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Design assignment (a)

Hebei a city sewage treatment plant engineering design

I. Project Overview

A sewage treatment plant serves about 500,000 people, the catchment area is 40km2, the design scale of the first phase is 160,000m3/d, the long-term 32,000m3/d, the use of foreign loans to build. The city discharges 35% of its sewage from domestic sewage and 65% from industrial sewage, which is discharged to the outskirts of the city through a pipeline, and then discharged into the surrounding rivers through a 37km nullah.

II. Designed water quality and quantity and discharge quality

1. Designed treatment water quality and quantity

Designed treatment capacity of 160,000m3/d (maximum 208,000m3/d).

Due to the influence of the city drainage system and the change of the actual water intake, its sewage treatment capacity has basically remained at about 130,000m3/d for several years. Inlet water quality of domestic sewage water quality is relatively stable, while the industrial wastewater water quality fluctuations, sewage plant actual inlet and outlet water quality is shown in the table below.

Items BOD5(mg/L) COD(mg/L) SS(mg/L) pH Toxic substances Heavy metals

Inlet 100-200 150-350 80-200 7-9 - trace

Outlet ≤30 ≤120 ≤30 6-9 - trace

Designed inlet water quality (without considering toxic substances and heavy metals)

Designed inlet water quality (without considering toxic substances and heavy metals)

Item of the water quality is (without considering toxic substances and heavy metals). Discharge standard

The quality of the effluent water reaches the national secondary discharge standard, and the quality of the effluent water is designed as follows

BOD5 ≤20mg/L COD ≤120mg/L SS ≤25mg/L pH value 6-9

Effluent water ≤30 ≤120 ≤30 6-9 - trace

The quality of the effluent water is designed as follows (without considering the toxic substances and heavy metals)

BOD5 ≤20mg/L COD ≤120mg/L SS ≤25mg/L pH value 6-9

Three, the choice of treatment process programs and processes

1. Treatment process to determine the principles

In order to achieve the same time to achieve efficient and stable operation of wastewater treatment plants and infrastructure investment, low operating costs, based on the following principles of the wastewater treatment process selection:

① Mature technology, stable treatment results to ensure that the quality of effluent to meet the emission standards;

① Mature technology, stable treatment results, to ensure that the quality of effluent to achieve Emission standards;

② low investment, operating costs, low investment and high efficiency;

③ selected process technology and equipment advanced, reliable, high degree of localization, good performance.

2. Determination of treatment process

The ordinary activated sludge method.

Sewage into the plant through the automatic coarse grating into the catchment basin, set up in the catchment basin submersible pumps, sewage lifting through the fine grating into the aeration sedimentation tank to remove sand particles, and then through the primary sedimentation tank to remove most of the suspended solids, primary sedimentation of water through the plant elevated channel into the aeration tank. The aeration tank adopts the form of circulating push-flow reaction, and its effluent is discharged into the surrounding rivers after being separated by the advection type secondary sedimentation tank.

The primary sludge and the remaining sludge from the secondary sedimentation firstly enter into the former thickener, and after thickening, they enter into the egg-shaped digester for medium-temperature digestion, so as to stabilize the sludge. The digested sludge is further concentrated by the post-thickening pool to reduce the volume, dewatered by belt filter press, and the mud cake is transported out for disposal.

3. Introduction to the treatment process

Activated sludge method is an aerobic treatment process. Sewage in the aeration tank aeration and oxygenation, so that a variety of activated sludge microorganisms grow and multiply, can form a bacterial colloid bacteria to form flocs, protozoa attached to it, filamentous bacteria and fungi are also intertwined during the interspersed, the formation of a floc particles suspended in the mixture, each particle is a microbial group. Such activated sludge particles and enter the aeration tank of sewage contact, that is, the pollutants in the sewage adsorption, decomposition, absorption and other roles, after a period of time after the aeration, most of the organic matter in the sewage is assimilated into the microbial organisms, and then enter the sedimentation tank. The flocculated activated sludge particles can settle well to the bottom of the tank, and the supernatant is treated water, which can be discharged out of the system. Part of the settled sludge is replenished and returned to the aeration tank to mix with the untreated sewage to repeat the above effect; the other part of the sludge is discharged as residual sludge.

III. Design process requirements

The process uses ordinary activated sludge method (or multi-point water intake).

There is a total gate before sewage entering the plant, and there is another overflow pipe for direct discharge before the total gate.

