Ecological non-harmful treatment system for domestic sewage

Abstract

The application discloses a domestic sewage ecological harmless treatment system and relates to the technical field of sewage treatment. The domestic sewage ecological harmless treatment system comprises a septic tank, a clear liquid collecting tank and a deodorization tank which are connected in sequence, and a water outlet of the deodorization tank is further provided with an ecological treatment tank. The ecological treatment tank comprises an algae treatment ecological tank arranged in the center and a plurality of earthworm ecological filter tanks which are arranged around the algae treatment ecological tank. A plurality of water-permeable holes are formed in the side wall of the algae treatment ecological tank corresponding to the earthworm ecological filter tanks. The domestic sewage ecological harmless treatment system can treat the collected domestic sewage through the deodorization tank, the algae treatment ecological tank and the earthworm ecological filter tanks, is ecological and environmentally friendly, and the algae, earthworms and the like in the treatment process can be further used as resources.

Description

TECHNICAL FIELD

[0001] The present application relates to sewage treatment technical field, especially to the system of domestic sewage ecological harmless treatment. BACKGROUND

[0002] With the continuous advancement of urbanization, the discharge of domestic sewage is increasing year by year, causing water environmental pollution to become increasingly serious. The main pollutants of domestic sewage are organic matter, such as starch, fat, protein, cellulose, sugar, mineral oil, etc., resulting in high COD (chemical oxygen demand) and BOD5 (biological oxygen demand) values in water. The untreated or substandard discharge of these water bodies will cause great pollution to the environment. At present, the domestic and foreign treatment technologies for domestic sewage mainly include biochemical method (activated sludge method, MBR method) and electrochemical method. Among them, the electrochemical method mainly uses electrochemical method to remove or directly oxidize organic matter in sewage, thereby reducing the COD and BOD5 values in water, and generating oxidizing agent to kill E. coli in water. The biochemical method uses the decomposition and digestion of microorganisms on organic matter in domestic sewage to generate carbon dioxide and water harmless to the environment, thereby achieving the purpose of purifying sewage. With the increasing emphasis on environmental protection, the ecological treatment method is increasingly valued. SUMMARY

[0003] In view of the above problems, the purpose of the present application is to disclose the system of domestic sewage ecological harmless treatment. The collected domestic sewage is treated by the deodorization tank, the algae treatment ecological tank and the earthworm ecological filter tank. The treatment is ecological and environmentally friendly, and the algae and earthworms in the treatment process can be used for subsequent resource utilization.

[0004] Specifically, the system of domestic sewage ecological harmless treatment of the present application comprises a septic tank, a supernatant collection tank and a deodorization tank connected in sequence. The outlet of the deodorization tank is further provided with an ecological treatment tank. The ecological treatment tank comprises an algae treatment ecological tank arranged in the center and a plurality of earthworm ecological filter tanks arranged around the algae treatment ecological tank. A plurality of water permeable holes are formed in the side wall corresponding to the earthworm ecological filter tank of the algae treatment tank.

[0005] The system of domestic sewage ecological harmless treatment of the present application uses a septic tank to collect domestic sewage. The supernatant collected is introduced into the supernatant collection tank, then treated in the deodorization tank to eliminate odor, and finally introduced into the ecological treatment tank. First, the algae in the algae treatment ecological tank absorb and treat nitrogen, phosphorus and other elements in the sewage. Then, the sewage permeates into the earthworm ecological filter tank through the water permeable holes in the side wall. The soil is used to filter the sewage, and the earthworms are used to treat the soil, thereby achieving the effect of ecological harmless treatment of domestic sewage. The system is not only green and environmentally friendly, but also the algae and earthworms can be used for subsequent resource utilization. Moreover, the soil treated by the earthworms has good fertility and can be used for planting crops to achieve the purpose of resource utilization.

[0006] Furthermore, the algae treatment ecological pond was used to cultivate *Scenedesmus obliquus* and *Chlorella vulgaris*, with a cultivation density ratio of 3:1.

[0007] Furthermore, the earthworm breeding density in the earthworm ecological filter pond is 15,000-20,000 earthworms per square meter.

