Promote the high-quality development of the sewage treatment industry under the framework of ecological civilization
2021-08-13
Entering the "14th Five-Year Plan", my country is facing the building of a well-off society in all respects and achieving the first centenary goal, and then embarking on a new journey of building a socialist modern country in an all-round way and marching towards the second centenary goal in the first five years.
For the sewage treatment industry, on the one hand, it shoulders the important task of continuing to improve the quality of the urban water ecological environment, and on the other hand, it needs to deal with the major challenge of increasing the people's satisfaction with the ecological human settlement environment. In the new historical period of ecological civilization construction, whether for the improvement of the quality and efficiency of the existing system or the improvement of incremental construction, the sewage treatment industry needs to embark on the path of upgrading and transformation of high-quality development.
01
Reviewing the birth, upgrading and transformation development stages of the sewage treatment industry
The first industrial revolution in the 1860s marked the entry of human beings into the era of industrial civilization. During the industrialization phase, the population shifted to cities, and small-scale, low-load domestic pollution was transformed into large-scale, high-load combined life and industrial pollution. Farming The natural cycle of the times has been broken, and the new balance after the intervention of human engineering has not yet been established. The amount of pollutants produced far exceeds the capacity of the environment, causing a series of serious consequences such as black and odorous water and the breeding of diseases.
Until 1914, a hundred years ago, the activated sludge process was born in England, where the industrial civilization originated, marking the rise of the modern sewage treatment industry.
With the advancement of tools in the later stages of industrialization, larger-scale and global environmental problems have come into people's vision, rivers, lakes, ocean blooms, red tides and other water eutrophication problems have emerged, and sewage treatment technology has moved from solving black and odor control to control Nitrogen and phosphorus pollution develops and eventually develops to control various types of micro-pollutants that generate potential health risks.
At present, activated sludge technology has undergone many rounds of changes, and a series of sewage treatment processes with various functions and configurations have evolved, including AAO process, oxidation ditch process, AB process, etc., and a large-scale pipe network has been gradually constructed Collection, centralized transmission and centralized treatment of urban sewage treatment mode. With the increase in urbanization rate and the emergence of large cities, sewage treatment plants have become an important part of urban infrastructure.
In 1987, the World Environment and Development Commission headed by Mrs. Brunland published "Our Common Future", which formally proposed that "it can meet the needs of contemporary people without compromising the ability of future generations to meet their needs." Concept of sustainable development. The 1992 "United Nations Framework Convention on Climate Change" sought to stabilize the atmospheric concentration of greenhouse gases at a certain level, thereby preventing human activities from having "negative effects" on the climate system.
While reducing pollutants, the sewage treatment industry began to focus on reducing the consumption of non-renewable resources, such as energy, land, mineral chemicals, building materials, etc., and used economical methods to recycle the resources in wastewater, such as reclaimed water and nutrition. Elements, energy (biogas, heat), etc. Entering the stage of sustainable development, the sewage treatment industry has further upgraded and transformed in the direction of material recycling, energy recovery and reclaimed water reuse.
While the western developed countries took the lead in proposing the concept of sustainable development, they have also successfully led this round of development of the sewage treatment industry.
In 2003, the world's first NeWater reclaimed water plant was built in Singapore, and the wastewater reuse and reuse reached drinking water standards.
In 2005, the Strass Wastewater Treatment Plant in Austria achieved energy self-sufficiency for the first time in the world. It only relied on the recovery of chemical energy in wastewater to meet the energy consumption of wastewater treatment.
In 2016, Swiss legislation forced the recovery of non-renewable phosphorus resources from pollutants such as sewage (sludge) and animal manure.
In addition, a series of green and low-carbon sewage treatment technologies such as anammox autotrophic denitrification, aerobic granular sludge, and thermal hydrolysis advanced anaerobic digestion have gradually been promoted and applied. The Dutch sewage treatment industry proposes to transform the sewage treatment plant into a three-in-one sustainable sewage treatment facility (resource plant, energy plant, and reclaimed water plant) that integrates material recycling, energy recovery and reclaimed water reuse, so as to build a long-term vision of a sustainable society.
my country's sewage treatment industry started late, but it has developed rapidly and has gone through a period of ultra-high-speed construction.
