Novel landfill leachate treatment system

Abstract

The utility model discloses a novel landfill leachate treatment system which comprises a high-density sedimentation tank, an outdoor regulating tank, an activated carbon and sand added high-density sedimentation tank, a denitrification and nitrification tank, a denitrification tank, a biological rotary disc filter and a nanofiltration system which are connected in sequence. Then enabling the filtrate to enter an adjusting tank containing a titanium dioxide photocatalyst at the periphery for photocatalysis, and degrading part of refractory organic matters into CO2 and H2O; effluent enters Actiflocarb, and particulate matters, heavy metals, organic matters, chromaticity and the like are removed through combination of activated carbon and coagulation and flocculation; then entering a Biostyr NDN and a Biostyr PDN, and carrying out biochemical treatment, so as to degrade ammonia nitrogen; effluent enters nanofiltration through the biological rotating disc, so that organic matters, multivalent ions, chromaticity and SS in water are further removed, and the effluent is discharged after reaching the standard.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the garbage leachate processing technical field, concretely relates to a garbage leachate processing system. BACKGROUND

[0002] Garbage leachate refers to high-concentration organic wastewater carrying pollutants leached from garbage landfill sites or garbage, including liquid formed by dissolving organic and inorganic substances in garbage landfill sites when rainwater or surface water penetrates through the garbage landfill sites. Garbage leachate is complex in composition, containing various organic substances, inorganic salts, heavy metals, SS, ammonia nitrogen and microorganisms, etc., and is greatly variable in water quality and quantity, so it is crucial to treat garbage leachate for protecting groundwater and the surrounding environment.

[0003] The current garbage leachate treatment process can be roughly divided into a pretreatment stage, a main treatment stage and a deep treatment stage. The pretreatment stage includes grid filtration to remove large suspended solids, and removal of part of suspended solids and oil by sedimentation or flotation. The main treatment stage often uses biochemical treatment methods, such as activated sludge method or biofilm method, to decompose organic matter by microorganisms. The deep treatment stage includes reverse osmosis, ultrafiltration or ozone oxidation, etc., to further remove residual dissolved organic matter, nitrogen and phosphorus nutrients and microorganisms, etc. Although the above garbage leachate treatment methods are effective, they also have disadvantages, such as unstable treatment effect: affected by water quality fluctuations, especially when seasonal changes cause large changes in water quality, the efficiency of the treatment system will decrease, sometimes it is difficult to achieve the expected purification standard. Garbage leachate treatment often requires a large land area, which is a challenge for urban planning and land-scarce areas. Conventional processes are prone to membrane clogging after treatment, increasing the consumption of membranes and the operating cost. SUMMARY

[0004] The utility model provides a novel garbage leachate treatment system, which solves the above problems, improves the treatment efficiency and recycling rate, and reduces the impact on the environment.

[0005] The utility model discloses a garbage leachate treatment system, including high density sedimentation tank, outdoor adjustment pool, add activated carbon and sand high density sedimentation tank, denitrification nitrification tank, denitrification tank, biological rotary disc filter and nanofiltration system that connect gradually, and the sludge of high density sedimentation tank and add activated carbon and sand high density sedimentation tank enters sludge thickener, and the backwash water of denitrification nitrification tank, denitrification tank, biological rotary disc filter also enters sludge thickener, and the concentrated water of nanofiltration system returns to high density sedimentation tank, the pool wall and pool bottom of outdoor adjustment pool are attached photocatalyst, and add activated carbon and sand high density sedimentation tank connects activated carbon dosing mechanism, quartz sand dosing mechanism, second PAC dosing mechanism and second PAM dosing mechanism, and sets up aeration pipe in denitrification nitrification tank, and aeration pipe is located in filter material middle.

[0006] The photocatalyst is titanium dioxide photocatalyst.

[0007] Compared with the prior art, the utility model combines filtration+photocatalysis+adsorption filtration+biodegradation+membrane method, garbage leachate first enters Multiflo and carries out preliminary filtration, removes the suspended solid in the filtrate, and then the filtrate enters the outdoor adjustment pool containing titanium dioxide photocatalyst all around and carries out photocatalysis, and degrades part of refractory organic matter into CO2 and H2O, the effluent enters Actiflo carb, removes particulate matter, heavy metal, organic matter, colority etc. through activated carbon and coagulation flocculation combination, and then enters Biostyr NDN and Biostyr PDN and carries out biochemical treatment, and degrades ammonia nitrogen, and the effluent enters nanofiltration through biological rotary disc, removes organic matter, polyvalent ion, colority and SS in water further, and discharges to standard. The garbage leachate treatment system disclosed by the utility model has small floor area, simple operation, certain adaptability to water quality change, keeps stable effluent quality, does not easily cause membrane blockage, and has low operation cost. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 It is the flow chart of the utility model. DETAILED DESCRIPTION

[0009] The utility model is further explained below in combination with the drawings and specific embodiments. It should be understood that these embodiments are only for illustrating the utility model, and are not used for limiting the scope of the utility model, and after reading the content of the utility model, those skilled in the art can make various changes or modifications to the utility model, and these equivalent forms are also within the range defined by the utility model.

