CN115196793A - Single-factor high-hardness industrial wastewater deep softening method and equipment system - Google Patents

Abstract

The invention discloses a single-factor high-hardness industrial wastewater deep softening method, which comprises alternate homogenization treatment, primary calcium removal and chemical addition treatment, solid-liquid separation treatment and cation exchange resin fluidized bed softening treatment which are sequentially carried out; the equipment system comprises two water inlet devices, a reaction device, a clarification device and a cation exchange resin fluidized bed which are connected in sequence, wherein water is alternately fed into the reaction device, and the reaction device is used for removing calcium ions; the water softening method and the equipment system are particularly suitable for deep softening treatment of high-hardness salt-containing industrial wastewater, adopt the combined special design of double-alternative water inlet, single-stage chemical softening and dosing and resin cation bed, aim at single treatment of calcium ions, reduce the dosing types and dosing amounts, effectively reduce the softening treatment cost, fully cope with water quality fluctuation, greatly reduce the sludge production amount, and can meet the scaling-resistant stable operation of subsequent high-concentration-ratio membrane equipment such as reverse osmosis, electrodialysis, nanofiltration and the like.

Description

Single-factor high-hardness industrial wastewater deep softening method and equipment system

Technical Field

The invention belongs to the field of environmental protection treatment, in particular to the field of hardness removal of industrial wastewater. In particular to a method and a device system for deeply softening single-factor high-hardness industrial wastewater.

Background

In order to meet environmental protection regulations, agree with sustainable development concepts and bear more social responsibility, in industrial production, resource recycling and near-zero emission treatment of discharged industrial wastewater are encouraged. This can also assist the implementation of the national double carbon strategy from the side. Many production effluent contains a large amount of hardness ions, such as recirculated cooling water drainage, desulfurization wastewater, acid-base regeneration wastewater, high-salt mine water and the like, and the water quality fluctuation is large. The higher water hardness causes scaling risk of related water treatment technical equipment, increases operation and maintenance cost, and seriously influences the further treatment of methods for extracting fresh water from industrial wastewater, such as reverse osmosis and the like. Therefore, the wastewater to be recovered needs to be softened.

Through investigation, the hardness wastewater softening technology applied in the existing environmental protection method mainly comprises a chemical dosing method, a nanofiltration salt separation technology, an ion resin adsorption technology and the like. The equipment investment cost of the nanofiltration salt separation technology is high, and the divalent ion salt separation effect of the existing nanofiltration membrane still needs to be further improved. The ionic resin method is not suitable for treating wastewater with high hardness and high salinity. The chemical dosing method has many embodiments, such as a scheme of adding calcium hydroxide and sodium carbonate by a two-stage dosing method, a scheme of adding sodium hydroxide and sodium carbonate by a two-stage dosing method, and a scheme of adding sodium sulfate, calcium hydroxide and sodium carbonate by a three-stage dosing method. When a chemical dosing method is used for treating high-hardness industrial wastewater, a series of problems exist, namely firstly, a secondary dosing device or a tertiary dosing device needs to be linked, the running complexity is increased, and the dosing and dispensing system is more in configuration; secondly, when the hardness content of the wastewater is higher, the dosage of the medicament is correspondingly increased greatly, the operation cost is also increased sharply, and the amount of the reaction precipitate and the discharged sludge is also increased; thirdly, the quality of the inlet water fluctuates, the control difficulty of the dosing amount is increased, and the problems of inaccurate dosing amount, reduced medicament utilization rate and frequent substandard hardness content of the outlet water exist in multi-stage reaction. In consideration of further recovery treatment of wastewater, in order to meet the stable operation of a subsequent concentration method, the economic cost and the operation management pressure of softening treatment are very high when severe water quality of high-hardness industrial wastewater is treated.