According to the Urban and Rural Construction Statistical Yearbook, as of 2019, my country has built 5,970 urban sewage treatment plants covering cities, counties, and towns, with a treatment capacity of more than 200 million m³/d, which has surpassed the United States and has become the world's largest sewage treatment plant. nation.
Sewage collection, treatment and resource utilization facilities built in the past two decades have become a core component of urban environmental infrastructure, and have played a very important role in realizing pollution prevention and improving the urban living environment.
At the same time, in the process of rapid development of the sewage treatment industry in my country in the past two decades, due to a series of problems such as "heavy ground and light underground", "heavy water and light mud", and we are busy making up for the lag in the construction of sewage treatment plants. This lesson ignores the international sustainable development transformation and related technological progress, which has led to a series of congenital deficiencies and major technical flaws in my country's sewage treatment system.
For example, they generally face practical problems such as poor pipeline construction quality and serious leakage; sewage treatment plants adopt a large number of high-energy-consuming delayed aeration processes and cancel the design of primary sedimentation tanks, which are inconsistent with the international mainstream technology; lack of pollution control Considering the system of sludge resource treatment and disposal, the proportion of sludge anaerobic digestion projects is very low (less than 3%), and future carbon emission reduction requirements cannot be achieved in the short term; nitrogen and phosphorus resource recovery has begun to enter the industrialization stage abroad, while my country At present, there is no clear top-level design and thinking on the direction of future sustainable development.
Urban sewage treatment plants pay more attention to pollution control and discharge standards, but lack of thinking about the functionality and systematicness of urban sewage treatment, and even due to excessive attention to high standard discharge, the sewage treatment industry generally suffers from energy consumption and waste of resources, etc. A series of questions.
In response to the general trend of global sewage treatment development and the many problems that exist in the rapid development of China's sewage treatment, in 2014, the industry expert committee headed by Academician Qu Jiuhui proposed to "build a future-oriented Chinese urban sewage treatment concept plant "The concept of ", the leading concept of the future is summarized into the four pursuits of "sustainable water quality, energy self-sufficiency, resource recycling, and environmental friendliness." The transition from "running" to "leading".
Change the industry's practice of "taking one step at a time, looking at one step" and "continuous patching", guide the overall forward, achieve leapfrog development, practice advanced low-carbon and green concepts, and focus on applications and demonstrations of the world that has been and will be engineered Advanced technology fully meets the strategic requirements of sustainable development of Chinese cities.
02
The leading role of the concept of ecological civilization in the sewage treatment industry
The century-old history of the sewage treatment industry began with the rapid rise of solving urban human settlements and sanitation problems, through the mature period of solving the river environment, and the upgrading and transformation of the sustainable development stage, social needs, technological innovation, management systems, and civilization. Concepts and other factors interact and influence each other at different stages of development, and promote the continuous deepening and upgrading of human society's awareness of environmental protection.
Figure 1 The concept of "ecological civilization" upgrades and deepens the concept of environmental protection
The concept of "environmental protection" in the narrow sense is a simple cognition based on the survival process of human beings as intelligent creatures. In other words, human existence cannot do without dependence on the surrounding environment, so it is necessary to protect it. This is a one-way relationship between man and nature.
The concept of "sustainable development" is a social development model based on limited resources. Reflects a one-way relationship between human and social development, that is, people need to consider for social development (later people). The concept of "sustainable development" is a review of human beings in the era of industrial civilization regarding the development of productivity and the consumption of production resources. It is an upgrade of the concept of "environmental protection" and provides a practical rule, that is, the need not to affect the "descendants" Demand.
The concept of "ecological civilization" describes a civilization that has never appeared in history. It proposes a social form with "human and nature, nature and society, harmonious coexistence between man and society, virtuous circle, all-round development, and sustained prosperity" as the basic purpose.
Its connotation includes and surpasses previous understanding. The word "ecology" reflects the relationship between man and nature, protects nature while enjoying nature; the word "civilization" reflects the relationship between man and nature and society. Human beings must respect nature, personally obey society, and society supports personal development; the convergence of "ecology" and "civilization" reflects the relationship between nature and society. Nature provides a material foundation for society in the form of resources, and society uses technology The way respects nature.
