Treatment method of concentrated solution produced from landfill leachate by membrane method

Abstract

The invention discloses a treatment method of a concentrated solution produced from landfill leachate by a membrane method. The treatment method comprises the following steps of enabling the concentrated solution produced from the landfill leachate by the membrane method to sequentially pass through a composite softening coagulation and sedimentation pond, an ozone oxidation reactor, a hydrolyzing pond and an anaerobic MBR pond, and enabling effluent water from the anaerobic MBR pond to enter a nanofiltratoin system; enabling a permeation solution obtained through treatment of the effluent water in the nanofiltratoin system to be treated by a pressure contact oxidation reactor, and directly discharging the treated permeation solution, or after filtering the treated permeation solution by a multi-medium filter, discharging the filtered permeation solution; mixing a concentrated solution obtained after treatment by the nanofiltratoin system with the landfill leachate so as to obtain a mixed solution; and performing concentration treatment on the mixed solution by a biochemical method, an MBR method and the membrane method so as to obtain a concentrated solution, enabling the concentrated solution to enter the composite softening coagulation and sedimentation pond, and performing subsequent operations. The treatment method disclosed by the invention not only is suitable for treatment of the concentrated solution produced from the landfill leachate by membrane filtration, but also is suitable for treatment of other membrane concentrated solutions containing high concentration of organic compounds which are difficult to degrade.

Description

technical field

[0001] The invention relates to a method for treating landfill leachate, in particular to a method for treating the concentrated solution produced by the treatment of landfill leachate through reverse osmosis membrane, nanofiltration membrane or other filtration membrane methods. Background technique

[0002] In 2008, the state promulgated the "Standards for Pollution Control of Domestic Waste Landfills" (GB16889-2008), which put forward higher requirements for the treatment of landfill leachate. Nowadays, NF and RO membrane treatment processes are mostly used for the treatment of landfill leachate. The landfill leachate membrane filtration concentrate is the residual liquid retained by the NF membrane (or RO membrane) after the biodegradation of the landfill leachate. Generally, it is not biodegradable. And it contains a lot of inorganic ions, TDS is between 20000 ~ 60000mg / L, COD is usually between 1000 ~ 5000mg / L, ammonia nitrogen concentration is 100 ~ 10...

Examples

Embodiment 1

[0033] Typical leachate treatment and nanofiltration, reverse osmosis concentrate production process see figure 1 . The leachate enters the conditioning tank through the grid pretreatment system, and then enters the UBF anaerobic system. The anaerobic effluent enters the intermediate tank, and the effluent from the intermediate tank enters the denitrification tank and the two-stage aerobic nitrification tank in turn. The effluent from the nitrification tank enters the tubular ultrafiltration membrane system. The ultrafiltration concentrate is returned to the denitrification tank. The ultrafiltration liquid enters the clear liquid tank and then enters the nanofiltration system to generate nanofiltration concentrate and clear liquid. The nanofiltration liquid can be directly discharged, or collected in the nanofiltration liquid tank and then injected into the reverse osmosis system to generate Reverse osmosis concentrate and reverse osmosis clear liquid.

[0034] In this proc...

Embodiment 2

[0036] The landfill leachate membrane concentrate obtained in Example 1 was first passed through a composite softening coagulation sedimentation tank. The composite softening coagulation sedimentation tank was composed of a three-level reaction tank and a sedimentation tank. The first-level reaction tank was filled with sodium carbonate, and the sodium carbonate The total number of moles added is 1 times the total number of moles of calcium and magnesium ions in the wastewater, 200mg / L polyaluminum chloride is added to the second-stage reaction pool, and 2mg / L polyacrylamide polymer flocculant is added to the third-stage reaction pool PAM, the total reaction time is 30min, and then enters the sedimentation tank for precipitation, reduces the hardness of the wastewater and removes COD, and the total residence time of the wastewater in the composite softening coagulation sedimentation tank is 3h.

[0037] The effluent from the sedimentation tank enters the ozone oxidation reactor...

