On January 19, the central news mainstream media Science and Technology Daily reported on the ZEHO ECO‘s biological treatment technology of water body, and Cao Zhe, the company’s technical director of ecological environment, was interviewed by reporters. Taking the Jiaxing “Green Water Action” project and the ecological restoration project of Erhai Lake riparian zone in Dali, Yunnan Province built by ZEHO ECO as examples, Cao Zhe introduced the outstanding technical advantages, significant implementation benefits and long-term promotion significance of water biological treatment technology to reporters.

January 19, Science and Technology Daily Biology Edition © Science and Technology Daily

Simple operation, eco-friendly and outstanding comprehensive benefits

Biological Treatment Technology: Use Natural Methods to Deal with Pollution

The biological treatment technology of the water body fully follows the ecological laws and gives full play to the natural biological action mechanism, which will not interfere in the surrounding ecological environment. The overall operation is simple, the cost is relatively low, the landscape effect is good, and there will be no secondary pollution. Aquatic plant purification technology and microbial technology are often used together, and are most widely used in the current case of river water ecological restoration and treatment.

In the clear river, the luxuriant submerged plants sway with the waves, like a “underwater forest”, where small fish and shrimp shuttle back and forth for food... “In the past, the river was yellow, and the river was full of weeds and garbage. Now the water is getting cleaner and cleaner, and the feeling of living here is getting better and better.” Recently, Ma Xueli, a resident near Huayuanbang, Wangdian Town, Xiuzhou District, Jiaxing City, Zhejiang Province, looked at the small river when she saw it from childhood.

The magnificent turn of Huayuanbang is only one result of the five-year action plan of Bishui Jiaxing. The action plan focuses on improving the transparency of water bodies and building underwater forests, and systematically promotes sewage treatment, flood prevention, waterlogging drainage, water conservation and water conservation. Water biological treatment technology is used to build the underwater forest.

01 Purification of water body by plants or microorganisms

Professor Zheng Xiangyong, deputy dean of the School of Life and Environmental Sciences of Wenzhou University, introduced that the biological treatment technology of water body usually refers to the water body treatment technology that uses specific aquatic plants, microorganisms, aquatic animals and other biological species in the process of water body treatment of rivers, lakes, reservoirs, bays and other water bodies, and combines with other engineering measures to achieve water purification and water ecological restoration.

Commonly used water biological treatment technologies include aquatic plant purification technology, microbial technology, etc. Aquatic plant purification technology is to plant emergent plants, floating plants, submerged plants and other aquatic plants, and use the growth characteristics of aquatic plants that need to absorb a large amount of nitrogen, phosphorus and other nutrient elements in the process of growth to achieve water purification effect.

Microbial technology mainly controls the composition and quantity of microbial flora in the water body by adding microbial agents to the polluted water body, and optimizes the community structure, to improve the removal efficiency of pollutants by microorganisms with self-purification ability in the water body. Common microbial agents include microbial groups mainly composed of photosynthetic bacteria, lactobacillus and nitrifying bacteria. These microorganisms can decompose organic substances from external pollution discharge, sediment release, algae growing in water and other organic substances for their own growth and reproduction, thus reducing algae breeding and improving water quality.

“The biological treatment technology of water body is usually used in combination with engineering measures such as aeration, ecological floating bed, artificial wetland, and flow generation to build a complex ecosystem that interacts and interacts with each other in the water body, and realize the treatment of water body through the synergy of various species and engineering measures,” Zheng Xiangyong said.

“Different from the traditional physical and chemical methods of water body treatment, water body biological treatment technology has the advantages of long-term treatment, ecological friendliness, and outstanding comprehensive benefits.” Cao Zhe, the director of ecological environment technology of Beijing ZEHO Waterfront Ecological Environment Treatment Co., Ltd. (ZEHO ECO), said that water body biological treatment technology fully follows the ecological laws, and plays the role of natural organisms, There will be no major disturbance to the surrounding ecological environment, and the overall operation is simple, the cost is relatively low, the landscape effect is good, and there will be no secondary pollution. Aquatic plant purification technology and microbial technology are often used together, and are most widely used in the current case of river water ecological restoration and treatment. The associated technologies, such as preparation and delivery of microbial agents, cultivation and maintenance of aquatic plants, have mature industrial chains.

02 Water biological treatment technology has been widely applied in the market

Zheng Xiangyong said that in China, water biological treatment technology has been widely used in the market. For example, Jiaxing City implemented the “Nine Rivers One Connection” project, with the amount of treatment projects reaching 1.4 billion RMB yuan, of which a considerable part of the projects adopted water biological treatment technology.