The concept of "ecological civilization" contains multiple two-way relationships, which transcends the narrow sense of "environmental protection" and "sustainable development". On the basis of the traditional concept of focusing on the relationship between "people and nature", it adds a question of "nature and society". The emphasis on the harmonious relationship between "and "people and society" is a creative upgrade and deepening of the concept of environmental protection, providing a new form of human civilization that transcends "industrial civilization", that is, it is a kind of " The "civilization" of "ecology", this "civilization" treats "ecology" in a civilized way.
For a long time, environmental protection has been an area that focuses on social public interests rather than directly creating economic benefits. The demand for low-cost has often been prioritized over high-quality. "The Search for the Ultimate Sink: Urban Pollution in Historical Perspective" (The Search for the Ultimate Sink: Urban Pollution in Historical Perspective) pointed out that the governance concept of seeking low-cost, short-term pollutant disposal solutions is common in Western urban environmental policies. This concept permeates the economic evaluation, social mobilization, engineering design and even the construction of related disciplines of the governance plan, and eventually lays down the long-term hidden dangers that cause catastrophic environmental consequences.
In our country, there are similar situations where attention is paid to short-term results and long-term planning is ignored. Our pipe network problems and sludge problems are "disastrous long-term hidden dangers."
Traditional environmental protection concepts have always been unable to avoid the contradictory relationship between social economic development and environmental protection, that is, the contradiction between nature and society. For example, even in western developed countries, the upgrading and transformation of the sewage treatment industry is far from satisfactory.
Sewage treatment systems have become the most energy-consuming public infrastructure in many communities in the United States. From 2009 to 2021, the American Civil Engineering Association's comprehensive rating of water supply and drainage systems every four years was a failure.
The U.S. sewage treatment industry has also awakened that outdated water treatment facilities are in urgent need of large-scale transformational technology application, management system and model innovation. In particular, it is proposed that sewage treatment plants need to manage sewage resources in the future. The role of community members is integrated into the surrounding economic development and maximized environmental benefits in the most economical way.
The concept of ecological civilization provides a breakthrough strategy. The concept of "ecological civilization" belongs to China's creation in the development of human society. The overall layout and development strategy of the "five in one" of the 18th National Congress of the Communist Party of China will "ecological civilization" When construction reaches a new level, it must be integrated into economic construction, political construction, cultural construction, and social construction. This fully reflects the connotation of ecological civilization's pursuit of comprehensive development.
The American National Academy of Humanities and Humanities Academician John Cobb (COBB JB, Jr.) keenly discovered that China proposes the substantive connotation of ecological civilization. He once wrote an article that "direct entry into the development of ecological civilization will bring China a once-in-a-lifetime experience. Great opportunity, this opportunity is China's unique opportunity to lead the world.......
China should seize the once-in-a-lifetime great historical opportunity of directly entering ecological civilization. "The development goal of socialism with Chinese characteristics is not only to be satisfied with sustained development, but also to consider the continued prosperity of the Chinese nation.
At the same time, the main contradiction in our society has been transformed into the contradiction between the people's growing need for a better life and the unbalanced and inadequate development. This requires us to pay more attention to people and nature, nature and society, and people than ever before. Harmonious and symbiotic relationship with society. This is the essence of the reason why ecological civilization surpasses industrial civilization and the concept of sustainable development.
The author believes that the concept of ecological civilization is not a political slogan. It requires various industries in society to reconstruct their industries and development models in accordance with the principles of ecological civilization. Qiu Baoxing, former deputy minister of the Ministry of Housing and Urban-Rural Development, once regarded traditional sewage treatment plants as products of the industrial age, called "Ford-style" sewage treatment plants, which are difficult to cope with the new challenges brought by a series of environmental issues such as current climate change, energy crisis and resource recycling. .
In the field of urban domestic sewage treatment, the sequelae of industrial civilization have gradually emerged-high energy consumption and frequent secondary pollution problems have made sewage treatment facilities that should serve the society become the city's "negative assets" .
In the era of ecological civilization, the sewage treatment industry needs to think about a question: can we get rid of the mental constraints of the industrial age and transform water treatment by changing the model?
03
my country's characteristic practice in the field of water ecological civilization construction
The national conditions of my country's rapid urbanization have led to a wide range of contradictory relationships between the sewage treatment plants built in the early stages and the surrounding communities in subsequent developments.
