What are the ways to manage rivers and what are the plants?

1. There are three ways to manage rivers, namely physical methods, chemical methods, ecological-biological methods, ecological-biological methods (including river aeration and re-oxygenation, biofilm methods, and bioremediation methods). , land treatment method, aquatic plant purification method)

1. Physical methods

Physical methods mainly refer to sediment dredging, mechanical algae removal, water diversion, siltation and water diversion, etc. Dredging polluted bottoms means removing pollutants from the (waterway) system. It can greatly reduce the pollution contribution rate of sediment to the overlying water body, thus improving water quality. The purpose of water diversion is to introduce clean water sources from or near the upstream of polluted rivers through the control of water conservancy facilities (such as gates and pumping stations) to improve the water quality of downstream polluted rivers. Such methods often treat the symptoms rather than the root cause.

2. Chemical methods

Chemical methods such as coagulation and precipitation, adding chemicals to kill algae, adding iron salts to promote the precipitation of phosphorus, adding lime to denitrify, etc. Studies have shown that this method has a good removal effect on turbidity, eoD, ss, and TP, and also has a certain removal effect on TN, heavy metals, etc., and the daily dosage of chemicals is small. However, this river sewage treatment method can easily cause secondary pollution.

3. Ecology--biological methods Ecology--biological methods (mainly including river aeration and reoxygenation, biofilm method, bioremediation method, land treatment method, aquatic plant purification method, etc.)

(1) Bioremediation technology

refers to the use of microorganisms and other organisms to degrade toxic and harmful pollutants in water or soil on-site into c02 and water, or convert them into non-toxic and harmless substances Engineering technology systems. There are two main types of bioremediation technologies used for river sewage treatment. One type is to directly add one or more microbial strains that have been cultured and screened into polluted river water bodies. Tests have proven that the COD removal rate is more than 9096%. The other is to add microbial growth promoters (nutrients) to polluted river waters to promote the growth of "indigenous" microorganisms. After the agent is put in, the growth of pollutant-degrading microorganisms is promoted through the growth-promoting effect. The microorganisms in the river succeed from anaerobic to aerobic, and the organisms from lower to higher. The diversity of organisms continues to increase, so that the BOD5 of polluted water bodies , COD drops rapidly, dissolved oxygen rises significantly, and black odor is eliminated. This method has a significant effect on eliminating black and odorous water bodies and increasing dissolved oxygen in water bodies.

(2) Land treatment technology

Land treatment technology is an ancient but effective river sewage treatment technology. It uses land as a treatment facility and utilizes the adsorption, filtration, purification and self-regulation functions of the soil and plant systems to achieve a certain degree of water purification.

(3) Aquatic plant purification method

This method is a sewage purification method that fully utilizes the natural purification function of aquatic plants. For example, duckweed and reeds in wetlands can be used to purify a certain water area. However, the discharge of domestic sewage will cause problems such as odor, pests and landscape impact. Therefore, the above issues must be comprehensively considered when selecting, such as choosing to plant reeds in the downwind position in spring and summer.

(4) River aeration method

Artificial aeration and re-oxygenation refers to artificially oxygenating a river in an anoxic (or anaerobic) state to enhance the self-purification ability of the river. Improve water quality and improve or restore the ecological environment of rivers. River aeration and reoxygenation generally adopt two forms: fixed oxygenation stations and mobile oxygenation platforms. This process has the advantages of simple equipment, flexibility, safety, low investment, quick results, convenient operation, wide adaptability, and no harm to aquatic ecology. It is suitable for the treatment of urban landscape rivers and micro-polluted source water.

(5) Biofilm technology

It refers to making the microbial groups adhere to the surface of certain carriers in the form of a film, and through contact with sewage. The microorganisms on the biofilm ingest the wastewater. Organic matter is absorbed as nutrients and assimilated, thereby purifying sewage. At present, the biofilm technologies commonly used in river sewage treatment mainly include inter-gravel contact oxidation method, water-holding ditch (channel) contact oxidation method, biologically activated carbon packed column purification method, thin laminar flow method and submerged flow purification method, which are more commonly used. It is the contact oxidation method.