[0008] Furthermore, a retaining filter layer is filled between the earthworm ecological filter pond and the algae treatment ecological pond, and the retaining filter layer is formed by filling several modified ceramic microspheres.

[0009] The soil retaining filter layer serves two purposes: firstly, it prevents soil erosion from the earthworm ecological filter into the algae treatment ecological filter; secondly, the modified ceramic microspheres pre-treat the water entering the earthworm ecological filter. Especially in the initial stage of treatment, when the algae treatment ecological filter is less effective, the soil retaining filter layer can initially absorb pollutants in the water seeping into the earthworm ecological filter, thus ensuring the stability of the treatment effect to a certain extent.

[0010] Furthermore, a plurality of partition nets are horizontally arranged within the retaining filter layer, and the plurality of partition nets are evenly distributed within the retaining filter layer.

[0011] The modified ceramic microspheres in the retaining filter layer can be easily replaced by the set separator mesh.

[0012] Furthermore, the modified ceramic microspheres are composed of porous ceramic microspheres as the core, with a polyhydroxyalkanoate / calcium peroxide composite layer wrapped around the core, and the polyhydroxyalkanoate / calcium peroxide composite layer having a porous structure.

[0013] The modified ceramic microspheres of this invention have a porous structure in both their core and the encapsulating polyhydroxyalkanoate / calcium peroxide composite layer, giving the entire modified ceramic microsphere a high adsorption capacity. Simultaneously, during treatment, the polyhydroxyalkanoate / calcium peroxide composite layer gradually decomposes, exposing the calcium peroxide which decomposes to generate oxygen, continuously replenishing the algae treatment pond with oxygen, promoting algae growth, and ensuring treatment effectiveness. Once the outer polyhydroxyalkanoate / calcium peroxide composite layer is consumed, the remaining porous ceramic microspheres can be removed and added to the algae treatment pond. The porous ceramic microspheres adsorb and collect algae in the pond, thereby controlling the algae density and preventing excessive algae growth that could negatively impact water quality. The recovered porous ceramic microspheres can be reused after cleaning.

[0014] Furthermore, the method for preparing the modified ceramic microspheres is as follows:

[0015] S1: Add dopamine hydrochloride to phosphate buffer, stir to dissolve, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir to mix well to obtain dopamine phosphate buffer for later use. Wash the polyhydroxy fatty acid ester with 50wt% ethanol solution, dry it, and then soak it in 0.02g / ml hexamethylenediamine / isopropanol mixed solution. After reacting at 37℃ for 10min, take it out, wash it with deionized water, dry it, and then soak it in dopamine phosphate buffer. Graft reaction at room temperature for 22-24h. After the reaction is completed, wash it with warm water and dry it to obtain dopamine-grafted polyhydroxy fatty acid ester.

[0016] S2: The prepared dopamine-grafted polyhydroxy fatty acid ester was dissolved in N-methylpyrrolidone solution, porous ceramic microspheres and calcium carbonate particles were added, and the mixture was stirred at room temperature for 30-40 min. Then, physiological saline was added, and the mixture was stirred at 100-120 r / min for 10-20 min. The porous ceramic microspheres coated with a dopamine-grafted polyhydroxy fatty acid ester / calcium carbonate layer were obtained. After drying, the microspheres were placed in 0.5% glutaraldehyde solution, and nano-calcium peroxide was added. The mixture was stirred and dispersed under ultrasonic conditions, and then dopamine phosphate buffer was added dropwise. The mixture was reacted under ultraviolet irradiation for 10-12 h. After the reaction was completed, the microspheres were removed, washed, and dried to obtain the modified ceramic microspheres.

[0017] Grafting polyhydroxyalkanoates (PHA) with dopamine can increase their adhesion properties, which is beneficial for subsequent coating with porous ceramic microspheres and nano-calcium peroxide. Furthermore, during subsequent calcium peroxide composite formation, dopamine polymerizes under light and crosslinking agents, coating the nano-calcium peroxide and allowing it to be better fixed onto the PHA matrix, thus increasing the calcium peroxide loading.