The patent of application number 202110467369.3 discloses a processing system and method for single-factor deep softening and sludge recycling of power plant desulfurization wastewater, the system only needs to be provided with a single-stage dosing device and a single-stage reaction tank, and deep softening of power plant desulfurization wastewater can be realized only by removing sulfate ions in wastewater, so that the reagent feeding is reduced, the method flow is simplified, the processing cost is reduced, the sludge yield can be greatly reduced, and the produced sludge can be recycled. However, the method and the system aim at the power plant desulfurization wastewater or wastewater with low calcium content, because when the content of sulfate ions is reduced from 50mg/L to 20mg/L, the content of the calcium ions can be increased from 5000mg/L to 12500mg/L on the premise of ensuring that no crystal salt is precipitated in the wastewater, and the content of the calcium ions in the power plant desulfurization wastewater is generally in the range of 1000-6000 mg/L, so that the sulfate ions are removed after being precipitated independently, and the standard reaching of softened water quality can be completely ensured. However, when the water quality is no longer the desulfurization waste water of the power plant, or the concentration of calcium-containing ions in the waste water is high, the single-index softening treatment of the waste water for sulfate ions is no longer suitable.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a single-factor high-hardness industrial wastewater deep softening method and a device system, and aims to solve the problems of large and complicated dosage, difficulty in control, substandard effluent hardness or high subsequent treatment pressure in high-hardness industrial wastewater treatment from the technical and economic aspects.

The invention aims to provide a single-factor high-hardness industrial wastewater deep softening method which comprises the following steps:

a single-factor high-hardness industrial wastewater deep softening method comprises alternate homogenization treatment, primary calcium removal and chemical addition treatment, solid-liquid separation treatment and cation exchange resin fluidized bed softening treatment which are sequentially carried out.

Further, the method is used for treating industrial wastewater with the molar content of calcium ions lower than that of other hardness ions.

By adopting the technical scheme, after the high-hardness industrial wastewater discharged from the industrial park is buffered and homogenized, the chemical dosing softening only has one-level single link, and only the calcium ions are removed in a targeted manner without controlling the magnesium ions and the sulfuric acidThe contents of root ions and the like are finally subjected to solid-liquid separation and clarification treatment by the conventional method, and then enter a cation bed for deep softening treatment, so that the softening and removing effects of calcium ions are fully guaranteed. The treatment method is used for carrying out deep softening treatment on the hardness wastewater, and is used for inhibiting hardness ions in the wastewater from reaching the solubility product upper limit of an insoluble compound in the later-stage further membrane concentration or thermal concentration treatment process so as to avoid the phenomenon that crystals are separated out to block membrane gaps or equipment flow channels. It is known that the insoluble compounds in the waste water, which are more influential, are mainly calcium sulfate and magnesium hydroxide precipitates, and the latter can be controlled by adjusting the water quality to be weakly acidic. However, the control of the calcium sulfate precipitate is relatively difficult. The solubility product constant Ksp of calcium sulfate in water is 3.16 multiplied by 10 ^-7 The solubility of the indissolvable compound is improved due to the influence of salt effect and homoionic effect in the wastewater, and is particularly influenced by conditions such as water content, temperature and the like. Through excessive sampling tests, the content of sulfate radicals in the wastewater can be expanded by 1 order of magnitude on the premise of ensuring that no crystal salt is precipitated in the wastewater when the content of calcium ions in the wastewater is reduced from 50mg/L to 5mg/L, for example, the content fluctuates from 5000mg/L to 50000mg/L, and at the moment, the calcium ion index is effectively controlled, the standard of softened water quality can still be ensured, and the subsequent membrane concentrated solution is ensured to be prevented from being crystallized. Correspondingly, the chemical agent only removes 45mg/L of calcium, the dosage of calcium ions is very small, and simultaneously the dosage of softening required by a large amount of calcium sulfate can be completely avoided. Therefore, by adopting the method, only the medicine for removing the calcium ions is singly added, and only a very small amount of medicine is added, so that the medicine adding amount is small, simple and easy to control, and the calcium sulfate precipitation is greatly reduced due to the lack of the calcium ions during water outlet, thereby greatly relieving the treatment pressure of subsequent equipment. The method can be applied to deep softening of industrial wastewater and industrial water, and can also be applied to pretreatment softening of industrial wastewater needing concentration treatment, such as steel wastewater, circulating cooling water sewage, desulfurization wastewater and the like.

