RECYCLING Essay, Research Paper
TABLE OF CONTENTS
Abstract3
Types of Construction and Demolition Wastes4
Type I- Roadway and Site Conversion C&D Waste4
Type II- Construction and Interior Demolition Waste5
C&D Waste Processing Strategies5
Type I C&D Waste Processing Strategy6
Type II C&D Waste Processing Strategy7
Conclusion9
References10
ABSTRACT
Environmental concerns about the huge landfill space that is being taken by construction and
demolition debris has brought up a new technique in salvaging construction material and recycling
demolition debris. Although one process exists for two types of waste, many have tried different strategies
in dealing with this problem. These strategies vary between “separating and sorting” then “crushing and
reducing” and “crushing and reducing” then “separating and sorting”.
PROCESS OF C&D DEBRIS RECYCLING
C&D debris refers to materials generated as a result of construction and demolition projects. Metals, wood,
rocks, concrete, rubble, soil, paper, plastics and glass are among the many materials that are considered
C&D debris. Realizing that the disposal of C&D debris in landfills consumes large amount of space and is
economically and environmentally costly, the need to get acquainted with suitable recycling processes is
becoming more and more essential (1, p.18). Although, only one recycling process has been developed,
there are different strategies for implementation.
TYPES OF CONSTRUCTION AND DEMOLITION WASTES
Type I – Roadway and Site Conversion C&D Waste
C&D waste is classified as Type I if it consists mainly of rubble with a little ratio of “clean”
materials such as wood, metals, and plastics. Type I waste should be easily separable in order to be
considered as “clean”. The composition by weight of a Type I C&D debris is (2, p.6.31):
Rubble
concrete, asphalt 40%
soil, rock 20%
Wood 30%
Metals, plastic10%
Type II – Construction and Interior Demolition Waste
This type is mainly generated from urban structure such as office buildings, stores, etc.. Type II contains
mixed fractions of concrete, drywall, framing, ductwork, roofing, windows, corrugated, packaging, etc.(2,
p.6.32) . Due to its high heterogeneous composition this type is difficult to separate, it is mainly made of:
Rubble25%
Wood33%
Metals20%
Corrugated12%
other (carpet, residue, etc.) 10%
C & D WASTE PROCESSING STRATEGIES
Primary separating equipment used with type I are very efficient while with type II this procedure
along with hand sorting will take lots of time. Processing procedure is determined by the type of waste and
the possible use of the output materials (2, p.6.32). Table 1 shows the different contents of C & D waste .
Table 1 Contents of C&D Waste (2, p.6.31)
Waste typeContents
RubbleSoil, rock, concrete, asphalt, bricks
Tar-based materialShingles, tar paper
Ferrous metalSteel rebar, pipes, roofing, flashing, structural members, ductwork
Nonferrous metalAluminum, copper, brass
Harvested woodStumps, brush, treetops and limbs
Untreated woodFraming, scrap lumber, pallets
Treated woodPlywood, pressure-treated, laminates
PlasterDrywall, sheetrock
GlassWindows, doors
PlasticVinyl siding, doors, windows, blinds, material packaging
White goods/bulky itemsAppliances, furniture, carpeting
CorrugatedMaterial packaging, cartons, paper
ContaminantsLead paint, lead piping, asbestos, fiberglass, fuel tanks
Type I C & D Waste Processing Strategy
Clean rubble can directly be placed into a grizzly feeder where a jawcrusher and hammermiller could act on
it for reduction.
Figure 1 Debris placed into grizzly feeder
Sorting and reducing first is more practical than crushing if the debris contains material such as plastics,
paper, rags, or contaminants such as paint, lead pipes, etc.. After crushing the mix is then screened to
remove fine soil and small rocks. Any contaminants, ferrous, and non ferrous material is removed by either
manual picking or magnetic field belt. If wood is present in the rubble then the mix is guided towards a
flotation tank where the wood will float and thus the separation from rocks is achieved. Another system
instead of a flotation tank could be used and that is an air classifier. The air system is more expensive to
use, but if the recycling plant is located in a region where there is strict rules about water pollution, thus
requiring that the water from the flotation tank to be treated, then an air system might be a better option.
