CN105399207B

CN105399207B - Backwash horizontal subsurface flow constructed wetland capable of relieving front section blockage

Info

Publication number: CN105399207B
Application number: CN201410469215.8A
Authority: CN
Inventors: 湛含辉; 王良杰; 刘彤
Original assignee: China University of Mining and Technology CUMT
Current assignee: China University of Mining and Technology CUMT
Priority date: 2014-09-16
Filing date: 2014-09-16
Publication date: 2020-04-28
Anticipated expiration: 2034-09-16
Also published as: CN105399207A

Abstract

The utility model provides a can slow down horizontal undercurrent constructed wetland that backflush of anterior segment jam which characterized in that: the top of the water outlet channel is sealed, the particle size of the matrix of the front section (front 1/4-1/2) of the wetland is larger than that of the matrix of the rear section, the water inlet end and the water outlet end are provided with a rising gradient, the water inlet end and the water outlet end both adopt perforated walls, the length is smaller than the common length of the conventional manual work and is generally within 15m and not more than 20m at most, the particle size of the matrix of the front section is 12-30 mm, the particle size of the matrix of the rear section is 4-12 mm, the rising gradient from the water inlet end to the water outlet end is 0.5-2%, and holes on the water inlet perforated wall and the water outlet perforated wall are uniformly arranged. The invention has the advantages that the diameter of the front telomere is larger than that of the rear section, the blockage of the front end of the wetland can be delayed, the hydraulic efficiency of the wetland can be improved, the water outlet channel can provide enough pressure, and the blockage of the wetland is solved through backwashing.

Description

Backwash horizontal subsurface flow constructed wetland capable of relieving front section blockage

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a backwash-capable horizontal subsurface flow constructed wetland capable of relieving front section blockage.

Background

The artificial wetland is a new wastewater biological treatment technology developed in the 70 s of the 20 th century, and has the characteristics of low investment, low energy consumption, good effluent quality, strong denitrification and dephosphorization functions, convenient operation and management and the like, so the technology is accepted by all countries in the world and is used for treating various forms of wastewater. According to the research of the United States Environmental Protection Agency (USEPA), more than 600 constructed wetland projects are used for treating municipal, industrial and agricultural wastewater in the United states, at least 200 constructed wetland (mostly subsurface wetland) systems are operated in member countries of European Union such as England of Denmark Germany, and more than 80 constructed wetland systems are put into use in New Zealand as well as in the United states of America 2000.

However, from the existing engineering practice, the constructed wetland faces great potential safety hazard in long-term operation, if the design or the management is not good, the wetland substrate is easy to block, and the blocking is one of the main factors restricting the popularization and the application of the constructed wetland as a natural phenomenon. According to the investigation of artificial wetlands in more than 100 operations by the USEPA, nearly half of the wetland systems are found to be blocked within 5 years after the wetland systems are put into use. The Shenzhen white-pit wild goose field constructed wetland built in 1990 in China also causes serious blockage due to insufficient pretreatment, overlarge hydraulic load and the like, and the purification effect is seriously influenced.

For the horizontal subsurface flow constructed wetland, the blockage mainly occurs at the front end, the most common method for solving the blockage of the constructed wetland at present is stop-and-go rotation, although the method has better effect and can recover a certain porosity, two obvious defects exist, firstly, the stop-and-go rotation needs other wetlands to replace the wetlands to operate and treat sewage, and thus, the occupied area and the construction cost are increased; secondly, the method can only solve the blockage caused by biological factors and can not solve the blockage caused by inorganic matters.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides the backwashing horizontal subsurface flow constructed wetland capable of relieving front section blockage.

The invention is characterized in that: the top of the water outlet channel is sealed, the particle size of the matrix of the front section (front 1/4-1/2) of the wetland is larger than that of the matrix of the rear section, a rising slope is formed from the water inlet end to the bottom of the water outlet end, and the water inlet and the water outlet adopt perforated walls, so that the length of the water outlet channel is smaller than that of the conventional artificial common channel.

The particle size of the front section substrate is 12 mm-30 mm, and the particle size of the rear section substrate is 4 mm-12 mm.

The ascending gradient range from the water inlet end to the water outlet end is 0.5-2%.

The holes on the water inlet perforated wall and the water outlet perforated wall are uniformly arranged in the horizontal direction and the vertical direction.

The length is generally within 15m and not more than 20m at most.