[0018] Furthermore, the pretreatment of the porous ceramic microspheres is as follows: alumina, silica, acrylamide, polyacrylamide, ammonium persulfate, and fly ash are weighed and added to a ball mill. After ball milling and mixing, a slurry with a solid content of 15-20% is obtained. Sodium dodecyl sulfate is added to the slurry, stirred for 1-2 hours, allowed to stand for 12 hours, dried, and then calcined in a muffle furnace for 6-8 hours. The slurry is then removed and ground to obtain crude porous ceramic microspheres. The crude porous ceramic microspheres are washed with clean water, dried, and then placed in a plasma reactor for plasma reaction for 5-10 minutes to obtain porous ceramic microspheres.

[0019] Furthermore, the plasma reaction uses air as the working gas, with a pressure of 25-30 Pa and a power of 100-120 W.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention discloses a system for the ecological and harmless treatment of domestic sewage. The system treats the collected biological sewage through a deodorization pond, an algae treatment ecological pond, and an earthworm ecological filter pond. The system is ecological and environmentally friendly, and the algae and earthworms produced during the treatment process can be utilized as resources in the future.

[0022] 2. The system for ecological harmless treatment of domestic sewage of the present invention fills the space between the algae treatment ecological pond and the earthworm ecological filter pond with modified ceramic microspheres to form a retaining filter layer. This layer can serve as a filter layer, ensuring the stability of the treatment effect to a certain extent. At the same time, it can continuously provide oxygen to the algae treatment ecological pond, further ensuring the treatment effect. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the system for the ecological harmless treatment of domestic sewage according to the present invention;

[0024] 1. Septic tank, 2. Clear liquid collection tank, 3. Deodorization tank, 41. Algae treatment ecological tank, 42. Earthworm ecological filter, 43. Retaining soil filter layer, 44. Separation net. Detailed Implementation

[0025] The present invention will be described in detail below with reference to specific embodiments:

[0026] The present invention discloses a system for the ecological and harmless treatment of domestic sewage, comprising a septic tank 1, a clear liquid collection tank 2, and a deodorization tank 3 connected in sequence. The outlet of the deodorization tank 3 is further equipped with an ecological treatment tank, which includes an algae treatment ecological tank 41 located in the center and multiple earthworm ecological filter tanks 42. The earthworm ecological filter tanks 42 have an earthworm breeding density of 15,000-20,000 per square meter. Multiple earthworm ecological filter tanks 42 are arranged around the algae treatment ecological tank 41. The algae treatment tank has several permeable holes on the side walls corresponding to the earthworm ecological filter tanks. The algae treatment ecological tank cultivates *Scenedesmus obliquus* and *Chlorella vulgaris*, with a breeding density ratio of 3:1. Aquatic plants can also be planted in the algae treatment ecological tank, and plants can also be planted in the earthworm ecological filter tanks. The plant roots can further treat pollutants in the water. Absorption treatment is employed to achieve better treatment results. A baffle plate is installed on the inner wall of the algae treatment ecological pond 41 to block the water permeability holes. When necessary, it can separate the earthworm ecological filter pond 42 and the algae treatment ecological pond. A retaining soil filter layer 43 fills the space between the earthworm ecological filter pond 42 and the algae treatment ecological pond 41. Several horizontally arranged partition nets 44 are placed within the retaining soil filter layer 43. The retaining soil filter layer 43 is formed by filling several modified ceramic microspheres. The modified ceramic microspheres have a porous ceramic microsphere core, wrapped with a polyhydroxyalkanoate / calcium peroxide composite layer. The polyhydroxyalkanoate / calcium peroxide composite layer has a porous structure. The partition nets facilitate the replacement of the modified ceramic microspheres later. Details are as follows:

[0027] Example 1: Preparation of Modified Ceramic Microspheres

[0028] Pretreatment: Weigh alumina and silica at a mass ratio of 1:2 and add them to a ball mill. Add deionized water and mix at 80 r / min for 30 min. Add acrylamide, polyacrylamide, ammonium persulfate, and fly ash and continue ball milling and stirring for 20-24 h. The mass ratio of acrylamide, polyacrylamide, ammonium persulfate, fly ash, and silica is 1:1:0.2:0.6:1. After ball milling, a slurry with a solid content of 15-20% is obtained. Add 0.3 times the amount of silica to the slurry. Sodium dodecyl sulfate of silica quality was rapidly stirred for 1-2 hours, allowed to stand for 12 hours, dried for 48 hours, and calcined in a muffle furnace at 1450℃ for 6-8 hours. The product was then removed and ground to obtain crude porous ceramic microspheres. The crude porous ceramic microspheres were washed with water, dried, and then placed in a plasma reactor. Using air as the working gas, a plasma reaction was carried out for 5-10 minutes, preferably 8 minutes, under the conditions of 25 Pa and 100 W.

[0029] S1: Add dopamine hydrochloride to phosphate buffer, stir to dissolve, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir to mix well to obtain a dopamine phosphate buffer with a mass concentration of 2 g / L for later use. The mass ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and dopamine hydrochloride is 0.2:0.1:1. Wash the polyhydroxy fatty acid ester with 50 wt% ethanol solution, dry it, and then soak it in a 0.02 g / ml hexamethylenediamine / isopropanol mixed solution. After reacting at 37℃ for 10 min, take it out, wash it with deionized water, dry it, and then soak it in dopamine phosphate buffer. Graft reaction at room temperature for 22 h. After the reaction is completed, wash it with warm water and dry it to obtain dopamine-grafted polyhydroxy fatty acid ester dopamine dopamine.

[0030] S2: The prepared dopamine-grafted polyhydroxy fatty acid ester was dissolved in N-methylpyrrolidone solution. Porous ceramic microspheres and calcium carbonate particles with a particle size of 60 nm were added to the dopamine-grafted polyhydroxy fatty acid ester solution at a solid-liquid ratio of 30 g / L. The mass ratio of dopamine-grafted polyhydroxy fatty acid ester to calcium carbonate was 10:1. The mixture was stirred at room temperature for 40 min, and then physiological saline was added. After stirring at 120 r / min for 10 min, the mixture was collected to obtain a surface coated with dopamine-grafted polyhydroxy fatty acid. Porous ceramic microspheres with ester / calcium carbonate layers were washed with deionized water, dried at 30°C, and then placed in a 0.5% glutaraldehyde solution. 0.5 times the amount of dopamine-grafted polyhydroxy fatty acid ester nano-calcium peroxide was added, and the mixture was stirred and dispersed under ultrasonic conditions at a frequency of 20 kHz and a power of 120 W. Then, 0.1 times the mass of the porous ceramic microspheres of dopamine phosphate buffer was added dropwise, and the mixture was reacted under 275 nm ultraviolet light irradiation for 11 h. After the reaction was completed, the microspheres were removed, washed with acetone, and dried to obtain modified ceramic microspheres.

[0031] Example 2: Preparation of Modified Ceramic Microspheres

[0032] The pretreatment is the same as in Example 1.

[0033] S1: Add dopamine hydrochloride to phosphate buffer, stir to dissolve, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir to mix well to obtain a dopamine phosphate buffer with a mass concentration of 2 g / L for later use. The mass ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and dopamine hydrochloride is 0.2:0.1:1. After washing and drying the polyhydroxy fatty acid ester with 50 wt% ethanol solution, it is immersed in a 0.02 g / ml hexamethylenediamine / isopropanol mixed solution and reacted at 37℃ for 10 min. After that, it is taken out, washed with deionized water and dried, and then immersed in dopamine phosphate buffer. The grafting reaction is carried out at room temperature for 23 h. After the reaction is completed, it is washed with warm water and dried to obtain dopamine-grafted polyhydroxy fatty acid ester.