Further, water quality detection is also carried out in the alternate homogenization treatment process.

Further, the alternate homogenization treatment is that two homogenization devices alternately operate, one homogenization device is used for water inlet, the other homogenization device is used for water outlet at the same time, and water quality sampling detection is carried out before water outlet of any one homogenization device. Because the quality and the quantity of the wastewater fluctuate in real time, two homogenizing devices are arranged to operate alternately, wherein one homogenizing device starts to discharge water after water is fed and homogenized, and meanwhile, the wastewater enters the other homogenizing device to be homogenized, and the two homogenizing devices alternately feed and discharge water, namely one water inlet and one water outlet. Therefore, the detection of the homogenized water sample is convenient, because the online hardness monitoring of the instrument is inaccurate at present, the sample can be tested in a laboratory, certain delay exists, and the two homogenizing devices can provide sufficient laboratory test time by alternately operating. Therefore, the two homogenizing devices not only ensure the sufficient buffering of water quality and water quantity, but also ensure the continuous water inlet and treatment, and can control the chemical dosing according to the accurate water quality detection index in a laboratory, and the dosing amount is stable and accurate.

Further, the medicament used in the first-stage calcium removal and dosing treatment is one or two of aluminum chloride, aluminum sulfate, sodium fluoride, sodium carbonate, sodium fluoride and aluminum phosphate. The dosage of the medicine is specifically adjusted according to the homogenized effluent quality and is within 110-125% of the molar ratio of the excessive medicine. In order to optimize reaction conditions and be beneficial to precipitation, crystallization and precipitation of calcium ions and the like, a small amount of lime milk can be selectively and primarily added, and the pH value of the wastewater is controlled to be more than 8.0.

Further, the solid-liquid separation treatment is carried out by using one or more of a clarification tank, a multi-media filter, a hollow fiber microfiltration membrane, a tubular microfiltration membrane and a tubular ultrafiltration membrane.

Further, a bottom sludge suspension is obtained after the solid-liquid separation treatment, and sludge and weakly alkaline wastewater are generated after the bottom sludge suspension is subjected to dehydration treatment and clarification filtration.

By adopting the technical scheme, specifically, the bottom sludge suspension can be subjected to dehydration treatment by a dehydrator such as a plate-and-frame filter press, then further clarified and filtered, the produced sludge is taken as solid waste and sent to a factory for treatment outside the factory, and the wastewater subjected to clarification to remove SS indexes (suspended solids) is alkalescent.

Further, acid-base neutralization treatment is carried out after the solid-liquid separation treatment.

Further, the acid-base neutralization treatment is carried out by adding acid liquor.

Further, the acid solution is one of hydrochloric acid, dilute sulfuric acid and nitric acid.

Further, the softening treatment of the cation exchange resin fluidized bed is also followed by periodic cation exchange resin transformation treatment.

Further, the regeneration solution of the cation exchange resin conversion treatment is a magnesium-containing solution.

Still further, the magnesium-containing solution is a magnesium chloride solution.

By adopting the technical scheme, the magnesium-containing solution converts hydrogen ions on the sulfonic functional group of the strong acid ion resin into magnesium sulfonate ions, so that the cation bed has the effect of preferentially and selectively adsorbing calcium ions. This is because the ion exchange resin already contains magnesium ions, which results in a faster calcium ion adsorption rate than magnesium and sodium ions, and thus achieves a calcium ion preferential adsorption effect, unlike a conventional cation bed, which can adsorb all cations. The regenerated water of the transformation ion resin is mainly calcium chloride and magnesium chloride brine.