Sewage into the plant through the automatic coarse grating into the catchment pond,

in the catchment pond with submersible pumps,

sewage lifting through the fine grating into the cyclone sedimentation tank to remove sand particles,

and then through the primary sedimentation tank to remove most of the suspended solids,

the primary sedimentation outflow through the plant elevated channel into the aeration tank. The aeration tank adopts the form of circulating push-flow reaction,

and its effluent is discharged into the surrounding rivers after being separated by the advection type secondary sedimentation tank.

The primary sludge and the remaining sludge from the secondary sedimentation firstly enter the former thickener,

and after thickening, they enter the egg-shaped digester for medium temperature digestion to stabilize the sludge.

The digested sludge is further concentrated by the post-thickening pool to reduce the volume, dewatered by belt filter press, and the mud cake is transported for disposal.

Four, engineering design

1. General layout design

(1) principles of layout

The general layout, including: sewage and sludge treatment, process buildings and facilities of the general layout, a variety of pipelines, pipelines and channels of the layout, a variety of auxiliary buildings and facilities of the layout, the general layout should comply with the following principles.

1. Processing structures and facilities should be arranged in accordance with the process, centralized and compact in order to save land and operational management.

2. Process structures do not have to change the facilities and different functions of the auxiliary buildings should be arranged according to the function of the differences in the relative independence and coordination of the relationship with environmental conditions (such as terrain trends, sewage outlet direction, wind direction).

3. The spacing between the building should meet the requirements of traffic, pipeline (canal) laying, construction and operation management.

4. Pipeline (line) and channel layout should be coordinated with its elevation arrangement, should comply with the requirements of the sewage treatment plant for a variety of media transport, try to avoid multiple lifting and meandering, to facilitate energy saving and operation and maintenance.

5. Coordination of auxiliary buildings, roads, greening and treatment of the relationship between buildings, to facilitate production and operation to ensure the safety of the plant environment.

(2) Layout characteristics

1. Compact layout, clear flow.

2. Living activities area, sewage area, sludge area, the boundaries are clear from the gate in for the complex, forming the entrance to the living area, which is located in the dominant wind direction upwind from the grill, sludge area is very far away from the enhancement of greening, the environment is better.

3. The sludge area is located in the downwind direction and in the bottom corner of the plant, the digesting tank is far away from the structure of the building, and does not affect other facilities.

4. The auxiliary production area is closer to the buildings that need more electricity for maintenance, which is convenient for the staff.

5. The road design in the plant takes into account the fact that the staff can reach any place smoothly.

6. There is a back door, the production process of slag, sand, mud cake, etc. produced by the back door transported away from the front door to avoid the impact of the gate at the living area of the environmental cleanliness.

The process of wastewater treatment is composed of a number of different functions of the unit treatment structures (equipment) and water pipelines. With the development of wastewater treatment technology, on the one hand, the same function of the type of treatment facilities in the increasing, on the other hand, the same facilities, some of the treatment function is also expanding. In the wastewater treatment plant process and structure type determination, wastewater treatment process calculation task is mainly to determine the geometry and number of structures (equipment) and pipes and drains, as well as auxiliary devices, materials and pharmaceuticals, etc. specifications and dosage. Thus providing a basis for the arrangement of the treatment plant.

①Qingdao Licun River sewage treatment plant design scale 17 × 104m3 / d, the bottom of the grille from the ground 8.0 m. Coarse grille room adopts a semi-underground form, within the set of mechanical coarse grille 3, grille gap 25mm, grille width of 1.36m, grille grating intercepted slag collected by the belt conveyor, screw conveyor to lift the slag into the ground after the box, and in the grating near the surface of the water to set up The width of 1.0 m maintenance platform. 4 sets of ventilators are located in the semi-subterranean room, the air intake is located in the channel and the room, the ventilator air volume of 8000 m3/h. The sewage flowing through the coarse grating is lifted by the lifting pump room and then entered the fine grating room, the fine grating room is designed with 3 sets of ladder-type mechanical grating, with a gap of 6 mm and a grating width of 1.28 m, and the fine grating residue is dewatered by the screw compactor for external transportation. ② Hohhot Xinxin plate sewage treatment plant design scale 10 × 104m3 / d, the bottom of the grille from the ground 5.4 m. Coarse grille room using ground type, set up two mechanical grille, grille gap 25 mm, grille width 2.0 m, height 8.4 m, design in the roof 2.5 m × 1.5 m skylight, so that the height of the grille room from 11.5 m to 6.2 m. Exhaust fan taking The air outlet is located in the water channel where the maintenance personnel often appear, *** set up 2 sets of exhaust fan, ventilation 8 250m3/h.