2. The commonly used aquatic plants in river management are:

1. Lentinus edodes: a perennial emergent ornamental plant with plant height of 5-15cm, leaves alternate, long-stemmed and shield-shaped , 2 to 4cm in diameter, with wavy edges, grass green, and radial veins. It is often used as clump planting or patch planting on the banks of water bodies. It is a good material for courtyard waterscape landscaping, especially landscape detail design.

2. Dajucao: a perennial emergent or submerged herb, with a plant length of 50-80cm, the upper part of the stem is upright, and the lower part is submerged. The leaves are whorled, mostly 5-leaf whorls, and are of high ornamental value. aquatic flowers. Plant them in clusters, and when the plants are established, they will add a pleasant green color to the environment.

3. Purple taro: The plant height can reach 1.2m, with stem bulbs underground, petioles and veins purple-black, very eye-catching. It has huge leaves and is mainly used as a water edge foliage plant.

4. Umbrella: Also known as water bamboo, it is a perennial hygrophytic plant, 40-150cm high, with thick stems, upright growth, nearly round stems, and clusters. The flowering period is from July to September. They are often placed in the gaps between rockery rocks on the banks of streams for decoration, creating a unique natural scenery.

5. Zailihua: a perennial emergent plant with a plant height of 2 to 3m and a plant width of 2m. The flowering period is in July. It grows vigorously and likes moisture and is afraid of drought. It is suitable for planting on floating platforms in water bodies. The plant shape is beautiful and free-spirited, and the leaves are green and lovely. It is a top-quality flower for waterscape greening.

6. Canna with mosaic leaves: plant height 50-80cm, yellow and green leaves, wide, racemes drawn out from the top of the stem, flowering period from July to October, and green period for 240 days throughout the year. The flowers are red and the leaves are brightly colored. In addition to being decorative, it can also purify air and water quality.

7. Canna: The plant height can reach 100-150cm. The leaves are alternate, wide and oval in shape. The flowers are rich and colorful and suitable for planting in shallow water in wetlands. It has the function of purifying the air and protecting the environment. It is an ideal flower for greening, beautifying and purifying the environment

8. Purple-leaf Canna: plant height 100-150cm, purple leaves, wide, oval-lanceolate, racemes drawn from the top of the stem, flowering period 7 ~October, the green period is 240 days throughout the year.

9. Arundodium mosaic: The stem is 1 to 3m high, the stem is thick and nearly lignified, the leaves are 1 to 3.5cm wide, with white stripes, and the stem is straight on the ground with internodes, like bamboo. It is mainly used as background material for waterscape gardens. It can also be used as decoration around bridges, pavilions and pavilions. It can also be used as potted plants for garden viewing.

10. Pickerel grass: perennial emergent or hygrophytic herbaceous plant, with large leaves, 20-80cm high, changeable leaf shape, blue flowers, erect scape, usually higher than the leaf surface, during the flowering period July to October. Pickerel grass has emerald green leaves, charming flowers, and a long flowering period. It can be used as home potted plants, pond plants, and can also be widely used for landscaping.

11. Siberian iris: The plant height is 40-59cm, and the flowering period is from May to June. The biggest feature of this variety is that it is evergreen all year round. It is a rare evergreen variety among aquatic flowers. It not only has beautiful leaves, but also It also has flowers and is an aquatic plant with high ornamental value.

12. Yellow irises: a perennial upright herb that likes warmth, is relatively cold-tolerant, and is afraid of drought. The flowering period is from April to June. It is a favorite among aquatic flowers. It has bright yellow flowers and bright flowers. Beautiful appearance, like a golden butterfly flying among the flowers, with high ornamental value

13. Iris: a perennial, emergent aquatic flower, 50-80cm long, large purple flowers with yellow spots in the middle, flowering period from late April to Late May. The flowers are large and beautiful, and the colors are rich. The leaves are green and sword-like, and have high ornamental value.

14. Water lily: a perennial aquatic flower with clustered leaves floating on the water, 6 to 11 cm in diameter, white flowers, 3 to 6 cm in diameter, and the flowering period is from mid-May to September. Planted in a large area, when growing vigorously, it can present a magnificent landscape.