A wastewater treatment system and method using a constructed wetland with iron-sulfur autotrophic denitrification and a plurality of plants

Abstract

The application discloses a kind of artificial wetland treatment sewage system and method using sulfur iron autotrophic denitrification and multiple plant combinations, belong to wastewater treatment technical field.The system includes in order of water flow inlet to outlet, first purification zone, second purification zone, third purification zone, fourth purification zone in turn, water flow sequentially through first purification zone, second purification zone, third purification zone, fourth purification zone.First purification zone includes main body filler A and plant combination a, second purification zone includes main body filler B and plant combination b, third purification zone is planted with submerged plant combination c, and fourth purification zone is planted with submerged plant combination d.The present application is simple to implement, raw material ore, plant is easy to get, low in cost, good effect;Back-end surface flow wetland can be combined with existing pit pond implementation, without adding reagent;Water outlet main index can reach the above standard of "Surface Water Environmental Quality Standard" III class water, with good ecological, economic and social benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage treatment, and particularly relates to a sewage treatment system and method using a combination of sulfur-iron autotrophic denitrification and multiple plants. BACKGROUND

[0002] As an important measure to improve the ecological environment of rivers and lakes, and as an important way to realize the resource utilization of sewage, in recent years, artificial wetlands have been constructed at key points such as downstream of sewage treatment plant discharge outlets, river inflow into lakes, and tributary inflow into main streams in Shandong, Anhui, Yunnan, Shanghai, Qinghai and other places, to further improve the treated discharge and slightly polluted river water in an ecological way, and good environmental, ecological and social benefits have been achieved.

[0003] However, the artificial wetland treatment technology still has the following problems at the present stage:

[0004] 1. Accumulation and clogging of organic matter: Wetlands are usually oxygen-deficient, and with the passage of time, the accumulation of suspended solids and the growth of microorganisms in the wetland will weaken the seepage capacity of the substrate layer. If not properly maintained, it is easy to cause accumulation and clogging, reducing the hydraulic conductivity, wetland treatment effect and service life. With the continuous operation of the sewage treatment process, the adsorption capacity of the substrate will usually tend to be saturated within a few years, which will also affect the treatment effect of the wetland.

[0005] 2. Difficulty in improving treatment capacity: From the mechanism of pollutant removal by artificial wetlands, it can be seen that the removal of pollutants is mainly through microbial action, substrate adsorption and plant absorption. However, the oxygen transfer of plants alone cannot fully meet the needs of microbial activity, substrate adsorption will reach a dynamic balance, and the direct absorption of plants is relatively low, such as the removal of nitrogen and phosphorus by harvesting wetland plants is less than 20%. Therefore, after the stable operation of the artificial wetland, it is difficult to further improve the treatment capacity.

[0006] 3. Oxygen transfer capacity of plants: Wetlands used for tertiary or advanced treatment are not suitable for treating heavily polluted sewage, and the treatment mechanism of low load operation is not suitable for heavily polluted urban sewage, as a large amount of oxygen is required to treat the sewage according to the aerobic mechanism. Practice and research have shown that the small amount of oxygen permeated from the roots of plants is negligible compared to the actual load of urban sewage, such as reed, submerged plants and floating leaf plants, which are 0.02-12, 0.5-5.2 and 0.25-9.6 g / (m 2 ·d) respectively, so the oxygen transferred by wetland plants is limited.

[0007] 4. The problem of the sustainable use of constructed wetlands: the treatment function of constructed wetlands is not long-lasting, and after a few years, it can evolve into a natural wetland feature. Studies have shown that the life of a constructed wetland is 20-25 years, and after about 25 years, the filler and sediment deposited in the wetland should be completely removed, and some constructed wetland projects have experienced serious clogging after 5 years.

[0008] 5. The problem of breeding mosquitoes and emitting odors: constructed wetlands are often a good environment for many disease carriers, such as mosquitoes, flies, and snails, which are prone to breed in wetlands.

[0009] At present, there are more studies on the application of sulfur-iron autotrophic denitrification technology in wastewater treatment, but there are fewer practical engineering cases, and its application in constructed wetlands is still in the experimental stage, and there is no practical application engineering. There are only a few cases of municipal wastewater treatment plant denitrification deep bed filter modification, trying to use in some low carbon-nitrogen ratio industrial wastewater.

[0010] The plant design of the constructed wetland at the present stage is landscape and programmed, and the exploration of the synergistic effect, pollution tolerance, competition inhibition, purification mechanism, and limiting purification capacity of plants is insufficient. At present, the research on the use of plants in wastewater treatment projects still focuses on a single plant, and there is no attempt to use multiple plants for collaborative wastewater treatment. There is no precedent for the use of sulfur-iron autotrophic bacteria to treat wastewater. SUMMARY

[0011] The purpose of the present application is to provide a constructed wetland wastewater treatment system and method using sulfur-iron autotrophic denitrification and multiple plant combinations to solve the problems of difficult implementation, high cost, and unstable system of the constructed wetland treatment technology at the present stage, so that the main indicators of the effluent can meet the standards above Class III water in the "Surface Water Environmental Quality Standard".

[0012] The purpose of the present application can be achieved by the following technical solutions:

[0013] A constructed wetland wastewater treatment system using sulfur-iron autotrophic denitrification and multiple plant combinations, comprising a set of structures, characterized in that: the set of structures is sequentially divided into a first purification zone, a second purification zone, a third purification zone, and a fourth purification zone in the order of water inflow to outflow, and the water flows through the first purification zone, the second purification zone, the third purification zone, and the fourth purification zone in sequence; a water distribution channel is provided at the inlet of the first purification zone, and a water distribution channel is provided between the first purification zone and the second purification zone, between the second purification zone and the third purification zone, and between the third purification zone and the fourth purification zone.

[0014] In the first purification zone, a main packing material A and a plant combination a are configured. The main packing material A is mainly used for the growth of microorganisms. A layer of planting soil is placed on top of the main packing material A, and then plant combination a is planted. The main packing material A is made of three raw materials selected from ceramsite, zeolite, gravel, or volcanic rock. Two of the raw materials are ceramsite and zeolite, and the other is gravel or volcanic rock. The volume ratio of the three raw materials is 1:2:1. Plant combination a is any three or more of the following: water onion, loosestrife, pickerelweed, bulrush, umbrella sedge, and reed. The number of each plant in plant combination a is the same.

