Up-to-standard discharge for low-concentration copper-containing wastewater in semiconductor industry and efficient sedimentation process thereof

Abstract

The invention relates to an up-to-standard discharge for low-concentration copper-containing wastewater in the semiconductor industry and an efficient sedimentation process. The process comprises thefollowing process steps: 1) adding a FeSO4 solution into the low-concentration copper-containing wastewater; 2) adding a calcium hydroxide solution into an inlet of a pipeline mixer at the bottom of an inclined plate sedimentation tank, and reacting the wastewater with calcium-containing modified sludge flowing back from the inclined plate sedimentation tank; 3) adding a recapturing agent for a chelating reaction; 4) adding polyacrylamide to carry out a flocculation reaction; and (5) introducing the sludge in the inclined plate sedimentation tank for mud-water separation, wherein one part of the sludge is conveyed to a sludge storage tank, the other part of the sludge is conveyed to a pipeline mixer, and performing the step (2). The method has the advantages that the FeSO4-recapturing agent combination is adopted according to wastewater characteristics, the use amount is reduced, the process is simple, the investment cost is low, coagulant adding and calcium hydroxide adding of returned sludge are omitted, the water content is low, the density is high, sludge sedimentation is accelerated, the surface load of the inclined plate sedimentation tank is increased, the occupied area is reduced, and a sludge concentration tank does not need to be arranged.

Description

technical field

[0001] The invention relates to a treatment process for the low-concentration copper-containing wastewater produced in the semiconductor industry to meet the standard discharge and high-efficiency sedimentation, and belongs to the technical field of wastewater treatment. Background technique

[0002] Various wastewaters are produced in the semiconductor manufacturing process, including copper-containing wastewater with a large proportion of water. At present, high-concentration copper-containing waste liquid is generally treated by outsourcing treatment, and low-concentration copper-containing waste water is discharged into the waste water treatment system for treatment. The pollutants in copper-containing wastewater mainly include hydrogen peroxide, copper ions and complexed copper. The content of complexed copper is as high as 70%, and it is difficult to precipitate complexed copper by adding alkali.

[0003] In the prior art, copper-containing wastewater ...

Examples

Embodiment 1

[0041] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids (SS) is 50-100 mg / L, the concentration of copper ions is 7-10 mg / L, and the concentration of complexed copper is 4-5 mg / L. 2 o 2 The concentration is 1000~1100mg / L, and the pH is 3~4. The waste water flow rate is 20t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0042] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 16L / h (FeSO 4 : total copper=8 (mass ratio)).

[0043] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 10~15min, the flow rate of copper-containing sludge is 5~1...

Embodiment 2

[0049] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids is 50-150 mg / L, the concentration of copper ions is 10-15 mg / L, the concentration of complexed copper is 5-8 mg / L, H 2 o 2 The concentration is 400-500 mg / L, and the pH is 2-3. The waste water flow rate is 30t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0050] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 21L / h (FeSO 4 : total copper=9 (mass ratio)).

[0051] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 15-20min, the copper-containing sludge flow rate is 8-16m 3 / h; ...

Embodiment 3

[0057] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids is 20-50 mg / L, the concentration of copper ions is 3-5 mg / L, the concentration of complexed copper is 2-3 mg / L, H 2 o 2 The concentration is 300-500 mg / L, and the pH is 2-4. The waste water flow rate is 40t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0058] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 20L / h (FeSO 4 : total copper=10 (mass ratio)).

[0059] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 10~15min, the flow rate of copper-containing sludge is 10~15m 3 / h...

technical field

[0001] The invention relates to a treatment process for the low-concentration copper-containing wastewater produced in the semiconductor industry to meet the standard discharge and high-efficiency sedimentation, and belongs to the technical field of wastewater treatment. Background technique

[0002] Various wastewaters are produced in the semiconductor manufacturing process, including copper-containing wastewater with a large proportion of water. At present, high-concentration copper-containing waste liquid is generally treated by outsourcing treatment, and low-concentration copper-containing waste water is discharged into the waste water treatment system for treatment. The pollutants in copper-containing wastewater mainly include hydrogen peroxide, copper ions and complexed copper. The content of complexed copper is as high as 70%, and it is difficult to precipitate complexed copper by adding alkali.

[0003] In the prior art, copper-containing wastewater ...

Examples

Embodiment 1

[0041] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids (SS) is 50-100 mg / L, the concentration of copper ions is 7-10 mg / L, and the concentration of complexed copper is 4-5 mg / L. 2 o 2 The concentration is 1000~1100mg / L, and the pH is 3~4. The waste water flow rate is 20t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0042] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 16L / h (FeSO 4 : total copper=8 (mass ratio)).

[0043] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 10~15min, the flow rate of copper-containing sludge is 5~1...

Embodiment 2

[0049] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids is 50-150 mg / L, the concentration of copper ions is 10-15 mg / L, the concentration of complexed copper is 5-8 mg / L, H 2 o 2 The concentration is 400-500 mg / L, and the pH is 2-3. The waste water flow rate is 30t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0050] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 21L / h (FeSO 4 : total copper=9 (mass ratio)).

[0051] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 15-20min, the copper-containing sludge flow rate is 8-16m 3 / h; ...

Embodiment 3

[0057] The water quality of copper-containing wastewater in a semiconductor factory: the content of suspended solids is 20-50 mg / L, the concentration of copper ions is 3-5 mg / L, the concentration of complexed copper is 2-3 mg / L, H 2 o 2 The concentration is 300-500 mg / L, and the pH is 2-4. The waste water flow rate is 40t / h, and it operates 24 hours a day. The implementation steps of this case are as follows:

[0058] The first step: directly add 10% FeSO to the low-concentration copper-containing wastewater 4 solution; reaction time 25-30min, 10% FeSO 4 The solution dosage is 20L / h (FeSO 4 : total copper=10 (mass ratio)).

[0059] The second step: the return copper-containing sludge and the copper-containing wastewater react in the second reaction tank 2. By adding calcium hydroxide solution at the inlet of the pipeline mixer, the pH of the second reaction tank 2 is maintained at 10-12, and the reaction 10~15min, the flow rate of copper-containing sludge is 10~15m 3 / h...

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