CN117923734B

CN117923734B - Comprehensive treatment method for rural domestic sewage

Info

Publication number: CN117923734B
Application number: CN202410327278.3A
Authority: CN
Inventors: 张媛; 张艳杰; 张焱; 史密伟; 王云霞; 张荣芝; 侯翔龙; 申一文
Original assignee: Institute Of Geography Hebei Academy Of Sciences
Current assignee: Institute Of Geography Hebei Academy Of Sciences
Priority date: 2024-03-21
Filing date: 2024-03-21
Publication date: 2024-05-31
Anticipated expiration: 2044-03-21
Also published as: CN117923734A

Abstract

The invention provides a comprehensive treatment method for rural domestic sewage, which divides rural domestic sewage into black water and grey water for respective treatment; the grey water is subjected to multiple treatments such as filtration, coagulation, flocculation, aeration, disinfection and the like, so that the organic matter content and the ammonia nitrogen content in the water are greatly reduced, and the standard of the residential water is nearly reached; the black water is filtered and fermented by a biological filter to obtain an organic fertilizer which can directly act on farmlands; the invention takes local materials according to local conditions, self-prepares the activated sludge in the whole process flow, self-produces and self-sells the activated sludge, does not need to purchase the activated sludge on the market, and greatly saves the cost; the invention has the advantages of low cost, wide raw material sources, simple process and strong operability, can effectively treat domestic sewage, and does not produce secondary pollution to the environment.

Description

Comprehensive treatment method for rural domestic sewage

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a comprehensive treatment method for rural domestic sewage.

Background

Rural domestic sewage contains a large amount of organic matters, inorganic matters, microorganisms and nutrient elements, but basically contains no heavy metals and refractory organic matters.

At present, rural domestic sewage treatment technology includes: constructed wetland, stabilization pond, land infiltration, MBR technology, and the like. Constructed wetland, stabilization pond and land infiltration are ecological treatment technologies, but the biggest problem of ecological treatment technology is that the effluent quality is unstable, is easily influenced by external environment, and occupies a large area. MBR technology belongs to typical biological treatment technology, but the MBR technology is easy to have the problems of uneven gas distribution, blockage, poor sanitary conditions and the like.

The existing rural domestic sewage treatment technology has higher cost, and for rural areas with slower development and weaker economic basis, because the burden is not high, a sound sewage collection pipe network is not provided, most of sewage is directly discharged nearby without treatment, the development of rural sewage treatment work is restricted, and the water quality of surface water and underground water and the physical health of local residents are seriously influenced.

Therefore, the rural domestic sewage treatment method with low cost, good treatment effect, economy and high efficiency is provided to be a problem to be solved urgently.

Disclosure of Invention

In order to solve the problems, the invention provides a comprehensive treatment method for rural domestic sewage, which comprises the following steps:

Step (1), sewage classification

Separating sewage discharged by households into grey water and black water for respective treatment; the grey water comprises shower water, laundry water and kitchen water; the black water comprises toilet water;

Step (2), grey water treatment

(2.1) Filtering the grey water for the first time to remove insoluble impurities in the water;

(2.2) adding a coagulant into the grey water, shearing for 10-20min, and rotating at 800-1000r/min;

(2.3) carrying out secondary filtration on the grey water, and collecting filtered sludge for later use;

(2.4) adding a flocculating agent into the grey water, shearing for 10-20min, and rotating at 200-500r/min;

(2.5) carrying out third filtration on the grey water, and collecting the filtered sludge for later use;

(2.6) introducing ozone to aerate the grey water;

(2.7) adding disinfectant into the grey water to obtain reclaimed water;

step (3), black water treatment

(3.1) Carrying out filter pressing on black water, wherein the pressure is 0.4-0.5MPa;

(3.2) mixing urine with reclaimed water, and filtering by a biological filter to obtain an organic fertilizer;

(3.3) the solid obtained after the filter pressing is feces, and the feces are divided into two parts;

Mixing the first part of excrement with sludge filtered by the second and third times according to any proportion, and aerating to obtain activated sludge after aeration is finished;

Mixing the second part of the excrement and the activated sludge in a stirring tank at the rotating speed of 300-500r/min for 10-20min;

And (3.4) stirring, adding aerobic bacteria, performing aerobic fermentation treatment, and fermenting to obtain the organic fertilizer.

