CN111807614A

CN111807614A - Facility and method for carrying out micro-well soil infiltration treatment on washing wastewater of rural household

Info

Publication number: CN111807614A
Application number: CN202010633242.XA
Authority: CN
Inventors: 范彬; 李亚惠; 朱仕坤; 钱婷婷
Original assignee: Research Center for Eco Environmental Sciences of CAS
Current assignee: Research Center for Eco Environmental Sciences of CAS
Priority date: 2020-07-02
Filing date: 2020-07-02
Publication date: 2020-10-23

Abstract

The invention belongs to the technical field of life sanitation and pollution control, and relates to a facility and a method for percolating soil of a micro-well of washing wastewater of rural household after source separation. The facility comprises top transparent top cover, bottom of the pool planting layer, sponge brick pool wall, wetland plant and facility surrounding soil, the transparent top cover material in top is the ya keli panel, and the hole is seted up to the top cover main part, pending washing wastewater gravity flow gets into the bottom of the pool and plants the layer, the wetland plant is planted on the bottom of the pool planting layer, sponge brick pool wall encloses to step around the facility, the main raw and other materials of sponge brick are aeolian sand, soil is regional normal position soil around the facility, does not disturb, the final play water of facility gets into the subsurface groundwater.

Description

Facility and method for carrying out micro-well soil infiltration treatment on washing wastewater of rural household

One, the technical field

The invention belongs to the technical field of life sanitation and pollution control, and particularly relates to a facility for carrying out micro-well soil infiltration treatment on household washing wastewater separated from rural sources.

Second, background Art

The rural areas have low population density, dispersed residence, imperfect drainage facilities and centralized treatment can increase the pipeline construction cost, so that the rural household washing wastewater after source separation is not suitable for centralized treatment. The concentration of TN and ammonia nitrogen of the washing wastewater after source separation is lower than the first-level A standard of pollutant discharge standard of urban sewage treatment plant, the concentration of TP is less than 1mg/l, pollutants are mainly organic matters, the average concentration of COD and LAS are 337mg/l and 14.9mg/l respectively, and relative to pollutants such as nitrogen, phosphorus and the like, the organic matters in the washing wastewater are easily treated, but if the traditional integrated rural decentralized sewage treatment equipment is used, the price is high, energy waste can be caused, the sustainable development requirement is not met, the ecological treatment technology for domestic wastewater not only has suitable economy, but also can effectively treat the pollutants in the domestic wastewater by using a biological chain in the natural world, thereby not only achieving the ecological balance effect, but also achieving the purification and environmental protection effects and meeting the sustainable development requirement. Therefore, the washing wastewater after source separation is treated by adopting a household ecological treatment process in rural areas.

The rural areas have abundant land resources, the soil is an active dynamic balance ecological system, not only a complex colloid system exists, but also the soil is rich in microorganisms, soil animals and the like, the pollutants entering the soil can be adsorbed, desorbed, replaced, decomposed and the like, the pollutants are transferred and converted, a 0-30cm soil layer can intercept more than 85% of organic matters in domestic wastewater, the concentrations of COD and LAS of inlet water are 350mg/L and 17mg/L respectively, and the hydraulic load is 300L/(m/L)²D) when the washing wastewater passes through a sand layer of 50cm, the average concentration of effluent is 20mg/l and 0.06mg/l respectively, which is close to the environmental background value of the groundwater in a certain village in south China. The water level burial depth of shallow groundwater in the areas except the south, the south and the southwest in China is generally shallow, mostly between less than 1 meter and more than 20 meters, the water level of submerged groundwater in most other areas is generally more than 1 meter, the water level burial depth of submerged groundwater in the northwest areas is generally more than one hundred meters, and the water level burial depth of partial areas is even up to 280 meters.

Based on the situation, the treatment process of the washing wastewater of rural household families after the soil percolation is selected as the source separation is based on the concept of simple process, mature technology, convenient maintenance, environmental protection and energy conservation, and is in line with the sustainable development. However, most of the existing soil infiltration systems mainly aim at removing nitrogen and phosphorus in wastewater, have complex process structures and high engineering cost, and cannot well meet the actual requirements of pretreatment of washing wastewater after source separation. The patent "a two-section enhanced denitrification multistage soil infiltration system" (patent number: CN 105502656A), "a biological-soil infiltration sewage treatment method and device" (patent number: CN 103030247B) have good pollutant removal effect, but the process is complex and consumes electric energy, which causes higher construction investment burden and operation and maintenance management pressure for using families, thus being neither economical nor convenient. The soil infiltration device (patent No. CN 104496110B) has simple process, but the absorption rate of pollutants is ensured by improving soil, and the water outlet is arranged at the bottom of the system, so that the construction cost of the system is increased by draining the discharged water.