Another object of the present application is to provide a single-factor high-hardness industrial wastewater deep softening equipment system, which comprises the following components:

the utility model provides a single factor high rigidity industrial waste water degree of depth softening installation system, is including the water installations, reaction unit, clarification device and the cation exchange resin fluidized bed that connect gradually, the quantity of water installations is two, is first water installations and second water installations respectively, through first water installations and second water installations intake in turn extremely reaction unit, reaction unit is used for single calcium ion of getting rid of.

By adopting the technical scheme, the water inlet device at the most front end of the equipment system is set as a homogenizing device or a raw water tank, and is designed into two sets, so that water inlet and water outlet alternately run in the two water inlet devices, the sufficient buffering of water quality and water quantity is ensured, the continuous water inlet and treatment of the process are also ensured, the water quality detection is carried out at the position, the chemical dosing of the reaction device at the back is convenient to control according to the water quality index, and the dosing quantity is stable and accurate. The equipment system is used for softening the hardness wastewater, and is used for inhibiting hardness ions in the wastewater from reaching the upper limit of the solubility product of an insoluble compound in the later-stage further membrane concentration or thermal concentration treatment process so as to avoid crystal precipitation, so that membrane gaps or equipment flow channels are blocked by dirt.

Further, the reaction device is connected with a dispensing device. The medicine dispensing device is internally provided with a medicine which can enable calcium ions to generate precipitates. The medicament is one or two combined medicaments of aluminum chloride, aluminum sulfate, sodium fluoride, sodium carbonate, sodium fluoride and aluminum phosphate. In order to optimize reaction conditions and be beneficial to precipitation, crystallization and precipitation of calcium ions and the like, a small amount of lime milk can be selectively and primarily added, and the pH value of the wastewater is controlled to be more than 8.0.

Further, the hydraulic retention time of the reaction device is more than 1 hour.

Further, the equipment system also comprises a dehydrator.

Further, the dewatering machine is arranged in front of the clarifying device. And (4) the dehydrated filtrate enters a clarifying device, and the dehydrated bottom sludge is collected and accumulated and is intermittently transported and treated.

Further, the clarification device can selectively use a vertical flow type clarification tank, a high-density clarification tank, a mechanical accelerated clarification tank, an integrated clarification tank and the like according to specific working conditions.

Further, a filter is arranged behind the clarifying device. For re-filtering suspended solids from the supernatant of the clarification device.

Further, the filter is one or more of a multi-media filter, a hollow fiber microfiltration membrane, a tubular ultrafiltration membrane, a security filter and a disc filter.

Further, a first return pipe is connected between the filter and the clarification device. For returning the filter residue filtered by the filter to the clarifying device.

Furthermore, the clarifying device is connected with the dewatering machine through a second return pipe. The settling bottom sludge of the clarifying device is conveniently dewatered to obtain sludge, and the sludge is taken as solid waste to be pulled out of a factory and is treated by outsourcing.

Furthermore, the dehydrator is one of a plate-and-frame filter press, a centrifugal dehydrator, a vacuum belt dehydrator or a stacked screw dehydrator, and is specifically selected according to working conditions such as solid content of wastewater.

Further, a pH adjusting device is arranged in front of the cation exchange resin fluidized bed.

The invention has the following beneficial effects:

1. compared with the existing common softening process, the process method and the equipment system of the invention have the advantages that the process flow is optimized and simplified, and the effluent quality can meet the scaling-resistant stable operation of high-concentration-ratio membrane equipment such as subsequent reverse osmosis, electrodialysis, nanofiltration and the like.

2. Compared with the existing chemical dosing process, the chemical dosing amount of the process method and the equipment system provided by the invention is greatly reduced, the softening operation cost can be effectively reduced, the sludge amount is greatly reduced, and the introduction of water for a dosing solution is reduced.

