CN107244776A - A kind of handling process of percolate - Google Patents

Abstract

A kind of handling process of percolate, belongs to sewage treatment area, it includes：（1）Percolate is introduced into collecting pit and collected；（2）Percolate is handled by magnetic separating apparatus, the sludge of generation enters sludge filter press press filtration；（3）Magneto separate water outlet is filtered into ultrafiltration system；（4）Ultra-filtration water enters SUPER RO membranous systems, and after the filtering of SUPER RO membrane devices, its concentrated water part is evaporated into vapo(u)rization system, produces water qualified discharge；Described Magneto separate before processing, to the percolate of collection add sodium hydroxide and sodium carbonate soften and add flocculant, flocculation aid and magnetic.The present invention is small with floor space, and cost of investment is relatively low, and effluent quality is guaranteed, the high advantage of the rate of recovery.

Description

A treatment process for landfill leachate

technical field

The invention belongs to the field of sewage treatment and relates to a process for treating landfill leachate.

Background technique

Landfill leachate is the product of gravity flow of liquid in landfill, mainly from precipitation and waste, and its own embedded water. It has the characteristics of high concentration of BOD5 and COD, high metal content, large changes in water quality and quantity, high content of ammonia nitrogen, and imbalance of microbial nutrient elements. If it is not treated and discharged directly, it will lead to ecological deterioration and cause serious environmental pollution problems. . Traditional landfill leachate treatment methods at home and abroad include: aeration stabilization pond, anaerobic biological filter, upflow anaerobic sludge bed, anaerobic-oxidation ditch-facultative pond process, UASB-oxidation ditch-stabilization pond , soil irrigation, etc. In 2008, China promulgated and implemented the newly revised GB 16889-2008 "Pollution Control Standards for Domestic Garbage Landfill Sites", which put forward stricter emission standards for indicators such as BOD ₅ , COD _Cr , ammonia nitrogen, total nitrogen, and heavy metals in landfill leachate. . Traditional biological treatment processes are difficult to meet emission standards.

The main methods of the existing domestic landfill leachate are as follows: the leachate is concentrated in the collection tank, the sludge enters the concentration tank after coagulation and sedimentation, the liquid part is anaerobically treated, the generated sludge enters the concentration tank again, and the generated biogas is discharged , the liquid part produced will enter the anaerobic/aerobic (A/O) process combined with the biochemical membrane system of the membrane bioreactor (MBR) for treatment, and the mud generated will enter the concentration tank, and the effluent will be treated by the roll type NF/RO to produce The water is discharged up to the standard, and the concentrated water is sprayed back to the incinerator. The collected sludge is concentrated in the sludge concentration tank, and the filtrate is returned to the collection tank. The concentrated sludge is processed by a sludge filter press to form a mud cake for landfill, and the filtrate produced by the filter press is also returned to the collection tank. Coagulation sedimentation is used in this process, and the area required to build a coagulation sedimentation tank is large, and the stability of the effluent is difficult to control through coagulation sedimentation; the biochemical system occupies a large area and the investment cost is high; the volume RO/NF system is used to produce water The recovery rate is low.

Contents of the invention

The object of the present invention is to overcome the disadvantages of the prior art, and provide a landfill leachate treatment process with small footprint, low investment cost, guaranteed effluent quality and high recovery rate.

The present invention is realized through the following technical solutions:

A treatment process for landfill leachate, comprising the following steps:

(1) Introduce the landfill leachate into the collection tank for collection;

(2) The landfill leachate is processed by magnetic separation equipment, and the generated sludge enters the sludge filter press for pressure filtration;

(3) The magnetically separated water enters the ultrafiltration system for filtration;

(4) The ultrafiltration effluent enters the SUPER RO membrane system, and after being filtered by the SUPER RO membrane device, the concentrated water part enters the evaporation system for evaporation, and the produced water is discharged up to the standard;

Add sodium hydroxide and sodium carbonate to the leachate collected before the magnetic separation to soften; further, add flocculant, coagulant and magnetic powder to the softened landfill leachate to form a magnetic powder in the reaction tank flocs; further, the flocculant is PAC, and the coagulant aid is PAM; the landfill leachate after the reaction passes through the high-intensity magnetic field in the magnetic separation equipment, and the flocs containing the magnets are absorbed to achieve softening Landfill leachate and clarification purpose of leachate.

Further, the COD removal rate after the magnetic separation treatment is not lower than 57%.

