CN102992485B - Method for treating sewage by constructing artificial wetland with vetiver grass - Google Patents

Abstract

The invention discloses a method for constructing an artificial wetland with vetiver to treat sewage, and the specific steps are as follows: a. raising seedlings; b. constructing a wetland; c. diverting sewage. The bed wall and the bottom of the wetland constructed by the invention are waterproof structures to prevent groundwater from being polluted by sewage leakage. The wetland bed is filled with coal gangue, broken bricks, cinder, sand, and gravel as a composite matrix. The composite matrix can better absorb, filter, and intercept suspended solids in sewage; plant vetiver with a row spacing of 40cm×40cm , leave enough space for the vetiver to grow by itself, and will not let the vetiver grow too thin. After the artificial wetland constructed by the present invention, the removal effect of SS (suspended solids), TN (total nitrogen), COD (chemical oxygen demand) and BOD (biochemical oxygen demand) in domestic sewage is very good, and the quality of effluent water reaches the national level Emission Standards.

Description

A method of constructing artificial wetland with vetiver to treat sewage

technical field

The invention belongs to the technical field of sewage treatment methods, in particular to a method for constructing artificial wetlands with vetiver to treat sewage.

Background technique

At present, the current status of sewage treatment in my country is not optimistic. Some domestic sewage and industrial wastewater are treated by existing sewage treatment equipment, and there are problems such as substandard treatment, high cost, and hidden dangers. Although some sewage treatment agents have treated sewage, they have polluted the soil; wastewater treated with microorganisms has also brought many potential hazards to us humans due to the rapid mutation of microorganisms. Constructed wetland system water purification technology is a new type of ecological sewage purification treatment method, which is economical and environmentally friendly. Its basic principle is to plant specific wetland plants on the constructed wetland filler to establish a constructed wetland ecosystem. When sewage passes through the wetland system , the pollutants and nutrients in it are absorbed or decomposed by the system, so as to achieve the purpose of water purification. However, the existing methods for treating sewage in constructed wetlands still have many defects. For example, the document of Patent No. ZL200610052475.0 discloses a method for treating sewage in constructed wetlands. Porous iron clapboard submerged artificial wetlands and sump, but because of the need to build multiple wetlands, laying pipes, welding iron clapboard, the cost is high, and the porous iron clapboard in the matrix is easy to rust and rot in sewage. Therefore, it is urgent to develop an effective method for treating sewage.

Contents of the invention

The purpose of the invention is to overcome the deficiencies of the prior art, and provide a method for constructing artificial wetlands with vetiver to treat sewage.

A method for constructing artificial wetlands to treat sewage with vetiver, the specific steps are as follows:

a. Seedling cultivation: cultivate vetiver seedlings in the nursery in the first year;

b. Construction of wetland: Excavate a wetland bed with a depth of 1.5m to 2.5m. The bed wall is a brick structure with cement plaster and the bottom is a concrete structure. The wetland bed is made of coal gangue, broken bricks, cinder, sand and gravel as a composite matrix Fill the wetland, crushed bricks, coal gangue, particle size of 2cm to 5cm, gravel particle size of 1cm to 3cm, the mass ratio of the five substrates is 1:1:1:1:1, and the broken bricks are laid in order from bottom to top block, coal gangue, gravel, cinder, sand, the height of the composite substrate is 1m, plant vetiver with a row-to-plant spacing of 40cm×40cm, pay attention to watering when planting to ensure the survival of the seedlings, and wait for one month before introducing clean water into the wetland , immerse the roots of the vetiver at a depth of 3cm to 15cm;

c. Diversion of sewage: 1 to 2 months after the introduction of clean water into the wetland, domestic sewage is introduced into the wetland. The residence time of the sewage in the artificial wetland is 2 to 5 days, and then it is drawn out.

The effective water depth of the constructed wetland is 0.8m-1.2m.