3. The process method and the equipment system only use the cation bed (cation exchange resin fluidized bed) for deep softening treatment, aim at selectively removing calcium ions with a single index, and do not need the matching use of the cation bed, the anion bed, the cation-anion mixed bed, the carbon remover and the like, thereby avoiding the complicated flow of the conventional water treatment process and reducing the corresponding investment and the operation and maintenance cost.

4. The process method and the equipment system are particularly suitable for softening treatment of industrial wastewater with high hardness content, and the cost advantage can be further expanded when the industrial wastewater with low calcium content and high sulfate radical bicarbonate radical content is treated.

Drawings

FIG. 1 is a schematic view of a single-factor high-hardness industrial wastewater deep softening device system according to the invention.

In the figure: 1. a first water inlet device; 2. a second water inlet device; 3. a reaction device 4, a dehydrator; 5. a clarification device; 6. a filter; 7. a pH adjusting device; 8. a fluidized bed of cation exchange resin; 9. a dispensing device.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples.

A single-factor high-hardness industrial wastewater deep softening method comprises alternate homogenization treatment, primary calcium removal and chemical addition treatment, solid-liquid separation treatment and cation exchange resin fluidized bed softening treatment which are sequentially carried out. The method is used for treating the industrial wastewater with the calcium ion molar content lower than other hardness ions, the process target is mainly hardness treatment, and the method can be used as a process unit to be combined and coupled with other water quality index control equipment for use.

In some embodiments, water quality testing is also performed during the alternate homogenization treatment.

In some embodiments, the alternate homogenization treatment is that two homogenization devices operate alternately, one homogenization device is used for water inlet and the other homogenization device is used for water outlet at the same time, and water quality sampling detection is carried out before water is discharged from any one homogenization device.

In some embodiments, the agent used in the first-stage calcium-removal dosing treatment is one or a combination of two of aluminum chloride, aluminum sulfate, sodium fluoride, sodium carbonate, sodium fluoride and aluminum phosphate. The dosage of the medicine is specifically adjusted according to the homogenized effluent quality and is within 110-125% of the molar ratio of the excessive medicine. In order to optimize reaction conditions and be beneficial to precipitation, crystallization and precipitation of calcium ions and the like, a small amount of lime milk can be selectively and primarily added, and the pH value of the wastewater is controlled to be more than 8.0.

In some embodiments, the solid-liquid separation treatment is treatment using one or more of a clarifier, a multimedia filter, a hollow fiber microfiltration membrane, a tubular ultrafiltration membrane, a security filter, and a disc filter.

In some embodiments, the solid-liquid separation treatment is performed to obtain a bottom sludge suspension, and the bottom sludge suspension is subjected to dehydration treatment, clarification and filtration to generate sludge and weakly alkaline wastewater.

In some embodiments, the solid-liquid separation treatment is followed by an acid-base neutralization treatment.

In some embodiments, the acid-base neutralization treatment is a neutralization treatment by adding an acid solution.

In some embodiments, the acid solution is one of hydrochloric acid, dilute sulfuric acid, and nitric acid.

In some embodiments, the cation exchange resin fluid bed softening process is further followed by a periodic cation exchange resin conversion process.

In some embodiments, the regeneration solution of the cation exchange resin conversion treatment is a magnesium-containing solution.

In some embodiments, the magnesium-containing solution is a magnesium chloride solution.

The utility model provides a single factor high rigidity industrial waste water degree of depth softening installation system, as shown in figure 1, including water installations, reaction unit 3, clarification plant 5 and the cation exchange resin fluidized bed 8 that connect gradually, the quantity of water installations is two, is first water installations 1 and second water installations 2 respectively, through first water installations 1 and second water installations 2 intake in turn extremely in the reaction unit 3, reaction unit 3 is used for single calcium ion of getting rid of.