Process:

Third, the main structures

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No. ?

Name ?

Specifications (m) ?

Quantity (seat) ?

Design parameters

? ?

Main equipment

1 Grid L×B=3.16×1.65 2 flow rate Q=165600m3/d

Grate gap b=15mm flow rate v=1.0m/s Mechanical slag remover two sets

2 lifting pumping house L×B×H=10×8×5 1 flow rate Q=165600m3/d

Single pump flow Q=2400m3/h Submersible pumps 4 sets of manual starters

3 Sedimentation tank L×B=18×3.22 2 flow rate Q=165600m3/d

Horizontal flow rate v=0.3m/s Effective depth of water h=1.0m Sand-water separator

4 Primary sedimentation tank L×B=×27×6 2 flow rate Q=165600m3/d

4 Primary sedimentation tank L×B=×27×6 2 flow rate Q=165600m3/d

4 Primary sedimentation tank L×B×H=10×8×5 165600m3/d

q=2.0m3/(m2-h) retention time t=1.5h scraper sludge storage hopper

5 ?

Aeration tank L×BH=71.5×7.55 2 flow rate Q=120,000m3/d BOD=200,90% efficiency blower Microporous aerator

6 Dual sedimentation tank D×H=46.1×6.15 2 flow rate Q=120,000m3/d

q=1.5m3/(m2-h)

Dwell time t=2.5h Scraper outlet weir plate

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(1) coarse grating (two groups, one with one backup)

Function: to remove the larger floating debris in the sewage to ensure the normal operation of sewage lifting pumps, using mechanical grating, two channels running at the same time under normal conditions, and one running in case of accidents.

Main parameters: design maximum flow Qmax = 208,000 m3/d = 2.4 m3/s

Grate gap width b = 25.0mm

Grate before the depth of water h = 1.0m

Over the grating flow rate v = 0.8m/s

Grate inclination α = 60 °

Grate width S = 0.01m (grate width). 0.01m (the grating section is a sharp-edged rectangle)

The number of grating gaps:

n==112

The width of the grating groove:

B=S(n-1)+bn=3.91m

The length of the tapering part of the inlet channel:

The width of the inlet channel is set to be B1=2.3m, and the angle of the tapering part of the width is set to be α1=20°.

L1=(B-B1)/2tgα1=2.21m

Length of tapering part: L2= L1/2=1.10m

Head loss over the grating:

h1=4/3 ()k=0.061m

Total height after the grating:

The protected height of the channel before the grating h2 = 0.3m

H=h+ h1+ h2=1.36m≈1.4m

Total length of grating channel:

L= L1+ L2+0.5+1.0+H1/tgα=5.56m

Daily slag volume:

In the case of grating clearance of 25mm, set the slag volume as 0.03m3/ 103m3 sewage, Kz is set to 1.2.

W=86400Qmaxw1/1000Kz=5.2 m3/d>0.2m3/d

Therefore, it is necessary to use mechanical slag removal.

(2) Catch basin and lifting pump room

Use rectangular combined self-irrigation dry pump room, catch basin and machine room separated by partition wall, only suction pipe and impeller submerged in water, machine room can often remain dry, in order to facilitate the overhaul and maintenance of pumps, and can avoid sewage corrosion of bearings, pipe fittings, instrumentation.

Design flow Qmax = 208000 m3/d = 2.4 m3/s

The flow rate of 0.6 m3/s submersible pumps, 4 with a backup.

Catch basin is divided into 2 compartments, the total effective volume of a pump 8 minutes of water:

V = qt = 288 m3

Set the effective depth of the catch basin for 2.0 m

Catch basin area F = 144 m2, width 10 m, length 14.4 m, take 15 m

The required head of water pump: H = 3.3 +0.1+0.2+0.6+0.2+0.6+0.5+0.4+1.5=7.4m

(3) Fine grating

Function: to remove the floating debris in the sewage in order to ensure the normal operation of the subsequent treatment process.