The magnetic separation is to use the magnetism of the impurity particles in the wastewater to separate, and to make the non-magnetic or weakly magnetic particles in the water magnetic by using the magnetic inoculation technology. With the help of the external magnetic field, the magnetic suspended solids in the wastewater are separated, so as to achieve the purpose of purifying the water. Since there are many suspended solids in the landfill leachate, and the hardness of the landfill leachate is too high, if it is not treated in time, the suspended solids will enter the membrane system and cause fouling, which will affect the stable operation of the entire process; Possibility of system structure contamination to ensure the normal operation of the system.

After magnetic separation treatment, the removal rate of chroma and turbidity in the landfill leachate is high, but there is still a very small amount of light suspended flocs flowing out. After ultrafiltration treatment, the visible suspended matter in the landfill leachate is removed to reach SUPER RO membrane system requirements.

Further, the generated sludge enters the sludge filter press, and the effluent generated by pressure filtration is returned to the collection tank, and the formed filter cake is landfilled.

Further, the ultrafiltration system is hollow fiber ultrafiltration or tubular ultrafiltration system.

Further, the temperature of the SUPER RO membrane system is 25-50°C, and the pressure is 50-90bar.

Further, the pH in the SUPER RO system is 4.5-6.5; landfill leachate contains ammonia nitrogen, and ammonia nitrogen is partially formed in the form of ammonia gas under alkaline conditions, and SUPER RO has a poor interception ability for gases, so it is necessary Adjust the pH in weak acidity, further, the pH in the SUPER RO system is preferably 6.0; under weak acidic conditions, ammonia nitrogen exists in the form of NH ₄ ⁺ , and the rejection rate of SUPER RO to NH ₄ ⁺ is above 95% , so as to ensure that the effluent ammonia nitrogen reaches the standard by controlling the pH.

Further, the COD removal rate after treatment by the SUPER RO system is not lower than 94%.

Further, the concentrated water filtered by the SUPER RO membrane device enters the evaporation system, the evaporative condensate is discharged up to the standard, and the miscellaneous salt produced by evaporation is landfilled.

The present invention has the following beneficial effects:

(1) Compared with coagulation and sedimentation, magnetic separation has a high degree of automation, covers an area of only 1/6 of the sedimentation tank, requires less civil engineering, and shortens the construction period, thereby reducing labor costs and land investment, further reducing the total invest;

(2) In the technological process of the present invention, SUPER RO with strong anti-pollution ability is adopted, and the COD of the membrane entering the membrane can be as high as 20000mg/L, while the COD of the membrane entering the traditional roll-type membrane requires less than 200mg/L; most of the water quality is treated by magnetic separation, The effluent COD can meet the requirements of entering the SUPER RO system, which saves the cost input in the biochemical treatment stage, reduces the floor area of the system, simplifies the process, and reduces the cost;

(3) Compared with the traditional roll-type RO system, the SUPER RO system has a higher effluent recovery rate, more stable effluent quality, and stronger anti-pollution ability.

Description of drawings

Fig. 1: Process flow chart among the present invention.

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and examples, and the embodiments of the present invention are not limited to the following descriptions.

As shown in Figure 1, the processing technology of this a kind of landfill leachate comprises the following steps:

(1) The landfill leachate is introduced into the collection tank for collection; sodium hydroxide and sodium carbonate are added to the collected leachate to soften; then flocculant, coagulant and magnetic powder are added to form flocs containing magnetic powder in the reaction tank; The flocculant is PAC, and the coagulant aid is PAM; the reacted landfill leachate is subjected to the action of a high-intensity magnetic field in the magnetic separation equipment, and the flocs containing magnets are adsorbed to soften the landfill leachate and clarify the leachate the goal of;

(2) The landfill leachate is processed by magnetic separation equipment, and the generated sludge enters the sludge filter press for press filtration; the generated sludge enters the sludge filter press for press filtration, and the effluent generated by the filter press is returned to the collection pool, and the formed filter Cake landfill treatment; COD removal rate after magnetic separation treatment is not less than 57%;

(3) The magnetically separated water enters the ultrafiltration system for filtration;

(4) The ultrafiltration effluent enters the SUPER RO membrane system. After being filtered by the SUPER RO membrane device, the concentrated water part enters the evaporation system to evaporate, and the produced water is discharged up to the standard; the evaporative condensate is discharged up to the standard, and the miscellaneous salt produced by evaporation is buried.

Use further instructions for the methods in this process. The magnetic separation is to use the magnetism of the impurity particles in the wastewater to separate, and to use the magnetic inoculation technology to make the non-magnetic or weakly magnetic particles in the water magnetic. With the help of the external magnetic field, the magnetic suspended solids in the wastewater are separated, so as to achieve the purpose of purifying the water. Since there are many suspended solids in the landfill leachate, and the hardness of the landfill leachate is too high, if it is not treated in time, the suspended solids will enter the membrane system and cause fouling, which will affect the stable operation of the entire process; Possibility of system structure contamination to ensure the normal operation of the system. After magnetic separation treatment, the removal rate of chroma and turbidity in the landfill leachate is high, but there is still a very small amount of light suspended flocs flowing out. After ultrafiltration treatment, the visible suspended matter in the landfill leachate is removed to reach SUPER RO membrane system requirements.