Third, the invention

In view of the above problems, the present invention has two objects:

one of the purposes of the invention is to develop a facility which has simple process, low cost and convenient operation and maintenance and can effectively purify the washing wastewater, thereby providing a feasible way for the local treatment of the washing wastewater of rural household after source separation.

Another object of the present invention is to provide a method for on-site treatment of rural household washing wastewater after source separation using a micro-well soil infiltration facility.

According to the invention, the sponge bricks with good water permeability are used for being surrounded and built around the percolation pool, so that on one hand, soil around the percolation pool is prevented from collapsing and falling back into the percolation pool to influence the normal use of the percolation pool, and on the other hand, after washing wastewater enters the percolation pool, the sponge bricks can be used for percolating the washing wastewater to the periphery of the percolation pool through the soil at the bottom, so that the hydraulic permeability of the washing wastewater in the percolation pool is enhanced.

The method utilizes the in-situ soil to backfill the planting layer at the bottom of the infiltration pond, the planting layer is used for planting the perennial wetland plants, the plants can directly absorb and utilize nutrient substances in the wastewater and convey oxygen to the root zone, the oxygen requirement of microbial growth, reproduction and degradation reaction in the root zone is provided, the soil is loosened, and the hydraulic transmission capability of the soil is enhanced and maintained.

The invention utilizes the transparent acrylic plate as the top cover of the infiltration tank, and the top cover is provided with the vent hole, so that on one hand, sunlight is irradiated to facilitate photosynthesis of wetland plants in the infiltration tank, and on the other hand, gas exchange between the interior of the infiltration tank and the outside is enhanced through the vent hole.

The invention provides a facility for on-site treatment of household washing wastewater, which comprises a transparent top cover, a pool bottom planting layer, wetland plants, sponge brick pool walls and soil around the facility, and is characterized in that:

the facility is buried, the shape is generally a cuboid, the top of the facility is a transparent top cover with holes, the facility is made of transparent acrylic plates, the bottom of the facility is a planting layer backfilled with in-situ soil, and the four walls of the facility are formed by surrounding building of sponge bricks. The height difference between the horizontal line of the top end of the sponge brick pool wall and the horizontal line is greater than 10 cm; the height difference of 20-35cm is formed between the horizontal line of the bottom end of the sponge brick pool wall and the horizontal line of the top end of the planting layer at the bottom of the pool; the transparent top cover with the holes is a cuboid without a cover, the height of four sides of the cuboid is more than 5cm, the transparent top cover covers the top ends of the four walls of the sponge brick of the percolation pool and is easy to separate from the top ends of the four walls of the sponge brick; the washing wastewater to be treated enters the facility intermittently through the gravity flow of the drainage pipeline, passes through the wetland plant planting layer, the sponge brick pool wall and the surrounding soil layer, and finally enters the underground water of the submerged layer.

The top end of the sponge brick pool wall is higher than the horizon line, the bottom end of the sponge brick pool wall is lower than the planting layer at the bottom of the pool, and the main raw material is aeolian sand so as to ensure the water permeability and the cold resistance of the infiltration pool;

the transparent top cover with the holes is a cuboid without a cover, the height of four sides of the cuboid is greater than 5cm, the bottom of the cuboid is a top cover main body, vent holes are formed in the top cover main body, the area occupancy rate of the vent holes in the top cover main body is 10% -40%, and the top cover covers the top ends of the four walls of the sponge brick of the percolation pool;

the planting layer at the bottom of the pool is formed by backfilling in-situ soil and planting wetland plants;

the wetland plants are cold-resistant wetland plants, such as houttuynia cordata, phyllostachys praecox, evergreen iris tectorum, hydrangea macrophylla, loosestrife and the like;

and the facility effluent enters the subsurface groundwater after being percolated by the soil layer.

The method comprises the following process flows: the gravity flow of the country household washing wastewater after source separation enters a pretreatment device and then enters the facility, most pollutants are intercepted by a planting layer at the bottom of the facility and sponge bricks on four walls, the pollutants are further decomposed and converted through the actions of microorganisms, plants, soil animals and the like in the facility, effluent enters the next soil layer, a small amount of pollutants which are not intercepted are intercepted, decomposed and converted on the layer, and finally the effluent enters underground water of a submerged layer.

