CN105271608A

CN105271608A - Deep processing method for landfill leachate

Info

Publication number: CN105271608A
Application number: CN201410644362.4A
Authority: CN
Inventors: 刘军; 宫建瑞; 戴昕
Original assignee: NANJING WANDERS ENVIRONMENTAL PROTECTION SCIENCE & TECHNOLOGY Co Ltd
Current assignee: NANJING WANDERS ENVIRONMENTAL PROTECTION SCIENCE & TECHNOLOGY Co Ltd
Priority date: 2014-11-14
Filing date: 2014-11-14
Publication date: 2016-01-27

Abstract

The invention discloses a non-membrane-method deep processing method for a landfill leachate. The technology units comprise a physicochemical processing unit, an electrochemical oxidation unit and a filtering unit. A secondary biochemical unit in a conventional landfill leachate processing technology discharges water, the water is collected and goes to the above units, the units are coupled effectively, By utilization of characteristics of thephysicochemical processing technology, strong impact resistance and high-efficiency reaction of electrochemical processing and good economical property of the biochemical processing technology, the method has advantages of strong impact resistance, economical and reliable operation, no generation of a concentrated solution, simple operation and the like.

Description

A kind of deep treatment method of percolate

Technical field

The invention belongs to landfill leachate treatment field, be specifically related to a kind of non-embrane method deep treatment method of percolate.

Background technology

In garbage loading embeading treating processes, because the reasons such as anaerobically fermenting, organic substance decomposing, rainwater shower, underground water immersion produce multiple meta-bolites and moisture, define the high concentrated organic wastewater-percolate of complicated component.The composition of percolate and complexity thereof, containing a large amount of heavy metal ion, ammonia nitrogen and refractory organic, being a kind of poisonous and hazardous high concentrated organic wastewater, if this waste water is without dealing carefully with, will bringing tremendous influence to surrounding environment.

The percolate emission request of China is very strict, as directly discharged at de-militarized zone, perform " consumer waste filling and embedding Environmental capacity standard " (GB16889-2008) table 2 standard, wherein COD≤100mg/L, ammonia nitrogen≤25mg/L, total nitrogen≤40mg/L, total phosphorus≤3mg/L, in addition, some heavy metal indexs also need to reach corresponding emission standard.

The garbage leachate treatment process of current China main flow is: pre-treatment+biochemical treatment (MBR)+nanofiltration+reverse osmosis.This technique effectively can ensure that the indexs such as water outlet ammonia nitrogen, COD, ammonia nitrogen are stable and reach GB16889-2008 table 2 standard, and water quality of selling is better.

But existing treatment process mainly has the following disadvantages:

1) nanofiltration, feed water by reverse osmosis COD concentration are up to good hundreds of, and wherein cannot, by the pollutent of knot and biochemical metabolism product, cause membrane reactor easily blocked containing large number of biological, the frequency of cleaning and replacing be higher; 2) reverse osmosis (or nanofiltration) dense water is difficult to process, salt is very high, and current most of Sewage Plant limits due to condition, can only by dense Water Spreading to front end landfill yard, cause salt to accumulate in percolation liquid treating system for a long time, seriously add the difficulty of percolate subsequent disposal; Ye You partially disposed factory adopts the mode of evaporation concentration liquid to realize the minimizing of dope, but the method processing cost is very high: the running cost of common triple-effect evaporator reaches 200 yuan/ton of concentrated solutions, even if adopt MVR technique, its running cost also reaches 60 ~ 100 yuan/ton of concentrated solutions.Moreover, remaining after evaporation process concentrated mother liquor does not find good treatment process yet.

Summary of the invention

The object of the invention is to overcome prior art deficiency, and a kind of non-embrane method deep treatment method of percolate is provided.