Preferably, the filter material used in the first filtering in the step (2.1) is 3-5 layers of gauze, the mesh distance is 3-5cm, and the mesh number is 20-30 meshes;

the filtering material used in the second filtering in the step (2.3) is 3 layers of gravel, and the width of each layer is 8-10cm; the first layer is quartz sand with density of 1.5-2.0kg/L and particle size of 1.0-2.0mm; the second layer is anthracite with density of 2.5-3.0kg/L and particle size of 0.5-1.0mm; the third layer is quartz sand with density of 5-6kg/L and particle size of 0.25-0.5mm;

The filtering materials used in the third filtering in the step (2.5) are ceramsite and zeolite, and the mass ratio is (1-2); the grain size of zeolite is 1.0-1.5mm, and the grain size of ceramsite is 1.0-2.0mm.

Preferably, the coagulant in step (2.2) is used in an amount of 20-50g per ton of grey water; the coagulant is aluminum sulfate, alum and ferric chloride, and the mass ratio is 1:4:2;

The flocculant in the step (2.4) is used in an amount of 10-20g per ton of grey water; the flocculant is polyvinyl alcohol;

The disinfectant in the step (2.7) is used in an amount of 10-20g per ton of grey water, and is a 3% hydrogen peroxide solution by mass fraction.

Preferably, the flow rate of the ozone in the step (2.6) is 3-4L/min, and the aeration time is 3-5h.

Preferably, the width of the biological filter in the step (3.2) is 40-60cm; the filter materials of the biological filter are ceramsite, quartz sand, activated carbon and coke, and the mass ratio is 2:2:10:3; the particle size of the ceramsite is 1.0-2.0mm, the particle size of the quartz sand is 1.0-2.0mm, the particle size of the activated carbon is 5-10mm, and the particle size of the coke is 1.0-1.5mm.

Preferably, the mass ratio of the urine to the reclaimed water in the step (3.2) is 1:10;

preferably, in step (3.3), the mass ratio of the first portion of faeces to the second portion of faeces is 1:3.

Preferably, in the step (3.3), oxygen aeration is used, and the oxygen flow is 4-5L/min; aerating for 20-22h every day, standing for 2-4h, adding water accounting for 4% of the total mass of the excrement before aeration, and discharging water with the same mass after aeration is finished; after 10-15d, aeration is carried out for two periods per day, aeration is carried out for 10h per period, and standing is carried out for 2h; and after 20d, obtaining the activated sludge.

Preferably, in the step (3.3), the mixing mass ratio of the activated sludge to the second part of the feces is 1:5.

Preferably, the use amount of the aerobic bacteria in the step (3.4) is 1-5 g/ton of excrement, and the aerobic bacteria are bacteroides, bacillus and escherichia coli in a mass ratio of 1:2:3;

The aerobic fermentation treatment is that auxiliary materials are put into a fermentation tank to be fermented together with the excrement, the fermentation process is kept ventilated, the fermentation temperature is 50-70 ℃, the fertilizer pile is turned once every 3d, and the fermentation is finished after 3-4 weeks; the mass ratio of the auxiliary materials to the excrement is 1:5, and the auxiliary materials are straw, wood dust and mushroom residues, wherein the mass ratio is 5:1:2.

The invention has the following advantages:

1) The invention uses gauze to filter out water-insoluble pollutants such as cigarette ends, toilet paper, plastic bags and the like to primarily purify water quality; the three layers of different sand materials can filter large-particle suspended matters, colloid substances, microorganisms, organic matters and the like in water, the sand material particles can also provide microorganism adhesion matrixes, promote the growth and metabolism of microorganisms, further facilitate the removal of the organic matters in sewage, and further improve the water quality; the ceramsite and zeolite can adsorb a large amount of phosphorus elements and heavy metal ions, so that the water quality is further purified;

2) The invention adopts the coagulant and the flocculant to cooperatively treat sewage, the coagulant coagulates water-soluble pollutants into tiny insoluble matters, the flocculant coagulates tiny particles into large alum flowers, and the two medicaments are mutually matched and cooperatively act to furthest remove the pollutants in water; the polyvinyl alcohol used in the invention is nontoxic to human body, environment-friendly, green and pollution-free;