[0034] S2: The prepared dopamine-grafted polyhydroxy fatty acid ester was dissolved in N-methylpyrrolidone solution. Porous ceramic microspheres and calcium carbonate particles with a particle size of 75 nm were added to the dopamine-grafted polyhydroxy fatty acid ester solution at a solid-liquid ratio of 30 g / L. The mass ratio of dopamine-grafted polyhydroxy fatty acid ester to calcium carbonate was 10:1. The mixture was stirred at room temperature for 35 min, and then physiological saline was added. After stirring at 110 r / min for 15 min, the mixture was collected to obtain a surface coated with dopamine-grafted polyhydroxy fatty acid ester. Porous ceramic microspheres with a calcium carbonate layer were washed with deionized water and dried at 30°C. They were then placed in a 0.5% glutaraldehyde solution, and 0.5 times the mass of dopamine-grafted polyhydroxy fatty acid ester nano-calcium peroxide was added. The mixture was stirred and dispersed under ultrasonic conditions at a frequency of 20 kHz and a power of 120 W. Then, 0.1 times the mass of the porous ceramic microspheres of dopamine phosphate buffer was added dropwise. The mixture was reacted under 275 nm ultraviolet light irradiation for 10 h. After the reaction was completed, the microspheres were removed, washed with acetone, and dried to obtain modified ceramic microspheres.

[0035] Example 3: Preparation of Modified Ceramic Microspheres

[0036] The pretreatment is the same as in Example 1.

[0037] S1: Add dopamine hydrochloride to phosphate buffer, stir to dissolve, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir to mix well to obtain a dopamine phosphate buffer with a mass concentration of 2 g / L for later use. The mass ratio of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride, N-hydroxysuccinimide and dopamine hydrochloride is 0.2:0.1:1. Wash the polyhydroxy fatty acid ester with 50 wt% ethanol solution, dry it, and then soak it in a 0.02 g / ml hexamethylenediamine / isopropanol mixed solution. After reacting at 37℃ for 10 min, take it out, wash it with deionized water, dry it, and then soak it in dopamine phosphate buffer. Graft reaction at room temperature for 24 h. After the reaction is completed, wash it with warm water and dry it to obtain dopamine-grafted polyhydroxy fatty acid ester.

[0038] S2: The prepared dopamine-grafted polyhydroxy fatty acid ester was dissolved in N-methylpyrrolidone solution. Porous ceramic microspheres and calcium carbonate particles with a particle size of 70 nm were added to the dopamine-grafted polyhydroxy fatty acid ester solution at a solid-liquid ratio of 30 g / L. The mass ratio of dopamine-grafted polyhydroxy fatty acid ester to calcium carbonate was 10:1. The mixture was stirred at room temperature for 30 min, and then physiological saline was added. After stirring at 100 r / min for 20 min, the mixture was collected to obtain a surface coated with dopamine-grafted polyhydroxy fatty acid ester. Porous ceramic microspheres with a calcium carbonate layer were washed with deionized water and dried at 30°C. They were then placed in a 0.5% glutaraldehyde solution, and 0.5 times the mass of dopamine-grafted polyhydroxy fatty acid ester nano-calcium peroxide was added. The mixture was stirred and dispersed under ultrasonic conditions at a frequency of 20 kHz and a power of 120 W. Then, 0.1 times the mass of the porous ceramic microspheres of dopamine phosphate buffer was added dropwise. The mixture was reacted under 275 nm ultraviolet light irradiation for 12 h. After the reaction was completed, the microspheres were removed, washed with acetone, and dried to obtain modified ceramic microspheres.

[0039] Example 4

[0040] Modified ceramic microspheres prepared in Examples 1-3 were used to fill the space between an earthworm ecological filter pond and an algae treatment ecological pond to form a retaining filter layer. The height of the retaining filter layer was the same as the height of the ecological treatment pond, and the thickness was 8-15 cm, preferably 10 cm. The collected biological wastewater was treated using a treatment system. A collection pond was set up at the bottom of the earthworm ecological filter pond to collect the filtered water. The collected domestic sewage and the filtered water were tested for chemical indicators, and the test results are shown in the table below:

[0041] Item CODcr BODs SS TN TP Influent 72 23 20 22 1 Example 1 effluent 32 9.1 8.3 12 0.4 Example 2 effluent 29 8.6 7.9 11 0.3 Example 3 effluent 35 8.7 8.0 12 0.4

[0042] As can be seen from the data in the table above, the ecological harmless treatment system of the present invention can effectively remove pollutants from domestic sewage, so that the water quality indicators of the effluent are lower than the Class A standard in the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB18918-2002).

