Waste treatment and utilization

Author: Chief Editor: Dai Qun
Publisher:
Publish Date: 2002-04-19
Features: "Waste Treatment and Utilization" is a specialized book on waste treatment and utilization technologies, characterized by systematicity, scientific rigor, and practicality. The book is divided into five parts: General Introduction; Waste Water Treatment and Utilization; Waste Gas Treatment and Utilization; Solid Waste Treatment and Utilization; Waste-Free Production Processes and Bionic Groups. The book is rich in content, illustrated with visuals, and includes numerous practical examples, covering many fields of light and heavy industries such as mining, chemical industry, metallurgy, environmental engineering, water treatment, papermaking, food, dyeing and printing, leathermaking, pharmaceuticals, and building materials. It is suitable for researchers, technicians, and students from relevant research institutions, factories, enterprises, and universities.
Excerpt: Introduction to the Environment
I. Environment and Environmental Pollution
Environment refers to the surrounding conditions relative to a certain subject. Different subjects have different environments. Here, the subject refers to humans, so the environment being discussed is the human environment. Over the long course of development, as social productivity has advanced, production methods have evolved, and science and technology have improved, human environments have faced problems, and these problems have become increasingly severe, threatening human survival and development. Environmental pollution is one such problem. It refers to the alteration of the chemical, physical, biological, or radioactive characteristics of the environment due to the introduction of certain substances, organisms, or energy, thereby affecting environmental quality, endangering human health, or disrupting ecosystems.
(1) Human Environment
Human environments can be divided into social and natural environments. Social environment refers to the conditions of a certain economic base and superstructure in which people live. The economic base is the sum of production relations at a certain historical stage of society, also known as the mode of production; the superstructure is the political, legal, moral, philosophical, artistic, and religious ideas established on the economic base, as well as the political and legal systems that correspond to these ideas. We all live in a certain social environment. However, the human environment primarily refers to the natural environment. The natural environment refers to the material conditions necessary for human survival and development, the sum of various natural factors, and the objective material world surrounding humans, i.e., nature. From a geological and geographical perspective, the natural environment includes the atmosphere, hydrosphere, soil sphere, lithosphere, and biosphere; from an ecological perspective, it refers to the ecosystem centered on humans. According to natural science attributes, the natural environment can be classified as:
(1) Physical environment, which includes natural environmental factors such as meteorology, hydrology, geology, and topography, as well as artificial physical factors such as noise, radioactivity, electromagnetic radiation, and thermal pollution.
(2) Chemical environment, which refers to natural and artificial chemical substances (elements and compounds).
(3) Biological environment, which refers to animals, plants, and microorganisms.
Typically, the natural environment can be divided into four hierarchical systems based on its closeness to humans and size, from near to far:
(1) Settlement environment, which refers to areas where humans live. It consists of basic environmental factors essential for human survival and reproduction, such as sunlight, air, water, soil, and food. Based on their nature, function, and scale, they can be further categorized as village environments, urban environments, regional environments, national environments, and global environments.
(2) Geographical environment, which is composed of the atmosphere (bounded by the top of the troposphere, about 10–20 km thick, and the bottom of the weathering crust and sedimentary layer), the hydrosphere, the soil sphere, and the biosphere. It provides humans with the physical, chemical, and biological conditions necessary for survival, as well as various living resources and renewable resources.
(3) Geological environment, which primarily refers to the hard crust layer underground, extending as far as the inner core. It provides humans with a large number of non-renewable mineral resources.
(4) Cosmic environment, which includes the entire Earth and the interstellar space beyond the atmosphere. The cosmic environment may seem distant, but it has a significant impact on humans. Solar activities affect Earth's climate, and lunar movements influence Earth's tides. The energy on Earth primarily comes from solar radiation. Currently, the scope of human activity is limited to a portion of the atmosphere around Earth (within 12 km) and a thin layer of the Earth's crust surface, from the (below 9 km) to the Mariana Trench in the Pacific Ocean (above 11 km). Of course, human activity has now expanded to the depths of the Earth's crust and interstellar space, but it is primarily still within the biosphere. Therefore, the human environment we study is primarily composed of non-living elements (such as sunlight, air, water, and soil) and living elements (such as animals, plants, and microorganisms). As stated in the "Environmental Protection Law of the People's Republic of China," the environment refers to: the atmosphere, water, land, mineral resources, forests, grasslands, wildlife, wild plants, aquatic organisms, famous historical and cultural sites, scenic areas, hot springs, health resorts, nature reserves, and residential areas.
To improve living environments, humans have always struggled against natural conditions. As productivity has developed, humans have enhanced their ability to transform natural environments. However, without scientific knowledge, they lack the understanding of how to protect the environment, leading to the destruction of natural environments and the emergence of environmental issues.
(2) Environmental Pollution
The environmental problems that arise include the destruction of the environment caused by the unreasonable development and utilization of natural resources. This is due to the over-exploitation of land, deforestation, overgrazing, and the destruction of vegetation, leading to soil erosion, desertification, and the transformation of fertile land into eroded or barren areas. For example, the ancient northwest of China, the Mediterranean coast, the Middle East, and the northern part of Africa.
The second type of environmental pollution is caused by urban and industrial/agricultural activities. Especially since the 20th century, the growth of urban populations, the development of transportation, the proliferation of factories, the exploitation of mineral resources, and the use of fertilizers and pesticides have released large amounts of SO?, smoke and dust, acids, alkalis, salts, heavy metals, inorganic and organic waste, polluting the atmosphere, water bodies, and soil, leading to frequent severe pollution incidents. These incidents shocked the world and forced people to seek solutions to environmental pollution. In the early 1970s, environmental science emerged as a new discipline. It is a science that studies the quality of the human environment and its control, aiming to protect and improve environmental quality.
II. Destruction of Ecosystems and Ecological Balance
Ecology is the theoretical foundation for solving human environmental problems and is a science that studies the relationship between organisms and their environment. Modern ecology includes humans as part of the biosphere in its studies. The latest achievements in various modern sciences have permeated the field of ecology, such as systems engineering, economics, technology, chemistry, physics, and mathematics. This has led to the development of system ecology, economic ecology, ecological technology, chemical ecology, physical ecology, and mathematical ecology. These disciplines help people gain a deeper understanding of, recognize, and fundamentally solve complex problems in ecosystems and human environmental issues. They also provide guidance for balancing rapid economic development with environmental protection.
An ecosystem is a primary ecological unit composed of both living and non-living elements. In a normal ecosystem, energy flow and material cycles continue uninterrupted, and a dynamic balance is maintained among organisms. The internal ecosystem has a certain regulatory capacity. However, if human activities cause excessive environmental changes or if the amount of harmful substances entering the system exceeds its regulatory capacity, environmental problems will arise, the ecological balance will be disrupted, and both humans and organisms will suffer damage. Therefore, the preservation and improvement of environmental quality, as well as the restoration and establishment of ecological balance, depend on people's understanding and application of ecological principles and the structure and functions of ecosystems.
(—) Ecosystem
A population refers to a group of individuals of the same species that can freely mate and reproduce within a certain natural region (also known as a group). A biological community refers to the overall organisms of various different populations that have direct or indirect relationships with each other. Any biological community interacting with its surrounding non-biological environment forms a specific spatial combination of life and environmental systems, known as an ecosystem.