Advanced treatment method of daily chemical wastewater

Abstract

The invention relates to the technical field of water treatment, and discloses an advanced treatment method of daily chemical wastewater. The advanced treatment method of the daily chemical wastewater comprises the following steps: S1, carrying out primary filtration on the daily chemical wastewater treated by a sewage station through a self-cleaning filter to obtain pretreated wastewater; s2, the pretreated wastewater enters a biological aerated filter for biochemical treatment, and biochemical treatment wastewater is obtained; s3, performing chemical disinfection on the biochemical treatment wastewater, and performing intermediate filtration through an interception type filter and an adsorption type filter in sequence; s4, enabling the wastewater subjected to intermediate filtration to enter a reverse osmosis system, performing physical disinfection, enabling the wastewater to enter a security filter for deep filtration, and performing membrane separation deep treatment to obtain a treated water body. The advanced treatment method provided by the invention can efficiently remove pollutants such as organic matters, chlorides, total dissolved solids and the like in water, kill microorganisms such as bacteria and the like, reduce the hardness, turbidity and conductivity of a water body and optimize the treatment effect of daily chemical wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a method for deep treatment of daily chemical wastewater. Background Art

[0002] As the sales volume of daily chemical products grows rapidly, a large amount of production wastewater is generated. The production wastewater of the daily chemical industry contains surfactants, fatty acids, additives, inorganic salts, flavors and other substances. It has the characteristics of complex composition, high organic content, poor biodegradability, large water quality fluctuations, and difficulty in treatment.

[0003] There are many methods for treating daily chemical wastewater, such as coagulation, electrochemical method, electron beam method, traditional anaerobic aerobic biochemical method, rotary contact oxidation method, ozone oxidation method, activated carbon treatment method, membrane treatment method, etc. The sewage treatment process often uses one or several of the above methods to treat sewage to improve the sewage treatment rate so that the treated daily chemical wastewater can be recycled and reused. However, the wastewater that meets the discharge standards after treatment at the daily chemical wastewater treatment station can only be reused as air conditioning cooling circulating water, greening water, and toilet flushing water, that is, it can only be used for non-production purposes and cannot meet the production and cleaning water index requirements of the production workshop. Therefore, it is also necessary to deeply treat the effluent from the daily chemical wastewater treatment station to meet the reuse standards of the production workshop. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art.

[0005] To this end, one of the objects of the present invention is to provide a method for deep treatment of daily chemical wastewater. After the effluent from the daily chemical wastewater sewage station is deeply treated by this treatment method, the water quality indicators such as wastewater COD, total colony count, total hardness (measured in CaCO3), conductivity, turbidity, etc. are greatly reduced. The core water quality indicators of the effluent can simultaneously meet the requirements of "Suzhou Drinking Water Quality Index Limits (2021)", "GB / T 19923-2005 Urban Wastewater Recycling Industrial Water Quality" and "GB3838-2002 Surface Water Environmental Quality Standards", and the wastewater conductivity is less than 100μs / cm, which meets the reuse water standards for production workshops.

[0006] The second purpose of the present invention is to provide an application of the treated water obtained by the deep treatment method of daily chemical wastewater.

[0007] A third object of the present invention is to provide a system for treating daily chemical wastewater.

[0008] The basic principle of the present invention is described as follows:

[0009] Daily chemical wastewater is preliminarily treated in the sewage station, and after a series of treatment procedures such as flotation tank, hydrolysis acidification tank, oxidation tank, and sedimentation, the main pollutants such as COD, anionic surfactants, ammonia nitrogen, and petroleum in the wastewater are efficiently removed, and the water quality meets the relevant national emission standards. However, at this time, the content of pollutants such as organic matter, chloride, and total dissolved solids in the water is still high, and it contains a large number of bacteria and other microorganisms, and the total colony count and total coliform group exceed the standard; in addition, the wastewater has high hardness, high turbidity, and high conductivity, which cannot meet the requirements of recycled water in the production workshop. Therefore, the method provided by the present invention will mainly remove organic matter, chloride, total dissolved solids, and bacteria and other microorganisms in the precipitated water of the daily chemical wastewater sewage station, reduce the hardness, turbidity and conductivity of the water body, and make the treated water meet the standards for recycled water for production purposes. Specifically:

[0010] (1) The daily chemical wastewater treated by the sewage station is pre-treated through a self-cleaning filter to remove large particle impurities such as suspended matter;

[0011] (2) The pretreated wastewater enters the aerated biological filter, which is filled with filter media. The filter media has a rough surface, which is easy to adhere to and grow high-concentration biofilms. The biofilms are not limited by the sludge age and are rich in species. Under the biochemical reaction and adsorption filtration of the aerated biological filter, the concentration of suspended solids in the wastewater is reduced, the organic matter in the water is oxidized and degraded, and the ammonia nitrogen is removed by aerobic nitrification;

[0012] (3) Adding agents to the biochemical wastewater for chemical disinfection can kill various types of microorganisms such as bacteria, spores, viruses, fungi, etc., and prevent the growth of microorganisms in subsequent filtration; the interception filter can further filter and remove impurities such as suspended matter and particulate matter in the wastewater; the adsorption filter can remove the residual chlorine generated by the aforementioned disinfection device and organic matter in the wastewater through adsorption;

[0013] (4) The water discharged from the adsorption filter enters the reverse osmosis system. Physical disinfection can kill bacteria, viruses and other microorganisms, while avoiding the formation of microbial film and protecting the reverse osmosis membrane at the back end. The security filter has high filtration accuracy and can deeply remove particulate matter and suspended matter in the wastewater, protecting the reverse osmosis membrane at the back end. Membrane separation can deeply remove floating solids, organic matter, bacteria, viruses, etc., thereby reducing water quality indicators such as chemical oxygen demand and conductivity in the water, and improving the water quality of the effluent.

[0014] In order to achieve the above object, the technical solution adopted by the present invention is:

[0015] The first aspect of the present invention provides a method for deep treatment of daily chemical wastewater, comprising the following steps:

[0016] S1. The daily chemical wastewater treated by the sewage station is filtered through a self-cleaning filter to obtain pre-treated wastewater;

[0017] S2, the pretreated wastewater enters an aerated biological filter for biochemical treatment to obtain biochemically treated wastewater;

[0018] S3, after chemical disinfection, the biochemical treatment wastewater is sequentially filtered through a trapping filter and an adsorption filter;

[0019] S4. The wastewater after the intermediate filtration enters the reverse osmosis system, and after physical disinfection, enters the security filter for deep filtration, and then undergoes deep treatment by membrane separation to obtain treated water.

[0020] Preferably, the daily chemical wastewater is production wastewater of daily chemical products such as laundry detergent, hand soap, and dishwashing liquid.

[0021] Preferably, the water quality parameters of the daily chemical wastewater after treatment by the sewage treatment plant include at least one of the following: COD content of 150-200 mg / L; NH3-N content of 0.2-0.5 mg / L; chloride content of 1000-1500 mg / L; sulfate content of 100-150 mg / L; total dissolved solid content of 2000-2500 mg / L; total bacterial colony count of 1.0×10 4 -1.5×10 4 CFU / mL; total coliform bacteria: 1.0×10 4 -1.5×10 4 CFU / 100mL; total hardness (calculated as CaCO3) is 600-630mg / L; conductivity is 1700-2400μs / cm; pH is 6-9; turbidity is 3-5NTU.

[0022] Further preferably, the water quality parameters of the daily chemical wastewater after treatment in the sewage treatment plant include at least one of the following: COD content is 160-180 mg / L; NH3-N content is 0.2-0.4 mg / L; chloride content is 1400-1300 mg / L; sulfate content is 120-130 mg / L; total dissolved solid content is 2200-2400 mg / L; total bacterial colony count is 1.0×10 4 -1.3×10 4 CFU / mL; total coliform bacteria: 1.1×10 4 -1.4×10 4 CFU / 100mL; total hardness (calculated as CaCO3) is 610-620mg / L; conductivity is 2000-2200μs / cm; pH is 7-8; turbidity is 3-4NTU.