3) The ozone can oxidize and decompose organic substances remained in the sewage into inorganic substances, so that peculiar smell is eliminated, and the water quality is improved; ozone can kill bacteria and viruses in the sewage, so that pollutants in the sewage are reduced;

4) The invention takes local materials according to local conditions, self-prepares the activated sludge in the whole process flow, self-produces and self-sells the activated sludge, does not need to purchase the activated sludge on the market, and greatly saves the cost;

5) The grey water treated by the method can be reused as greening water and agricultural water; the black water treated by the method can be used as an organic fertilizer to act on farmlands, so that the cost is saved to the greatest extent;

6) The invention has the advantages of low cost, wide raw material sources, simple process and strong operability, can effectively treat domestic sewage, and does not produce secondary pollution to the environment.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

FIG. 1 is a general flow chart of the gray water treatment process and the black water treatment process of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Example 1

As shown in fig. 1, rural domestic sewage is treated according to the following steps:

Step (1), sewage classification

Separating sewage discharged by households into grey water and black water, and independently treating; the grey water comprises shower water, laundry water and kitchen water; the black water comprises toilet water;

Step (2), grey water treatment

(2.1) Carrying out first filtration on the grey water in a first filter tank to remove insoluble impurities in the water; the filter material used in the first filter tank is 5 layers of gauze with a mesh distance of 3cm and a mesh number of 25 meshes;

(2.2) feeding the gray water into a coagulation tank, adding a coagulant into the coagulation tank, shearing for 20min, and rotating at 800r/min; the usage amount of the coagulant is 35g per ton of grey water; the coagulant is aluminum sulfate, alum and ferric chloride, and the mass ratio is 1:4:2;

(2.3) carrying out secondary filtration on the grey water in a second filtering tank, and collecting filtered sludge for later use; the filter material in the second filter tank is 3 layers of gravel, and the width of each layer is 10cm; the first layer is quartz sand with density of 2.0kg/L and particle size of 2.0mm; the second layer is anthracite, the density is 3.0kg/L, and the grain diameter is 1.0mm; the third layer is quartz sand with the density of 6kg/L and the grain diameter of 0.5mm;

(2.4) feeding the grey water into a flocculation tank, adding a flocculating agent into the flocculation tank, shearing for 20min, and rotating at 200r/min; the dosage of the flocculant is 20g per ton of grey water; the flocculant is polyvinyl alcohol;

(2.5) carrying out third filtration on the grey water in a third filter tank, and collecting filtered sludge for later use; the filtering materials used in the filtering tank III are ceramsite and zeolite, and the mass ratio is 1:2; the grain diameter of zeolite is 1.0mm, and the grain diameter of ceramsite is 2.0mm;

(2.6) feeding the grey water into the first aeration tank, and introducing ozone to aerate the grey water; the flow of the ozone is 4L/min, and the aeration time is 4h;

(2.7) feeding the grey water into a disinfection tank, adding disinfectant into the grey water, and disinfecting to obtain middle water; the usage amount of the disinfectant is 15g per ton of grey water, and the disinfectant is 3% hydrogen peroxide solution by mass fraction;

step (3), black water treatment

(3.1) Carrying out filter pressing on black water in a plate-and-frame filter press, wherein the pressure is 0.5MPa;

(3.2) mixing urine with reclaimed water according to a mass ratio of 1:10, and filtering by a biological filter to obtain an organic fertilizer; the width of the biological filter is 60cm; the filter materials of the biological filter are ceramsite, quartz sand, activated carbon and coke, and the mass ratio is 2:2:10:3; the particle size of the ceramsite is 1.5mm, the particle size of the quartz sand is 1.0mm, the particle size of the activated carbon is 5mm, and the particle size of the coke is 1.5mm;

(3.3) the solid obtained after the filter pressing is feces, the feces is divided into two parts, and the mass ratio of the first part to the second part is 1:3;

Mixing the first part of excrement with the sludge filtered by the second and third times in a second aeration tank according to any proportion, and aerating to obtain activated sludge after aeration;

