CN209759145U

CN209759145U - High-efficient landfill leachate processing system

Info

Publication number: CN209759145U
Application number: CN201822269160.2U
Authority: CN
Inventors: 谢军英; 李方越
Original assignee: Jiangsu Kunyi Environmental Engineering Co Ltd
Current assignee: Jiangsu Kunyi Environmental Technology Co.,Ltd.
Priority date: 2018-12-29
Filing date: 2018-12-29
Publication date: 2019-12-10
Anticipated expiration: 2028-12-29

Abstract

The utility model relates to a high-efficient landfill leachate treatment system belongs to sewage treatment technical field. The device comprises an adjusting tank, wherein the adjusting tank is sequentially connected with an air flotation unit, an air flotation water tank, a sand filtration unit, a sand filtration tank and a first-stage membrane module water inlet end through pipelines, the first-stage membrane module water production end is connected with a second-stage membrane module water inlet end, the first-stage membrane module concentrated water end is sequentially connected with a coagulating sedimentation unit, a first middle water tank, a tubular microfiltration membrane module, a second middle water tank and a third-stage membrane module water inlet end, and the third-stage membrane module water production end is communicated with the sand filtration tank; the concentrated water end of the three-stage membrane module is connected with an evaporation unit, and the water production end of the evaporation unit is communicated with the inlet end of the air flotation unit; the concentrated water end of the second-stage membrane component is communicated with the inlet end of the sand filter tank; and water is produced outside the water production end of the secondary membrane component. The method has the advantages of simple process flow, small occupied area, and zero discharge of the concentrated solution, and ensures that the quality of the produced water is discharged after reaching the standard; and the recovery rate of the produced water is extremely high.

Description

High-efficient landfill leachate processing system

Technical Field

the utility model relates to a high-efficient landfill leachate treatment system belongs to sewage treatment technical field.

Background

In recent years, with the continuous development of the urbanization process of China, the urban garbage also grows at the speed of 8-10% per year on average; the growth rate of the extra-large cities is as high as 15-20%. In 2010, the urban domestic garbage reaches 2.64 hundred million tons, 4.09 hundred million tons in 2030 and 5.28 hundred million tons in 2050. At present, due to the restriction of factors such as economic technology and the like, the garbage treatment in China still adopts a sanitary landfill mode. In large cities, each city has a plurality of harmless garbage disposal facilities, and the landfill accounts for 91 percent. However, during the landfill process, landfill leachate threatening the surrounding water sources and public health is generated, secondary pollution is generated, and the phenomenon can be continued even years after the landfill is buried and sealed. Research has shown that, until 1997, there were 18500 landfills in the united states, and almost half of them produced varying degrees of pollution to water. According to the 2010 annual survey report, it is shown that: leachate discharged from municipal refuse landfill sites in China generates 32.46 ten thousand tons of chemical oxygen demand and 3.22 ten thousand tons of ammonia nitrogen. Therefore, the treatment of landfill leachate as wastewater with serious pollution has become a research and development hotspot.

Landfill leachate is the product of the gravity flow of liquids in landfills, mainly from precipitation and the inherent water content of the landfill itself. It has BOD₅Compared with the characteristics of high COD concentration, higher metal content, large water quality and water quantity change, higher ammonia nitrogen content, imbalance proportion of microbial nutrient elements and the like, if the waste water is directly discharged without treatment, the ecological deterioration can be caused, and the serious environmental pollution problem is caused. The traditional landfill leachate treatment method at home and abroad comprises the following steps: aeration stabilization pond, anaerobic biological filter, upward flow type anaerobic sludge bed, anaerobic-oxidation ditch-facultative pond process, UASB-oxidation ditch-stabilization pond, soil irrigation method and the like. GB 16889 newly revised pollution control Standard for municipal refuse landfill 2008 issued in 2008 to BOD in landfill leachate₅、COD_crindexes such as ammonia nitrogen, total nitrogen, heavy metal and the like are provided more strictlyAnd (4) the emission standard of the grid. The traditional biological treatment process is difficult to meet the emission requirement.

