CN-119330543-B - Cyanide-containing wastewater treatment method

CN119330543BCN 119330543 BCN119330543 BCN 119330543BCN-119330543-B

Abstract

The invention relates to a cyanide-containing wastewater treatment method which comprises the following specific steps of physical filtration, permeable membrane filtration, PH value adjustment, stripping treatment, secondary PH value adjustment, condensation precipitation and biological activated carbon treatment, wherein a waste liquid spray head and a plurality of packing layers are arranged in a stripping tower adopted in the step S4, a blower is connected to the outside of the lower part of the bottommost packing layer, a plurality of liquid outlet branch pipes are communicated in parallel in a liquid collecting area at the bottom of the stripping tower, an ultra-micro bubble air outlet pipe is coaxially sleeved in the liquid outlet branch pipes, the end parts of the liquid outlet branch pipes, which are positioned in the stripping tower, are arranged in an open shape, and a flow divider is coaxially and fixedly arranged, the end parts of the flow divider, which are positioned at the open end parts of the liquid outlet branch pipes, are arranged in a spherical shape, and the end parts, which are positioned at one side of the ultra-micro bubble air outlet pipe, are arranged in a conical shape. The invention can ensure the absorption capacity and efficiency of stripping only by carrying out stripping treatment through the primary stripping tower, so as to improve the treatment quality of cyanide-containing wastewater, ensure environmental protection and effectively avoid secondary pollution.

Inventors

CHEN QISHENG
CAO YAN
ZHANG HENGXING
CAO ZILIANG
Zuo Sicheng

Assignees

福建紫金贵金属材料有限公司

Dates

Publication Date: 20260512
Application Date: 20241129

Claims (10)