[0023] Preferably, the water quality parameters of the daily chemical wastewater treated by the sewage station also include: oxygen consumption (COD Mn, calculated as O2) is 2-5mg / L; fluoride content is 0.1-0.5mg / L; nitrate (calculated as N) content is 0.1-0.5mg / L; nitrite (calculated as N) content is 0.01-0.05mg / L; chloroform content is 0.001-0.005mg / L; chromaticity is 5-7 degrees; aluminum content is 0.1-0.5mg / L; iron content is 0.05-0.1mg / L; manganese content is 0.005-0.01mg / L; TOC content is 2-6mg / L; total alpha radioactivity is 1-2Bq / L; total beta radioactivity is 1-2Bq / L.

[0024] Further preferably, the water quality parameters of the daily chemical wastewater after treatment at the sewage station also include: oxygen consumption (COD Mn , calculated as O2) is 3-4mg / L; fluoride content is 0.2-0.4mg / L; nitrate (calculated as N) content is 0.2-0.4mg / L; nitrite (calculated as N) content is 0.01-0.03mg / L; chloroform content is 0.002-0.003mg / L; chromaticity is 5-6 degrees; aluminum content is 0.2-0.3mg / L; iron content is 0.05-0.08mg / L; manganese content is 0.007-0.009mg / L; TOC content is 3-5mg / L; total alpha radioactivity is 0.5-2Bq / L; total beta radioactivity is 1.5-2Bq / L.

[0025] Preferably, the water quality parameters of the treated water body include at least one of the following: COD content is 5-20 mg / L; NH3-N content is 0.001-0.04 mg / L; chloride content is 1-50 mg / L; sulfate content is 0.5-3 mg / L; total soluble solids content is 10-300 mg / L; total colony count is <0.1 CFU / mL; total coliform group is <0.1 CFU / 100 mL; total hardness (in terms of CaCO3) is 1-15 mg / L; conductivity is 20-50 μs / cm; pH is 7-8; turbidity is ≤1 NTU.

[0026] Further preferably, the water quality parameters of the treated water body include at least one of the following: COD content is 5-15 mg / L; NH3-N content is 0.001-0.035 mg / L; chloride content is 1-40 mg / L; sulfate content is 0.5-2.5 mg / L; total soluble solids content is 15-260 mg / L; total colony count is <0.1 CFU / mL; total coliform group is <0.1 CFU / 100 mL; total hardness (in terms of CaCO3) is 1-11 mg / L; conductivity is 30-40 μs / cm; pH is 7-8; turbidity is ≤1 NTU.

[0027] Preferably, the water quality parameters of the treated water body also include: oxygen consumption (COD Mn , calculated as O2) is 0.1-2mg / L; fluoride content is 0.1-0.3mg / L; nitrate (calculated as N) content is 0.1-0.3mg / L; nitrite (calculated as N) content is 0.001-0.01mg / L; chloroform content is 0.00001-0.00005mg / L; chromaticity is ≤5 degrees; aluminum content is 0.005-0.02mg / L; iron content is 0.01-0.05mg / L; manganese content is 0.02-0.05mg / L; TOC content is 0.1-2mg / L; total alpha radioactivity is 0.01-1Bq / L; total beta radioactivity is 0.01-1Bq / L.

[0028] Further preferably, the water quality parameters of the treated water body also include: oxygen consumption (COD Mn , calculated as O2) is 0.1-0.5mg / L; fluoride content is 0.1-0.2mg / L; nitrate (calculated as N) content is 0.1-0.2mg / L; nitrite (calculated as N) content is 0.001-0.03mg / L; chloroform content is 0.00001-0.00003mg / L; chromaticity is ≤5 degrees; aluminum content is 0.005-0.01mg / L; iron content is 0.01-0.02mg / L; manganese content is 0.02-0.04mg / L; TOC content is 0.1-0.5mg / L; total alpha radioactivity is 0.01-0.03Bq / L; total beta radioactivity is 0.01-0.05Bq / L.

