CN101921050A - Bottom sludge dehydration and drying device and method - Google Patents

Abstract

The invention relates to a device and method for dehydrating and drying underwater sludge, comprising a filter screen, a filter press, a purification tower and a centrifuge connected in series by a pipeline and a delivery pump, wherein the filter press, the purification tower and the centrifuge The input pipeline is provided with a flocculant adding machine, and the outlet of the centrifuge is connected to the input of the purification tower. The present invention rationally selects multiple water treatment equipments, utilizes the advantages of various equipments to construct a whole set of equipment, avoids the defect of low treatment efficiency of a single equipment, and can efficiently dehydrate and dry underwater sludge. The invention has the characteristics of small occupied area, low energy consumption, no clogging in continuous operation, large amount of mud output, good mobility, and can be conveniently installed on the sludge treatment site; it not only reduces the time required for natural drying of the sludge yard time, the efficiency of sludge treatment is improved, and the cost of dredging is also greatly reduced, meeting the needs of large-scale, batch, and engineering sludge treatment.

Description

Bottom sludge dehydration and drying device and method

technical field

The invention relates to the field of environmental protection equipment, in particular to an underwater sludge dehydration and drying device and method.

Background technique

In recent years, the water quality of the lake has been polluted, the pollutants in the sediment sediment have accumulated seriously, and the content of nitrogen, phosphorus, and organic matter is relatively high, which provides the necessary nutrients for the outbreak of blue-green algae and lake flooding. Therefore, the removal of lake sediment Particularly important. The lake sediment has a large water content, and the use of sludge drying technology can greatly reduce the transportation pressure of subsequent treatment, improve the efficiency of dredging, and reduce the cost of dredging. At present, the sludge drying technology at home and abroad mainly adopts chemical solidification method or dehydration drying method. The processing object of the chemical solidification method is mainly fluid sludge with high moisture content, which needs to add a large amount of curing agent and weighting agent, which is difficult and costly in actual use. The dehydration and drying method mainly uses mechanical dehydration to achieve solid-liquid separation. At present, a single solid-liquid separation equipment is often used, such as vacuum filter, plate and frame filter press, belt filter press or horizontal centrifuge for solid-liquid separation. Separation; these devices require pretreatment of sewage, and the effluent is usually not directly discharged, and cannot be used for large-scale and batch sludge treatment projects, and the treatment effect is not ideal.

Contents of the invention

Aiming at the shortcomings of the above-mentioned existing mechanical dehydration equipment used for drying underwater sludge, the effluent cannot be directly discharged, and cannot be produced in a large scale or in batches, the applicant provides a device and method for dehydrating and drying underwater sludge with reasonable technology and low consumption. The energy is low, and the sludge drying treatment can be carried out on a large scale and in batches.

The technical scheme adopted in the present invention is as follows:

An underwater sludge dehydration and drying device, comprising a filter screen, a filter press, a purification tower and a centrifuge connected in series by a pipeline and a delivery pump, wherein the input pipelines of the filter press, the purification tower and the centrifuge are provided with A flocculant adding machine, the outlet of the centrifuge is connected to the input port of the purification tower. It is further characterized by:

The filter sieve is a vibrating sieve or a rolling sieve;

The filter press is a plate and frame filter press or a belt filter press.

The bottom sludge dehydration and drying method carried out by the above-mentioned device is used for four-stage treatment of sewage:

In the first stage, filter sieves are used to pre-treat muddy sewage;

In the second stage, the filter press is used for sludge dewatering;

In the third stage, a purification tower is used to carry out secondary treatment on the effluent of the filter press;

In the fourth stage, a centrifuge is used to dehydrate the concentrated sludge of the purification tower, and the effluent of the centrifuge is returned to the upper purification tower for reprocessing. It is further characterized by:

A flocculant is added to the influent of the second stage, the third stage, and the fourth stage;

The flocculant is polyaluminum chloride and polyacrylamide;

The addition concentration of polyaluminium chloride in the second-stage influent water is 100-150ppm; the addition concentration of polyacrylamide is 6-8ppm;

The addition concentration of polyaluminium chloride in the third-stage influent water is 20-50ppm; the addition concentration of polyacrylamide is 1-3ppm;

The addition concentration of polyaluminium chloride in the fourth stage influent is 200ppm; the addition concentration of polyacrylamide is 5-10ppm.