The aeration operation is that oxygen is used for aeration, and the oxygen flow is 5L/min; aerating for 20h each day, standing for 4h, adding water accounting for 4% of the total mass of the excrement before aeration, and discharging water with the same mass after aeration is finished; after 10d, aeration is carried out for two periods each day, aeration is carried out for 10h each period, and standing is carried out for 2h; after 20d, ending aeration;

Mixing the second part of excrement and activated sludge in a stirring tank according to a mass ratio of 5:1, wherein the rotating speed is 500r/min, and the stirring time is 10min;

(3.4) after stirring, feeding the mixture into a fermentation tank, adding aerobic bacteria, and performing aerobic fermentation treatment to obtain an organic fertilizer after fermentation; the using amount of the aerobic bacteria is 2.5g per ton of excrement, the aerobic bacteria are bacteroides, bacillus and escherichia coli, and the mass ratio is 1:2:3;

The aerobic fermentation treatment is that auxiliary materials are put into a fermentation tank to be subjected to composting fermentation together with the excrement, the fermentation process is kept at a ventilation temperature of 60 ℃, a fertilizer pile is turned every 3 days, and the fermentation is finished after 4 weeks; the mass ratio of the auxiliary materials to the excrement is 1:5, and the auxiliary materials are straw, wood dust and mushroom residues, wherein the mass ratio is 5:1:2.

Test example 1

Collecting domestic sewage of 5 villagers in a local rural area, dividing the domestic sewage into a plurality of parts averagely, and treating the sewage according to the method of the embodiment 1; the ash water is sent to a local detection mechanism after collecting samples before and after water outlet, COD, ammonia nitrogen and other substance contents in the water are detected, the urine is sent to the local detection mechanism after filtering, urea nitrogen content is detected, the excrement is fermented, and then the collected samples are sent to the local detection mechanism, organic substance content is detected, and the result is shown in Table 1.

TABLE 1

As can be seen from table 1, the content of COD, ammonia nitrogen, TP and TN in the gray water treated by the method is remarkably reduced, and the gray water is close to the standard of daily water, and can reach the standard of drinking water after further purification by a household water purifier; the black water treated by the method has greatly reduced urea nitrogen and other components in urine components, and can be used as liquid fertilizer for irrigating farmlands; the organic fertilizer formed by decomposing and fermenting the fecal component has higher nutrient content and can be used as an organic fertilizer to act on farmlands.

Comparative example 1

Unlike example 1, this comparative example did not perform the first filtration.

Comparative example 2

Unlike example 1, this comparative example did not undergo a second filtration.

Comparative example 3

Unlike example 1, this comparative example did not undergo a third filtration.

Comparative example 4

Unlike example 1, this comparative example was not coagulated.

Comparative example 5

Unlike example 1, this comparative example was not flocculated.

Comparative example 6

Unlike example 1, this comparative example does not produce activated sludge.

Test example 2

The domestic sewage collected in the test example 1 is treated according to the method of the comparative examples 1-6, and the treated domestic sewage is sent to a local mechanism for detection; since comparative examples 1 to 5 were modified only for the grey water treatment process, comparative examples 1 to 5 were tested only for grey water, and the results are shown in table 2; since comparative example 6 was modified only for the black water treatment process, comparative example 6 was examined only for decomposed feces, and the results are shown in Table 2.

TABLE 2

As can be seen from table 2, the pipeline is blocked after the first filtration is not performed, and the sewage treatment process cannot be performed; when the second and third filtering is not performed, the removal effect of COD, NH ₄ ⁺ -N, TN and TP is obviously reduced, and when coagulation or flocculation is not performed, the content of COD, NH ₄ ⁺ -N, TN and TP is obviously improved compared with that of the embodiment 1, and the purification effect is obviously reduced; when the activated sludge is not prepared, the fecal fermentation effect is poor, and the nutrition content and the organic matter content of the activated sludge are obviously reduced.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. The comprehensive rural domestic sewage treatment method is characterized by comprising the following steps of:

Step S1, sewage classification

step S2, grey water treatment

S21, carrying out first filtration on the grey water to remove insoluble impurities in the water;