The existing domestic landfill leachate has the following main modes: the leachate is concentrated in the collecting tank, sludge enters the concentrating tank after coagulating sedimentation, the liquid part is subjected to anaerobic treatment, the generated sludge enters the concentrating tank again, the generated methane is discharged, the generated liquid part enters the biochemical membrane system of an anaerobic/aerobic (A/O) process combined Membrane Bioreactor (MBR) for treatment, the generated sludge enters the concentrating tank again, the effluent is treated by roll type NF/RO, the produced water is discharged after reaching the standard, and the concentrated water can be sprayed to the incinerator. And concentrating the collected sludge in the sludge concentration tank, returning filtrate to the collection tank, treating the concentrated sludge by using a sludge filter press to form a mud cake for landfill, and returning the filtrate generated by filter pressing to the collection tank. The stability of effluent in the process is difficult to control; the biochemical system occupies a large area and has high investment cost; the practical roll type RO/NF system has low water recovery rate.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem of providing a high-efficiency garbage leachate treatment system aiming at the prior art, which not only has simple process flow and small occupied area, but also ensures that the quality of produced water is discharged after reaching the standard and the zero discharge of concentrated solution is realized; and the recovery rate of the produced water is extremely high.

The utility model provides a technical scheme that above-mentioned problem adopted does: a high-efficiency landfill leachate treatment system comprises an adjusting tank, an air flotation unit, a sand filtration unit, a primary membrane assembly, a secondary membrane assembly, a coagulating sedimentation unit, a tubular microfiltration membrane assembly, a tertiary membrane assembly and an evaporation unit, wherein the adjusting tank is sequentially connected with the air flotation unit, an air flotation water tank, the sand filtration unit, a sand filtration tank and a water inlet end of the primary membrane assembly through pipelines, a water production end of the primary membrane assembly is connected with a water inlet end of the secondary membrane assembly, a concentrated water end of the primary membrane assembly is sequentially connected with the coagulating sedimentation unit, a first intermediate water tank, the tubular microfiltration membrane assembly, a second intermediate water tank and a water inlet end of the tertiary membrane assembly, and a water production end of the tertiary membrane assembly; the concentrated water end of the three-stage membrane module is connected with an evaporation unit, and the water production end of the evaporation unit is communicated with the inlet end of the air flotation unit; the concentrated water end of the second-stage membrane component is communicated with the inlet end of the sand filter tank; and water is produced outside the water production end of the secondary membrane component.

The first-stage membrane module is composed of a plurality of sets of 90Bar DTRO membrane systems, the second-stage membrane module is composed of a plurality of sets of 75Bar DTRO membrane systems, and the third-stage membrane module is composed of a plurality of sets of 120Bar DTRO membrane systems.

Compared with the prior art, the utility model has the advantages of: the utility model provides a high-efficient landfill leachate processing system, adopts shallow layer coagulating ion air supporting + quartz sand mechanical filtration + one-level DTRO + second grade RO + air stripping + coagulating sedimentation + tubular PP membrane +120 bars DTRO + evaporative crystallization "as main body technology processing landfill leachate, can guarantee to produce the discharge to reach standard of water quality, can guarantee the processing requirement of concentrate zero release again, and the whole rate of recovery of system is close to 96.4%. The investment is saved, the operation cost is lowest and the treatment effect is best on the premise of meeting the emission requirement.

Drawings

FIG. 1 is a schematic flow chart of a high-efficiency landfill leachate treatment system according to an embodiment of the present invention;

In the figure, 1, a regulating tank, 2, an air flotation unit, 3, an air flotation water tank, 4, a sand filtration unit, 5, a sand filtration tank, 6 first-stage membrane modules, 7 second-stage membrane modules, 8, a coagulating sedimentation unit, 9 first intermediate water tanks, 10 tubular microfiltration membrane modules, 11 second intermediate water tanks, 12 third-stage membrane modules and 14 evaporation units.

Detailed Description

The present invention will be described in further detail with reference to the following embodiments.

As shown in fig. 1, the high-efficiency landfill leachate treatment system in this embodiment includes an adjusting tank 1, an air flotation unit 2, a sand filtration unit 4, a first-stage membrane module 6, a second-stage membrane module 7, a coagulating sedimentation unit 8, a tubular microfiltration membrane module 10, a third-stage membrane module 12 and an evaporation unit 14, wherein the adjusting tank 1 is sequentially connected with the air flotation unit 2, the air flotation tank 3, the sand filtration unit 4, the sand filtration tank 5 and a water inlet end of the first-stage membrane module 6 through pipelines, a water producing end of the first-stage membrane module 6 is connected with a water inlet end of the second-stage membrane module 7, a concentrated water end of the first-stage membrane module 6 is sequentially connected with the coagulating sedimentation unit 8, a first intermediate tank 9, the tubular microfiltration membrane module 10, a second intermediate tank 11 and a water inlet end of the third-; the concentrated water end of the three-stage membrane module 12 is connected with the evaporation unit 14 for evaporation, and the water production end of the evaporation unit 14 is communicated with the air flotation unit 2 for cyclic recycling; the concentrated water end of the second-stage membrane component 7 is communicated with the sand filter tank 5; so that the concentrated water in the second-stage membrane component 7 is recycled through the first-stage membrane component 7, and the produced water in the second-stage membrane component 7 is discharged after reaching standards.