[0015] In the second purification zone, a main packing material B and a plant combination b are configured. The main packing material B is primarily used for the growth of microorganisms. A layer of planting soil is placed on top of the main packing material B, and then plant combination b is planted. The main packing material B is made of three or more raw materials selected from siderite, pyrite, pyrrhotite, sulfur, maifanite, and ceramsite. Siderite is a must, and at least one of pyrite or pyrrhotite is included. At least one of sulfur, maifanite, and ceramsite is included. The volume percentage of siderite in the main packing material B is 35-45%, and the total volume percentage of siderite, pyrite, pyrrhotite, and sulfur is 60%. Plant combination b is any three or more of cattail, calamus, water onion, canna lily, umbrella sedge, and water chestnut. The number of each plant in plant combination b is the same.

[0016] In the third purification zone, submerged plant combination c is planted; submerged plant combination c consists of two or more of the following: *Hydrilla verticillata*, *Elodea nuttallii*, *Vallisneria natans*, *Ceratophyllum demersum*, and *Potamogeton microdentatum*; among them, *Vallisneria natans* and *Ceratophyllum demersum* are essential; the proportion of *Vallisneria natans* in submerged plant combination c is not less than 60%, and the proportion of *Ceratophyllum demersum* is not less than 10%.

[0017] In the fourth purification zone, a submerged plant combination d is planted; the submerged plant combination d is a combination of two or more of the following: Potamogeton malaianus, Myriophyllum spicatum, Potamogeton pectinatus, Vallisneria natans, and Vallisneria natans; Vallisneria natans and Vallisneria natans are essential plants; the proportion of Vallisneria natans and Vallisneria natans in the submerged plant combination d is not less than 70%.

[0018] Furthermore, in both the first and second purification zones, the plant density ranges from 20 to 25 plants per square meter. 2 In the third and fourth purification zones, the plant density ranges from 40 to 60 plants per square meter. 2 .

[0019] Furthermore, in the first purification zone, the main packing material A is prepared by crushing, ball milling, sieving, mixing and granulating, with a particle size of 10-30 mm.

[0020] In this area, the removal of pollutants mainly includes microbial degradation absorption, plant absorption and soil adsorption complexation.

[0021] In this area, the removal of nitrogen mainly through the following ways: nitrification and denitrification, ammonia volatilization, exchange of ammonia ions, absorption, etc. The main denitrifying microorganisms are heterotrophic denitrifying bacteria. A large number of microorganisms contained in the sewage will further enrich in the main filler area, and this process is completed during the system establishment and debugging stage.

[0022] Further, in the second purification zone, the main filler B is prepared by crushing, ball milling, sieving and mixing granulation, and the particle size is 2-6 mm.

[0023] In this area, the removal of nitrogen mainly through the following ways: sulfur autotrophic denitrification, iron autotrophic denitrification, microbial assimilation, etc. The main denitrifying microorganisms are autotrophic denitrifying bacteria. Due to the difference of the main filler, the filler area mainly enriches autotrophic denitrifying bacteria.

[0024] Further, in the third purification zone and the fourth purification zone, plankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish are put in, and the density is respectively: plankton 30-50 / m 3 , snails 2-3 / m 2 , shellfish 0.3-0.5 / m 2 , shrimps 1-2 / m 2 , filter-feeding fish 3-5 tails / m 2 , 100-200g / tail; predatory fish 20-40 tails / mu, 8-12 cm / tail.

[0025] In this area, the function of the planted submerged plants has direct and indirect effects. The direct effect is the decomposition and absorption of pollutants. The indirect effect is the decomposition and absorption of submerged plants, microbial decomposition and absorption, and the increase of water dissolved oxygen; a large number of sulfur-iron autotrophic denitrifying bacteria in the second purification zone are greatly reduced due to the increase of dissolved oxygen, and a large number of aerobic microorganisms are proliferated, which improves and promotes the removal efficiency of microorganisms on pollutants; the proliferation of sulfate reducing bacteria (SRB) in the second purification zone will result in a certain amount of S 2- in the effluent, and then generate toxic and harmful gas hydrogen sulfide, which can be rapidly oxidized by the increase of dissolved oxygen to reduce the concentration of hydrogen sulfide overflow. 2-

[0026] Further, the third purification zone and the fourth purification zone are constructed by using a pit pond. The shallow water area in the pit pond is the third purification zone, and the deep water area in the pit pond is the fourth purification zone. The effective use of the pit pond can save land occupation and reduce investment cost.

[0027] ​In this area, the area ratio of the third and fourth purification zones is not less than 7:3; in the third purification zone, the submerged plant combination c in the front 50% area of the purification zone is E. verticillata and E. nuttallii, and the planting quantity ratio is 1:1, and the planting density is 10-15 buds / clump, 25-36 clumps / m 2 ; the submerged plant combination c in the rear 50% area of the purification zone is V. oxycarpa and C. demersum, and the planting quantity ratio is 6:1, and the planting density is 40-60 plants / m 2 . The submerged plant combination d in the fourth purification zone is V. spiraeifolia, V. mutica and M. malacoides, and the plant quantity ratio is 3:1:1, and the planting density is 40-60 plants / m 2 .

[0028] Such plant combination has strong pollution tolerance and grows rapidly, and can make the effluent of the subsurface flow wetland quickly recover dissolved oxygen, so as to create a suitable environment for the growth of fish, shrimp, snail, shellfish and microorganisms.

[0029] Such submerged plant combination and other animal combination help to quickly build a complete ecological system, have strong purification capacity, can indirectly promote the decomposition capacity of microorganisms and planktonic animals and plants, enhance the stability of the ecological system, and improve the pollutant decomposition capacity.

[0030] Further, the water depth of the first purification zone is 1.2-1.8 m, the hydraulic retention time is 1-5 days, and the surface hydraulic load is 0.2-1.0 m 3 / (m 2 ·d).

[0031] Further, the water depth of the second purification zone is 1.2-1.8 m, the hydraulic retention time is 0.6-4 days, and the surface hydraulic load is 0.3-1.5 m 3 / (m 2 ·d).