The invention provides a method for in-situ pretreatment of washing wastewater in rural families, which comprises the following steps:

the washing wastewater to be treated is connected into the system, most suspended matters are removed by the pretreatment device, and then the washing wastewater flows into the micro-well soil infiltration facility. The facility purification unit divide into the two-stage, the one-level is the inside purification unit of facility, the inside purification unit of facility is including planting district and sponge brick pool wall, cold-resistant wetland plant is planted in planting district, can loosen soil, can strengthen the water permeability of planting district, the main raw and other materials of sponge brick are aeolian sand, water permeability is good, after washing waste water gets into the facility, most pollutants are detained by planting district and sponge brick pool wall, it then gets into next stage purification unit to go out water, the outside purification unit of facility promptly, the soil district around the facility, a small amount of pollutants that is not detained on this layer, decompose and the conversion, most pollutes and has been got rid of at last stage purification unit, consequently can not take place to block up on this layer. The effluent passes through the soil layer around the facility and finally enters the underground water of the subsurface layer. The washing wastewater to be treated comprises toilet washing water, bath water, wash basin water and miscellaneous drainage water which are collected by independent connection pipes and kitchen rinsing water.

Compared with the prior art, the facility and the method for the local treatment of the washing wastewater of rural families have the following beneficial effects:

(1) the invention provides a method for separately collecting household washing wastewater to be treated on site by means of source separation, compared with centralized treatment, the method can save the transportation and treatment cost of domestic wastewater, and is suitable for being applied to rural areas with dispersed settlement forms, low economic development degree and immature underground pipe network systems;

(2) the method of soil infiltration can replace expensive integrated rural dispersed sewage biomembrane treatment equipment, realize effective removal of pollutants in the washing wastewater and save construction and maintenance costs.

(3) The effluent finally enters the subsurface groundwater, the collection and discharge processes of effluent facilities are reduced, the energy consumption is reduced, the difficulty of operation and maintenance is reduced, the economic cost can be saved, and the sustainable development requirement can be met.

Description of the drawings

FIG. 1 is a process flow diagram of the method for treating the washing wastewater of village household after source separation.

FIG. 2 is a top view of an in-situ treatment facility for rural household washing wastewater after source separation according to the present invention. Sequence numbers shown in the figures: 3-a transparent top cover; 31-a cap body; 32-a vent hole; 4-soil around the facility.

FIG. 3 is a longitudinal sectional view of a facility for on-site treatment of washing wastewater from rural households after source separation according to the present invention. Sequence numbers shown in the figures: 1-water inlet pipe; 2-sponge brick pool wall; 21-sponge brick; 3-a transparent top cover; 4-wetland plants; 5-planting layer; 6-soil around the facility; 7-subsurface groundwater.

Fig. 4 is a structural surface view of the sponge brick provided by the invention. Sequence numbers shown in the figures: 21-sponge brick top view.

Fifth, detailed description of the invention

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

As shown in figure 1, a method for the in-situ treatment of country household washing wastewater after source separation is characterized in that the country household washing wastewater (comprising bath water, washing water, wash basin water and miscellaneous drainage water) is intermittently discharged into a treatment device after being separated and classified from a source and concentrated kitchen wastewater, and the wastewater is stabilized through a pretreatment device, so that the wastewater flows into a microwell soil infiltration facility by gravity.

As shown in fig. 2, 3 and 4, the present embodiment provides an on-site treatment facility for the washing wastewater in the village, which is detailed as follows:

the treated wastewater is mainly domestic washing wastewater generated by rural household families, and the water quality indexes are as follows: COD: 350mg/l, LAS 17.6mg/l, TN 11.8mg/l, ammonia nitrogen: 4.6mg/l, TP: 0.68 mg/l.

The facility is the cuboid, and normal position preparation on the spot, facility four walls (2) are enclosed with sponge brick (21) and are built, adopt the formula of burying to build, and upper portion covers transparent top cap (3), can carry out the switching, clearly draw mud or reap the plant, and equipment heat preservation printing opacity does benefit to the microbial reaction and stably goes on, and the bottom of the pool is planting layer (5), plants wetland plant (4) on planting layer (5), and the outside is soil (6) around the facility. Once the household washing wastewater is generated, the household washing wastewater automatically and intermittently enters a facility through a water inlet pipe (1), firstly enters a 20-35cm planting layer (5), wetland plants such as houttuynia cordata, phyllostachys praecox, evergreen iris tectorum, thalictrum sinense, celandine and the like are planted on the planting layer, the plant density is 10-25 plants/m 2, most pollutants in the washing wastewater are intercepted in the planting layer (5), if the water discharge is a little bit larger, and the water surface is higher than the top horizontal line of the planting layer, the water in the washing wastewater can also permeate through the sponge brick pool wall (2), when the washing wastewater enters the soil layer (6) around the facility through the planting layer and the sponge brick pool wall, the pollutant concentration in the washing wastewater is close to the regional background value, a small amount of pollutants are intercepted, decomposed and converted in the soil layer around the facility, the effluent reaches or is lower than the regional subsurface groundwater background value, and finally the effluent enters the subsurface water (7).