The first-stage membrane module 6 comprises 6 sets of 90Bar DTRO membranes which are connected in series, the second-stage membrane module 7 comprises 6 sets of 75Bar DTRO membranes which are connected in series, and the third-stage membrane module 12 comprises 2 sets of 120Bar DTRO membranes which are connected in series.

The technical parameters of the air floatation unit 2 are shown in table one:

Watch 1

Serial number	item	Design value	Unit of
				1	number of air flotation tanks	1	Sleeve
2	Flow of incoming water	120	m3/hr
				3	Size of air floatation tank	Φ7000*H1200
4	Surface load of air floatation tank	3.2	m3/m2.hr
				5	Amount of dissolved gas and water	50	m3/hr

The technical parameters of the sand filtration unit 4 are shown in table two:

Watch two

Serial number	Item	Design value	unit of
				1	Number of sand filtration tanks	2
2	Flow of incoming water	85	m3/hr
				3	Diameter of sand filtering tank	Dia2500*2
4	Flow rate of sand filter tank	8.7	m/hr
				5	Blower flow	7.7	m3/min
6	Strength of air backwash	26	L/(m2·s)
				7	backwash pump flow	250	m3/hr
8	Backwash strength of backwash water pump	13	L/(m2·s)
				9	Filling rate of quartz sand	70	％

The design parameters of the coagulating sedimentation unit 8 are shown in the third table:

Watch III

The design parameters of the PP-MF tubular microfiltration membrane module 10 (5 sets in total) are shown in the fourth table:

Watch four

Serial number	Item	Design value	Unit of
				1	Type of membrane	PP-MF-16
2	Material of	PP
				3	Inner diameter	5.5	mm
4	Number of membrane filaments	324	Root of herbaceous plant
				5	Circulation flow rate	4	m/s
6	Amount of circulating water	110	m3/h
				7	Calculating the water inflow	6	m3/h
8	Actual water inflow	40	m3/h
				9	Size of gap	0.2	Micron meter
10	Maximum feed water pressure	3	bar
				11	Area of membrane column	16	m2
12	number of membrane modules	5	Only by
				13	Temperature of	5-50	℃
14	pH value	1～14
				15	Average flux	22.89	LMH

The above 90bar DTRO (total required 6 sets) design parameters are shown in table five:

Watch five

The above 75bar DTRO (total required 6 sets) design parameters are shown in table five:

Watch six

Serial number	Item	design value	Unit of
				1	Type of membrane	75bar DTRO
2	Calculating the water inflow	13.47	m3/h
				3	recovery rate	92％	％
4	Multiple of concentration	12.5
				5	Pressure of water supply	25	bar
6	Area of membrane column	9.405	m2
				7	Number of membrane columns	40	Only by
8	Temperature of	25.00	℃
				9	pH value	6～8
10	Average flux	33	LMH

the above 120bar DTRO (total required 2 sets) design parameters are shown in table five:

watch seven

the treatment process based on the landfill leachate treatment system comprises the following steps:

(1) introducing 1600m3/d landfill leachate into a regulating reservoir 1 for collection, regulating the pH value of raw water to Ph6.5, and effectively preventing carbonate inorganic salt from scaling;

(2) The water discharged from the adjusting tank 1 is delivered to an air flotation unit 2, the suspended matters are descumed, the water discharged from the air flotation unit 2 enters an air flotation water tank 3 for buffering and further adjusting the pH value of the water, and the scum enters a scum collecting tank and is dehydrated by a dehydrator to form a filter cake which is delivered outside;

(3) The effluent of the air floatation water tank 3 enters a sand filtering unit 4 for filtering particles, the filtering precision is about 50um, the particles larger than 50um can be filtered, and the effluent of the sand filtering unit 4 enters a sand filtering tank 5 for homogenizing and homogenizing water quality;

