System and method for in-situ ameliorationremediation of saline-alkali soil using microalgae
A system and method for in-situ amelioration of saline-alkali soil using microalgae. Sewage and microalgal seeds are pumped into an microalgae growth pond for growing microalgae, and online equipment is used for monitoring the level of nutrients in the pond. When the microalgae reach the stationary phase of their growth, the screen mesh is lifted to separate microalgae from liquid, so that they are conveniently harvested by scraping. The harvested microalgae are returned to the soil as a soil ameliorant.
1 . A system for in-situ amelioration of saline-alkali soil using microalgae, comprising a top cover, a microalgae growth pond, a screen mesh, a soil layer, and an impermeable layer, wherein:
the top cover covers a top opening of the microalgae growth pond, the microalgae growth pond being for culturing the microalgae;
the screen mesh is disposed within the microalgae growth pond and on top of a bottom portion of the microalgae growth pond, and the screen mesh drains off water when the screen mesh is lifted so that the microalgae are trapped on the screen mesh at an end of a microalgae culture cycle;
the soil layer is disposed below the screen mesh, wherein extracellular secretions secreted by the microalgae have infiltrated into the soil layer below the microalgae growth pond, and have reshaped a structure of a soil microbial community; and
the impermeable layer is disposed under the soil layer.
2 . The system according to claim 1 , wherein the screen mesh is made of polyamides, and a pore diameter of the screen mesh is less than 10 μm.
3 . The system according to claim 1 , wherein the top cover is made of polymethyl methacrylate or plastic film.
4 . The system according to claim 1 , wherein a depth of the microalgae growth pond is 15-20 cm.
5 . The system according to claim 1 , wherein a thickness of the soil layer is 20-40 cm.
6 . The system according to claim 5 , wherein the thickness of the soil layer is 30 cm.
7 . The system according to claim 1 , wherein the extracellular secretions secreted by the microalgae are extracellular polymeric substances.