Concrete technical scheme of the present invention is: a kind of non-embrane method deep treatment method of percolate, and technique unit includes but not limited to: physicochemical treatment unit, electrochemical oxidation unit, biochemical treatment unit and filtering unit.Concrete treatment step is as follows:

1) first the secondary biochemical unit water outlet of conventional spam percolate treating process enters physicochemical treatment unit after collecting, and utilizes one or more the materializing strategy means in neutralization, coagulation, precipitation, filtration to remove the pollutents such as part COD, ammonia nitrogen, SS, TDS, heavy metal;

2) physicochemical treatment unit water outlet enters electrochemical processing cell, utilizes the direct oxidation of electrochemical cell, indirect oxidation, direct-reduction, indirect reduction effect macromole hardly degraded organic substance remaining in waste water to be decomposed into the small molecules organic pollutant of easy biochemical degradation and the heavy metal contaminants in further removal waste water;

3) wastewater biodegradability enters biochemical treatment unit after improving, the small molecules organic pollutant utilizing the microorganism in system to be generated by electrochemical cell further economy, effectively to degrade removal;

4) bio-chemical effluent finally mainly removes qualified discharge after the indexs such as SS via filtering unit, when the indexs such as draining COD, heavy metal do not meet emission standard, also can by before filtration end add the medicament such as oxygenant, metal traps realize water quality reaching standard discharge.

In above-mentioned physicochemical treatment unit, neutralization regulates pH in 5 ~ 10 scopes, one or more combinations in coagulating agent aluminium salt, molysite, poly-aluminium, Polyferric Sulfate, organic polymer, diatomite or microbial flocculant.Coagulant charging quantity is 100 ~ 5000ppm.

In above-mentioned electrochemical processing cell, plate material adopts the one in graphite electrode plate, stainless steel polar plate, alloy pole plate, boron-doped diamond film pole plate.

In above-mentioned electrochemical processing cell, throw the filler with catalytic activity in system into, filler adopts one or more the combination in activated-carbon catalyst, activated carbon doped noble metal catalyst, alloy catalyst.

In above-mentioned electrochemical processing cell, filler add that quality is electrochemical processing cell volume of equipment 5% ~ 50%.

In above-mentioned electrochemical processing cell, current density adopts 5-50mA/cm ²; Running voltage 2-36V; Electrochemistry residence time 15-240min;

In above-mentioned biochemical treatment processing unit, be provided with biologic packing material, biologic packing material adopts one or more the combination in activated carbon, quartz sand, hard coal, haydite, combined stuffing, polyhedron empty ball.Biologic packing material dosage is 5%-50%;

0.5-5h is adopted in the above-mentioned biochemical treatment processing unit residence time;

Above-mentioned electrochemistry-biochemical treatment system can adopt uniprocessing, also can adopt multistage electrochemistry-biochemical treatment system series connection process, specifically arrange according to water quality characteristics;

In above-mentioned filtration treatment processing unit, be provided with filter packing, filter packing adopts one or more the combination in activated carbon, quartz sand, hard coal, haydite, alloy packing;

In above-mentioned filtration treatment processing unit, when effluent quality worsens, the water quality effect of checking on can be realized by adding of agent.When needs reduce organic concentration in water outlet, H can be added ₂o ₂, O ₃, clorox etc. has the medicament of oxidisability; When needs reduce heavy metal concentration in water outlet, the medicaments such as metal chelator can be added;

When advanced treatment process mesophytization processing unit effluent quality reaches emission standard, above-mentioned filtration treatment processing unit can save.

Beneficial effect:

1. produce without concentrated solution problem.Compare traditional membrane method treating process, the present invention does not produce concentrated solution substantially, solves concentrated solution in traditional membrane method treating process preferably and is difficult to by the problem effectively disposed or cost of disposal is too high;

2. strong shock resistance.Leading portion physicochemical treatment unit of the present invention effectively can reduce the concentration of CODcr in waste water, heavy metal energy pollutent, can improve the impact resistance of system while reducing subsequent cell processing load;

3. economical operation is reliable.The present invention adopts the method for electrochemical treatment technology coupled biological treatment technology, efficient, the stability of electrochemical techniques and the economy of biologic treating technique is combined, and under the prerequisite of the system of guarantee treatment effect, running cost is lower; End filtration unit effectively can reduce water outlet SS index, when effluent quality worsens, can realize the water quality effect of checking on by adding of agent;

4. simple to operate, without the need to routine cleaning, change membrane module.