The present invention rationally selects various water treatment equipments, utilizes the advantages of various equipments to construct a whole set of equipment, avoids the defect of low processing efficiency of a single equipment, and can efficiently dehydrate and dry underwater sludge. The invention has the characteristics of small occupied area, low energy consumption, no clogging in continuous operation, large amount of mud output, good mobility, and can be conveniently installed on the sludge treatment site; time, the efficiency of sludge treatment is improved, and the cost of dredging is also greatly reduced, meeting the needs of large-scale, batch, and engineering sludge treatment. In actual operation, the output of mud cake is large, and the effluent of the purification tower fully meets the first-level standard in the discharge index (GB18918-2002).

Description of drawings

Fig. 1 is the schematic diagram of connection of the underwater sludge dehydration and drying device of the present invention;

Fig. 2 is the front view of vibrating screen in Fig. 1;

Fig. 3 is the front view of the belt filter press in Fig. 1;

Fig. 4 is the front view of purification tower among Fig. 1;

Fig. 5 is the front view of the centrifuge in Fig. 1;

Fig. 6 is a detailed flow chart of the method for dehydrating and drying underwater sludge of the present invention.

Detailed ways

The specific implementation manner of the present invention will be described below in conjunction with the accompanying drawings.

As shown in Fig. 1, the underwater sludge dehydration and drying device according to the present invention includes a vibrating screen 100, a filter press 200, a purification tower 300 and a centrifuge 400 connected in series by a pipeline and a delivery pump, wherein the filter press 200 . The input pipeline of the purification tower 300 and the centrifuge 400 is provided with a flocculant adding machine, and the outlet 407 of the centrifuge 400 is connected to the inlet of the purification tower 300 . Referring to Fig. 6, the method for dehydrating and drying underwater sludge according to the present invention is mainly divided into four stages for sludge treatment.

The first stage: muddy sewage pretreatment. Vibrating screen 100 is selected as the pretreatment equipment for muddy sewage. In the dredging and dredging projects of rivers and lakes, there are many solid wastes and impurities in the sediment, which must be pretreated before subsequent sludge dewatering. The working principle of the vibrating screen is that the two motors rotate in reverse synchronously to make the exciter generate a reverse exciting force, forcing the screen body to drive the screen to move longitudinally, so that the materials on it are periodically thrown forward by the excited vibration force. process to complete the screening of materials. As shown in Figures 1 and 2, the top of the frame 104 is provided with an inclined screen 103, and the screen 103 vibrates up and down under the action of the vibrating pump 102 to buffer the sewage containing solid waste and impurities flowing out of the water tank 101, and its liquid Filter through the sieve holes of the screen cloth 103 and flow out from the water outlet 105, while the large particles of solid waste or impurities cannot pass through the sieve holes, but move downward along the slope, and finally fall into the vibrating screen sludge collection box 601 arranged on the side.

Of course, this pretreatment step can also be completed by using a filter sieve such as a rolling sieve, which is used to initially separate large solid impurities in muddy water; It is not easy to cause clogging, which saves the time of backwashing and improves the processing efficiency.

The second stage: sludge dewatering. The present invention selects the belt filter press 200 as the sludge dewatering equipment. The working principle of the belt filter press is to apply pressure on the filter belts, and the sludge is squeezed on the two filter belts. Due to the pressure of the filter cloth or tension to dewater the sludge. As shown in Figure 3, the belt filter press 200 is mainly composed of an upper rotary filter belt 205 and a lower rotary filter belt 213 arranged up and down. The upper rotary filter belt 205 rotates counterclockwise under the drive of the upper rotary wheel 208, while the lower rotary filter belt The rotary filter belt 213 rotates clockwise under the drive of the lower rotary wheel 214; the adjacent surface between the upper and lower rotary filter belts is oppositely provided with a rolling shaft 212 inside the filter belt; a flushing nozzle 207 is arranged above the filter belt for flushing the filter belt. belt; a T-shaped drainage tank 206 is arranged under the filter belt; an upper scraper 209 and a lower scraper 210 are arranged at the rotating end of the filter belt to scrape off residual impurities attached to the filter belt respectively. As shown in Figure 1, the effluent 502 of the vibrating sieve and the flocculant 503 of the flocculant adding machine 201 imported by the bypass merge into the concentration reaction tank 202, and flocculation reaction occurs in the reaction tank, and the effluent 504 of the reaction tank flows into the belt filter press 200 buffer water tank 204, and unloading on the upper rotary filter belt 205 of the belt filter press 200, first under the action of gravity, the filtrate is dehydrated through the filter belt and filtered out through the T-shaped drain tank 206, realizing the initial solid-liquid Separation, and the concentrated sludge 203 left on the upper rotary filter belt 205 is brought into the adjacent surface between the upper and lower rotary filter belts, dehydrated under the rolling pressure of the rolling shaft 212, and the filtrate 211 flows to the bottom The drain tank is discharged, and the sludge after pressing and dehydration forms filter press mud cake 602.