[0032] Further, the water depth of the third purification zone is 0.8-1.5 m, the hydraulic retention time is 2.5-8 days, and the surface hydraulic load is 0.02-0.2 m 3 / (m 2 ·d).

[0033] Further, the water depth of the fourth purification zone is 2.0-3.5 m, the hydraulic retention time is 0.8-3 days, and the surface hydraulic load is 0.03-0.5 m 3 / (m 2 ·d).

[0034] A method for treating sewage by using a subsurface flow wetland with sulfur-iron autotrophic denitrification and multiple plant combinations, comprising the following steps:

[0035] S1. Establishing the above system;

[0036] S2. Introduce the sewage into the water inlet of the system, and sequentially flow through the four purification zones for purification treatment; wherein the hydraulic retention time, water depth and surface hydraulic load of each purification zone are controlled;

[0037] S3. Discharge the purified water from the water outlet of the system.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] 1. The present application is simple to implement, and the raw materials, ore and plants, are easy to obtain, and the cost is low, and the effect is good; no additional pipe network engineering, electrical equipment, etc. is needed; the surface flow wetland at the rear end can be implemented in combination with the existing pit pond; no chemicals need to be added; the combined treatment technology of biology + ecology is adopted, which is resistant to impact load and stable in system; the main indicators of the effluent can reach the standard above the III class water in the "Surface Water Environmental Quality Standard"; after implementation, the effluent can be used for ecological water replenishment of river channels, has good landscape effect, high biodiversity, and has good ecological, economic and social benefits.

[0040] 2. The present application adopts the combined treatment measures of biology + ecology, does not need pipe network, and has few soil installations, and can realize the deep denitrification and phosphorus removal effect that the traditional artificial wetland cannot achieve.

[0041] 3. The present application applies the sulfur-iron autotrophic denitrification and plant combined process to the treatment of effluent of a municipal sewage plant, which is the first in the field of water treatment.

[0042] 4. The present application adopts a plurality of different combination modes, realizes the combination of microorganisms and emergent plants, and the combination of microorganisms and submerged plants, and through the combination of different microorganisms and plants, the shortcomings of single microorganism and plant technology are made up, and a more stable treatment system, better treatment effect and higher treatment efficiency are realized.

[0043] 5. The effluent of the system of the present application can be used for ecological water replenishment of river channels, and has good landscape effect and good ecological benefits. BRIEF DESCRIPTION OF DRAWINGS

[0044] The present application will be further described below in combination with the drawings.

[0045] Figure 1 is a vertical plane schematic view of the artificial wetland in embodiment 1 of the present application;

[0046] Figure 2 is a top view schematic view of the artificial wetland in embodiment 1 of the present application;

[0047] Figure 3 is a vertical plane schematic view of the artificial wetland in embodiment 2 of the present application;

[0048] Figure 4 is a top view schematic view of the artificial wetland in embodiment 2 of the present application.

[0049] Fig. 1, distribution channel; 2, horizontal subsurface flow constructed wetland; 3, collection and distribution channel; 4, vertical subsurface flow constructed wetland; 5, collection and distribution channel; 6, shallow surface flow constructed wetland; 7, collection and distribution channel; 8, deep surface flow constructed wetland; 9, effluent channel. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0051] Embodiment 1

[0052] Fuxi County Sewage Plant Tail Water Wetland Project:

[0053] Reference Figure 1 and Figure 2 The effluent of the municipal sewage plant in this embodiment meets the first level A effluent standard, and the effluent after entering the constructed wetland meets the class III water. The constructed wetland treatment sewage system in this embodiment uses a combination of sulfur-iron autotrophic denitrification and multiple plants, which includes a group of structures, which are divided into a horizontal subsurface flow constructed wetland 2 (i.e., a first purification zone), a vertical subsurface flow constructed wetland 4 (i.e., a second purification zone), a shallow surface flow constructed wetland 6 (i.e., a third purification zone), and a deep surface flow constructed wetland 8 (i.e., a fourth purification zone) in order of water flow from the inlet to the outlet. The water flows through the horizontal subsurface flow constructed wetland 2, the vertical subsurface flow constructed wetland 4, the shallow surface flow constructed wetland 6, and the deep surface flow constructed wetland 8 in turn. The first purification zone inlet is provided with a distribution channel 1, a collection and distribution channel 3 is arranged between the first purification zone and the second purification zone, a collection and distribution channel 5 is arranged between the second purification zone and the third purification zone, and a collection and distribution channel 9 is arranged between the third purification zone and the fourth purification zone.

[0054] The horizontal subsurface flow constructed wetland 2 (first purification zone) uses a main filler A with a particle size of 10-30 mm, which is obtained by crushing, ball milling, sieving, and mixing and granulating ceramsite, zeolite, and volcanic rock in a volume ratio of 1:2:1, and is uniformly filled in the wetland. The plant combination a in the horizontal subsurface flow constructed wetland 2 is Echinodorus bleheri, Xerosicyos danguyi, and Scirpus triqueter, and the planting quantity ratio of the three plants is 1:1:1. The planting density of the plant combination a is 23 plants / m 2 .

[0055] Vertical subsurface flow constructed wetland 4 (second purification area): the main filler B with a particle size of 2-6 mm is obtained by crushing, ball milling, sieving and mixing granulation of 40% siderite, 20% pyrite and 40% medical stone by volume ratio, and uniformly filled in the wetland; the plant combination b in the vertical subsurface flow constructed wetland 4 is cattail, acorus calamus, canna indica and scirpus lacustris, and the planting quantity ratio of the four plants is 1:1:1:1, and the planting density of the plant combination b is 23 plants / m 2 .

[0056] Shallow surface flow constructed wetland 6 (third purification area): the submerged plant combination c is elodea nuttallii, ceratophyllum demersum, azolla imbricata and potamogeton pusillus; wherein, the planting quantity of elodea nuttallii accounts for 60%, the planting quantity of ceratophyllum demersum accounts for 20%, the planting quantity of azolla imbricata accounts for 10%, and the planting quantity of potamogeton pusillus accounts for 10%; the planting density of the plant combination c is 50 plants / m 2 .