The comprehensive impact of sewage treatment plants on surrounding communities and even cities is a new issue that has only been raised in recent years and is one of the important characteristics of my country's sewage industry.
my country started the rapid large-scale construction of sewage treatment plants by issuing national bonds with the support of urban infrastructure construction for the first time in 1998.
With the "Eleventh Five-Year Plan" listing COD as a national binding indicator, it has accelerated greatly. During the period from 2010 to 2020, it has experienced an extraordinary period of rapid development (see Figure 2).
Due to planning considerations such as sanitation, the site selection of sewage treatment plants was basically around the city at that time.
However, with the continuous urbanization process in my country in the past decade, the urban area has continued to expand and the boundaries have continued to expand. Many sewage treatment plants that were originally located in the suburbs are now located in densely populated urban core areas.
Due to the impact of the sewage treatment plant on the surrounding landscape, its own noise and odor, etc., the impact on the surrounding environment is often not properly handled, making it a "gray" facility. The avoidance effect of sewage treatment plants has become an obvious industry problem.
Figure 2 The construction of urban sewage treatment plants and urban development and construction in China have been carried out almost simultaneously. Contradictory relationship
The contradictory relationship between the sewage treatment plant and surrounding communities caused by rapid urbanization is a characteristic problem faced by the sewage treatment industry in my country, which is related to the historical background of rapid urbanization in my country. From 2000 to 2020, my country only took 20 years to complete the goal of increasing the urbanization rate from 30% to 60%.
Therefore, it can be said that the construction of sewage treatment plants is almost synchronized with the development and construction of the city. In other words, the construction speed of the city has exceeded the planning speed, resulting in a large number of sewage plants built in the early stage being surrounded by urban construction.
In contrast, the United States and Europe began the urbanization process at the beginning of the last century, nearly two hundred years earlier than my country, and took nearly 70 years to complete the urbanization rate from 30% to 60%. At this stage, the planning and construction of sewage treatment plants in Western countries began in the later stages of urbanization and after the emergence of water pollution problems.
Therefore, the emergence of contradictions between my country's sewage treatment plants and urban development has certain national conditions, which also requires innovative solutions in line with China.
The underground treatment plant provides a new choice of construction space, which has changed the antagonistic relationship between the traditional water plant and the community, and has become one of the characteristic practices in the field of water ecological civilization construction.
Objectively, the construction of underground sewage treatment plants in my country has shown an increasing trend year by year, and the development is very rapid.
According to incomplete statistics, as of the end of 2020, the number of underground sewage treatment plants in my country has reached 109, with a total treatment capacity of 15.86 million m³/d, of which half of the underground plants have a scale of more than 100,000 m³/d, and nearly half of the sewage is 200,000. ~500,000 m³/d large-scale underground plant processing, which is the country with the largest number of underground plants in the world.
Specifically, the distribution of underground sewage treatment plants in my country has obvious regional concentration characteristics. They are mainly distributed in economically developed areas such as the Bohai Rim, the Yangtze River Delta and the Pearl River Delta, as well as the Yunnan-Guizhou-Sichuan region with more complex geomorphology.
As shown in Figure 3, in terms of sewage treatment scale, the provinces with the largest scale of underground plants are Guangdong, Hubei and Beijing, with daily treatment scale exceeding one million cubic meters. Guangdong Province ranks first, reaching 4.17 million m³ /d.
In terms of quantity, the provinces with the largest number of underground factories are Guizhou, Guangdong, and Yunnan, all with more than 10 underground factories. Underground sewage treatment plants in different regions have significant differences in their sewage treatment scale. The scale of underground plants in Yunnan and Guizhou is relatively small, with an average scale of 40,000 to 50,000 m³/d; while the average scale of underground plants in Beijing and Zhejiang is relatively small. Larger, reaching 140,000 to 150,000 m³/d; while the average scale of underground plants in Guangdong and Hubei is larger, 230,000 m³/d and 380,000 m³/d respectively. Underground sewage treatment plants have become a new growth point in the municipal sewage treatment industry during the "14th Five-Year Plan" period.
Figure 3 Regional distribution of underground sewage treatment plants in China (left) and main statistics (right)
Take the Nanming River governance in Guiyang as an example. The location of the Nanming River is a karst landform. At the same time, it is difficult to dispatch urban water and land resources are scarce. The original "large cut row" scheme has high investment, difficult collection, and difficult reuse.