[0029] Preferably, in step S1, the filtering accuracy of the self-cleaning filter is 80-100 μm; further preferably, the filtering accuracy of the self-cleaning filter is 50-100 μm.

[0030] Preferably, in step S1, the flow rate of the self-cleaning filter is 8-12m 3 / h; Further preferably, the flow rate of the self-cleaning filter is 9-11m 3 / h.

[0031] Preferably, in step S2, the aerated biological filter is filled with fillers; the particle size of the fillers is 3-5 mm; the specific surface area is 100-400 m 2 / m 3 .

[0032] Preferably, in step S2, the filler includes at least one of ceramsite, anthracite, quartz sand, and lightweight plastic particles; further preferably, the filler is ceramsite.

[0033] Preferably, in step S2, the dissolved oxygen content in the aerated biological filter is 2-8 mg / L; further preferably, the dissolved oxygen content in the aerated biological filter is 2-6 mg / L.

[0034] Preferably, in step S2, the hydraulic retention time of the aerated biological filter is 2-5 hours; further preferably, the hydraulic retention time of the aerated biological filter is 2-4 hours.

[0035] Preferably, in step S3, the chemical disinfection includes adding a disinfectant; the disinfectant includes at least one of sodium hypochlorite and chlorine dioxide.

[0036] Preferably, in step S3, the dosage of the disinfectant is ≤2 mg / L; further preferably, the dosage of the disinfectant is 0.5-2 mg / L.

[0037] Preferably, in step S3, the filtering accuracy of the retaining filter is 30-50 μm; further preferably, the filtering accuracy of the retaining filter is 10-50 μm.

[0038] Preferably, the retention filter comprises one of a bag filter and a core filter.

[0039] Preferably, in step S3, the filter material of the adsorption filter includes activated carbon.

[0040] Preferably, the iodine value of the activated carbon is 800-1300 mg / g; further preferably, the iodine value of the activated carbon is 800-1000 mg / g.

[0041] Preferably, in step S3, the activated carbon filter material includes at least one of coconut shell activated carbon, fruit shell activated carbon, coal-based granular activated carbon, and coal-based columnar activated carbon; further preferably, the activated carbon filter material is fruit shell activated carbon.

[0042] Preferably, the adsorption filter comprises one of a multi-media filter, an activated carbon filter, and a core filter.

[0043] Preferably, in step S4, the physical disinfection includes ultraviolet irradiation.

[0044] Preferably, in step S4, the time for the physical disinfection is 10-15 s; further preferably, the time for the physical disinfection is 10-12 s.

[0045] Preferably, in step S4, the filtration accuracy of the security filter is 3-5 μm; further preferably, the filtration accuracy of the security filter is 1-5 μm.

[0046] Preferably, in step S4, the operating pressure of the reverse osmosis system is ≤4.1 MPa; further preferably, the operating pressure of the reverse osmosis system is 1.0-1.5 MPa.

[0047] Preferably, in step S4, the operating temperature of the reverse osmosis system is 20-45°C; further preferably, the operating temperature of the reverse osmosis system is 20-30°C.

[0048] Preferably, in step S4, the flow rate of the reverse osmosis system is 8-12m 3 / h; Further preferably, the flow rate of the reverse osmosis system is 9-11m 3 / h.

[0049] Preferably, in step S4, the effective membrane area of ​​the reverse osmosis system membrane element is 35-40m 2 Further preferably, the effective membrane area of ​​the reverse osmosis system membrane element is 35-37m 2 .

[0050] Preferably, in step S4, the water production of the reverse osmosis system membrane element is 40-45m 3 / d; Further preferably, the water production of the reverse osmosis system membrane element is 40-42m 3 / d.

[0051] Preferably, in step S4, the desalination rate of the membrane element of the reverse osmosis system is ≥ 99.35%; further preferably, the desalination rate of the membrane element of the reverse osmosis system is 99.35-99.5%.

[0052] Preferably, in step S4, the reverse osmosis system membrane element comprises a polyamide composite film.