Of course, a plate and frame filter press can also be used to complete this step to achieve the purpose of sludge dehydration; however, compared with other similar products, the belt filter press has wider applicability, excellent mechanical properties, strong durability, and low consumption. Low energy, low noise, high sludge output, continuous production, is an ideal engineering sludge dewatering equipment.

The third level: secondary treatment of effluent. The filter press effluent 505 of the belt filter press 200 cannot be discharged directly, and the present invention adds a purification tower 300 as a secondary treatment device for the tail water. As shown in Figure 4, in the present invention, the filter press effluent 505 is added into the flocculant 506 pre-prepared in a certain proportion by the flocculant adding machine 301 through the bypass dosing pipeline, and then input into the reaction tank 302 for thorough mixing, and passed The outlet pipe 507 at the top of the reaction tank enters the inlet of the purification tower 300 . During the initial commissioning of the equipment, the reaction in the separation tower can be known by observing the water quality samples exported from the pipelines 305 set at different heights, so that the dosing amount can be adjusted; It is discharged from the water outlet 303 on the top of the tower. At this time, the quality of the effluent water is good, which meets the standard of direct discharge and can be directly discharged to the lake; the settled silt water at the bottom of the tower is discharged through the mud outlet 304 at the bottom. Part of the effluent water 508 from the purification tower can be used as reused water 509, which can be sent to various equipment as cleaning water through the reuse pipeline, which improves the utilization efficiency of the internal circulating water.

The purification tower is equivalent to a movable sedimentation tank, which works on the principle of flocculation sedimentation and gravity separation. Compared with the sedimentation tank, the sludge separation tower can not only achieve the effect of the sedimentation tank, but also has a small footprint and saves land resources; saves investment, does not need to build a pool and equip special mud scraping equipment; has high flexibility and does not require Advantages such as limited to fixed point use.

The fourth stage: dewatering of concentrated sludge. In the present invention, the centrifuge 400 is used to dehydrate the concentrated mud in the purification tower, which can avoid the impact of the concentrated mud on the flocculation effect caused by returning to the equipment in the previous section. As shown in Figure 5, the centrifuge 400 is provided with a drum 406 and a screw conveyor with the same rotation center axis and the same rotation direction on the frame. Composition, which rotates at a low speed driven by the drive wheel 402 provided at the end, while the drum 406 rotates at a high speed. As shown in Figure 1, the concentrated muddy water 510 of the purification tower merges the flocculant 511 prepared in advance according to a certain proportion by the bypass input flocculant adding machine 401, enters the inner cavity of the hollow main shaft 403 of the centrifuge 400, and passes through the main shaft shown in Figure 5 A number of distributing holes 404 distributed on the top are thrown out to the space between the main shaft 403 and the drum 406. Since the screw conveyor and the drum 406 rotate in the same direction, but at different speeds, the dehydrated cake 603 with a larger specific gravity is thrown to the drum 406, and is pushed down by the blade 405 to the end of the screw conveyor, and discharged through the mud discharge port 408, while the separated liquid with a smaller specific gravity is discharged from the drain port 407 at the other end. The separator effluent 512 is refluxed to the inlet of the purification tower equipment, and re-enters the purification tower for treatment to prevent the separator effluent 512 from being directly discharged to pollute the environment.

