Demolition & Disposal
Criteria for Demolition
In order to repurpose buildings within urban regions, Terrascope Class of 2024 has established criteria to determine which buildings can be demolished in order to accommodate new green spaces. It must be noted that although abandoned lots are also being considered in the solution, they require no structural removal and are therefore not included within the demolition criteria. Because demolition is a labor-intensive and financially demanding plan of action, buildings that don’t fit the criteria can instead be considered for re-entry into the market.
CRITERIA TO DEMOLISH ABANDONED BUILDINGS
|Consideration||Conditions Conclusive to Demolition|
|Safety Hazards||1. Asbestos or other hazardous materials found|
2. Extremely structurally unsound due to neglect or improper construction
3. Fire hazards
2. Infestations of various pests
|Structural Deficiencies||1. Rotting wood|
2. Unstable foundation
3. Corroded metal
|Weathering||1. Prior damage due to the elements/natural disasters|
2. Damage is significant enough that the building is structurally unsound.
Issues with Disposal
Once demolition has been selected for a particular lot, the disposal of waste must be managed. It would be counter-productive to demolish a building in an attempt to promote biodiversity only to dispose of the waste in an environmentally hazardous way. Unfortunately, a proportion of demolition projects nowadays operate in this manner. For example, a 2018 study in southern China found that most of construction and demolition (C&D) waste is illegally dumped; contractors will take the risk of breaking the law just to reduce the costs associated with disposal. It is difficult to calculate the number of demolition projects that participate in illegal dumping, as it’s done covertly, but there are situations where the magnitude of this issue is apparent. In February 2017, New York City spent two days targeting the illegal dumping of C&D materials. After conducting the operation, the Department of Environmental Conservation, New York State Police, Department of Transportation, and Suffolk County Police identified nine illegal dumpsites, and issued 167 tickets for a range of misdemeanors and safety violations regarding the dumping of construction and demolition materials. This type of disposal would only negate all of the positive benefits that our proposed solution intends to bring.
It is also important to emphasize the quantity of waste produced from construction and demolition. In 2017, the United States generated 569 million tons of C&D debris, more than twice the amount of municipal solid waste (268 million tons). The magnitude of this statistic further drivers why proper disposal is critical: large quantities of waste cannot be dumped at the expense of the environment. As a result, a component of our solution is to recycle as much of the waste generated as possible.
Environmental Impact of Illegal Dumping
Improperly disposed of waste and pose a variety of threats to the environment. Chemicals from waste materials can seep into the soil, destroy sensitive microbial environments, and render the soil sterile for plant growth. Waste can also be ingested by surrounding organisms, negatively impacting their health when absorbing harmful substances. Large amounts of flammable waste also pose as major fire hazards, particularly in areas where the climate may be dry or hot. Lastly, improperly disposed waste provides ample breeding grounds for pests such as mosquitos and flies. The diseases these organisms carry can infect fauna and negatively impact the health of other organisms.
Main Types of Waste
The most cost-friendly way of recycling is onsite recycling. This means certain waste materials generated during demolition are to be reused directly. The major benefit of this recycling is that it saves money by reducing the production of new materials. While there is some cost in sorting materials into their respective groups, Figure 4 indicates that unsorted mixed debris recycling is still cheaper per ton than directly landfilling all unsorted C&D waste. Examples of onsite recycling are reusing doors and fixtures, reusing insulation in houses, and using bricks or concrete as fill or driveway bedding. Terrascope Class of 2024’s approach to demolition waste is to repurpose and/or reuse all materials collected from abandoned sites that are suitable for reuse on other building projects. Assessment of the materials originally from the abandoned buildings and their ability to be recycled must be meticulously carried out, since certain factors that made the materials unsafe in the original building could carry over into new projects they are being used in. For example, with a building that is unsafe due to mold and mildew, any organic/wood products cannot be reused due to health hazards associated. On the other hand, the concrete could be reused for driveway bedding; the recycling process diminishes hazards associated with mold and mildew, and the new location is not an enclosed space where spores could cause harm. Eventually, the resulting projects will be inspected by the appropriate agencies to ensure they reach appropriate legal standards of quality.
Ideally, our adaptive land solution would recover as many materials as possible from the site to be reused in new buildings and construction projects. All the remaining material is to be sorted through and processed through centralized recycling. Centralized recycling generally consists of asphalt, concrete, and rubble being recycled into aggregate or new concrete products. Wood can be recycled into furniture, mulch, and compost. Metals can be melted down and reused. While centralized recycling is found to be more expensive than controlled dumping at landfills (Fig 2.), the benefit is that centralized recycling is more cost-effective than the cost involved in ameliorating the environments that are being deteriorated by illegal dumping. For example the cost to clean up illegal dumping in Baltimore City according to the Baltimore City Department of Public Works in 2017 was $21,164,771, where nearly 10,000 tons of waste are dumped annually. The net cost to the city for recycling that same year was $18 per ton. Although, it’s not possible to recycle all of the waste generated, to make an estimate of how much more expensive centralized recycling is compared to illegal dumping we can calculate the price if all 10,000 tons illegally dumped had been recycled properly. In this case the city would’ve only had to pay $180,000 instead of the $21,164,771 it needed for clean-up.
Although this proposal to tackle demolition aims to recycle as much of the waste produced as possible, there will always be non-reusable waste materials. As a result, these waste materials must be sent to a landfill for proper processing. The aim of only demolishing buildings that fit specific demolition criteria is to reduce the number of buildings demolished, and thus reduce the overall waste produced. The ultimate goal is to create green spaces that do not significantly increase the influx of the waste stream into landfills. Since construction and demolition waste ranges from 24-28% of the total waste stream in landfills, and current construction and demolition waste recycling rates for building materials are only around 37.6%, Terrascope Class of 2024 intends to significantly increase this recycling rate utilizing the recycling methods outlined above, and significantly decrease the total waste stream into landfills. San Diego has already implemented responsible recycling measures similar to the ones outlined above, which have been predicted to increase the recycling rate of C&D materials up to 65%. Following these general standards of recycling and responsible demolition, it is plausible for the Terrascope Class of 2024 to generate new green spaces while not significantly increasing the waste stream of construction and demolition materials into landfills.
Relevance to Biodiversity
Overall, these considerations regarding demolition are to ensure that our plans to generate green spaces and promote biodiversity do not actually harm the environment or generate an opposite effect that is harmful to biodiversity.