The invention has the following advantages and innovation achievements: the front section substrate has large particle size, large porosity and pore size, can delay the blockage of the wetland, is easy to back flush, and the rear section substrate has small particle size, can ensure the treatment effect, and can ensure that water flow is more uniformly dispersed in the front end wetland due to the increased resistance, thereby improving the hydraulic efficiency; the top of the water outlet channel is sealed, so that water flow with enough pressure can be provided to flush wetland substrates, and the problem of wetland blockage is solved; the bottom slope of the water ascending from the water inlet end to the water outlet end is beneficial to the deposition of suspended matters at the front end, and the backwashing is convenient. The length of the wetland is small, so that the hydraulic loss and the used back washing pressure can be reduced, and the problem of blockage of the wetland can be solved by back washing from the water outlet end.

Drawings

FIG. 1 is a cross-sectional view A-A of the present invention.

Fig. 2 is a plan view of the present invention.

In the drawings, the main reference symbols indicate: 1, feeding water into a channel; 2, water inlet perforated wall; 3, a water inlet valve; 4, back flushing a water outlet valve; 5, a water distribution area with uniform large particle size; 6, a large-particle-size substrate area at the front end; 7, a small-particle-size matrix area at the rear section; 8, a water collecting area with uniform large grain size is formed; 9, a water outlet device with adjustable water level; 10 an impermeable layer; 11 surface soil; 12 water outlet perforated wall; 13, discharging a water channel; 14 back flushing the valve.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

Mode 1: as shown in fig. 1 and fig. 2, it is an implementation manner of the present invention: the artificial wetland comprises a large-particle-diameter uniform water distribution area 5, a large-particle-diameter uniform water collection area 8, a water level adjustable water outlet device 9, an impermeable layer 10 and surface soil 11 as in the conventional artificial wetland. The front 1/3 section of the wetland is filled with substrates with the particle size of 16 mm-25 mm, the rear section is filled with substrates with the particle size of 4 mm-8 mm, the top of the water outlet channel 13 is sealed, and the gradient of the bottom is 0.5%.

When sewage is treated in the wetland, the back-flushing water outlet valve 4 and the back-flushing valve 14 need to be closed, the sewage enters wetland substrates through the water inlet valve 3, the water inlet channel 1 and the water inlet perforated wall 2 in sequence, is uniformly distributed through the large-particle-diameter uniform water distribution area 5, and then sequentially passes through the front-end large-particle-diameter substrate area 6 and the rear-section small-particle-diameter substrate area 7, the front-end large-particle-diameter substrate area 6 is used for slowing down the blockage of the front section of the wetland, the rear-section small-particle-diameter substrate area 7 is used for ensuring the treatment efficiency, and after the sewage passes through the substrate area and is uniformly collected by the large-particle-diameter uniform water collection area 8, the sewage sequentially passes through the water outlet perforated wall 12. When the porosity of the wetland matrix is reduced to 10-20% of the original porosity, the water inlet valve 3 and the water level adjustable water outlet device 9 are closed, the back flush water outlet valve 4 and the back flush valve 14 are opened, clear water enters the water outlet channel 13 from the back flush valve 14, enters the wetland matrix through the water outlet perforated wall 12, back flushes the wetland matrix, and back flushes water after entering the water inlet channel 1 through the water inlet perforated wall 2 and then exits through the back flush water outlet valve 4.

Mode 2: as shown in fig. 3 and 4, it is an implementation manner of the present invention: the particle size of the substrate of the front 1/3 section is 12 mm-20 mm, the particle size of the substrate of the rear section is 6 mm-12 mm, the bottom gradient is 1%, the two wetlands are oppositely arranged and share one water outlet, and the rest is the same as the mode 1.

Claims

1. The utility model provides a can slow down horizontal undercurrent constructed wetland that backflush of anterior segment jam which characterized in that:

the top of the water outlet channel is sealed, the particle size of front 1/4-1/2 matrixes at the front section of the wetland is larger than that of matrixes at the rear section, a rising slope is formed from the water inlet end to the bottom of the water outlet end, the water inlet and the water outlet adopt perforated walls, and the length of the artificial wetland is within 15 m;

the particle size of the front section substrate is 12 mm-30 mm, and the particle size of the rear section substrate is 4 mm-12 mm;

the ascending gradient range from the water inlet end to the water outlet end is 0.5 to 2 percent;