Specifically, the first water inlet device 1 and the second water inlet device 2 are both raw water tanks or are both homogenization tanks, the reaction device 3 is a conventional reaction tank, the reaction device 3 is connected with a dispensing device 9, and the dispensing device 9 can be a dispensing box or other conventional dosing systems. The dispensing device 9 is filled with a medicament which can enable calcium ions to generate precipitates. The medicament is one or two of aluminum chloride, aluminum sulfate, sodium fluoride, sodium carbonate and sodium fluoride. In order to optimize reaction conditions and be beneficial to precipitation, crystallization and precipitation of calcium ions and the like, a small amount of lime milk can be selectively and primarily added, and the pH value of the wastewater is controlled to be more than 8.0.

In some embodiments, the hydraulic retention time of reaction apparatus 3 is greater than 1 hour.

In some embodiments, the clarification device 5 is a clarifier, and a vertical flow clarifier, a high density clarifier, a mechanical accelerated clarifier, an integrated clarifier, etc. can be selectively used according to specific working conditions.

In some embodiments, the plant system further comprises a dewatering machine 4, the dewatering machine 4 being arranged before the clarification device 5.

In some embodiments, the dewatering machine 4 is one of a plate-and-frame filter press, a centrifugal dewatering machine, a vacuum belt type dewatering machine, and a stacked screw type dewatering machine, and is specifically designed and selected according to the working conditions such as the solid content of the wastewater.

In some embodiments, the clarifying device 5 is followed by a filter 6. For re-filtering the suspended solids of the supernatant of the clarification device 4. The filter 6 is one or more of a multi-medium filter, a hollow fiber microfiltration membrane, a tubular ultrafiltration membrane, a security filter and a disc type filter.

In some embodiments, a first return line is connected between the filter 6 and the clarification device 5.

In some embodiments, the clarifying device 5 is also connected to the dewatering machine 4 via a second return line.

In some embodiments, a pH adjusting device 7 is arranged in front of the cation exchange resin fluidized bed 8, and the pH adjusting device 7 is a pH adjusting box or a pipeline static mixer.

The following is an example of a specific different type of wastewater treatment, wherein only calcium ions and SS are controlled in the effluent quality. The process only removes hardness, but can be used as a process unit to be combined and coupled with other water quality index control equipment.

Example 1 treatment of thermal power desulfurization wastewater

In the embodiment, the method and the equipment system of the invention are adopted to treat the thermal power desulfurization wastewater, and the water quality of the thermal power desulfurization wastewater is shown in the following table 1:

TABLE 1 thermal power desulfurization wastewater quality characteristic table

Table 1 is a thermal power desulfurization wastewater quality characteristic table, wherein the parenthesis of the content of some components is a range value of the content in a certain time period, and a specific value is a detection value at a certain time point, and the specific conditions of the thermal power desulfurization wastewater treatment are as follows:

thermal power desulfurization waste water is earlier in turn through two former water tanks save, buffering, all contain electric stirring device in two former water tanks. And then the buffered wastewater continuously enters a primary reaction tank, lime milk is added through a medicine preparation tank and a medicine adding system, the pH is controlled to be more than or equal to 8, aluminum phosphate is added, and the pH is controlled to be more than or equal to 9.5. The specific dosage of the medicine is adjusted according to the water quality of the outlet water of the raw water tank and is within the molar ratio of 110-125% of the excessive medicine. And (4) feeding the wastewater after the dosing reaction into a plate-and-frame filter press for solid-liquid separation. After the water removed by the plate-and-frame filter press is treated by a clarification tank and a multi-medium filter, the clarified water enters a next-stage pipeline static mixer for pH neutralization treatment, and the pH of the effluent is controlled to be 6.0-7.5. And dehydrating the precipitated bottom mud by using a plate-and-frame filter press. And (4) the neutralized effluent enters a transformation cation bed for treatment after passing through a security filter, and finally softened produced water is obtained. The calcium ion content in the softened water can be controlled below 5mg/L, and the SS index can be controlled below 20 mg/L.