Embodiment 3

[0043] The landfill leachate membrane concentrate obtained in Example 1 is first passed through a composite softening coagulation sedimentation tank, which consists of a 4-level reaction tank and a sedimentation tank, and sodium hydroxide is added to the first to second-level reaction tanks. The total number of moles of sodium hydroxide added is 0.8 times the total number of moles of calcium and magnesium ions in the wastewater, 500mg / L of polymeric ferric sulfate is added to the second-stage reaction pool, and 2mg / L of polyacrylamide is added to the third-stage reaction pool. Molecular flocculant PAM, the total reaction time is 60min, and then enters the sedimentation tank for precipitation to reduce the hardness of the wastewater and remove COD. The total residence time of the wastewater in the composite softening coagulation sedimentation tank is 5h.

[0044] The effluent from the sedimentation tank enters the ozone oxidation reactor for treatment. The ozone oxidation reacto...

technical field

[0001] The invention relates to a method for treating landfill leachate, in particular to a method for treating the concentrated solution produced by the treatment of landfill leachate through reverse osmosis membrane, nanofiltration membrane or other filtration membrane methods. Background technique

[0002] In 2008, the state promulgated the "Standards for Pollution Control of Domestic Waste Landfills" (GB16889-2008), which put forward higher requirements for the treatment of landfill leachate. Nowadays, NF and RO membrane treatment processes are mostly used for the treatment of landfill leachate. The landfill leachate membrane filtration concentrate is the residual liquid retained by the NF membrane (or RO membrane) after the biodegradation of the landfill leachate. Generally, it is not biodegradable. And it contains a lot of inorganic ions, TDS is between 20000 ~ 60000mg / L, COD is usually between 1000 ~ 5000mg / L, ammonia nitrogen concentration is 100 ~ 10...

Examples

Embodiment 1

[0033] Typical leachate treatment and nanofiltration, reverse osmosis concentrate production process see figure 1 . The leachate enters the conditioning tank through the grid pretreatment system, and then enters the UBF anaerobic system. The anaerobic effluent enters the intermediate tank, and the effluent from the intermediate tank enters the denitrification tank and the two-stage aerobic nitrification tank in turn. The effluent from the nitrification tank enters the tubular ultrafiltration membrane system. The ultrafiltration concentrate is returned to the denitrification tank. The ultrafiltration liquid enters the clear liquid tank and then enters the nanofiltration system to generate nanofiltration concentrate and clear liquid. The nanofiltration liquid can be directly discharged, or collected in the nanofiltration liquid tank and then injected into the reverse osmosis system to generate Reverse osmosis concentrate and reverse osmosis clear liquid.

[0034] In this proc...

Embodiment 2

[0036] The landfill leachate membrane concentrate obtained in Example 1 was first passed through a composite softening coagulation sedimentation tank. The composite softening coagulation sedimentation tank was composed of a three-level reaction tank and a sedimentation tank. The first-level reaction tank was filled with sodium carbonate, and the sodium carbonate The total number of moles added is 1 times the total number of moles of calcium and magnesium ions in the wastewater, 200mg / L polyaluminum chloride is added to the second-stage reaction pool, and 2mg / L polyacrylamide polymer flocculant is added to the third-stage reaction pool PAM, the total reaction time is 30min, and then enters the sedimentation tank for precipitation, reduces the hardness of the wastewater and removes COD, and the total residence time of the wastewater in the composite softening coagulation sedimentation tank is 3h.

[0037] The effluent from the sedimentation tank enters the ozone oxidation reactor...

Embodiment 3

[0043] The landfill leachate membrane concentrate obtained in Example 1 is first passed through a composite softening coagulation sedimentation tank, which consists of a 4-level reaction tank and a sedimentation tank, and sodium hydroxide is added to the first to second-level reaction tanks. The total number of moles of sodium hydroxide added is 0.8 times the total number of moles of calcium and magnesium ions in the wastewater, 500mg / L of polymeric ferric sulfate is added to the second-stage reaction pool, and 2mg / L of polyacrylamide is added to the third-stage reaction pool. Molecular flocculant PAM, the total reaction time is 60min, and then enters the sedimentation tank for precipitation to reduce the hardness of the wastewater and remove COD. The total residence time of the wastewater in the composite softening coagulation sedimentation tank is 5h.

[0044] The effluent from the sedimentation tank enters the ozone oxidation reactor for treatment. The ozone oxidation reacto...

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