Crushing, reducing and then sorting and separating is much more recommended with systems made from
80% to 90% rubble, wood, a!
nd few contaminants. A general processing layout is shown in figure 2 and is available as both fixed and
portable designs(2, p.6.34).
Figure 2. Recycling plant
Type II C&D Waste Processing Strategy
It is essential that type II C&D waste be sorted and separated before being crushed and reduced
since this type of waste could have asbestos, paint, lead pipe, etc.. These contaminants could render the
mixture hazardous if they where to be crushed into small pieces, consequently making hand-picking
extremely difficult or even impossible to do.
Figure 3. Separating and sorting
After removing big contamineous material, the mix is introduced into a disk screen in order to separate the
soil from rocks.
.
Figure 4. Hand-picking
This has proven to be essential in order to increase the efficiency of handpicking in a later stage.
Eventually, material recovered will be free from contaminants and rubble will further be processed
according to the need of the local market(2, p.6.36).
Figure 5. Aggregate of size 0-60mm
CONCLUSION
In recycling C&D debris, many considerations should be accounted for; such as the nature and the
type of the material. Knowing these properties, it is possible to choose and apply the suitable process
strategy: with type II materials, sorting and separating at an early stage before crushing reduces the risk of
coming out with a contaminated recycled material. In contrast to type II material, type I material can be ,in
most cases, more easily and safely crushed before being sorted since the percentage of contaminants is
negligible.
REFERENCES
1. Nesmith, L. (1993, December). Ready or not, Construction Recycling is on the way.
Architectural Record, pp.18-23.
2. von Stein, E. McGraw-Hill Encyclopedia for Recycling . New Haven, Connecticut :
McGraw-Hill.
Другие работы по теме:
Romeo An Juliet Essay Research Paper hi
Romeo An Juliet Essay, Research Paper hi i need an essay about a character in romeo and juliet that demonsrtated maturity. in a well developed multi pagraph essay and say why you think the character’s maturity was greater than the other characters in the play.
Illistration Essay Essay Research Paper Wasteful PeopleA
Illistration Essay Essay, Research Paper Wasteful People A major problem in the USA today is the fact that Americans waste a lot. The main focus of this fact is the many different things that we waste, although steps are being made to fix the problem of us wasting so many resources.
Oh Really Essay Research Paper Oh Reallyyou
Oh Really? Essay, Research Paper Oh Really, you think i am a lark, the dogs they run and bark, but when i say to them, shut up shut up shut up, you say to be nice to them,
Office Paper Recycling Essay Research Paper I
Office Paper Recycling Essay, Research Paper I. Introduction Environmental science is concerned with the global impact of human activity on the planet. Indeed, at the dawn of this new century, close to 25 percent of the earth?s usable water is contaminated. In addition, during the last hundred years, we have increased the amount of carbon dioxide in the atmosphere, by burning fossil fuels, such as coal and petroleum and in so doing we have increased the amount of gases in the atmosphere.
Reduce Reuse And Recycle To Save Our
Earth Essay, Research Paper I believe that the world is on a crash course to destruction and humans are plotting the path. Every day we do little things that destroy a part of the Earth. Every time we make a plastic bottle or tin can that is another little resource that is used up and another non biodegradable thing that will end up in a landfill.
Nuclear Waste Essay Research Paper I believe
Nuclear Waste Essay, Research Paper I believe it s a good thing we are putting our nuclear waste underground for as long as it is needed and until we find a new place to store it without causing any harm to our environment.