Implementing water biological treatment technology can improve the ecological and economic benefits of the water body and its surrounding areas to a certain extent.” Cao Zhe said.

For example, in the “Clean Water Action” project, which further expanded the scope based on the “Nine Rivers One Conncetion” project, ZEHO ECO adopted the combined application of aquatic plant purification technology and microbial technology to build the underwater forest system of the river. Based on the investigation of the ecological background of the water area of the site, measures such as topographic transformation and artificial replanting were taken according to local conditions. Emergent plants were planted in the area with a water depth of 0-0.5 meters, and submerged plants were planted in the area with a water depth of 0.5-2 meters. The 230,000 square meters of local aquatic plant communities with stable ecological structure and rich landscape types were restored. Emergent plants have developed roots and tall plants, which can effectively intercept external pollution, improve the ability of water conservation and water and soil conservation, and provide suitable habitat conditions for organisms; The growth of submerged plants can effectively increase the absorption capacity of nutrients in water body, reduce the release of pollutants caused by sediment disturbance, and improve the anaerobic and anoxic environmental conditions of the water body through photosynthetic oxygenation capacity; Optimize the composition and structure of aquatic animals and microbial communities, strengthen the aquatic ecological food network, promote the recovery of a healthy and stable aquatic ecosystem, and enrich biodiversity.

In the Jiaxing “Clean Water Action” project, ZEHO ECO restored a healthy and stable water ecosystem and enriched biodiversity

ZEHO ECO has jointly applied aquatic plant purification technology and microbial technology in the Jiaxing “Clean Water Action” project to build the underwater forest system in the river

Through the application and implementation of water biological treatment technology, the content of ammonia nitrogen and total phosphorus in the water body of the rivers implementing the “Clean Water Action” project in Jiaxing has been reduced, and the quality of the water environment has been significantly improved. Each river will gradually reach the surface Class III water standard and effectively improve the water transparency to over 0.8 meters.

In the Jiaxing “Clean Water Action” project, ZEHO ECO has made the water clear through the biological treatment technology

“The ecological restoration project of the Erhai Lake riparian zone in Dali, Yunnan Province, is also an excellent case of water biological treatment technology.” Cao Zhe said that ZEHO ECO measured the water volume and pollution load of over 200 channels entering the lake and 18 major rivers one by one, and used aquatic plants to arrange and form purification wetland modules. The ecological corridor in the demonstration area built with biological treatment technology not only improves the “beauty” of Erhai Lake but also gradually forms a good ecological, economic and social complex human-lake symbiosis system.

Surface flow wetland formed by purification of aquatic plants in Erhai Lake, Dali

Dali Erhai Meixi, Taoxi, Yinxian River estuary delta wetland

“In the process of Erhai Lake treatment, Shanghai Jiaotong University and others adopted the local submerged plant Ottelia acuminata to repair the water body. The Ottelia acuminata can be eaten, and the price of the online purchase of Ottelia acuminata is about ten yuan per kilogram. This technology can not only purify water quality but also bring benefits to residents, with good economic and ecological benefits.” Zheng Xiangyong said.

The submerged plant Ottelia acuminata brings good economic and ecological benefits to the Erhai Lake in Dali

03 Only by establishing a long-term management mechanism can we merge the fruits of victory

Zheng Xiangyong believes that the significance of promoting the biological treatment technology of the water body lies in using low-carbon, environmental protection and ecological methods to achieve the treatment of the water body. “However, the difficulty in promoting the technology in a large area is that it is necessary to select the suitable aquatic organisms according to the local climate, water quality and other natural environment characteristics, and carry out the combination and application in a reasonable mode. It is necessary to have a reasonable operation maintenance and resource utilization plan to ensure the long-term operation.” Zheng Xiangyong said.

Water biological treatment technology has a wide range of applications, but it still has certain limitations in practical application. For example, in the selection of aquatic plants, we should select native purification plants, strengthen the protection of native aquatic animals and plants, and strictly control alien invasive species; In planting aquatic plants, preventing the impact of fish on the survival of submerged plants in the seedling stage is still an important research topic. It is necessary to regulate the fish population structure and timely remove large fish to ensure the recovery and stability of submerged plant communities.

“At the initial stage of construction and after implementing water body biological treatment technology, certain maintenance measures are needed, especially for aquatic plants. A long-term management mechanism must well play its ecological value.” Cao Zhe said that at present, many water body treatment projects focus on construction but neglect operation and maintenance, with good initial effect, but lack of later maintenance, and water quality are prone to deteriorate again. Therefore, it is very important to establish a good water ecosystem operation and maintenance management mechanism.