The main components of the water treatment flocculation agent used in the present invention are PAC (polyaluminum chloride) and PAM (polyacrylamide). PAC is an inorganic coagulant. When it is added to a certain critical value, its hydrolyzed product precipitates out rapidly, and the colloidal particles and fine suspended matter in the water can be captured by these precipitates as crystal nuclei or adsorption nets when they are formed, becoming Fine flocs; PAM is an organic polymer flocculant, which is a water-soluble long-chain compound, which ionizes a large number of dissociated groups during hydrolysis, and captures fine flocs through electrical neutralization and bridging adsorption. Play a flocculation effect. See Table 1 for the amount of chemicals added to the belt filter press, purification tower and centrifuge.

Table 1 Pharmaceutical composition and content

PAC dosage (ppm) PAM dosage (ppm) Belt filter press 100-150 6-8 Purification tower 20-50 1-3 Centrifuge 200 5-10

The present invention adopts the principle of gravity separation of flocculation and sedimentation to purify the effluent of belt filter press and centrifuge by using purification tower, and quickly flocculates and settles under the action of high-efficiency flocculant. This treatment method can effectively remove various pollutants in sewage. Impurity components, effluent fully meet the discharge standards (GB18918-2002 Class A), which solves the problem that the effluent cannot be discharged directly. The comparison table of influent and effluent water quality is shown in Table 2. Part of the effluent is extracted as reuse water for cleaning equipment, saving water resources.

Table 2 Inlet and outlet water quality comparison table

The above description is an explanation of the present invention, not a limitation of the invention. For the limited scope of the present invention, refer to the claims. Without violating the spirit of the present invention, the present invention can be modified in any form, such as using bioflocculants and other flocculant. Or on the premise of engineering operation as the purpose, add sludge treatment equipment to improve its production capacity; add adjustment pools between water treatment units at all levels to control water quality and water volume to meet the optimal treatment concentration and treatment of different equipment amount to achieve the best performance.

Claims (9)

1. water-bed sludge dewatering desiccation apparatus, it is characterized in that: comprise the filter sieve, pressure filter, scavenging tower and the whizzer that are connected in series by pipeline and transferpump, the intake line of wherein said pressure filter, scavenging tower and whizzer is provided with the flocculation agent adding machine, and the water port of whizzer is connected to the input aperture of described scavenging tower.

2. according to the described water-bed sludge dewatering desiccation apparatus of claim 1, it is characterized in that: described filter sieve is vibratory screening apparatus or roller grizzly.

3. according to the described water-bed sludge dewatering desiccation apparatus of claim 1, it is characterized in that: described pressure filter is plate-and-frame filter press or belt filter press.

4. the water-bed sludge dewatering drying method that adopts the described device of claim 1 to carry out is characterized in that, sewage is carried out level Four handle:

The first step adopts filter sieve to carry out pre-treatment to containing dirt water;

The second stage adopts pressure filter to carry out sludge dewatering;

The third stage adopts scavenging tower that secondary treatment is carried out in the pressure filter water outlet;

The fourth stage adopts whizzer that the scavenging tower thickened sludge is dewatered, and whizzer effluent recycling to higher level's scavenging tower is handled again.

5. according to the described water-bed sludge dewatering drying method of claim 4, it is characterized in that: in the water inlet of the described second stage, the third stage, the fourth stage, be added with flocculation agent.

6. according to the described water-bed sludge dewatering drying method of claim 5, it is characterized in that: described flocculation agent is polymerize aluminum chloride and polyacrylamide.

7. according to the described water-bed sludge dewatering drying method of claim 6, it is characterized in that: polymerize aluminum chloride interpolation concentration is 100～150ppm in partial water inlet; It is 6～8ppm that polyacrylamide adds concentration.

8. according to the described water-bed sludge dewatering drying method of claim 6, it is characterized in that: polymerize aluminum chloride interpolation concentration is 20～50ppm in the water inlet of the third stage; It is 1～3ppm that polyacrylamide adds concentration.

9. according to the described water-bed sludge dewatering drying method of claim 6, it is characterized in that: polymerize aluminum chloride interpolation concentration is 200ppm in the water inlet of the fourth stage; It is 5～10ppm that polyacrylamide adds concentration.

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