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A system for the ecological and harmless treatment of domestic sewage, characterized in that, It includes a septic tank, a clear liquid collection tank and a deodorization tank connected in sequence. The outlet of the deodorization tank is also equipped with an ecological treatment tank. The ecological treatment tank includes an algae treatment ecological tank set in the center and multiple earthworm ecological filter tanks. The multiple earthworm ecological filter tanks are set around the algae treatment ecological tank. The algae treatment ecological tank has several water permeable holes on the side wall corresponding to the earthworm ecological filter tank. A retaining filter layer is filled between the earthworm ecological filter pond and the algae treatment ecological pond. The retaining filter layer is formed by filling several modified ceramic microspheres. The modified ceramic microspheres are composed of porous ceramic microspheres as the core, with a polyhydroxyalkanoate / calcium peroxide composite layer wrapped around the core. The polyhydroxyalkanoate / calcium peroxide composite layer has a porous structure.

2. The system for ecological harmless treatment of domestic sewage according to claim 1, characterized in that, The algae treatment ecological pond was incubated with *Scenedesmus obliquus* and *Chlorella vulgaris*, with a culture density ratio of 3:

1.

3. The system for ecological harmless treatment of domestic sewage according to claim 2, characterized in that, The earthworm breeding density in the earthworm ecological filter pond is 15,000-20,000 earthworms per square meter.

4. The system for ecological harmless treatment of domestic sewage according to claim 1, characterized in that, Several partition nets are horizontally arranged inside the retaining filter layer, and the partition nets are evenly distributed inside the retaining filter layer.

5. The system for ecological harmless treatment of domestic sewage according to claim 1, characterized in that, The modified ceramic microspheres are prepared by: S1: Add dopamine hydrochloride to phosphate buffer, stir to dissolve, then add 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide, stir to mix well to obtain dopamine phosphate buffer for later use. Wash the polyhydroxy fatty acid ester with 50wt% ethanol solution, dry it, and then soak it in 0.02g / ml hexamethylenediamine / isopropanol mixed solution. After reacting at 37℃ for 10min, take it out, wash it with deionized water, dry it, and then soak it in dopamine phosphate buffer. Graft reaction at room temperature for 22-24h. After the reaction is completed, wash it with warm water and dry it to obtain dopamine-grafted polyhydroxy fatty acid ester. S2: The prepared dopamine-grafted polyhydroxy fatty acid ester was dissolved in N-methylpyrrolidone solution, porous ceramic microspheres and calcium carbonate particles were added, and the mixture was stirred at room temperature for 30-40 min. Then, physiological saline was added, and the mixture was stirred at 100-120 r / min for 10-20 min. The porous ceramic microspheres coated with a dopamine-grafted polyhydroxy fatty acid ester / calcium carbonate layer were obtained. After drying, the microspheres were placed in 0.5% glutaraldehyde solution, and nano-calcium peroxide was added. The mixture was stirred and dispersed under ultrasonic conditions, and then dopamine phosphate buffer was added dropwise. The mixture was reacted under ultraviolet irradiation for 10-12 h. After the reaction was completed, the microspheres were removed, washed, and dried to obtain the modified ceramic microspheres.

6. The system for ecological harmless treatment of domestic sewage according to claim 5, characterized in that, The preparation method of the porous ceramic microspheres is as follows: alumina, silica, acrylamide, polyacrylamide, ammonium persulfate, and fly ash are weighed and added to a ball mill. After ball milling and mixing, a slurry with a solid content of 15-20% is obtained. Sodium dodecyl sulfate is added to the slurry, stirred for 1-2 hours, allowed to stand for 12 hours, dried, and then calcined in a muffle furnace for 6-8 hours. The slurry is then removed and ground to obtain crude porous ceramic microspheres. The crude porous ceramic microspheres are washed with water, dried, and then placed in a plasma reactor for plasma reaction for 5-10 minutes to obtain porous ceramic microspheres.

7. The system for ecological harmless treatment of domestic sewage according to claim 6, characterized in that, The plasma reaction uses air as the working gas, with a pressure of 25-30 Pa and a power of 100-120 W.

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