Physical methods
Physical methods mainly refer to dredging of the bottom, mechanical algae removal, diversion of water to flush silt and water transfer. Dredging the contaminated bottom means removing pollutants from the (river) system. The pollution contribution of the substrate to the overlying water body can be reduced to a greater extent, thus improving water quality. Water transfer aims to improve the water quality of a polluted river downstream by introducing clean water upstream of or near the polluted river through the regulation of hydraulic facilities (e.g. gates, pumping stations). This type of method often treats the symptoms but not the root cause.
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 denitrification and other methods. Studies have shown that this method has a better effect on the removal of turbidity, and also has a certain effect on the removal of heavy metals and so on, with less dosage of daily agents. However, this method of river sewage treatment is easy to cause secondary pollution.
Ecological - biological method (including river aeration and reoxygenation, biofilm method, bioremediation, land treatment method, aquatic plant purification method).
River aeration method
Artificial aeration reoxygenation means that the river is in a state of hypoxia (or anaerobic) artificial oxygen to enhance the self-purification ability of the river, improve water quality, improve or restore the ecological environment of the river. River aeration reoxygenation generally use fixed oxygenation station and mobile oxygenation in two forms. The process has the advantages of simple equipment, maneuverability, security and reliable, provincial, quick results, convenient operation, adaptability, aquatic ecology does not produce any harm, etc., suitable for urban landscape river and micro-pollution source water treatment.
Biofilm technology
It is to make the microbial group attached to the surface of certain carriers in the form of a membrane, through the contact with sewage, biofilm microorganisms ingested sewage organic matter as nutrients absorbed and assimilated, so as to purify the sewage.
Bioremediation technology
It refers to the use of microorganisms and other organisms, the water or soil toxic and harmful pollutants on-site degradation of C02 and water, or transformed into non-toxic and harmless substances of the engineering technology system. There are two main types of bioremediation technologies used for river sewage treatment. One is to directly add one or more species of microorganisms that have been cultured and screened to the polluted river water, and the other is to add microbial growth promoters (nutrients) to the polluted river water to promote the growth of "indigenous" microorganisms. After putting the agent, through the action of promoting the growth of pollutant-degrading microorganisms, the microorganisms in the river channel from anaerobic to aerobic succession, organisms from the lower to the higher succession, the diversity of organisms continues to increase, the dissolved oxygen rises markedly, and the black odor is eliminated. This method is obvious for eliminating black odor and increasing dissolved oxygen in water bodies.
Land treatment technology
Land treatment technology is an ancient, but proven river sewage treatment technology. It is the land as a treatment facility, the use of soil, plant system of adsorption, filtration and purification and self-regulation function, to achieve a certain degree of water purification of the day.
Aquatic plant purification method
This method is to make full use of the natural purification function of aquatic plants sewage purification method. For example, the use of floating weeds, wetlands in the reed in a certain range of water purification treatment. But the discharge of domestic sewage will produce odor, pests and landscape impact and other issues, so the selection of the above issues should be considered comprehensively, such as choosing to plant reeds in the location of the downwind in the spring and summer.