China Water Environment Group adopted the "moderately centralized, on-site treatment, nearby reuse" decentralized sinking sewage treatment plant construction idea to re-optimize the original plan, saving about 1.1 billion yuan in pipeline network investment, water transfer and replenishment The electricity cost is only about 30 million yuan, the ecological water supply of the Nanming River is 160 million m³/year, and more than 1,000 acres of land are saved. At the same time, the water quality of the Nanming River and the basic conditions for economic development of the surrounding communities have been improved.
The construction of the underground plant is a pioneering work in the sewage treatment industry in my country, and an exploration that attempts to break the boundaries of the industry and promote the sewage treatment plant to play a more important social role.
The underground sewage treatment plant itself is not a new thing. It was first built in a small number of Nordic countries such as Finland and Norway due to limited land resources in the plains and the use of closed underground spaces to maintain water temperature in winter. However, my country uses underground sewage treatment plants as the starting point. Based on the needs of ecological civilization construction, it reconstructs the relationship between man and nature, nature and society, and people and society, making underground sewage treatment plants a characteristic of my country's water ecological civilization construction field. Practice one.
From the perspective of the times, looking at the phenomenon of underground sewage treatment plants in a macroscopic view, the construction of sewage treatment plants underground is only the first step, and the promotion of future technology towards land-saving and low-carbon development is the second step, as well as improving the underground The third and fourth steps such as the in-situ reuse model of plant resources and the construction of a composite functional ecological complex. Finally, after continuous efforts, the sewage treatment plant, modern agriculture, ecological landscape, etc. are integrated to achieve a virtuous cycle of materials, rational use of energy, The ecological block with integrated functions realizes the transformation of the traditional ecological "negative assets" of sewage treatment plants into ecological "positive assets", enabling the borderless sewage treatment plants to meet the needs of the times and become the water environment treatment industry for the realization of the value of ecological civilization Innovations and contributions made.
The concept of sewage treatment plant put forward the concept of ecological complex, especially in small and medium-sized cities and villages and towns, building a new shared space between urban and rural areas has become another important characteristic practice in the field of water ecological civilization construction.
The concept factory concept was brewed and launched against the background of the strategic decision to "vigorously promote the construction of ecological civilization" in the "18th National Congress" of the Party in November 2012. deepen.
From the initial pure focus on sewage treatment plants to the concept of green environmental infrastructure, from sustainable water quality to sewage recycling, from energy self-sufficiency to low-carbon development, from environmental friendliness to urban and rural sharing of new spaces.
In April 2020, the Yixing Concept Factory officially broke ground and will be fully completed and put into operation in the middle of 2021. The Yixing Concept Plant is the first sewage treatment plant to fully introduce the concept and pursuit of the concept plant, and is called the original version of the concept plant.
The Yixing concept plant expands the demonstration sewage treatment plant from the basic functions of pollutant reduction to urban energy plants, water source plants, and fertilizer plants, and then develops into a new type of environmental infrastructure that integrates with cities and villages in an all-round way and mutually beneficial.
Yixing Concept Plant redefines the relationship between sewage treatment plants and urban and rural areas, and will clearly convey the concept of "sewage is a resource, sewage treatment plants are resource factories" to the whole society, and change the public's inherent experience and perception of sewage treatment plants .
Among them, the concept factory goes from simply realizing environmental friendliness to constructing a new shared space between urban and rural areas. The integration and interaction of environmental infrastructure with urban and rural ecology, production and life is another important deepening of the relationship between sewage treatment and surrounding communities.
The concept factory owns and produces a number of important ecological elements. It can construct an urban and rural ecological complex through the supply of water and fertilizer to farmland, coordinate agricultural upgrading, and feed back the countryside. At the same time, the concept factory should cherish and make good use of national land resources, and constructing a shared and mutually promoting urban and rural space is its important value direction.
As a functional organic component of the city, the concept factory can expand the construction of public facilities such as gymnasiums, libraries, and science and technology centers.
While water quality is sustainable, environmental infrastructure should break through the traditional municipal category, actively integrate many elements such as architecture, landscape, ecology, environment, etc., to form a beautiful space that promotes urban-rural exchanges and carries regional cultural tastes and industrial characteristics.
Figure 4 Sewage treatment concept plant promotes the transformation from negative assets to positive assets and four pursuits
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