Construction of two groups, the design flow rate of Q = Qmax/3 = 0.8m3/s

Grate gap e = 6mm

Grate before the depth of water h = 0.8m

Over the grating flow rate v = 1.0m/s

Grate inclination α = 60 °

with the coarse grating calculated as follows:

The number of gates n = 155

The number of gaps in the grates. 155

Grate width B = 2.47m

The length of the tapering part of the inlet channel L1 = 1.33m

The length of the tapering part L2 = 0.66m

The head loss h1 = 0.633m

The total height of the grating after the gate H = 1.73m

The total length of the grating channel L = 4.12m

Daily slag volume W=5.2 m3/d>0.2m3/d

So it needs to be mechanically cleaned

(4) Cyclone sand sedimentation tank

Function: Sewage enters from the tangential direction of the sedimentation tank with a certain flow rate, sand particles generate centrifugal force, and the sand particles with larger density settle along the wall and the unique structure of the tank to the bottom of the sand collecting hopper. Flushing system will avoid the sand in the sand hopper sedimentation slate, and will be attached to the sand particles of organic particles and sand separation, so that organic particles from the sand hopper returned to the sewage. The rotation of the paddles makes the water flow in a complex vortex state, generating a slight upward flow, which drives the organic particles to flow with the water into the next process for treatment. By changing the rotational speed of the paddles and the gap between the sand collection hopper, the sand sedimentation effect of the sand sedimentation tank and the separation effect of organic particles can be optimized. The sunken sand in the sand collecting hopper is lifted to the shaftless spiral sand-water separator through the advanced air lifting system (or slurry pump) to realize the complete separation of sand particles and sewage.

The cyclone sand sedimentation tank system in operation, the import and export of water flow velocity is high, the treatment capacity is large, the effect of sand removal is good, the footprint is small, the equipment has a simple structure, energy saving, reliable operation, the whole system PLC control to realize the centralized control, continuous automatic operation, operation and maintenance is convenient for the use of large, medium and small sewage treatment plants, for the domestic wastewater treatment of the advection sand sedimentation tank is a good alternative product

The cyclone sand sedimentation tank is a good alternative product for domestic wastewater treatment. For the domestic sewage treatment, the flat-flow sand sedimentation tank is a very good alternative product

Main parameters: design flow Qmax =208,000m3/d =2.4 m3/s

Design residence time t=60s

Flow rate of water in the inlet pipe v1 =0.3m/s

Water in the pool rises at v2 =0.06m/s

Height of the conical bottom of the sand sedimentation tank h4 = 1.5 m

Supersize the sand sedimentation tank, the sand sedimentation tank can be used for the treatment of sewage from the bottom of the tank. m

Over-height h1 = 0.5m

Distance from the bottom of the center pipe to the sand surface h3 = 0.3m

It is suitable to be divided into three pools of inlet sand sedimentation n=3.

① Diameter of the inlet pipe:

d== ==1.84m

② Diameter of sand sedimentation pool:

D=====4.52m

Height of water flow part:

h2= v2t = 0.0660 = 3.6m

Volume required for sand sedimentation part:

V==10.37 m3

⑤ Actual volume of circular intercepting cone part:

V1=

⑥ Total height of pool:

H = h1+h2+h3+h4 = 0.5 +3.6+0.3+1.5 = 5.9m

(5)Primary sedimentation tank (spoke flow type)

The tank of spoke flow sedimentation tank is circular in shape, and adopts the form of center water inlet and peripheral water outlet. The water flow in the pool is horizontal to the surrounding spoke flow, mud bucket in the center of the pool, the bottom of the pool to the center of the tilt, the sludge is usually used to scrape the mud (or suction mud) mechanical exclusion. Spoke flow sedimentation tank using mechanical sludge, running better, simpler equipment, sludge removal equipment has the advantage of stereotyped products.

Main parameters: design flow Qmax =208,000m3/d =2.4 m3/s

Surface load q=2.0m3/(m2h)

Number of pools n=3

Sedimentation time t=2h

Sedimentation part of the water area:

F=Qmax/nq=1440m2

The diameter of the pool:

D==42.8m

Effective water depth of the sedimentation part:

h2=qt=4m

Effective volume of the sedimentation part:

V==6480m3

Required volume of the sludge part:

V=SNT/1000n=20.83m3<

Sludge hopper volume:

Let the radius of the upper part of the sludge hopper r1=2m, the radius of the lower part of the sludge hopper r2=1m, the inclination=,

h5=(r1-r2)tg=1.73m

The volume of the sludge hopper :V1=h5(r12+r1r2+r22)=12.7m3

⑦ The volume of sludge in the cone part of sludge above the sludge hopper. Cone part of the sludge volume:

Set the bottom of the radial slope of 0.05, the height of the cone

h4=(R-1)0.05=0.97m

Cone part of the sludge volume:

V2=h4(R2+Rr1+r12)=504.8m3

⑧ sludge hopper total volume:

V=V1+V2=517.5m3>20.83m3

⑨ Total height of sedimentation tank:

Set h1=0.3m, h3=0.5m

H=h1+h2+h3+h4+h5=7.5m

Sedimentation tank edge height:

H′=h1+h2+h3=4.8 m

⑩ Diameter-depth ratio:

=10.7 meets the requirements

(6) Aeration tank

Aeration tank adopts oxidation ditch tank shape, divided into 2 groups, each group is arranged into 4 corridors, each corridor is 82-88?m long, 9.5?m wide and 7?m deep, with a volume of 22?284?m3 for each group and a total volume of 44?568 m3. The average hydraulic The average hydraulic residence time is 5.1 h. In the aeration tank, the sewage is forced to form a circulating flow, and its flow pattern has the dual characteristics of push-flow type and completely mixed type. Therefore, not only has a strong impact resistance, but also not easy to short flow. The aeration and oxygenation system adopts a blast jet aerator, with 638 jets***, divided into 8 groups, and laid in the bottom of the pool in each corridor?1 group. Each group is provided with working medium by 1 pump, of which 6 working mediums are used to return sludge, and 2 use the mixture in the aeration tank. The aeration system is a microporous aeration, the blower sent into the air in the jetter and activated sludge fully mixed with the diffusion of the surface of the pool, and thus has a high oxygen utilization rate, under standard working conditions, the power efficiency of the aeration system up to 2.2?kg?O2/(kW?h). The working medium of the injector promotes the circulation of water in the pool, and keeps the sludge in suspension throughout the pool.

Main parameters: design flow Qmax =20.8104 m3/d =2.4 m3/s

Inlet water quality: BOD5 200mg/L COD 400mg/L SS 250mg/L

Outlet water quality: BOD5 ≤20mg/L COD ≤120mg/L SS ≤25mg/L

Sludge reflux ratio: BOD5 ≤20mg/L COD ≤120mg/L SS ≤25mg/L

< p> Sludge reflux ratio: R = 0.5

① Processing efficiency:

E=La-Lt/La*100%=90%

② Aeration tank volume:

Let the mixture of suspended solids concentration of 3g/L, the coefficient of f = 0.7, then Nw = 0.73 = 2.1kg / m3, take the sludge loading Fw = 0.4

< p> Aeration tank volume V=QLr/NwFw=44568m3

③ Nominal retention time:

Tm=V/Q=0.214d=5.1h

Ts=V/(1+R)Q=3.4h

④ Sludge production:

Sludge proliferation coefficient a=0.6, sludge oxidation rate b=0.08

Sludge oxidation rate is 0.08%. kgMLSS*d

O=a1QLr+b1VNw=33695kg/d

(7) two sedimentation tank

Adopting advection type sedimentation tank, sedimentation effect is good, construction is easy, the cost is low.

Main parameters: design water: Qmax =20.8104 m3/d =2.4 m3/s

Surface load: q=1.5 (m3/m2h)

Hydraulic retention time: t=2h

Sludge concentration: x=3500mg/L

Concentration of sludge return: x1=10000mg/L

The sludge return concentration: x1=1,000mg/L. 10000mg/L

Number of pools n=4

① Effective area of sedimentation part:

A=Qmax/nq=1445m2

② Effective water depth of sedimentation part:

h2=qt=3m

③ Effective volume of sedimentation part:

V==4333m3

④ Pool length:

Set horizontal flow rate 0.004m/s

L=vt*3.6=28.8m

⑤ Pool width:

B=A/L=50.2m

⑥ Sludge part of the total volume required:

Set T=2 days, each person's daily sludge volume take S=0.5 liters/person*day

V=SNT/1000=500m3

⑦ Sludge hopper volume:

Set the upper part of the sludge hopper radius r1=2m, the lower part of the sludge hopper radius r2=1m, inclination=,

hs=(r1-r2)tg=1.73m

Sludge hopper volume :V1= hs(r12+r1r2+r22)= 43.5m3

⑧ sludge hopper above the cone part of the sludge volume:

Set the bottom of the pool radial slope 0.05, the cone height

h4=(R-1)0.05=0.97m

cone part of the sludge volume:

V2=h4(R2+Rr1+r12)=527.6m3

⑨ Total volume of sludge hopper:

V=V1+V2=571.1 m3>500 m3

⑩ Total height of sedimentation tank:

Set the height of the buffer layer h3=0.5m

H=h1+h2+h3+h4+h5=6.5m

Height of sedimentation tank side

H '=h1+h2+h3=3.8m

(8) Sludge thickening pool

Continuous-flow gravity thickening pool is adopted, and the pool type is round and vertical flow type.

