Water is an essential resource for the sustainable development of society. With the development of urbanization and industrialization, more and more pollutants that are not easy to remove enter the natural water environment, affecting water quality and ultimately endangering human health.

Long-term practice has proved that traditional sewage treatment methods have been difficult to meet the needs of existing water pollutants, so the research and development of new effective treatment technologies is the main task at present.

Microbial treatment technology has attracted the attention of many scholars at home and abroad due to its advantages of good pollutant control effect, high enrichment rate of dominant strains, high microbial activity, strong resistance to environmental interference, low economic cost and reuse. With the development of technology, microorganisms that can "eat dirt" have gradually been widely used in the field of sewage treatment.

Microbial technology has obvious advantages in treating urban and rural sewage

Water pollution usually refers to the deterioration of water quality and the reduction of water use value caused by human causes, and the main pollutants include solid waste, aerobic organic matter, refractory organic matter, heavy metals, plant nutrients, acids, alkalis, petroleum substances and other chemicals.

At present, traditional sewage treatment separates insoluble pollutants through physical methods such as gravity sedimentation, coagulation clarification, buoyancy flotation, centrifugal separation, magnetic separation, etc., or transforms pollutants through chemical methods such as acid-base neutralization, chemical precipitation, and redox. In addition, dissolved pollutants in water can be separated by adsorption method, ion exchange method, membrane separation method, evaporation method, freezing method, etc.

However, among these traditional methods, treatment plants that use physical methods for sewage treatment usually occupy a large area, have high infrastructure and operating costs, large energy consumption, complex management, and are prone to sludge expansion, and the equipment cannot meet the requirements of high efficiency and low consumption. Chemical methods have high operating costs, consume a large amount of chemical reagents, and are prone to secondary pollution.

The use of microbial technology to treat urban and rural sewage has low energy consumption, high efficiency, low amount of residual sludge, convenient operation and management, and can also realize phosphorus recovery and treatment water recycling. Wang Meixia, a teacher at Baotou Light Industry Vocational and Technical College in Inner Mongolia, who has been engaged in bioengineering and environmental governance research for a long time, said that microbial technology has gradually developed into an effective means to solve outstanding environmental problems such as water pollution.

Small microorganisms have made miraculous achievements in "actual combat"

In the New Year of the Tiger, after the snow in Weining, Guizhou, hundreds of black-necked cranes danced on the lake, flocks of gray geese sometimes chirped and soared, sometimes recuperated in the water, and egrets paced on the shore to hunt, attracting passers-by to stop and watch, take photos and videos. Weining Caohai is a typical plateau freshwater lake and the largest natural freshwater lake in Guizhou. In the past few decades, with the increase in population and frequent human activities, Weining Caohai was once on the verge of disappearing, and the eutrophication of water bodies was prominent.

The team led by Zhou Shaoqi, vice president of Guizhou University, has overcome the long-term insurmountable problems in the field of biological denitrification research in the world, and cleverly used microbial denitrification technology to give Caohai a new lease of life. At the same time, Zhou Shaoqi's team has also promoted new technologies and engineering applications to urban sewage, refining wastewater, landfill leachate and rural sewage, and the pollution control effect is remarkable.

In 2016, the black and odorous water bodies of Xiao River and Lei Feng River in Changsha High-tech Zone attracted criticism. Hunan Sanyou Environmental Protection Technology Co., Ltd. used the water microbial activation system to eliminate the black odor problem of the Xiao River in just one and a half months, making microbial technology famous. "We reorganize, improve and optimize the water microbial ecosystem by effectively activating water microorganisms and reproducing them in large numbers, so as to promote the restoration of water bodies' self-purification capabilities." The company's Dr. Yi Jing said.

Coincidentally, in the West Lake Garden of Changhai New Village, Yangpu District, Shanghai, in a pond covered with a large area of cyanobacteria, the turbid green dirty water has become a clear stream for fish to swim in it, and the water quality of the lake has also changed from poor five to two or three categories. This miracle was created by the innovative technology developed by the environmental new technology team of Tongji University - water microbial activation system. This technology is also applied to the ecological restoration and purification project of 300,000 square meters of Haidong Wetland on the east bank of Dianchi Lake in Yunnan.

In 2021, our country launched a number of policies related to sewage treatment to promote the utilization of sewage resources, increasing the annual treatment volume of sewage and increasing investment in industrial sewage treatment. At present, with the transformation of scientific and technological achievements and the rise of a number of domestic biological environment treatment enterprises, microbial sewage treatment will be widely used in construction, agriculture, transportation, energy, petrochemical, environmental protection, urban landscape, medical catering and other fields.