Example 2 treatment of highly mineralized mine water

In the embodiment, the method and the equipment system are adopted to treat the high-salinity mine water, and the water quality of the high-salinity mine water is shown in the following table 2:

TABLE 2 characteristic table of water quality of highly mineralized mine water

Serial number	Item	Unit of	Index (I)	Serial number	Item	Unit of	Index (I)
								1	pH		6～9	14	Total zinc (Zn)	mg/L	2
2	Color intensity		40	15	Chlorine radical	mg/L	5000～18000
								3	Chemical Oxygen Demand (COD)	mg/L	～150	16	Sulfate radical	mg/L	4000-12000
4	Suspended Substance (SS)	mg/L	70	17	TDS	％										2％～5％
								5	Sulfide compound	mg/L	0.58	18	Calcium (Ca) 2+ )	mg/L	2000-10000
6	Fluoride compounds	mg/L	30	19	Magnesium (Mg) 2+ )	mg/L	600-10000
								7	Ammonia nitrogen	mg/L	50	20	Na + +K +	mg/L	Greater than 2000
8	Total mercury (Hg)	mg/L	0.05	21	HCO 3 -	mg/L	200
								9	Total cadmium (Cd)	mg/L	0.1	22	SO 3 2-	mg/L	50-100
10	Total chromium (Cr)	mg/L	1.5	23	Si	mg/L	70-100
								11	Total arsenic (As)	mg/L	0.5	24	NO 3 -	mg/L	100-500
12	Total lead (Pb)	mg/L	1	25	B (boron)	mg/L	10-400
								13	Total nickel (Ni)	mg/L	1

The water quality of the mine water with high mineralization degree is characterized as follows: firstly, the salinity is high, the TDS is about 1000-10000mg/L, the content of calcium ions is 2000-10000mg/L, and secondly, the salinity is relatively turbid under most conditions, the chromaticity is high, pollutants are mainly suspended matters (SS), the water quality changes greatly, the concentration of the suspended matters changes greatly, the content of the suspended matters is far higher than that of surface water, and the sense is poor; thirdly, the suspended matter particles have small diameter, smaller specific gravity and slower sedimentation speed, the diameter of the suspended matter particles in the mine water is generally only 2-8 μm, and the particle diameter of more than 85 percent of the suspended matter particles is below 50 μm.

The treatment of the mine water with high mineralization degree is as follows:

after the high-salinity mine water alternately passes through the water quantity buffering and water quality homogenizing effects of the two homogenizing tanks, the mine water enters the reaction tank, and a quantitative medicament is added by the dosing tank and the dosing system according to the calcium ion content index of water quality to generate calcium carbonate, ettringite precipitate and a small amount of calcium sulfate precipitate. And (4) feeding the wastewater after the dosing reaction into a centrifugal dehydrator for solid-liquid separation. And (3) treating the water separated by the centrifugal dehydrator through a clarification tank and a tubular membrane, dehydrating the sediment by the centrifugal dehydrator, allowing the clarified water to enter a next-stage pH adjusting box, allowing the clarified water to stay for more than 20min by waterpower, adding a hydrochloric acid medicament, stirring, and performing acid-base neutralization on the wastewater. Controlling the pH value of the effluent between 6.5 and 7.0. The neutralized effluent enters a rotary cation bed for treatment through a conventional disc filter. The calcium ion content of the softened water can be controlled below 5mg/L, and the SS index is controlled at 10mg/L.