S22, adding a coagulant into the grey water, shearing for 10-20min, and rotating at 800-1000r/min;

S23, carrying out secondary filtration on the gray water, and collecting filtered sludge for later use;

s24, adding a flocculating agent into the grey water, shearing for 10-20min, and rotating at 200-500r/min;

s25, carrying out third filtration on the gray water, and collecting filtered sludge for later use;

s26, introducing ozone to aerate the gray water;

S27, adding disinfectant into the grey water to obtain reclaimed water;

Step S3, black water treatment

S31, carrying out filter pressing on black water, wherein the pressure is 0.4-0.5MPa;

The liquid obtained after the filter pressing of S32 is urine, and is mixed with reclaimed water, and the mixture is filtered by a biological filter to obtain an organic fertilizer;

s33, the solid obtained after filter pressing is feces, and the feces are divided into two parts;

and S34, stirring, adding aerobic bacteria, and performing aerobic fermentation treatment to obtain the organic fertilizer.

2. The comprehensive rural domestic sewage treatment method according to claim 1, wherein the filter material used in the first filtering in the step S21 is 3-5 layers of gauze with a mesh distance of 3-5cm and a mesh number of 20-30 meshes;

The filtering material used in the second filtering in the step S23 is 3 layers of gravel, and the width of each layer is 8-10cm; the first layer is quartz sand with density of 1.5-2.0kg/L and particle size of 1.0-2.0mm; the second layer is anthracite with density of 2.5-3.0kg/L and particle size of 0.5-1.0mm; the third layer is quartz sand with density of 5-6kg/L and particle size of 0.25-0.5mm;

The filtering materials used in the third filtering in the step S25 are ceramsite and zeolite, and the mass ratio is (1-2); the grain size of zeolite is 1.0-1.5mm, and the grain size of ceramsite is 1.0-2.0mm.

3. The comprehensive treatment method for rural domestic sewage according to claim 1, wherein the coagulant in the step S22 is used in an amount of 20-50g per ton of grey water; the coagulant is aluminum sulfate, alum and ferric chloride, and the mass ratio is 1:4:2;

the flocculant in the step S24 is used in an amount of 10-20g per ton of grey water; the flocculant is polyvinyl alcohol;

The disinfectant in the step S27 is used in an amount of 10-20g per ton of grey water, and is a 3% hydrogen peroxide solution by mass.

4. The comprehensive treatment method for rural domestic sewage according to claim 1, wherein the flow rate of ozone in the step S26 is 3-4L/min, and the aeration time is 3-5h.

5. The comprehensive treatment method for rural domestic sewage according to claim 1, wherein the width of the biological filter in the step S32 is 40-60cm; the filter materials of the biological filter are ceramsite, quartz sand, activated carbon and coke, and the mass ratio is 2:2:10:3; the particle size of the ceramsite is 1.0-2.0mm, the particle size of the quartz sand is 1.0-2.0mm, the particle size of the activated carbon is 5-10mm, and the particle size of the coke is 1.0-1.5mm.

6. The comprehensive rural domestic sewage treatment method according to claim 1, wherein the mass ratio of the urine to the reclaimed water in the step S32 is 1:10.

7. The comprehensive rural domestic sewage treatment method according to claim 1, wherein the mass ratio of the first part of excrement to the second part of excrement in the step S33 is 1:3.

8. The comprehensive treatment method for rural domestic sewage according to claim 1, wherein oxygen aeration is used in the step S33, and the oxygen flow is 4-5L/min; aerating for 20-22h every day, standing for 2-4h, adding water accounting for 4% of the total mass of the excrement before aeration, and discharging water with the same mass after aeration is finished; after 10-15d, aeration is carried out for two periods per day, aeration is carried out for 10h per period, and standing is carried out for 2h; and after 20d, obtaining the activated sludge.

9. The method according to claim 1, wherein the mixing mass ratio of the activated sludge to the second portion of feces in the step S33 is 1:5.

10. The comprehensive rural domestic sewage treatment method according to claim 1, wherein the consumption of the aerobic bacteria in the step S34 is 1-5 g/ton of excrement, and the mass ratio of the aerobic bacteria is 1:2:3;