1. The cyanide-containing wastewater treatment method is characterized by comprising the following steps of: S1, physically filtering, namely filtering cyanide-containing wastewater through a grid, and then sending the cyanide-containing wastewater to a sand filtration treatment system to remove large-particle solid pollutants in the wastewater; S2, filtering by using a permeable membrane, namely introducing the wastewater into a reverse osmosis treatment system for reverse osmosis membrane treatment to obtain reverse osmosis concentrated solution; s3, regulating the PH value, namely adding sulfuric acid into the reverse osmosis concentrated solution to regulate the PH value to be between 2 and 3, and controlling the temperature of the reverse osmosis concentrated solution to be between 30 and 40 ℃; s4, carrying out stripping treatment, namely pumping the waste liquid with the temperature of 30-40 ℃ obtained in the step S3 into a stripping tower (1), introducing air to carry out acidification stripping treatment, and absorbing the stripped gas by using sodium hydroxide solution; S5, adjusting the pH value twice, namely, introducing the waste liquid after acidification and stripping into an adjusting tank (32), adjusting the pH value to 8-10 by using alkali liquor, and introducing ozone; S6, coagulating sedimentation, namely introducing oxidized waste liquid into a sedimentation tank (15), adding a coagulant in the stirring process to coagulate and sediment, and allowing the coagulated waste water to enter a sedimentation tank to stand for 15-120min; s7, biological activated carbon treatment, namely, putting the supernatant after precipitation into a biological activated carbon treatment system, and carrying out biological activated carbon treatment under the conditions of activated carbon filler, membrane-hanging strains and air; s8, the treated waste liquid enters a water return tank and is used for returning to the production process flow or reaching the discharge standard; Wherein a plurality of waste liquid spray heads (2) are distributed at the top of the stripping tower (1) adopted in the step S4, a plurality of filler layers (3) are arranged in the stripping tower (1) below the waste liquid spray head (2) at intervals up and down, and a corresponding blower (4) is connected to the outside of the lower part of the filler layer (3) at the bottommost side; the bottom of the stripping tower (1) is provided with a corresponding liquid collecting area (5), one side of the liquid collecting area (5) is respectively and outwardly communicated with a corresponding liquid outlet main pipe (6), the liquid inlet end of the liquid outlet main pipe (6) is connected in parallel and is provided with a plurality of liquid outlet branch pipes (7), the liquid outlet branch pipes (7) are arranged in the liquid collecting area (5) of the stripping tower (1) side by side at left and right intervals, one end of the liquid outlet branch pipe (7) which is not communicated with the stripping tower (1) is coaxially sleeved with a corresponding ultra-micro bubble outlet pipe (8), the ultra-micro bubble outlet pipe (8) extends outwards and is connected to an outer ultra-micro bubble generator (29); the end part of the liquid outlet branch pipe (7) positioned in the stripping tower (1) is arranged in an open way, the flow divider (9) is coaxially and fixedly arranged, the end part of the flow divider (9) positioned at the opening end part of the liquid outlet branch pipe (7) is arranged in a spherical shape, and the end part positioned at one side of the ultra-micro bubble air outlet pipe (8) is arranged in a conical shape; The stirring rod (21) is arranged in the sedimentation tank (15) in the step S6 through a stirring shaft (20) rotating positively and negatively, a stirring piece (23) which is arranged in a V shape and is adjustable in V-shaped opening angle is arranged at the end part of the stirring rod (21) through a sleeved tubular flexible piece (22), when waste liquid and coagulant are just thrown into the sedimentation tank (15) and the resistance is smaller, the stirring shaft (20) rotates positively to drive one side of the V-shaped opening of the stirring piece (23) to rotate in the stirring direction, a micro switch (25) is arranged on the stirring rod (21), when the V-shaped opening of the stirring piece (23) is opened to touch the micro switch (25), the stirring shaft (20) is controlled to rotate reversely through electric connection, the end part of the V-shaped pointed cone of the stirring piece (23) is driven to face the rotating direction, and when the V-shaped opening of the stirring piece (23) is closed until the extruded pressure of the tubular flexible piece (22) reaches a limiting pressure value F 1 , the positive and negative rotation motor (26) is stopped.
2. The cyanide-containing wastewater treatment method according to claim 1, wherein the alkali liquor in the step S5 is sodium hydroxide or lime milk, and the coagulant in the step S6 is a polymeric inorganic salt coagulant or a polymer inorganic salt solution with a mass fraction of 10% -30%.
3. The cyanide-containing wastewater treatment method according to claim 1, wherein the biological activated carbon treatment system in the step S6 is an up-flow or down-flow reaction tank, a water distribution device and an aeration device are arranged at the bottom of the tank, an activated carbon filler layer (3) is arranged above the aeration device, the carbon filling amount is 1/5-4/5 of the volume of the reactor, the membrane hanging strains are nitrosates and nitrifying bacteria or cyanide-reducing bacteria groups, the strain membrane hanging mode adopts a manual strain membrane hanging mode or a dynamic culture natural membrane hanging mode, the gas-liquid ratio is 1-15:1, and the biological activated carbon treatment time is 30min-120min.
4. The cyanide-containing wastewater treatment method according to claim 1, wherein a plurality of positioning rods (10) are circumferentially distributed at the spherical end of the flow divider (9) in the stripping tower (1) in the step S4, and two end parts of the positioning rods (10) are fixedly installed at the inner side wall of the liquid outlet branch pipe (7) and the spherical end of the flow divider (9).
5. A cyanide-containing wastewater treatment method according to claim 4, characterized in that the waste liquid spray head (2) is connected to the waste liquid outlet of step S3 through a corresponding liquid suction pump (11) and a liquid guide valve (12), a corresponding liquid outlet valve (13) and a corresponding liquid outlet pump (14) are mounted on the liquid outlet main pipe (6), and the liquid guide valve (12) and the liquid outlet valve (13) are automatic valves and are electrically connected to a control system with the liquid suction pump (11), the liquid outlet pump (14), the air blower (4) and the ultra-micro bubble generator (29).
6. The method for treating cyanide-containing wastewater according to claim 1, wherein the upper part of the sedimentation tank (15) in the step S6 is fixedly provided with a corresponding sealing cover (16), the sealing cover (16) is provided with a feed pipe (17) and a liquid inlet pipe (18), the middle side and the bottom of the sedimentation tank (15) are respectively provided with a corresponding supernatant liquid outlet pipe (30) and a discharge pipe (19), the stirring shaft (20) is rotatably arranged at the lower side of the sealing cover (16), a plurality of stirring rods (21) are fixedly arranged on the stirring shaft (20) at intervals from top to bottom in a staggered manner, the inner side surfaces of the stirring pieces (23) and the stirring rods (21) opposite to each other are respectively provided with a trigger piece (24) and a micro switch (25) which are matched, when the V-shaped opening of the stirring pieces (23) is opened, the trigger pieces (24) fixedly arranged on the stirring pieces (23) move towards one side of the stirring rods (21) along with the ends of the stirring pieces (23), the tubular switches (25) are used for detecting the conditions of the flexible pressure sensor (22) embedded in the tubular sensor (31), the detection end of the pressure sensor (31) is abutted to the joint of the stirring piece (23) and the tubular flexible piece (22).
7. A method of cyanide-containing wastewater treatment according to claim 6, characterized in that the feed pipe (18) is connected to the waste liquid outlet in step S5 by means of a corresponding intermediate pump and intermediate valve.
8. The cyanide-containing wastewater treatment method according to claim 6, wherein the stirring piece (23) comprises plate-type blades (2301) with two end parts hinged to each other, the plate-type blades (2301) are respectively and tangentially fixedly connected with the tubular flexible piece (22), the tubular flexible piece (22) is made of deformable rubber materials, and the tubular flexible piece (22) is stretched when the two plate-type blades (2301) on the stirring piece (23) are opened.
9. The cyanide-containing wastewater treatment method according to claim 6, wherein the stirring shaft (20) is driven to rotate in a forward and reverse direction by a forward and reverse rotation motor (26) installed above the cover (16), and the forward and reverse rotation motor (26) rotates in a reverse direction when the microswitch (25) is triggered.
10. The cyanide-containing wastewater treatment method according to claim 6, wherein the bottom side of the sealing cover (16) is fixedly connected with a corresponding mounting pipe (27) downwards at a position corresponding to the stirring shaft (20), the stirring shaft (20) is rotatably sleeved on the mounting pipe (27) through a corresponding bearing, the sedimentation tank (15) is supported and mounted by a corresponding support leg (28), a corresponding closing cover is arranged on the feeding pipe (17) in an openable and closable manner, and a corresponding liquid inlet valve, a corresponding liquid outlet valve and a corresponding discharge valve are fixedly arranged on the liquid inlet pipe (18), the supernatant liquid outlet pipe (30) and the discharge pipe (19) respectively.