Embodiment

Embodiment 1

Adopt the water outlet of the inventive method treating refuse percolate treatment plant MBR unit, CODcr=784mg/L.This strand of waste water is through coagulating sedimentation unit, and coagulating agent adopts bodied ferric sulfate, and when pH=6.5, added amount of chemical are 2000ppm, coagulation unit water outlet CODcr concentration is down to 375mg/L, and CODcr clearance reaches 52%; Coagulation water outlet enters electrochemical processing cell, and electrochemical processing cell adopts graphite electrode plate, and current density adopts 20mA/cm ², voltage adopts 6.9V, wherein adds activated-carbon catalyst, and dosage adopts 10%, and when being when reacted 45min, electrochemical processing cell water outlet CODcr is 196mg/L, COD clearance is 48%; Electrochemical processing cell water outlet enters biochemical treatment unit, biochemical treatment unit filler adopts polyhedron empty ball, the biochemical treatment unit residence time adopts 3h, biochemical treatment unit water outlet CODcr reaches 86mg/L, reach table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008), advanced treatment system direct operating cost 15 yuan/m ³left and right.

Embodiment 2

Adopt the water outlet of the inventive method treating refuse percolate treatment plant MBR unit.CODcr=784mg/L。This strand of waste water is through coagulating sedimentation unit, and coagulating agent adopts polymerize aluminum chloride, and when pH=6.5, added amount of chemical are 1000ppm, coagulation unit water outlet CODcr concentration is down to 534mg/L, and CODcr clearance reaches 32%; Coagulation water outlet enters electrochemical processing cell, and electrochemical processing cell adopts graphite electrode plate, and current density adopts 10mA/cm ², voltage adopts 5.2V, wherein adds activated-carbon catalyst, and dosage adopts 20%, and when being when reacted 60min, electrochemical processing cell water outlet CODcr is 357mg/L, COD clearance is 33%; Electrochemical processing cell water outlet enters biochemical treatment unit, and biochemical treatment unit filler adopts haydite, and the biochemical treatment unit residence time adopts 6h, biochemical treatment unit water outlet CODcr concentration to be 122mg/L, and bio-chemical effluent is through adding O ₃after enter filtration treatment processing unit, filtrate adopts activated carbon filtrate, final filtration processing unit effluent COD concentration is 47mg/L, reaches table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008), advanced treatment system direct operating cost 10 yuan/m ³left and right.

Embodiment 3

Adopt the water outlet of the inventive method treating refuse percolate treatment plant MBR unit, CODcr=784mg/L.This strand of waste water is through coagulating sedimentation unit, and coagulating agent adopts bodied ferric sulfate, and when pH=6.5, added amount of chemical are 1000ppm, coagulation unit water outlet CODcr concentration is down to 462mg/L, and CODcr clearance reaches 41%; Coagulation water outlet enters electrochemical processing cell, and electrochemical processing cell adopts titanium base tindioxide electrocatalysis pole plate, and current density adopts 20mA/cm ², voltage adopts 7.8V, wherein adds activated-carbon catalyst, and dosage adopts 10%, and when being when reacted 60min, electrochemical processing cell water outlet CODcr is 195mg/L, COD clearance is 58%; Electrochemical processing cell water outlet enters biochemical treatment unit, biochemical treatment unit filler adopts haydite, the biochemical treatment unit residence time adopts 3h, biochemical treatment unit water outlet CODcr concentration is 74mg/L, reach table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008), advanced treatment system direct operating cost 15 yuan/m ³left and right.

Comparative example 1

Adopt the water outlet of the inventive method treating refuse percolate treatment plant MBR unit, CODcr=784mg/L.This strand of waste water is through coagulating sedimentation unit, and coagulating agent adopts bodied ferric sulfate, and when pH=6.5, added amount of chemical are 1000ppm, coagulation unit water outlet CODcr concentration is down to 462mg/L, and CODcr clearance reaches 41%; Coagulation water outlet enters electrochemical processing cell, and electrochemical processing cell adopts titanium base tindioxide electrocatalysis pole plate, and current density adopts 20mA/cm ², voltage adopts 7.8V, when being when reacted 180min, electrochemical processing cell water outlet CODcr is 85mg/L, COD clearance is 82%, reach table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008), but advanced treatment system direct operating cost reaches 40 yuan/m ³left and right.

Comparative example 2

Adopt the water outlet of the inventive method treating refuse percolate treatment plant MBR unit, CODcr=784mg/L.This strand of waste water is through coagulating sedimentation unit, and coagulating agent adopts bodied ferric sulfate, and when pH=6.5, added amount of chemical are 2000ppm, coagulation unit water outlet CODcr concentration is down to 375mg/L, and CODcr clearance reaches 52%; Coagulation water outlet enters biochemical treatment unit, biochemical treatment unit filler adopts polyhedron empty ball, along with the biochemical treatment unit residence time without continuous increase, water outlet cannot reach table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008) always.