The laboratory operation results prove that after the facility of the invention is adopted and the source is separated by a sand layer of 50cm, the washing wastewater of rural household families is treated, during the stable operation, the average concentration values of COD, LAS, TN, ammonia nitrogen and TP effluent in the effluent are respectively 20mg/L, 0.06mg/L, 4.1mg/L, 0.39mg/L and 0.018mg/L, monitoring COD, LAS, TN, ammonia nitrogen and TP in 1.0-5m underground water of a potential layer in a certain village of the river network area in south China continuously for one year, wherein the average concentration values of all indexes are respectively 17mg/L, 0.029mg/L, 2.94mg/L, 0.32mg/L and 0.06mg/L, the device has good water outlet effect, can ensure the solid retention time of more than 1-2 years, does not need to remove solid slag during the period, and has no blocking phenomenon.

In conclusion, compared with the traditional soil infiltration facility, the country household washing wastewater on-site treatment facility after source separation has the advantages of simple process structure, direct effluent entering submerged groundwater, no effluent drainage facility, and capability of saving construction investment and operation and maintenance cost compared with the energy-consumption soil infiltration facility.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present invention, and it is therefore to be understood that the invention is not limited by the scope of the appended claims.

Claims

1. The invention provides a facility for on-site treatment of household washing wastewater, which comprises a transparent top cover, a pool bottom planting layer, wetland plants, sponge brick pool walls and soil around the facility, and is characterized in that:

the facility is buried, is generally cuboid, the top of the facility is a transparent top cover with holes, is made of transparent acrylic plates, the bottom of the facility is an in-situ soil backfilling planting layer, and the four walls of the facility are formed by surrounding building of sponge bricks; the height difference between the horizontal line of the top end of the sponge brick pool wall and the horizontal line is greater than 10 cm; the height difference of 20-35cm is formed between the horizontal line of the bottom end of the sponge brick pool wall and the horizontal line of the top end of the planting layer at the bottom of the pool; the transparent top cover with the holes is a cuboid without a cover, the height of four sides of the cuboid is more than 5cm, the transparent top cover covers the top ends of the four walls of the sponge brick of the percolation pool and is easy to separate from the top ends of the four walls of the sponge brick; the washing wastewater to be treated enters the facility intermittently through the gravity flow of the drainage pipeline, passes through the wetland plant planting layer, the sponge brick pool wall and the surrounding soil layer, and finally enters the underground water of the submerged layer.

2. The apparatus of claim 1, wherein: the top end of the sponge brick pool wall is higher than the horizon line, and the bottom end is lower than the planting layer at the bottom of the pool.

3. The apparatus as claimed in claims 1 and 2, wherein: the main raw material of the sponge brick is aeolian sand so as to ensure the water permeability and the cold resistance of the infiltration tank.

4. The apparatus of claim 1, further comprising: the transparent top cover with the holes is a cuboid without a cover, the height of four sides of the cuboid is greater than 5cm, the bottom of the cuboid is a top cover main body, and vent holes are formed in the top cover main body.

5. The apparatus of claims 1 and 4, wherein: the area occupancy of the vent hole in the top cover main body is between 10% and 40%.

6. The apparatus of claims 1 and 4, wherein: the transparent top cover covers the top ends of the four walls of the sponge brick of the percolation pool and can be separated.

7. The apparatus of claims 1 and 2, wherein: the planting layer at the bottom of the pool is backfilled by in-situ soil, and wetland plants are planted on the planting layer at the bottom of the pool.

8. The apparatus of claims 1 and 7, further comprising: the wetland plants are cold-resistant wetland plants, such as houttuynia cordata, phyllostachys praecox, evergreen iris tectorum, hydrangea macrophylla, loosestrife and the like.

9. The apparatus of claim 1, further comprising: and the facility effluent enters the subsurface water after being percolated by the surrounding soil layer.

10. A method for treating rural household washing wastewater after source separation by using the facility of any one of claims 1 to 9:

the washing wastewater to be treated is accessed into the system, most suspended matters are removed by the pretreatment device, and then the washing wastewater flows into the micro-well soil infiltration facility; the facility purification unit is divided into two stages, one stage is a facility internal purification unit, the facility internal purification unit comprises a planting area and a sponge brick pool wall, cold-resistant wetland plants are planted in the planting area, the soil can be loosened, the water permeability of the planting area can be enhanced, the main raw material of the sponge brick is aeolian sand, the water permeability is good, after washing wastewater enters the facility, most pollutants are intercepted by the planting area and the sponge brick pool wall, effluent enters the next stage purification unit, namely a facility external purification unit, the soil area around the facility, a small amount of pollutants which are not intercepted are intercepted, decomposed and converted on the layer, most of pollutants are removed by the previous stage purification unit, and therefore blockage can not occur on the layer; the effluent passes through the soil layer around the facility and finally enters the underground water of the submerged layer; the washing wastewater to be treated comprises toilet washing water, bath water, wash basin water and miscellaneous drainage water which are collected by independent connection pipes and kitchen rinsing water.