EXAMPLE 3 treatment of circulating Water Drain from Cooling Tower

The method and the equipment system are adopted to treat the circulating water drainage of the cooling tower. Generally, the TDS of the discharged circulating cooling water of the thermal power generating unit is about 1000mg/L-5000mg/L, the content of calcium ions is within 200mg/L-800mg/L, and the single water quality analysis table is shown in Table 3. The treatment of the circulating cooling water discharged water is as follows: and after the discharged circulating cooling water is homogenized and weighed alternately by the two homogenizing tanks, the discharged circulating cooling water enters the softening reaction tank, and a dosing tank and a dosing system are used for dosing quantitative medicaments according to the calcium ion content index of the water quality of the inlet water in the homogenizing tanks, wherein the dosage of the medicaments is in the molar ratio range of 110-125%. And treating the effluent by a mechanical accelerated clarification tank, and further treating the supernatant of the clarification tank by a tube type microfiltration membrane for SS treatment. And (3) carrying out solid-liquid separation on the sediment of the clarification tank through a screw-stacking type dehydrator, carrying out regular export transportation treatment on the produced sludge, and returning the produced filtrate into the clarification tank again. The produced water of the tubular microfiltration membrane is subjected to dosing and pH adjustment through a pH adjusting tank, the pH of the effluent is controlled to be 6.5-7.0, and the effluent is conveyed to a transformation cation bed for treatment. The content of calcium ions in softened water can be controlled below 0.1mmol/L, and the SS index is controlled at 5mg/L.

Table 3 water quality detecting meter for circulating cooling water discharged from certain thermal power generating unit

In conclusion, the water quality softening process method and the equipment system are particularly suitable for deep softening treatment of high-hardness salt-containing industrial wastewater. The process equipment system is designed in a combined special mode of double-alternative water inlet, single-stage chemical softening and dosing and transformation resin cation beds, the dosing type and the dosing amount are reduced aiming at single treatment of calcium ions, the softening treatment cost can be effectively reduced, water quality fluctuation is fully coped with, the sludge production amount is greatly reduced, and the scaling-resistant stable operation of high-concentration-ratio membrane equipment such as subsequent reverse osmosis, electrodialysis, nanofiltration and the like can be met.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the embodiments of the present invention and not for limiting the same, and although the embodiments of the present invention are described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot make the modified technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims (9)

1. The single-factor high-hardness industrial wastewater deep softening method is characterized by comprising alternate homogenization treatment, primary calcium removal and chemical addition treatment, solid-liquid separation treatment and cation exchange resin fluidized bed softening treatment which are sequentially carried out.

2. The method as claimed in claim 1, wherein the method is used for treating industrial wastewater with lower molar content of calcium ions than the rest hardness ions.

3. The method for deeply softening the single-factor high-hardness industrial wastewater according to claim 1, wherein the alternate homogenization treatment is that two homogenization devices are alternately operated, one homogenization device is used for water inlet and the other homogenization device is used for water outlet at the same time, and water quality sampling detection is carried out before water outlet of any one homogenization device.

4. The method as claimed in claim 1, wherein the agent used in the primary calcium removal and chemical addition treatment is one or two of aluminum chloride, aluminum sulfate, sodium carbonate, sodium fluoride and aluminum phosphate.

5. The single-factor high-hardness industrial wastewater deep softening method according to claim 1, characterized in that the solid-liquid separation treatment is followed by an acid-base neutralization treatment.

6. The method for deeply softening the industrial wastewater with the high hardness and the single factor according to claim 1, wherein the softening treatment of the cation exchange resin fluidized bed is further followed by a periodic transformation treatment of the cation exchange resin.

7. The method as claimed in claim 1, wherein the cation exchange resin fluidized bed softening treatment is followed by periodic cation exchange resin transformation treatment with magnesium-containing solution.

8. The method for deeply softening the single-factor high-hardness industrial wastewater according to claim 7, wherein the magnesium-containing solution is a magnesium chloride solution.

9. A single-factor high-hardness industrial wastewater deep softening equipment system applying the method of any one of claims 1 to 8, which is characterized by comprising a water inlet device, a reaction device, a clarifying device and a cation exchange resin fluidized bed which are connected in sequence, wherein the number of the water inlet devices is two, namely a first water inlet device and a second water inlet device, water is alternately fed into the reaction device through the first water inlet device and the second water inlet device, and the reaction device is used for singly removing calcium ions.

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