As can be seen from above-described embodiment, comparative example: coagulation technology, electrochemical techniques, biochemical technology, high-level oxidation technology combine by the present invention, make full use of the high efficiency of coagulation technology, electrochemical techniques and high-level oxidation technology and the economy of biochemical technology, under the system of guarantee stable water outlet reaches the prerequisite of table 2 standard in household refuse landfill sites Environmental capacity standard (GB16889-2008), the running cost of system can be reduced largely, the method is applied to the advanced treatment of percolate, significant.

Claims

1. a non-embrane method deep treatment method for percolate, it is characterized in that technique includes but not limited to: physicochemical treatment unit, electrochemical oxidation unit, biochemical treatment unit and filtering unit, concrete treatment step is as follows:

A the secondary biochemical unit water outlet of () conventional spam percolate treating process enters physicochemical treatment unit after collecting, utilize one or more the materializing strategy means in neutralization, coagulation, precipitation, filtration to remove the pollutents such as part COD, ammonia nitrogen, SS, TDS, heavy metal;

B the water outlet of () physicochemical treatment unit enters electrochemical processing cell, utilize the direct oxidation of electrochemical cell, indirect oxidation, direct-reduction, indirect reduction effect macromole hardly degraded organic substance remaining in waste water to be decomposed into the small molecules organic pollutant of easy biochemical degradation and the heavy metal contaminants in further removal waste water;

C () wastewater biodegradability enters biochemical treatment unit after improving, the small molecules organic pollutant utilizing the microorganism in system to be generated by electrochemical cell further economy, effectively to degrade removal;

D () bio-chemical effluent finally mainly removes qualified discharge after the indexs such as SS via filtering unit, when the indexs such as draining COD, heavy metal do not meet emission standard, also can by before filtration end add the medicament such as oxygenant, metal traps realize water quality reaching standard discharge.

2. in physicochemical treatment unit according to claim 1, neutralization regulates pH in 5 ~ 10 scopes, one or more combinations in coagulating agent aluminium salt, molysite, poly-aluminium, Polyferric Sulfate, organic polymer, diatomite or microbial flocculant, coagulant charging quantity is 100 ~ 5000ppm.

3., in electrochemical processing cell according to claim 1, plate material adopts the one in graphite electrode plate, stainless steel polar plate, alloy pole plate, boron-doped diamond film pole plate.

4. in electrochemical processing cell according to claim 1, the filler with catalytic activity is thrown in system, filler adopts activated-carbon catalyst, activated carbon doped noble metal catalyst, one or more combination in alloy catalyst, filler add that quality is electrochemical processing cell volume of equipment 5% ~ 50%.

5., in electrochemical processing cell according to claim 1, current density adopts 5-50mA/cm ²; Running voltage 2-36V; Electrochemistry residence time 15-240min.

6. in biochemical treatment processing unit according to claim 1, be provided with biologic packing material, biologic packing material adopts one or more the combination in activated carbon, quartz sand, hard coal, haydite, combined stuffing, polyhedron empty ball, and biologic packing material dosage is 5%-50%.

7. the biochemical treatment processing unit residence time according to claim 1 adopts 0.5-5h.

8. electrochemistry-biochemical treatment system according to claim 1 can adopt uniprocessing, also can adopt multistage electrochemistry-biochemical treatment system series connection process, specifically arrange according to water quality characteristics.

9. in filtration treatment processing unit according to claim 1, be provided with filter packing, filter packing adopts one or more the combination in activated carbon, quartz sand, hard coal, haydite, alloy packing.

10. in filtration treatment processing unit according to claim 1, when effluent quality worsens, the water quality effect of checking on can be realized by adding of agent, when needs reduce organic concentration in water outlet, can H be added ₂o ₂, O ₃, clorox etc. has the medicament of oxidisability; When needs reduce heavy metal concentration in water outlet, the medicaments such as metal chelator can be added.

11. when advanced treatment process mesophytization processing unit effluent quality reaches emission standard, and above-mentioned filtration treatment processing unit can omit.