[0010] As Figure 1As shown, the landfill leachate treatment system comprises, in sequence, a high-density sedimentation tank, an outdoor conditioning tank, a high-density sedimentation tank with activated carbon and sand, a denitrification and nitrification tank, a denitrification tank, a biological rotating disc filter, and a nanofiltration system, sludge from the high-density sedimentation tank and the high-density sedimentation tank with activated carbon and sand enters a sludge concentration tank, backwash water from the denitrification and nitrification tank, the denitrification tank, and the biological rotating disc filter also enters the sludge concentration tank, and concentrated water from the nanofiltration system is returned to the high-density sedimentation tank; the high-density sedimentation tank is connected to a first PAC dosing mechanism and a first PAM dosing mechanism, the walls and the bottom of the outdoor conditioning tank are coated with a photocatalyst, the high-density sedimentation tank with activated carbon and sand is connected to an activated carbon dosing mechanism, a quartz sand dosing mechanism, a second PAC dosing mechanism, and a second PAM dosing mechanism, an aeration pipe is arranged in the denitrification and nitrification tank, and the aeration pipe is located in the middle of the filter material.

[0011] The high-density sedimentation tank is divided into three areas, a first area for adding a flocculant polyaluminum chloride (PAC), a second area for adding a flocculant polyacrylamide (PAM), and a third area for a slant pipe sedimentation tank, the high-density sedimentation tank integrates mechanical mixing coagulation, mechanical enhanced flocculation, and slant pipe sedimentation into an organic whole, has a small footprint, is a high-efficiency clarification process, and achieves effective removal of suspended solids, and the flexibility lies in the ability to adjust operating parameters according to changes in the quality of the influent water, thereby maintaining stable effluent quality.

[0012] The walls and the bottom of the outdoor conditioning tank are coated with a photocatalyst, and the photocatalyst is a titanium dioxide photocatalyst. The landfill leachate treated by the high-density sedimentation tank enters the outdoor conditioning tank, the hydroxyl radicals (·OH) generated by the photocatalyst under light conditions efficiently degrade organic pollutants in the water, degrading them into non-toxic and harmless inorganic small molecules such as CO2 and H2O, and this process is not only efficient but also reduces secondary pollution. When treating pollutants, the photocatalytic oxidation is stronger than chemical oxidation, has the characteristics of low treatment cost, non-toxicity, and good treatment effect.

[0013] The photocatalyst is directly attached to the bottom and the walls of the tank, which maximizes exposure to natural light and increases the effective contact opportunities between the pollutants and the catalyst, thereby improving the purification efficiency. At the same time, the problem of recovery difficulty caused by direct addition of the catalyst in water is solved.

[0014] The photocatalyst is attached to the bottom and the walls of the tank, specifically, the walls and the bottom of the outdoor conditioning tank are built with tiles with firmly attached photocatalyst particles, and the tiles with firmly attached photocatalyst particles are a mature technology in the prior art.

[0015] The Actiflo®Carb process, which is an activated carbon and sand addition high-density settling tank, is a process that combines powdered activated carbon, quartz sand micro-sand addition, and a high-density settling tank (Actiflo). The core is the integration of coagulation, flocculation, sedimentation, and activated carbon adsorption, forming a high-efficiency and compact water treatment unit. Quartz sand micro-sand becomes the core of flocculation, improving sedimentation speed and enhancing sedimentation performance. The removal effect of particulate matter and suspended pollutants (suspended BOD5 and COD) in the filtrate is obvious. In addition, powdered activated carbon and organic matter, pigments, odor substances, heavy metals, and some dissolved pollutants in water undergo physical adsorption and certain chemical reactions, improving water quality. The process is efficient and compact, with very small land area.

[0016] Both the denitrifying nitrification tank (Biostyr NDN) and the denitrification tank (Biostyr PDN) are high-efficiency biological filter tank technologies. Their advantages are as follows: first, they use a combination of biology and filtration, and do not require a subsequent sedimentation tank; second, Biostyr biological aerated filters can be backwashed from top to bottom by gravity flow, do not require backwash pumps, and have low energy consumption; third, they have high treatment capacity, excellent effluent quality, and stable performance; fourth, they produce almost no odor, and have high surrounding environmental quality; and fifth, they have small land area and low capital investment.