[0057] Deep water surface flow constructed wetland 8 (fourth purification area): the submerged plant combination d is elodea nuttallii, myriophyllum spicatum, azolla imbricata and myriophyllum verticillatum, wherein, the planting quantity of elodea nuttallii accounts for 50%, the planting quantity of myriophyllum spicatum accounts for 20%, the planting quantity of azolla imbricata accounts for 20%, and the planting quantity of myriophyllum verticillatum accounts for 10%; the planting density of the plant combination d is 50 plants / m 2 .

[0058] The plankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish are put into the shallow surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8, and the densities are respectively: plankton 40 / m 3 ; snails 3 / m 2 ; shellfish 0.4 / m 2 ; shrimps 2 / m 2 ; filter-feeding fish 5 tails / m 2 , 150-180g / tail; predatory fish 35 tails / acre, 8-12cm / tail.

[0059] A method for treating sewage using sulfur-iron autotrophic denitrification and multiple plant combinations, comprising the following steps:

[0060] S1. Establishing the above system;

[0061] S2. Wastewater is introduced into the inlet of the above system, flows through distribution channel 1 into horizontal subsurface flow constructed wetland 2, effluent from horizontal subsurface flow constructed wetland 2 flows into collection and distribution channel 3, effluent from collection and distribution channel 3 flows into vertical subsurface flow constructed wetland 4, effluent from vertical subsurface flow constructed wetland 4 flows into collection and distribution channel 5, effluent from collection and distribution channel 5 flows into shallow water surface flow constructed wetland 6, effluent from shallow water surface flow constructed wetland 6 flows into collection and distribution channel 7, effluent from collection and distribution channel 7 flows into deep water surface flow constructed wetland 8, and effluent from deep water surface flow constructed wetland 8 flows into outlet channel 9; wherein, horizontal subsurface flow constructed wetland 2 (first purification zone) has a water depth of 1.5m, a hydraulic retention time of 2.5 days, and a surface hydraulic load of 0.6m. 3 / (m 2 •d); Vertical subsurface flow constructed wetland 4 (second purification zone): water depth 1.5m, hydraulic retention time 2.0 days, surface hydraulic loading 0.8m. 3 / (m 2 •d); Shallow surface flow constructed wetland 6 (third purification zone): water depth 1.2m, hydraulic retention time 4.5 days, surface hydraulic loading 0.08m. 3 / (m 2 •d); Deep-water surface flow constructed wetland 8 (Purification Zone 4): water depth 2.8m, hydraulic retention time 1.0 day, surface hydraulic loading 0.10m. 3 / (m 2 ·d).

[0062] S3. Discharge the purified water that meets the quality standards from the outlet of the above system into the external water area.

[0063] Example 2

[0064] A tailwater wetland project in Yijiang District:

[0065] Reference Figure 3 and Figure 4, the effluent of the first-stage A meets the Class III water after the constructed wetland; the example uses a constructed wetland treatment system of sulfur-iron autotrophic denitrification and multiple plants to treat sewage, which includes a group of structures and a pit pond, and is divided into horizontal subsurface flow constructed wetland 2 (i.e., a first purification zone), vertical subsurface flow constructed wetland 4 (i.e., a second purification zone), shallow water surface flow constructed wetland 6 (i.e., a third purification zone), and deep water surface flow constructed wetland 8 (i.e., a fourth purification zone) in the order of water flow from the inlet to the outlet. The shallow water area in the pit pond is the third purification zone, and the deep water area in the pit pond is the fourth purification zone. The water flows through the horizontal subsurface flow constructed wetland 2, the vertical subsurface flow constructed wetland 4, the shallow water surface flow constructed wetland 6, and the deep water surface flow constructed wetland 8 in turn. The first purification zone is provided with a water distribution channel 1, a water distribution channel 3 is arranged between the first purification zone and the second purification zone, a water distribution channel 5 is arranged between the second purification zone and the third purification zone, a water distribution channel 9 is arranged between the third purification zone and the fourth purification zone, and the zones are connected through the water distribution channels and pipelines.

[0066] The horizontal subsurface flow constructed wetland 2 (the first purification zone) uses ceramsite, zeolite, and gravel in a volume ratio of 1:2:1, which are crushed, ball milled, sieved, mixed, and granulated to form main filler A with a particle size of 10-30 mm, which is filled in the wetland. The plant combination a in the horizontal subsurface flow constructed wetland 2 is nuphar, air umbrella, and reed canary grass, and the quantity ratio of the three plants is 1:1:1.

[0067] The vertical subsurface flow constructed wetland 4 (the second purification zone) uses siderite with a volume ratio of 40%, pyrite with a volume ratio of 20%, and ceramsite with a volume ratio of 40%, which are crushed, ball milled, sieved, mixed, and granulated to form main filler B with a particle size of 2-6 mm, which is filled in the wetland. The plant combination b in the vertical subsurface flow constructed wetland 4 is cattail, acorus, canna, and scirpus, and the quantity ratio of the four plants is 1:1:1:1.

[0068] The area ratio of the shallow water surface flow constructed wetland 6 to the deep water surface flow constructed wetland 8 is 7:3.

[0069] In the shallow water surface flow constructed wetland 6, the submerged plant combination c in the first 50% area is hydrilla verticillata and elodea canadensis, and the quantity ratio of the two plants is 1:1, and the planting density is 13 shoots / clump, 30 clumps / m 2 ; the submerged plant combination c in the last 50% area is vallisneria nigra and ceratophyllum, and the quantity ratio of the two plants is 6:1, and the planting density is 50 plants / m 2 .

[0070] In the deep water surface flow constructed wetland 8, the submerged plant combination d is vallisneria spiralis, spirodela alterniflora, and potamogeton malayensis, and the quantity ratio of the three plants is 3:1:1, and the planting density is 50 plants / m 2 .

[0071] The zooplankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish are put into the shallow surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8, and the density is respectively: zooplankton 40 / m 3 ; snails 2.5 / m 2 ; shellfish 0.4 / m 2 ; shrimps 2 / m 2 ; filter-feeding fish 5 / m 2 , 120-150g / each; predatory fish 25 / m, 8-12cm / each.

