Plastic and Waste Management in the Context of Sustainable Building

Ellie Hayden and Pat Wendler

Problem: There is Plastic everywhere due to a lack of waste management in Senegal

Introduction:

One of the problems we identified while in Senegal was their lack of waste management. While high volumes of trash is not unusual for a large city, there are usually several receptacles and a system that prevents trash buildup. However, in the few days we spent walking around Dakar, not once did we see a trash can along the streets. Instead trash was just thrown on the streets. Even locating trash cans in buildings was often difficult. Although we did not witness the system in action, from our interviews, we understand that there is a waste management system, but it is not very well organized. Instead of leaving trash outside to be picked up, it seems that a truck simply drives down your road once a week and if you’re there to throw your trash in the truck as it drives by, great, but if not, you’re out of luck and that week’s trash is usually improperly disposed of.

As you get further from the city, trash becomes even more of an issue as there is a lack of infrastructure and less incentive to support any kind of formal system for dealing with waste. This results in high volumes of trash in the streets especially just outside the entrances to rural villages. The one form of waste management we identified in the rural areas stems from a social movement called “Set/Setal” meaning be clean/make clean. This is a movement that began around 1990 and was encouraged by a popular musician at the time whose hit song encouraged the youth to keep the streets clean. To this day, young women and men take time off from school to clean the streets and burn the trash piles. We witnessed this in Keur Momar Sarr and while this movement stems from good intentions, it causes even more problems for their health, the environment, the economy, and the society as a whole. To fully understand the depth of this problem, we have explored the root causes as well as the implications that have arose from it. Using that and the other information we gathered on our trip, we have come up with a few ideas of how we could approach this problem in a way that could advance sustainable building in Senegal.

Analysis:

After thoroughly exploring this issue, we came up with some questions we thought were important for moving forward.

• What challenges are worth trying to solve?
• How can solving part of the waste management challenge help with sustainable building?
• How can we think of the issue in the context of sustainable building?
• What differences exist between rural and urban waste management?
• How rapidly is Senegal urbanizing, and how will this affect waste management?
• What incentive for waste management would matter to the Senegalese?
• What consequence would be meaningful to them?
• Can we use trash for building? What effect would it have? Would it be sustainable?
• What’s being done currently to solve the waste management problem?

The main problems that arise from the current waste management (burning trash piles in the villages) are degradation of health and the environment. Having spent some time with several Senegalese families, I think the best way to create incentive for them to want to change their waste disposal methods would be to approach it from the health point of view. If we can help them understand that they are potentially making themselves, their children, and their loved ones sick by burning the plastic, I think we will have a better chance at getting them on board.

Health facts:

• Burning plastic releases dioxins and furans which are linked to cancer and respiratory diseases (dioxin comes from high chlorine amounts).
• Inhaled smoke from plastic can cause hormonal imbalance.
• The ash is potentially hazardous to soil.
• Dioxins can enter the food chain by settling out of the air and into water and vegetation that is then consumed by humans or animals.
• Dioxins can suppress immune system making people more susceptible to other sickness, disease, or infection.
• Particle pollution from burning plastic can cause respiratory problems, irregular heartbeat, and heart attack if the particles settle in lungs.
• The effects of burning plastic will be felt by the youth and elderly most.

• Lower respiratory infections are responsible for 8.4 years of life lost (YLLs) in Senegal.
• Lower respiratory infections are the third greatest cause of premature death in the country.
• Garbage piles are breeding grounds for disease and also attract animals that go on to spread the disease

Environmental Facts

• Littering kills wildlife.
• Wildfires can start from a spark or lit cigarette igniting a garbage pile - especially in dry conditions.
• Toxins from garbage piles can seep into the groundwater, which makes its way to water systems or plants.
• Garbage by bodies of water can cause algal blooms, which pollute freshwater sources and kill freshwater wildlife by leaching oxygen from the water and creating an unbalanced ecosystem.
• Plants and animals that don’t die from ingesting toxins from garbage are poisoned, and some of these poisoned plants and animals are eaten by humans.
• Burning garbage releases nitrogen oxides, volatile organic compounds, carbon monoxide, and particulate matter, which contribute to ruining a region’s air quality and polluting the atmosphere, which worsens global warming and climate change.

Moving Forward:

How can we approach this issue in a way that can apply to sustainable building in Senegal?

Potential Ideas:

• Plastic as an aggregate used in concrete used for building
• Plastic as an insulator for buildings

Research pertaining to future ideas:

In depth study of using plastic bags as aggregate for concrete in Nigeria:

• file:///Users/Ellie/Downloads/Evaluation%20of%20suitability%20of%20LDPE%20as%20fine%20aggregate%20in%20Concrete.pdf
• A plausible idea, but would work best for non-weight bearing structures, like tiles for partitions or maybe tiles for the roof

Plastic bags used as an aggregate for pavement in Mauritius and India

• https://books.google.com/books?id=Qj8oBgAAQBAJ&pg=PA560&lpg=PA560&dq=LDPE+as+an+aggregate&source=bl&ots=aVRdO3BCRd&sig=zI7wJEmawx2FKBgZMNDd2PLC7rw&hl=en&sa=X&ei=TwUoVYaDG8HBsAWL9YDYBw&ved=0CCkQ6AEwAg#v=onepage&q=LDPE%20as%20an%20aggregate&f=false
• http://blogs.worldbank.org/sustainablecities/plastic-pavement-another-example-creative-waste-management

Recycled plastic bottles as an insulator in building:

• http://www.gizmag.com/tvzeb-zero-energy-home-in-italy/26583/
• http://www.insulpro.co.nz/from-plastic-bottles-to-insulation/#.VSaBoBPF8Yc
• InsulPro recycles the fiber found in plastic bottles to create insulation for walls, ceilings, and floors
• http://bagsbegone.com/2010/12/05/plastic-bottles-as-house-insulation/

Potentially useful facts about plastic bags:

• plastic bags are made out of low density polyethylene (DLPE)
• tensile strength 8-30 MPa
• 100-650% elongation at break
• flexural modulus .25-.35 GPa
• density: .92-.93 g/cm^3
• moderate degree of crystallinity
• crystal melting temp = 110 C
• 20-1000 years to decompose
• “A copolymer of ethylene with some carbon monoxide contains ketone groups that absorb sufficient energy from sunlight to cause extensive scissioning of the polymer chain. The photodegradable plastic, very similar in appearance and properties to low-density polyethylene (LDPE), decomposes to a powder within a few months of exposure in sunny climates.”