Shane Essay Research Paper Sometimes I need
Shane Essay, Research Paper Sometimes, I need you more than I need air And sometimes I miss you more than I will forever, never forget the times that we have shaared. The are priceless
Poem Belong Essay Research Paper Where I
Poem: Belong Essay, Research Paper Where I belong I am weak, I am strong I will fit where I belong don’t know where it is for now but it will come, if I allow tomorrow, I start a brand new day
Him Essay Research Paper I think about
Him Essay, Research Paper I think about him day and night The though won’t go away And, oh, how I would hold him tight every second of the day He is perfect, that is true, not an average me or you
Poem She Sat Essay Research Paper She
Poem: She Sat Essay, Research Paper She sat… helpless in her room praying to whatever god there may be to let her call to him. could god ignore such a painful cry?
Descriptive Essay Essay Research Paper In the
Descriptive Essay Essay, Research Paper In the United Sates, where the population is inflated every year. The amount of space for landfills decreases every day. The need for recycling should not be asked, it should just be done out of habit. Everyone in America needs to recycle, to help the lamdfill problem, help the environment, and help produce new products from recycled goods.
Recycling Essay Research Paper There are many
Recycling Essay, Research Paper There are many ways we can conserve our resources, but one of the major ways is recycling. In an encycopedia recycling is defined as “the recovery and reprocessing of waste materials for use of new products.” Websters dictonary defines recycling as “a process (as liquid bodywaste, glass or cans) in order to regain material for human use.” There is actually two broad types of recycling, internal and external.
Household Recycling Easier Than You Think Essay
, Research Paper HOUSEHOLD RECYCLING: EASIER THAN YOU THINK! Amy Newman Thesis: After reading this essay, I will fully understand the issue of recycling and the three solutions I have found.
Recycling Essay Research Paper Raising Levels of
Recycling Essay, Research Paper Raising Levels of Recycling Recycling involves using materials which are at the end of their useful lives as the feedstocks for the manufacture of new products. The keys to improve participation in recycling are to either make recycling easier, to increase the reward for recycling (or the negative consequences of not recycling), or both.
Recycling Essay Research Paper RECYCLING Recycling
Recycling Essay, Research Paper RECYCLING. Recycling is an ancient practice with many modern applications. It refers to the recovery and reuse of materials from spent products. In recent years recycling has become a major part of environmental policy, mainly because of the increased costs of solid- and hazardous-waste disposal, the scarcity of natural resources, and the growing concern over polluted land, water, and air.
Ode To Boys Essay Research Paper We
Ode To Boys Essay, Research Paper We like them But do they like us The ones we do never fuss They don’t stop in And we wonder why We stress, we bitch We sometimes cry
Conservation Essay Research Paper ConservationWhen you think
Conservation Essay, Research Paper Conservation When you think about conservation what do you think about? I think about a better, more beautiful world. Without conservation where would the world be today? I know where we would be. We would be drinking polluted water and breathing polluted air. That is why it is our job and our government job to help conserve this beautiful land that we live in.
Global Oil Crisis Essay Research Paper When
Global Oil Crisis Essay, Research Paper When I was a child, recycling was only important at school. My teachers would always tell me that recycling was good for the earth. But, I didn’t really show any concern, because
Life Is Like Essay Research Paper Life
Life Is Like Essay, Research Paper Life is like a car. When it?s new, it usually works all right. As time drives by, it breaks down and needs repairs. Life is like a leaf. In its youth, it
Dare Essay Essay Research Paper What DARE
Dare Essay Essay, Research Paper What D.A.R.E Means To Me Dare has prepared me to say no to drugs in eight different ways. If anyone asks me to do drugs I will know what to do, such as- just ignoring the person or just
Recycling Essay Research Paper Why The Kids
Recycling Essay, Research Paper Why The Kids Won’t Recycle There are a few reasons why kids don’t think too highly of recycling. The first reason, haunting most of us, is the fact that we are lazy. Most kids will just throw their garbage away in the nearest garbage, no matter what it happens to be for. Another problem is that the paper recycling bins have the largest opening.
The Playground Essay Research Paper I have
The Playground Essay, Research Paper I have a friend I used to know who had a playground where we would go The times we had are fresh in my mind but they are from another time