Remediation technique | Technique principle | Characteristics |
---|---|---|
Physic method | ||
Artificial aeration | Increase the dissolved oxygen of the water body, reduce the concentration of dissolved pollutants in water, improve the living environment for aquatic organisms | High cost, need to be combined with other methods |
Sediment dredging | Dredging the whole or part of the river with serious deposition to restore the normal function of the river | A large amount of engineering, disrupt existing bio-systems |
Mechanical algal removal | Using ultrasonic wave to make algal cell burst, break algal cell inside the airbag, make it lose float ability and precipitate | Unsustainable method |
Chemical method | ||
Chemical precipitation | Adding iron salt or aluminum salt to produces chemical precipitation with inorganic phosphate through adsorption or flocculation, controlling the eutrophication | |
Enhanced coagulation | Add the appropriate coagulant and the decontamination is carried out by adsorption, chemical precipitation, destabilization flocculation, and adsorption bridging | The addition of chemicals agents raises the cost and introduce secondary pollution |
Acid–alkali neutralization | Acidic or alkaline substances are added to the water body to adjust the pH, meet the growing need and species reproduction in the aquatic ecosystem | |
Chemical algal removal | Add chemical algal removal agent, the effect is remarkable | Water table damage, high risk |
Ecological method | ||
Constructed wetlands | Simulates natural wetlands by extracting elements from them for artificial enhancement | Large floor space |
Ecological floating bed | Using the principle of soilless cultivation, plants are planted in water and absorb nutrients directly from the water | Generally used to repair small rivers, lakes |
Ecological revetment | Artificially reformed the river revetment to restore or strengthen the ecological capacity of water, which can protect the river bank and purify the water | Suitable for the long-term ecological remediation process |