(4) The outlet water of the sand filter tank 5 is conveyed to a 90bar DTRO membrane system by a lifting pump, the 90bar DTRO membrane system is of a skid-mounted structure, raw water firstly enters a cartridge filter, the precision of the cartridge filter is 10 mu m and is used for removing suspended matters and possible tiny sand grains brought by sand filtration, for an infiltration liquid system, because the content of calcium, magnesium, barium and other ions easy to scale and silicate in raw water is high, and the salts are easy to generate a supersaturated state on the concentrated solution side after being concentrated by the 90bar DTRO membrane module by high power, so a certain amount of scale inhibitor is added in front of the cartridge filter according to the actual water quality condition to prevent the occurrence of the scaling phenomena of silica scale and sulfate, the specific addition amount is determined by the field water quality condition, and the dilution multiple of the. The guard filter provides a final protective barrier for the membrane column. The percolate passing through the cartridge filter flows to a 90bar DTRO membrane system for filtering, 652m3/d of concentrated water flows to a coagulating sedimentation unit 8, 1676m3/d of produced water is led to the water inlet end of a 75bar DTRO membrane system through the water production end of the 90bar DTRO membrane system for further filtering treatment, the produced 134m3/d of concentrated water is led to a sand filtering pond 5 for circulating filtration, 1542m3/d of produced water flows to a water production tank, and the produced water meets the discharge requirement;

(5)652m3/d of concentrated water are introduced into the coagulating sedimentation unit 8, NaOH/Ca (OH) is added₂Precipitating with calcium and magnesium ions, adding Na₂CO₃The hardness of non-carbonate is removed, the salt content in the water treated by the chemical adding can not be changed, but most of divalent salt can be precipitated, most of the supernatant is mixed by monovalent salt, the first middle water tank 9 of the effluent of the coagulating sedimentation unit 8 buffers and pressurizes, and the precipitate enters a dehydrator for dehydration and then is extruded into a filter cake to be sent out;

(6) The effluent of the first intermediate water tank 9 flows to a PP-MF tubular microfiltration membrane component 10, and the tubular microfiltration membrane component 10 can filter particulate matters larger than 0.2um and remove fine calcium carbonate crystals and other solid particles; the safe operation of the next procedure is guaranteed; introducing the filtered water to a second intermediate water tank 11;

(7) The effluent of the second intermediate water tank 11 is filtered by a 120bar DTRO membrane system, 359m3/d of produced water is generated to flow into the sand filtration water tank 5, the step (4) is repeated again to start circulating filtration,

(8) The concentrated water with the yield of 293m3/d enters the evaporation unit 13 for evaporation, the concentrated water after evaporation is 58m3/d, the produced water is 235m3/d, and the concentrated water is introduced to the air flotation unit 2 for circulation, and the circulation is started from the step (2).

The water inlet amount of the raw water is 1600m3/d, after the treatment by the treatment process, the water yield reaching the standard is 1542m3/d, the concentrated solution after evaporation is 58m3/d, and the overall recovery rate of the system is close to 96.4%. The treatment requirement of zero discharge of the concentrated solution can be ensured; and the treatment system has stable operation, simple and convenient operation, the least investment, the lowest operating cost and the best treatment effect on the premise of meeting the emission requirement.

in addition to the above embodiments, the present invention also includes other embodiments, and all technical solutions formed by equivalent transformation or equivalent replacement should fall within the protection scope of the claims of the present invention.

Claims

1. The utility model provides a high-efficient landfill leachate processing system which characterized in that: comprises a regulating tank (1), an air flotation unit (2), a sand filtration unit (4), a first-stage membrane component (6), a second-stage membrane component (7), a coagulating sedimentation unit (8), a tubular microfiltration membrane component (10), a third-stage membrane component (12) and an evaporation unit (13), the adjusting tank (1) is sequentially connected with an air flotation unit (2), an air flotation water tank (3), a sand filtering unit (4), a sand filtering tank (5) and a water inlet end of a primary membrane component (6) through pipelines, the water producing end of the first-stage membrane component (6) is connected with the water inlet end of the second-stage membrane component (7), the concentrated water end of the first-stage membrane module (6) is sequentially connected with a coagulating sedimentation unit (8), a first middle water tank (9), a tubular microfiltration membrane module (10), a second middle water tank (11) and a water inlet end of a third-stage membrane module (12), the water production end of the three-stage membrane module (12) is communicated with the sand filter tank (5); the concentrated water end of the three-stage membrane module (12) is connected with an evaporation unit (13), and the water production end of the evaporation unit (13) is communicated with the inlet end of the air flotation unit (2); the concentrated water end of the secondary membrane component (7) is communicated with the inlet end of the sand filter tank (5); and water is produced outside the water production end of the secondary membrane component (7).

2. the high efficiency landfill leachate treatment system of claim 1, wherein: the first-stage membrane assembly (6) is composed of a plurality of sets of 90Bar DTRO membrane systems, the second-stage membrane assembly (7) is composed of a plurality of sets of 75Bar DTRO membrane systems, and the third-stage membrane assembly (12) is composed of a plurality of sets of 120Bar DTRO membrane systems.