Construction Wast-----It’s The "Gold" That Doesn’t Be Placed Correctly
Currently, recycling the construction wast has become the common research topic for each country in the world. Most developed countries implement “Construction waste source reduction strategy”, which is to control the construction wast through the scientific construction waste management plan before forming the construction wast. Only disposing the construction wast in scientific methods can it be recycled. In many countries, the construction wast has been a new kind of resource, promoting the rise of emerging industries. The recycling rate of construction waste has reached 95% or even 100%.
What can be called the construction wast
Construction waste refers to construction materials caused by man-made or natural factors in the project, including the waste soil, spoil, silt, and discarded materials. These materials that bring about from disposal of construction waste are not helpful to the construction itself. They need to be well processed so that can achieve the ideal project construction. The construction is a while project, so every step must be considered.
The classification of construction wast
As commonly stated, construction waste is a waste that is generated from the construction and demolition process of building products. Construction waste is produced in two processes: one is the construction process of building products. Another is the end of building products. Then, what construction waste material to recycle? Construction waste can be divided into three types according to its usability: one can be recycled directly like wood and bricks; another can be recycled indirectly like iron wore, rebar; the last is non-recyclable such as oil paint etc.
Harm of the construction waste
Construction waste pollution water resources
During the process of stacking and landfilling for construction waste, the sewage that is infiltrated by the scouring of fermentation and rain, as well as the immersion of surface water and groundwater, will seriously pollute the surrounding surface water and groundwater.
Construction waste dumps pollute the surface water in many ways. The garbage is scattered in the ponds and ditches during transporting process. Leachate in the dumping ground flows into the surface water, and infiltrates into the aquifer.
Besides, the river and lake pits polluted by garbage infiltrated into the recharge aquifer,which causes deep pollution. Landfill leachate not only contains plenty of organic pollutants, but also has much metal and non-metallic pollutants, so the water quality is complex. It will be greatly harmful to human they drink such contaminated water.
Construction waste affects air quality
With the constant development of city, more and more construction wast is stacked freely, which not only occupies land, but also pollutes environment or affects the air quality.
Under the action of temperature and moisture, some organic substances are decomposed and generate harmful gases because of stacking of construction waste. The waste gypsum contains a large amount of sulfate ions, which will be converted into hydrogen sulfide with rotten egg flavor under anaerobic conditions.
Waste paperboard and wood can dissolve lignin and tannic acid under anaerobic conditions and decompose to form volatile organic acids.This harmful gas will pollute the atmosphere when it is discharged into the air. Bacteria and dust in the garbage drift with the wind, and this will pollute the air; A small amount of combustible construction waste will produce toxic carcinogens in the process of incineration, causing secondary pollution to the air.
Construction waste occupies land and reduces soil quality
With the increasing of urban construction waste, the number of garbage dumps is also increasing, and its area is gradually expanding. Most of suburban garbage dumps are open-air.
After sunning and raining, the harmful substances in the garbage (including the polycyclic aromatic hydrocarbon structured materials released from paint, paint and asphalt in urban construction waste) penetrate into the soil through the landfill leachate, resulting in a series of physical, chemical and biological reactions. The harmful wast may be absorbed by plant roots or microorganisms, and this will pollutes the soil and reduce its quality.
In addition, under various external forces, smaller pieces of gravel will also enter the soil, change its composition,destroy its structure, and reduce its productivity. Furthermore, the content of heavy metals in urban construction waste is high, and chemical reactions will be occurred under the action of many factors, which results in high content of heavy metals in the soil.
Generally contaminated soils do not have the natural self-purification capacity, and it is difficult to reduce their pollution levels by diluting and diffusion, which must be addressed by a costly method of soil modification.
Recycling the construction waste
Germany is the first country to recycle the construction wast. During the reconstruction of World War II, the recycling of construction waste not only reduced the cost of cleaning, but also greatly alleviated the contradiction between supply and demand of building materials.
Until the end of 1955, the construction wast reproduced about 11.5 million steres of waste brick aggregate, and using them to build 175 thousand of houses. 450...
Do you already have an account? Log in here