The ultrafiltration system is a hollow fiber ultrafiltration or tubular ultrafiltration system.

The temperature of the SUPER RO membrane system is controlled at 25-50°C, the pressure is controlled at 50-90bar, and the pH of the SUPER RO system is controlled at 4.5-6.5; the landfill leachate contains ammonia nitrogen, and ammonia nitrogen is partially ammonia nitrogen under alkaline conditions. Morphological formation, SUPER RO has a poor interception ability for gas, so it is necessary to adjust the pH in weak acidity, ^and the pH in the entire SUPER RO system is preferably 6.0 _; The interception rate of ₄₊ is above 95%, so as to ensure that the effluent ammonia nitrogen ^reaches the standard by controlling the pH; the COD removal rate of the entire SUPER RO system after treatment is not lower than 94%.

The process is further illustrated by specific experiments.

Embodiment 1: According to the above method, the landfill leachate treatment experiment of the present invention was carried out in a waste factory, and the water quality of the magnetically separated water was detected as shown in Table 1.

Table 1 Magnetic separation water quality

COD(mg/L) Ammonia nitrogen (mg/L) Hardness (mg/L) TDS(mg/L) Leachate Raw Water 2696 1223 940 15000 magnetic separation of water 1144 715 200 7869 Removal rate (%) 57.57 41.54 78.72 47.54

The magnetically separated effluent is further treated by ultrafiltration and SUPER RO membrane system, and the quality of the treated effluent is shown in Table 2.

Table 2 SUPER RO effluent quality

In the SUPER RO membrane system, the temperature is 30°C, the pressure is 65 bar, and the pH is 6.0.

Example 2: On the basis of Example 1, the temperature in the SUPER RO membrane system was changed to 25°C, the pressure was 50 bar, and the pH was 4.5. After the landfill leachate treatment experiment of the present invention, the water quality of the SUPER RO effluent was detected as follows: Table 3 shows.

Table 3 SUPER RO effluent quality

Example 3: On the basis of Example 1, the temperature in the SUPER RO membrane system is changed to 50°C, the pressure is 90 bar, and the pH is 6.5. After the landfill leachate treatment experiment of the present invention, the water quality of the SUPER RO effluent is detected as follows: Table 4 shows.

Table 4 SUPER RO effluent water quality

The above-mentioned embodiments are only some embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. However, all changes made by adopting the design principle of the present invention and performing non-creative work on this basis shall belong to the scope of the present invention. scope of protection etc.

Claims (9)

1. a kind of handling process of percolate, it is characterised in that it comprises the following steps：

（1）Percolate is introduced into collecting pit and collected；

（2）Percolate is handled by magnetic separating apparatus, the sludge of generation enters sludge filter press press filtration；

（3）Magneto separate water outlet is filtered into ultrafiltration system；

（4）Ultra-filtration water enters SUPER RO membranous systems, after the filtering of SUPER RO membrane devices, and its concentrated water part enters evaporation and is System evaporation, produces water qualified discharge；

Described Magneto separate before processing, softens to the percolate addition sodium hydroxide and sodium carbonate of collection and adds flocculation Agent, flocculation aid and magnetic.

2. a kind of handling process of percolate according to claim 1, it is characterised in that step（3）Described in surpass Filter system is Hollow Fiber Ultrafiltration or tubular type ultrafiltration system.

3. a kind of handling process of percolate according to claim 1, it is characterised in that step（4）Described in SUPER RO membranous systems temperature is 25-50 DEG C, and pressure is 50-90bar.

4. a kind of handling process of percolate according to claim 1, it is characterised in that step（4）Described in PH is 4.5-6.5 in SUPER RO systems.

5. a kind of handling process of percolate according to claim 1, it is characterised in that step（4）Middle SUPER PH is 6.0 in RO systems.

6. the handling process of a kind of percolate according to claim 1, it is characterised in that the flocculant is PAC.

7. the handling process of a kind of percolate according to claim 1, it is characterised in that the flocculation aid is PAM.

8. the handling process of a kind of percolate according to claim 1, it is characterised in that after the Magneto separate processing COD clearances are not less than 57%.

9. a kind of handling process of percolate according to claim 1, it is characterised in that the SUPER RO systems COD clearances are not less than 94% after processing.