has been met, and the pool will last forever, right? Actually, the average lifespan of a concrete swimming pool is “50+ years” (Newsom) as long as it is well maintained and often resurfaced with another layer of finisher (to fix any wear and/or cracks). Not only this, but the maintenance for the pool is something the happy homeowner can’t ignore if they want to even reach that 50 year mark. Resurfacing, refilling the water, adding chlorine, etc is a cost that doesn’t only affect the electricity and water bill, but also affects the natural surroundings. Water often spills over the side of the pool, the chemicals along with it through “backwashing, refill, overflow, leaks and usage” (Forrest and Williams S6). Water doesn’t only return to the environment through those processes, but also as vapor and atmospheric emissions. Water is evaporated, and the chemicals in the water (chloride, trichloromethanes, hypochlorous acid, and hypochlorite) are vaporized with it. Aside from the toxic chemicals that now pollute the earth, water, and air, swimming pools are also causing more and more cities to go into water shortages. While the bulk of this research is focused on California homes, this is a problem everywhere. “Over the past two decades, more than 80 metropolitan cities across the world have faced severe water shortages due to droughts and unsustainable water use,”(Tigue). While this issue of overconsumption is seen around the world, it isn’t because of everyone. In Cape Town, South Africa, the city's, “wealthiest people consume 50 times more water than its poorest, ” and that usage is for unessential needs like, “garden watering, car washing and filling swimming pools,” (Tigue). With all this waste in liquid, solid, and gas form, can any part of a concrete pool be recycled? The chlorinated water is harder to recycle, and is recommended to slowly pour it into the surrounding environment, or let it evaporate completely (or get a pool service). The former option does have those negative impacts for the soil which is best to avoid. Aside from the water, most of the primary and secondary raw materials in a pool like concrete, cement, and steel decompose around 50 years after the pool’s construction (excluding the ceramic tiles because of the temperature it was heated to in the kiln). Empty inground pools can also be recycled wholly and turned into a multitude of things, including but not limited to skate bowls, sunken fire pit, a deck, a garden, or a pond. While this isn’t the traditional idea of recycling, now the material doesn’t have to get transported and processed in a recycling plant, and can instead be transformed into something completely new. 

In today’s society there are options to make the full life cycle of a concrete pool more sustainable, like biodesigned concrete, saltwater pools, and turning the inground concrete into something new entirely. However we are still far as a society from transitioning into a more sustainable extraction, manufacturing, development, and use process. Waste and emissions are more of a problem than people realize, and that it is up to the extractors, manufactures, contractors, developers, and the individual to either change how concrete pools are made, or make more sustainable decisions in the ownership of one.

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