[0072] A method for treating sewage by using sulfur-iron autotrophic denitrification and a plurality of plants, comprising the following steps:

[0073] S1. Establishing the system mentioned above;

[0074] S2. Introducing sewage into the water inlet of the system mentioned above, and the distribution channel 1 enters the horizontal subsurface flow constructed wetland 2, the water outlet of the horizontal subsurface flow constructed wetland 2 enters the collection distribution channel 3, the water outlet of the collection distribution channel 3 enters the vertical subsurface flow constructed wetland 4, the water outlet of the vertical subsurface flow constructed wetland 4 enters the collection distribution channel 5, the water outlet of the collection distribution channel 5 enters the shallow surface flow constructed wetland 6 through the channel, the shallow surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 are completed by transforming the existing pit pond, and the two are connected, and the water flows through the shallow surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 in turn; wherein the water depth of the horizontal subsurface flow constructed wetland 2 (the first purification area) is 1.5m, the hydraulic retention time is 2 days, the surface hydraulic load is 0.6m 3 / (m 2 ·d); the water depth of the vertical subsurface flow constructed wetland 4 (the second purification area) is 1.5m, the hydraulic retention time is 1.75 days, the surface hydraulic load is 0.6m 3 / (m 2 ·d); the water depth of the shallow surface flow constructed wetland 6 (the third purification area) is 1.2m, the hydraulic retention time is 5 days, the surface hydraulic load is 0.08m 3 / (m 2 ·d); the water depth of the deep water surface flow constructed wetland 8 (the fourth purification area) is 2.8m, the hydraulic retention time is 1.0 day, the surface hydraulic load is 0.12m 3 / (m 2 ·d).

[0075] S3. Discharging the water with qualified water quality from the water outlet of the system mentioned above to the external water area.

[0076] The water quality of the water inlet and outlet of example 1 and example 2 is detected:

[0077] The water quality before purification meets the Class A standard of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB 18918-2002), and the main control indexes (CODcr, total nitrogen, ammonia nitrogen and total phosphorus) of the water quality after purification can all meet the Class III water standard of the Environmental Quality Standard for Surface Water (GB 3838-2002). The specific data are shown in Table 1.

[0078] Table 1

[0079]

[0080] Example 3

[0081] A wetland project for tail water of a sewage plant in Feixi County:

[0082] In this example, the effluent of the municipal sewage plant meets the Class A standard, and the effluent after entering the artificial wetland meets the Class III water. In this example, the artificial wetland treatment system for sewage uses sulfur-iron autotrophic denitrification and a combination of multiple plants. The setting mode of the structures in the system is the same as that in Example 1, and the difference lies in that:

[0083] Horizontal subsurface flow artificial wetland 2 (first purification zone): the main filler A with a particle size of 10-30 mm is obtained by crushing, ball milling, sieving and mixing granulation of ceramsite, zeolite and gravel in a volume ratio of 1:2:1, and is uniformly filled in the wetland; the plant combination a in the horizontal subsurface flow artificial wetland 2 is cattail, Lythrum salicaria, reed and Vallisneria, and the planting quantity ratio of the four plants is 1:1:1:1, and the planting density of the plant combination a is 20 plants / m 2 .

[0084] Vertical subsurface flow artificial wetland 4 (second purification zone): the main filler B with a particle size of 2-6 mm is obtained by crushing, ball milling, sieving and mixing granulation of siderite with a volume ratio of 35%, pyrrholith with a volume ratio of 25% and sulfur with a volume ratio of 40%, and is uniformly filled in the wetland; the plant combination b in the vertical subsurface flow artificial wetland 4 is wild rice, Cyperus alternifolius and Canna indica, and the planting quantity ratio of the three plants is 1:1:1, and the planting density of the plant combination b is 20 plants / m 2 .

[0085] Shallow water area surface flow artificial wetland 6 (third purification zone): the submerged plant combination c is Hydrilla verticillata, Ceratophyllum demersum and Elodea canadensis; among them, the planting quantity ratio of Hydrilla verticillata is 70%, the planting quantity ratio of Ceratophyllum demersum is 15%, and the planting quantity ratio of Elodea canadensis is 15%; the planting density of the plant combination c is 40 plants / m 2 .

[0086] The deep water surface flow constructed wetland 8 (the fourth purification area) has a submerged plant combination d of Vallisneria, Myriophyllum spicatum and Potamogeton pectinatus, wherein the Vallisneria accounts for 45% of the plant quantity, the Myriophyllum spicatum accounts for 35% of the plant quantity, and the Potamogeton pectinatus accounts for 20% of the plant quantity; the planting density of the plant combination d is 40 plants per square meter 2 .

[0087] The shallow water surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 both have zooplankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish, and the densities are respectively: zooplankton 30 per square meter 3 ; snails 2 per square meter 2 ; shellfish 0.3 per square meter 2 ; shrimps 1 per square meter 2 ; filter-feeding fish 3 per square meter 2 , 150-180g per tail; predatory fish 25 per mu, 8-12cm per tail.

[0088] A method for treating sewage by using sulfur-iron autotrophic denitrification and multiple plant combinations, comprising the following steps:

[0089] S1. Establishing the above system;

[0090] S2. Introducing sewage into the water inlet of the above system, and then into the horizontal subsurface flow constructed wetland 2 through the water distribution channel 1, and then into the water collection and distribution channel 3, and then into the vertical subsurface flow constructed wetland 4 through the water outlet of the water collection and distribution channel 3, and then into the water collection and distribution channel 5 through the water outlet of the vertical subsurface flow constructed wetland 4, and then into the shallow water surface flow constructed wetland 6 through the water outlet of the water collection and distribution channel 5, and then into the water collection and distribution channel 7 through the water outlet of the shallow water surface flow constructed wetland 6, and then into the deep water surface flow constructed wetland 8 through the water outlet of the water collection and distribution channel 7, and then into the water outlet channel 9 through the water outlet of the deep water surface flow constructed wetland 8; wherein the horizontal subsurface flow constructed wetland 2 (the first purification area) has a water depth of 1.2m, a hydraulic retention time of 1 day, and a surface hydraulic load of 0.2m 3 / (m 2 ·d); the vertical subsurface flow constructed wetland 4 (the second purification area) has a water depth of 1.2m, a hydraulic retention time of 1 day, and a surface hydraulic load of 0.4m 3 / (m 2 ·d); the shallow water surface flow constructed wetland 6 (the third purification area) has a water depth of 1.5m, a hydraulic retention time of 3 days, and a surface hydraulic load of 0.02m 3 / (m 2 ·d); and the deep water surface flow constructed wetland 8 (the fourth purification area) has a water depth of 3.5m, a hydraulic retention time of 2 days, and a surface hydraulic load of 0.04m 3 / (m 2 ·d).