[0017] Biostyr NDN is a biological aerated filter with both nitrification and denitrification functions. The process is an upward flow filter, and the aeration pipe is located in the middle of the filter material. When the leachate enters the lower anoxic zone of the filter from the bottom water distribution pipe, the denitrifying bacteria degrade part of the BOD using the carbon source in the raw water, reducing not only the ammonia nitrogen load entering the aerobic zone but also the aeration volume in the aerobic zone. The leachate then enters the aerobic layer for nitrification reaction, converting ammonia nitrogen into nitrate. Biostyr NDN has the characteristics of a biofilm method, so there is no sludge age limitation caused by the long generation period of nitrifying bacteria. In addition, the water and gas flow upward in parallel, promoting uniform mixing of the gas and water, improving oxygen transfer efficiency, and being beneficial to reducing energy consumption.

[0018] The subsequent effluent enters the Biostyr PDN, where it undergoes denitrification reaction by adding carbon source, converting nitrate into nitrogen gas, which is discharged into the atmosphere.

[0019] Discfilter is a kind of physical filtration technology, mainly used for removing suspended solids in wastewater. It is composed of a series of parallel arranged filter discs, which have small pores on the surface. When wastewater passes through these filter discs, suspended solids are trapped on the surface of the filter discs. Discfilter is used as a pretreatment stage of nanofiltration to trap the biofilm shed by the biological filter. Its advantages include flexible design, convenient installation, small footprint, simple operation, certain adaptability to changes in water quality, low operating cost, etc.

[0020] Nanofiltration can effectively remove organic matter, multivalent ions (such as calcium and magnesium ions), part of color and turbidity in water, while allowing monovalent ions (such as sodium ions) to pass through, which enables it to effectively remove most of the refractory organic pollutants in the leachate while maintaining a certain osmotic pressure. In addition, nanofiltration technology has certain trapping capacity for trace amounts of antibiotics and drug residues that may be contained in landfill leachate.

[0021] Due to the previous photocatalysis, filtration, biological treatment and discfilter processes, most of the organic matter, ammonia nitrogen, heavy metals, SS, etc. in the landfill leachate are effectively removed, the water quality is optimized, the burden on the nanofiltration system is reduced, the energy consumption is reduced, and the overall performance is improved.

[0022] The sludge produced by Multiflo and Actiflo Carb is transported to the sludge thickening tank by a sludge pump; the backwash wastewater of Biostyr NDN, Biostyr PDN and discfilter is also collected to the sludge thickening tank, and the sludge is dewatered by a dewatering machine and then transported out.

[0023] The garbage leachate treatment system disclosed by the utility model combines photocatalysis, physics, chemistry, biology and membrane treatment and other treatment technologies to optimize the traditional process. This method still has relatively stable treatment effect under the condition of large fluctuation of water quantity and quality of influent, can well meet the characteristics of large change of production wastewater, has certain impact load capacity, solves the problems of high content of organic matter, color, ammonia nitrogen and heavy metals, reduces the burden of subsequent membrane treatment, and improves the overall system efficiency.

[0024] The garbage leachate treatment system disclosed by the utility model has small footprint, simple operation, certain adaptability to changes in water quality, stable effluent quality, is not easy to cause membrane blockage, and has low operating cost.

[0025] The above is only the preferred embodiment of the utility model, and it should be pointed out that for those skilled in the art, without departing from the overall concept of the utility model, a number of changes and improvements can be made, which should also be considered as the protection range of the utility model.

Claims

1. A novel leachate treatment system for waste characterized by: The system comprises high-density sedimentation tank, outdoor adjusting tank, activated carbon and sand high-density sedimentation tank, denitrification nitrification tank, denitrification tank, biological rotating disc filter and nanofiltration system connected in sequence, sludge of the high-density sedimentation tank and the activated carbon and sand high-density sedimentation tank enters sludge thickening tank, backwashing water of the denitrification nitrification tank, the denitrification tank and the biological rotating disc filter also enters the sludge thickening tank, concentrated water of the nanofiltration system is backflowed to the high-density sedimentation tank; the high-density sedimentation tank is connected with first PAC adding mechanism and first PAM adding mechanism, light catalyst is attached on the tank wall and tank bottom of the outdoor adjusting tank, the activated carbon and sand high-density sedimentation tank is connected with activated carbon adding mechanism, quartz sand adding mechanism, second PAC adding mechanism and second PAM adding mechanism, aeration pipe is arranged in the denitrification nitrification tank and located in the middle of filter material.

2. The novel landfill leachate treatment system according to claim 1, characterized by: The light catalyst is titanium dioxide light catalyst.

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