Description

Cyanide-containing wastewater treatment method Technical Field The invention relates to the technical field of wastewater treatment, in particular to a cyanide-containing wastewater treatment method. Background During gold dressing, gold cyanide enterprises can generate a large amount of cyanide-containing wastewater due to the cyanide gold extraction process, and the cyanide-containing wastewater not only contains a certain amount of highly toxic cyanide, but also contains thiocyanate and heavy metal ions such as copper, zinc and lead, and if the cyanide-containing wastewater cannot be effectively treated, serious environmental protection hidden danger can be generated. At present, the common methods for treating cyanide-containing wastewater at home and abroad include an acidification recovery method, an alkali-chlorine method, a Inclusion method, a sulfur dioxide method and the like. The cyanide-containing wastewater is treated by multistage series acidification stripping equipment, the waste liquid is sprayed to the filler layers of the multilayer distribution acid solution and then is introduced with air, the cyanide-containing wastewater is required to pass through the multistage series stripping equipment, and the waste liquid can be fully contacted with the acid by virtue of long-time treatment, so that the whole equipment structure is huge. However, as the cyanide-containing substances in the waste liquid are less and less, the contact rate behind the waste liquid is lower, the absorption amount is also less and less, so that the occupied space of equipment is large, the equipment is wasted, and under the condition that the waste liquid amount is large, the efficiency is low by only relying on a mode of prolonging the treatment duration, and more importantly, the production pressure and the demand are difficult to deal with, however, the blowing-off equipment is simply reduced, the blowing-off treatment quality is reduced, the treatment is not thorough, and larger pollution still exists. Therefore, the design of the cyanide-containing wastewater treatment method can ensure the absorption and efficiency of stripping only by carrying out stripping treatment through the primary stripping tower so as to improve the treatment quality of the cyanide-containing wastewater, ensure environmental protection and effectively avoid secondary pollution. Disclosure of Invention Aiming at the technical problems in the prior art, the invention provides a cyanide-containing wastewater treatment method which can effectively solve the technical problems in the prior art. The technical scheme of the invention is as follows: a cyanide-containing wastewater treatment method comprises the following steps: S1, physically filtering, namely filtering cyanide-containing wastewater through a grid, and then sending the cyanide-containing wastewater to a sand filtration treatment system to remove large-particle solid pollutants in the wastewater; S2, filtering by using a permeable membrane, namely introducing the wastewater into a reverse osmosis treatment system for reverse osmosis membrane treatment to obtain reverse osmosis concentrated solution; s3, regulating the PH value, namely adding sulfuric acid into the reverse osmosis concentrated solution to regulate the PH value to be between 2 and 3, and controlling the temperature of the reverse osmosis concentrated solution to be between 30 and 40 ℃; S4, carrying out stripping treatment, namely pumping the waste liquid with the temperature of 30-40 ℃ obtained in the step S3 into a stripping tower, introducing air to carry out acidification stripping treatment, and absorbing the stripped gas by using sodium hydroxide solution; s5, adjusting the pH value twice, namely, introducing the waste liquid after acidification and stripping into an adjusting tank, adjusting the pH value to 8-10 by alkali liquor, and introducing ozone; S6, coagulating sedimentation, namely introducing the oxidized waste liquid into a sedimentation tank, adding a coagulant in the stirring process for coagulating sedimentation, and allowing the coagulated waste water to enter a sedimentation tank for standing for 15-120min; s7, biological activated carbon treatment, namely, putting the supernatant after precipitation into a biological activated carbon treatment system, and carrying out biological activated carbon treatment under the conditions of activated carbon filler, membrane-hanging strains and air; s8, the treated waste liquid enters a water return tank and is used for returning to the production process flow or reaching the discharge standard; the top of the stripping tower adopted in the step S4 is provided with a plurality of waste liquid spray heads in a distributed manner, a plurality of packing layers are arranged in the stripping tower at intervals up and down below the waste liquid spray heads, corresponding blowers are connected to the outside in the lower direction of the bottommost packing lay