Main parameters:

Total amount of sludge production 14977kg/d

Water content ρ=99.2%, concentration=40Kg/m3

After shrinkage: sludge concentration 40g/L, water content ρ=96%

Effective depth of thickening pool h=4m

Time of thickening 10h

1) sludge Concentration after mixing:

C=(127368.5+224140)/14977=13.2Kg/m3

② Concentrator area:

Set the solid flux as M = 55Kg/m2d

A==847m2

③ Concentrator diameter:

D==19.5m

④ Height of the working part of the thickener:

h1==3.7m

⑤ Total height of the thickener:

The super height of the thickener is h2=0.3m, the buffer height is h3=0.3m, and the height of the thickener is

H=h1+h2+h3=3.7+0.3+0.3=4.3 m

(9) Digester

The sludge digester adopts fixed capacity egg type, ****3 seats, the size of each seat is as follows: maximum diameter 24?m, total height 42.93?m, liquid height 40.93?m, the volume of each seat is 10,400?m3. The digester adopts medium-temperature digestion, and is composed of 2 biogas boilers and 3 sets of heat exchangers and 3 sludge circulating pumps in the sludge heating system. The maximum designed biogas production is 13000?m3/d.

Compared with other digesters, egg-type digester has the following characteristics: ① sand or mud is not easy to accumulate at the bottom of the tank, so it will not reduce the effective tank capacity; ② easy to stir and mix, no dead zone in the tank, so that the effective capacity can be increased to the maximum; for the same mixing effect, the mixing and stirring energy consumption is lower than that of other types of tanks; ③ it is not easy for the top to collect slag; ④ for the same volume, its surface is not easy to collect sludge; ④ for the same volume, the surface is not easy to collect sludge. For the same volume, its surface area is smaller than other pools, so the heat loss is small; ⑤ structural stability, it is not easy to produce cracks; ⑥ pool type is streamlined, more beautiful.

(10) Sludge thickening and filter press room

Function: Thickening, filtering and dewatering of the remaining sludge, so that the water content of the sludge is reduced to as low as possible, in order to minimize the volume of the sludge and to facilitate loading and unloading operations. Belt filter press is used.

Belt filter press is an efficient solid-liquid separation equipment based on the principles of chemical flocculation contact filtration and mechanical squeezing, which is being more and more widely used due to a series of advantages such as simple process flow, high degree of automation, continuous operation, easy control operation and adjustable working process. The flocculated sludge firstly enters into the gravity dewatering area, most of the free water is filtered out through the filter belt under the action of gravity; with the operation of the filter belt, the sludge enters into the wedge area composed of two filter belts, the two filter belts implement slow pressurization on the sludge, and the sludge is gradually thickened with reduced mobility, and transitions to the pressing area; in the pressing area, the sludge is subjected to the increasing squeezing pressure and the shear force generated by the alternating position change of the upper and lower positions on the two filter belts, and most of the residual sludge will be separated from the sludge by the action of the shear force, and then it can be separated into the sludge. In the press area, the sludge is subjected to increasing squeezing pressure and the shear force generated by the alternating position change of the two filter belts, most of the free water and interstitial water remaining in the sludge is filtered out, and the sludge becomes a piece of cake with low water content; the upper and lower belts are separated by the discharge roller, and the solid-liquid separation of the material is realized by virtue of the change of the curvature of the belt and the use of scrapers to scrape off the cake, and the upper and lower filter belts are reused after rinsing for the thickening of the filtering in the next cycle.

1 structure, plane size 66m×40m, daily mud dry weight 18600kg/d, the remaining sludge mixture flow 2360m3/d, into the sludge water content of 92%, out of the sludge water content of 78%. The main equipment selection bandwidth of 2.0m for belt thickening filter press 8 sets, a single processing capacity of thickening section 25 m3 / h, filter press section 9 m3 / h, designed to work for 10 h.