[0091] S3. Discharging the water with qualified water quality from the water outlet of the above system to an external water area.

[0092] Example 4

[0093] A certain sewage plant tail water wetland project in Feixi County:

[0094] The effluent of the municipal sewage plant in this example meets the first level A effluent standard, and the effluent after entering the artificial wetland meets the Class III water; this example uses a combination of sulfur-iron autotrophic denitrification and various plants to treat sewage in the artificial wetland system, and the system is configured in the same way as in Example 1, except that:

[0095] Horizontal subsurface flow artificial wetland 2 (first purification zone): The main filler A with a particle size of 10-30 mm is obtained by crushing, ball milling, sieving, mixing and granulating ceramsite, zeolite and gravel in a volume ratio of 1:2:1, and uniformly filled in the wetland; the plant combination a in the horizontal subsurface flow artificial wetland 2 is cattail, anubis, reed, reed and spikerush, and the planting quantity ratio of the five plants is 1:1:1:1:1, and the planting density of the plant combination a is 25 plants / m 2 .

[0096] Vertical subsurface flow artificial wetland 4 (second purification zone): The main filler B with a particle size of 2-6 mm is obtained by crushing, ball milling, sieving, mixing and granulating siderite with a volume ratio of 45%, magnetite with a volume ratio of 8%, pyrite with a volume ratio of 7% and ceramsite with a volume ratio of 40%, and uniformly filled in the wetland; the plant combination b in the vertical subsurface flow artificial wetland 4 is acorus, cattail and canna, and the planting quantity ratio of the three plants is 1:1:1, and the planting density of the plant combination b is 25 plants / m 2 .

[0097] Shallow water surface flow artificial wetland 6 (third purification zone): The submerged plant combination c is elodea, cabomba, azolla and potamogeton; among them, the planting quantity ratio of elodea is 65%, the planting quantity ratio of cabomba is 12%, the planting quantity ratio of potamogeton is 15%, and the planting quantity ratio of azolla is 8%; the planting density of the plant combination c is 60 plants / m 2 .

[0098] Deep water surface flow artificial wetland 8 (fourth purification zone): The submerged plant combination d is eichhornia, myriophyllum, potamogeton malam and potamogeton pectinatus, wherein the planting quantity ratio of eichhornia is 40%, the planting quantity ratio of myriophyllum is 45%, the planting quantity ratio of potamogeton malam is 8%, and the planting quantity ratio of potamogeton pectinatus is 7%; the planting density of the plant combination d is 60 plants / m 2 .

[0099] Plankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish are put into the shallow water surface flow artificial wetland 6 and the deep water surface flow artificial wetland 8, and the planting density is 50 / m3 ; 3 snails / m 2 ; 0.5 shellfish / m 2 ; 2 shrimps / m 2 ; 5 filter-feeding fish / m 2 , 150-180 g / individual; 40 aggressive fish / m, 8-12 cm / individual.

[0100] A method for treating sewage using a sulfur-iron autotrophic denitrification and multiple plant combination constructed wetland, comprising the following steps:

[0101] S1. Establishing the system described above;

[0102] S2. Introducing sewage into the water inlet of the system described above, through the water distribution channel 1 into the horizontal subsurface flow constructed wetland 2, the effluent of the horizontal subsurface flow constructed wetland 2 into the water collection and distribution channel 3, the effluent of the water collection and distribution channel 3 into the vertical subsurface flow constructed wetland 4, the effluent of the vertical subsurface flow constructed wetland 4 into the water collection and distribution channel 5, the effluent of the water collection and distribution channel 5 into the shallow area surface flow constructed wetland 6, the effluent of the shallow area surface flow constructed wetland 6 into the water collection and distribution channel 7, the effluent of the water collection and distribution channel 7 into the deep water area surface flow constructed wetland 8, and the effluent of the deep water area surface flow constructed wetland 8 into the effluent channel 9; wherein the water depth of the horizontal subsurface flow constructed wetland 2 (first purification area) is 1.8 m, the hydraulic retention time is 5 days, and the surface hydraulic loading is 1.0 m 3 / (m 2 ·d); the water depth of the vertical subsurface flow constructed wetland 4 (second purification area) is 1.8 m, the hydraulic retention time is 4 days, and the surface hydraulic loading is 1.5 m 3 / (m 2 ·d); the water depth of the shallow area surface flow constructed wetland 6 (third purification area) is 0.8 m, the hydraulic retention time is 7 days, and the surface hydraulic loading is 0.2 m 3 / (m 2 ·d); the water depth of the deep water area surface flow constructed wetland 8 (fourth purification area) is 2.0 m, the hydraulic retention time is 3 days, and the surface hydraulic loading is 0.45 m 3 / (m 2 ·d).

[0103] S3. Discharging the water with qualified water quality after purification from the effluent outlet of the system described above to the external water area.

[0104] Example 5

[0105] A certain tail water wetland project in Yijiang District:

[0106] The effluent of this example reaches the Class III water after being treated by the artificial wetland; this example uses a sulfur-iron autotrophic denitrification and multiple plant combination constructed wetland sewage treatment system, and the setting mode of the structures in the system is the same as that of Example 2;

[0107] The shallow surface flow constructed wetland 6 (third purification zone) is provided with the plant combination c as in Example 2;

[0108] The deep water surface flow constructed wetland 8 (fourth purification zone) is provided with the plant combination d as in Example 2;

[0109] The horizontal subsurface flow constructed wetland 2 (first purification zone) is provided with the main filler A and the plant combination a as in Example 3;

[0110] The vertical subsurface flow constructed wetland 4 (second purification zone) is provided with the main filler B and the plant combination b as in Example 3;

[0111] The shallow water surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 are provided with the zooplankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish, and the density is the same as in Example 3;

[0112] The difference lies in that:

[0113] The area ratio of the shallow water surface flow constructed wetland 6 to the deep water surface flow constructed wetland 8 is 8:3.