Vetiver (Vetiveria zizanioides), known as the "magic grass", is a high-biomass amphibian plant with strong tolerance to environmental stresses such as acid, alkali, salt, heavy metals, eutrophication, and flooding. It is an ideal plant that can be used to construct artificial wetlands. Vetiver is widely used in the treatment of domestic sewage, industrial wastewater and landfill leachate, based on its following properties: higher evapotranspiration rate than most wetland plants; especially high amounts of ammonia, total nitrogen and total phosphorus And fast absorption rate; vetiver is sterile, so it does not form species invasion; High tolerance to soil acidity, alkalinity, salinity and sodium; High tolerance to flooding and water immersion; Can tolerate high concentration landfill leachate . The bed wall and the bottom of the wetland constructed by the invention are waterproof structures to prevent groundwater from being polluted by sewage leakage. The wetland bed is filled with coal gangue, broken bricks, cinder, sand, and gravel as a composite matrix, and the composite matrix can better absorb, filter, and intercept suspended matter in sewage; the broken bricks, coal gangue, granular The diameter should be 2cm to 5cm, the particle size of the gravel should be 1cm to 3cm, the ratio of the five substrates is 1:1:1:1:1, and the crushed bricks, coal gangue, gravel, cinder, and sand should be laid in order from bottom to top. , which is convenient for laying, reduces the workload, and is also conducive to the survival of vetiver; plant vetiver with a row spacing of 40cm×40cm, leaving enough space for vetiver to grow by itself, and will not let vetiver grow too much Thin; after 1 month, the root system of vetiver has grown to 80cm~200cm, lead clean water into the wetland, immerse the root of vetiver 3cm~15cm in depth, let the vetiver adapt to the water environment in advance, so as not to suddenly introduce high concentration Sewage makes vetiver unsuitable; 1 to 2 months after introducing purified water into the wetland, domestic sewage is introduced into the wetland, and the residence time of the sewage in the artificial wetland is 2 to 5 days before being drawn out. The reason is: the effect of water quality treatment It is related to the length of hydraulic retention time. The longer the time, the better the treatment effect. Therefore, when the concentration of sewage is too high, the hydraulic retention time should be extended. After the artificial wetland constructed by the present invention, the removal effect of SS (suspended solids), TN (total nitrogen), COD (chemical oxygen demand) and BOD (biochemical oxygen demand) in domestic sewage is very good, and the quality of effluent water reaches the national level Emission Standards.

Detailed ways

A kind of construction artificial wetland treatment domestic sewage with vetiver, concrete steps are as follows:

1. Seedling cultivation: Cultivate vetiver seedlings in the nursery in the first year;

2. Construct wetlands: Construct surface-flow artificial wetlands, such as villages with a population of 250-300, whose dimensions are 25m×6.5m×2m. The wall adopts the brick structure with cement plaster, and the bottom can be made of concrete structure. The bottom of the wetland is paved with broken bricks in sequence, and the coal gangue, gravel, cinder, and sand are used as the composite matrix. The vetiver cultivated in one year should pay attention to watering when planting to ensure the survival of the seedlings. After 3 months, the vetiver has grown to 1 m ~ 1.8 m. Bring clean water into the wetland and immerse the roots of the vetiver 10cm deep. ;

3. Sewage diversion: One month after introducing purified water into the wetland, domestic sewage is introduced into the wetland from one end, with an effective water depth of 0.8-1.5m, hydraulically retained for 3 days, and then drained from the other end;

The domestic sewage entering the wetland and the water discharged after 3 days of hydraulic retention were collected for water quality monitoring. See the table below for the values: (unit: mg/L)

Element grease chloride Total Phosphorus total nitrogen COD BOD suspended matter Fe Cu pH before processing 147 189 14.1 79.6 960 382 341 2.49 0.11 7.9 after treatment 7.3 26.1 2.6 9.5 57.6 30.5 6.8 0.11 0.03 7.1

The removal rate of various substances in domestic sewage is above 70%, and the pH value is also improved. Constructed wetland with vetiver grass can effectively treat domestic sewage by using the absorption and degradation function of vetiver grass. It has the advantages of small investment, good effect, greening and beautification, and simple maintenance. It has good ecological value, economic value and social value. Value, suitable for popularization and application in urban areas, especially in the sewage treatment process in rural areas.

Claims (1)

1. a method that builds Wastewater Treatment by Constructed Wetlands with Caulis Miscanthis floriduli, is characterized in that, its step is as follows:

A, grow seedlings: First Year is cultivated Caulis Miscanthis floriduli seedling in nursery;

B, build wetland: excavate wetland bed body, the degree of depth will be at 1.5m～2.5m, the brick structure that bed wall is finishing cement, bottom is concrete structure, wetland bed upper with coal gangue, queen closer, cinder, sandy soil, gravel does composite interstitial substance and fills wetland, queen closer, coal gangue particle diameter is 2cm～5cm, grain size of gravel is 1cm～3cm, five kinds of matrix mass ratios are respectively 1:1:1:1:1, spread successively from the bottom up queen closer, coal gangue, gravel, cinder, sandy soil, the height of composite interstitial substance is 1m, plant Caulis Miscanthis floriduli with distance between rows and hills 40cm × 40cm kind, while kind, note watering, guarantee that seedling survives, after 1 month, draw water purification and enter wetland, depth of water submergence Caulis Miscanthis floriduli root 3cm～15cm,

C, draw sewage: after drawing water purification to enter wetland 1～2 month, draw sanitary sewage and enter wetland, sewage deep is 0.8m～1.5m, the residence time of sewage in artificial swamp is 2～5 days, draws afterwards.