[0114] A method for treating sewage by using sulfur-iron autotrophic denitrification and multiple plant combinations, comprising the following steps:

[0115] S1. Establishing the above system;

[0116] S2. Introducing sewage into the water inlet of the above system, and the distribution channel 1 enters the horizontal subsurface flow constructed wetland 2, the water outlet of the horizontal subsurface flow constructed wetland 2 enters the collection and distribution channel 3, the water outlet of the collection and distribution channel 3 enters the vertical subsurface flow constructed wetland 4, the water outlet of the vertical subsurface flow constructed wetland 4 enters the collection and distribution channel 5, the water outlet of the collection and distribution channel 5 enters the shallow water surface flow constructed wetland 6 through the channel, and the shallow water surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 are completed by modifying and constructing the existing ponds, and the two are connected, and the water flows through the shallow water surface flow constructed wetland 6 and the deep water surface flow constructed wetland 8 in sequence; wherein the horizontal subsurface flow constructed wetland 2 (first purification zone) has a water depth of 1.2 m, a hydraulic retention time of 4 days, and a surface hydraulic load of 0.9 m 3 / (m 2 ·d); the vertical subsurface flow constructed wetland 4 (second purification zone) has a water depth of 1.2 m, a hydraulic retention time of 3.5 days, and a surface hydraulic load of 1.2 m 3 / (m 2 ·d); the shallow water surface flow constructed wetland 6 (third purification zone) has a water depth of 1.5 m, a hydraulic retention time of 7 days, and a surface hydraulic load of 0.18 m 3 / (m 2 ·d); and the deep water surface flow constructed wetland 8 (fourth purification zone) has a water depth of 3.5 m, a hydraulic retention time of 2.5 days, and a surface hydraulic load of 0.48 m 3 / (m 2 ·d).

[0117] S3. The water that meets the water quality standards after purification is discharged from the water outlet of the system to the external water area.

[0118] Example 6

[0119] A tail water wetland project in Yijiang District:

[0120] The effluent of the municipal sewage plant in this example meets the first level A effluent standard, and the effluent after entering the artificial wetland meets the class III water; this example uses a sewage treatment system of sulfur-iron autotrophic denitrification and a combination of multiple plants, and the setting mode of the structures in the system is the same as that in Example 2;

[0121] The plant combination c in the shallow area surface flow artificial wetland 6 (the third purification area) is set in the same way as in Example 2;

[0122] The plant combination d in the deep water area surface flow artificial wetland 8 (the fourth purification area) is set in the same way as in Example 2;

[0123] The main filler A and plant combination a in the flat subsurface flow artificial wetland 2 (the first purification area) are set in the same way as in Example 4;

[0124] The main filler B and plant combination b in the vertical subsurface flow artificial wetland 4 (the second purification area) are set in the same way as in Example 4;

[0125] Plankton, snails, shellfish, shrimps, filter-feeding fish and predatory fish are put into the shallow area surface flow artificial wetland 6 and the deep water area surface flow artificial wetland 8, and the density of the put-in is the same as in Example 4;

[0126] The difference lies in that:

[0127] The area ratio of the shallow area surface flow artificial wetland 6 to the deep water area surface flow artificial wetland 8 is 3:1.

[0128] A method for treating sewage using an artificial wetland combined with sulfur-iron autotrophic denitrification and multiple plants, comprising the following steps:

[0129] S1. Establishing the above system;

[0130] S2. Introducing sewage into the water inlet of the above system, and the distribution channel 1 enters the horizontal subsurface flow artificial wetland 2, the effluent of the horizontal subsurface flow artificial wetland 2 enters the collection and distribution channel 3, the effluent of the collection and distribution channel 3 enters the vertical subsurface flow artificial wetland 4, the effluent of the vertical subsurface flow artificial wetland 4 enters the collection and distribution channel 5, the effluent of the collection and distribution channel 5 enters the shallow area surface flow artificial wetland 6 through the channel, and the shallow area surface flow artificial wetland 6 and the deep water area surface flow artificial wetland 8 are completed by modifying and constructing the existing pit pond, and the two are connected, and the water flows through the shallow area surface flow artificial wetland 6 and the deep water area surface flow artificial wetland 8 in sequence; wherein the water depth of the horizontal subsurface flow artificial wetland 2 (the first purification area) is 1.8 m, the hydraulic retention time is 1.5 days, the surface hydraulic load is 0.4 m 3(m 2 • d); vertical subsurface flow constructed wetland 4 (second purification zone) water depth 1.8 m, hydraulic retention time 1.0 day, surface hydraulic loading 0.8 m 3 (m 2 • d); shallow water surface flow constructed wetland 6 (third purification zone) water depth 0.8 m, hydraulic retention time 3.5 days, surface hydraulic loading 0.06 m 3 (m 2 • d); deep water surface flow constructed wetland 8 (fourth purification zone) water depth 2.0 m, hydraulic retention time 1.5 days, surface hydraulic loading 0.25 m 3 (m 2 • d).

[0131] S3. Discharge water of the above system to the outside water area after purification.

[0132] The water quality of the water in and out of the system of Example 3-6 was detected:

[0133] The main control indicators (CODcr, total nitrogen, ammonia nitrogen, total phosphorus) of the water quality after purification can reach the water quality standard of class III water in the "Surface Water Environmental Quality Standard" (GB3838-2002) or above, and the specific data is shown in Table 2:

[0134] Table 2

[0135]

[0136]

[0137] It should be noted that in this paper, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0138] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. An artificial wetland wastewater treatment system utilizing pyro-iron autotrophic denitrification and a combination of various plants, comprising a set of structures, characterized in that: The set of structures is divided into a first purification zone, a second purification zone, a third purification zone, and a fourth purification zone in the order of water inlet to water outlet. Water flows through the first purification zone, the second purification zone, the third purification zone, and the fourth purification zone in sequence. A water distribution channel is set at the water inlet of the first purification zone, a collection and distribution channel is set between the first and second purification zones, a collection and distribution channel is set between the second and third purification zones, a collection and distribution channel is set between the third and fourth purification zones, and an outlet channel is set at the water outlet of the fourth purification zone. In the first purification zone, there is a main packing material A and a plant combination a. The main packing material A is made of three raw materials selected from ceramsite, zeolite, gravel, or volcanic rock, with two of them being ceramsite and zeolite, and the other being gravel or volcanic rock. The volume ratio of the three raw materials, ceramsite, zeolite, gravel, or volcanic rock, is 1:2:

1. Plant combination a is any three or more of the following: water onion, loosestrife, pickerelweed, bulrush, umbrella sedge, and reed. The number of each plant in plant combination a is the same. In the second purification zone, there is a main packing material B and a plant combination b. The main packing material B is made of three or more raw materials selected from siderite, pyrite, pyrrhotite, sulfur, maifanite, and ceramsite. Siderite is a must, and at least one of pyrite and pyrrhotite is included. At least one of sulfur, maifanite, and ceramsite is included. The volume percentage of siderite in the main packing material B is 35-45%, and the total volume percentage of siderite, pyrite, pyrrhotite, and sulfur is 60%. The plant combination b is any three or more of cattail, calamus, water onion, canna, umbrella sedge, and water chestnut. The number of each plant in the plant combination b is the same. In the third purification zone, submerged plant combination c is planted; submerged plant combination c consists of two or more of the following: *Hydrilla verticillata*, *Elodea nuttallii*, dwarf *Vallisneria natans*, *Ceratophyllum demersum*, and *Potamogeton microdentatum*; among them, dwarf *Vallisneria natans* and *Ceratophyllum demersum* are essential; the proportion of dwarf *Vallisneria natans* in submerged plant combination c is no less than 60%, and the proportion of *Ceratophyllum demersum* is no less than 10%; In the fourth purification zone, a submerged plant combination d is planted; wherein, the submerged plant combination d consists of two or more of the following: Potamogeton malaianus, Myriophyllum spicatum, Potamogeton pectinatus, Vallisneria natans, and Vallisneria natans; among which Vallisneria natans and Vallisneria natans are essential; the proportion of Vallisneria natans and Vallisneria natans in the submerged plant combination d shall not be less than 70%; In both the first and second purification zones, the plant density ranges from 20 to 25 plants per square meter. 2 In the third and fourth purification zones, the plant density ranges from 40 to 60 plants per square meter. 2 .

2. The constructed wetland wastewater treatment system using sulfur-iron autotrophic denitrification and a combination of multiple plants as described in claim 1, characterized in that, The main packing material A in the first purification zone is prepared by crushing, ball milling, sieving, mixing and granulation, with a particle size of 10-30mm.

3. The constructed wetland wastewater treatment system using sulfur-iron autotrophic denitrification and a combination of multiple plants as described in claim 1, characterized in that, In the second purification zone, the main packing material B is prepared by crushing, ball milling, sieving, mixing and granulation, with a particle size of 2-6 mm.

4. The constructed wetland wastewater treatment system using sulfur-iron autotrophic denitrification and a combination of multiple plants as described in claim 1, characterized in that, Zooplankton, snails, shellfish, shrimp, filter-feeding fish, and predatory fish were introduced into both the third and fourth purification zones. The stocking densities were 30-50 zooplankton / m². 3 ; 2-3 snails / m 2 ; 0.3-0.5 shellfish / m 2 Shrimp 1-2 per m 2 Filter-feeding fish 3-5 per m 2 100-200g / tail; 20-40 fish / acre for ferocious fish, 8-12cm / tail.

5. A constructed wetland wastewater treatment system using sulfur-iron autotrophic denitrification and a combination of multiple plants as described in claim 1, characterized in that: The first purification zone has a water depth of 1.2-1.8m, a hydraulic retention time of 1-5 days, and a surface hydraulic load of 0.2-1.0m. 3 m -2 d -1 The second purification zone has a water depth of 1.2-1.8m, a hydraulic retention time of 0.6-4 days, and a surface hydraulic load of 0.3-1.5m. 3 m -2 d -1 The third purification zone has a water depth of 0.8-1.5m, a hydraulic retention time of 2.5-8 days, and a surface hydraulic load of 0.02-0.2m. 3 m -2 d -1 The fourth purification zone has a water depth of 2.0-3.5m, a hydraulic retention time of 0.8-3 days, and a surface hydraulic load of 0.03-0.5 m. 3 m -2 d -1 .

6. A constructed wetland wastewater treatment system using pyrometallurgical autotrophic denitrification and a combination of multiple plants as described in claim 1, characterized in that, The third and fourth purification zones are constructed from pits and ponds, with the shallow water area of ​​the pits and ponds being the third purification zone and the deep water area of ​​the pits and ponds being the fourth purification zone.

7. A constructed wetland wastewater treatment system using pyrite autotrophic denitrification and a combination of multiple plants as described in claim 6, characterized in that, The area ratio of the third purification zone to the fourth purification zone shall not be less than 7:3; In the third purification zone, the submerged plant combination c in the first 50% of the area consists of *Hydrilla verticillata* and *Elodea nuttallii*, with a planting ratio of 1:1 and a planting density of 10-15 buds / clump and 25-36 clumps / m². 2 In the purified area, the submerged plant combination (c) for 50% of the area consists of dwarf Vallisneria natans and Ceratophyllum demersum, with a planting ratio of 6:1 and a planting density of 40-60 plants / m². 2 ; The fourth purification zone's submerged plant assemblage (d) consists of Vallisneria natans, Vallisneria natans, and Potamogeton malaianus, with a plant ratio of 3:1:1 and a planting density of 40-60 plants / m². 2 .

8. A method for treating wastewater using an artificial wetland employing sulfur-iron autotrophic denitrification and a combination of multiple plants, characterized in that, Includes the following steps: S1. To establish an artificial wetland wastewater treatment system using sulfur-iron autotrophic denitrification and a combination of multiple plants as described in any one of claims 1-7; S2. Introduce the wastewater into the inlet of the system in S1, and let it flow through four purification zones in sequence for purification treatment; control the hydraulic residence time, water depth and surface hydraulic load of each purification zone; S3. Discharge the purified water from the outlet of the above system.

Images