[0053] The second aspect of the present invention provides the use of treated water obtained by the deep treatment method of daily chemical wastewater described in the first aspect of the present invention in pre-cleaning of production workshop equipment or pipelines.

[0054] The third aspect of the present invention provides a treatment system for the deep treatment method of daily chemical wastewater described in the first aspect of the present invention. Along the water flow direction, the treatment system includes a self-cleaning filter, an aerated biological filter, a chemical dosing device, a bag filter, an activated carbon filter and a reverse osmosis system.

[0055] Preferably, the treatment water volume of the treatment system is 8-12m 3 / h; further preferably, the treatment water volume of the treatment system is 9-11m 3 / h.

[0056] Preferably, the water production rate of the treatment system is ≥ 65%.

[0057] Preferably, the treatment system also includes intermediate water tank 1, intermediate water tank 2, intermediate water tank 3 and intermediate water tank 4; the intermediate water tank 1 and intermediate water tank 2 are located at the front end of the self-cleaning filter, and are used to collect and store the effluent from the daily chemical wastewater sewage station; the intermediate water tank 3 stores the effluent from the aerated biological filter; and the intermediate water tank 4 stores the effluent from the activated carbon filter.

[0058] Preferably, the aerated biological filter includes a biological reaction filtration zone, an aeration device, and a backwashing device; the biological reaction filtration zone is filled with fillers; the aeration device includes a blower, and the air volume of the blower is 0.5-2.0m 3 / min, wind pressure is 3-7m, 1.0-5.0kw.

[0059] Preferably, the treatment system further comprises a backwash water tank; the backwash water of the aerated biological filter and the sewage discharged from the self-cleaning filter flow into the backwash water tank by gravity.

[0060] Preferably, the chemical dosing device is located at the rear end of the intermediate water tank 3 and is used to add disinfectant to chemically disinfect the biochemical treatment wastewater.

[0061] Preferably, the treatment system further comprises a discharge tank; the discharge tank is located between the intermediate water tank 4 and the physical disinfection device.

[0062] Preferably, the treatment system further comprises a cleaning water tank; the cleaning water tank inputs cleaning liquid into the reverse osmosis system to clean the RO membrane elements to avoid contamination and clogging of the membrane elements.

[0063] Preferably, the reverse osmosis system comprises a physical disinfection device, a security filter and a membrane assembly.

[0064] Preferably, the reverse osmosis system further comprises a dosing device for adding a reducing agent and an antiscalant.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] (1) The deep treatment method for daily chemical wastewater provided by the present invention has simple steps and mild conditions, and can efficiently remove pollutants such as organic matter, chloride, and total dissolved solids in water, effectively kill bacteria and other microorganisms, reduce water hardness, turbidity and conductivity, and further optimize the treatment effect of daily chemical wastewater;

[0067] (2) The deep treatment method for daily chemical wastewater provided by the present invention can ensure that the water quality index of the treated water meets the reuse standard of the production workshop and can be used as pre-cleaning water for equipment and pipelines in the production workshop;

[0068] (3) The daily chemical wastewater treatment system provided by the present invention has a simple structure, a high water production rate, a good treatment effect, and is suitable for practical use. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 The present invention is a flowchart of a method for deep treatment of daily chemical wastewater according to an embodiment of the present invention.

[0070] Figure 2 Schematic diagram of a system for treating daily chemical wastewater according to an embodiment of the present invention. DETAILED DESCRIPTION

[0071] The present invention is further described in detail below by specific examples. The raw materials, reagents or devices used in the examples can be obtained from conventional commercial sources or by prior art methods unless otherwise specified. Unless otherwise specified, the experiments or test methods are conventional methods in the art.

[0072] Figure 1 The following is a flow chart of a method for deep treatment of daily chemical wastewater according to an embodiment of the present invention. Figure 2 The schematic diagram of the treatment system of daily chemical wastewater in the embodiment of the present invention is as follows. Figure 1 and Figure 2 The treatment process of daily chemical wastewater in the embodiment is described.

[0073] Table 1 Main equipment and specifications in the daily chemical wastewater treatment system of the embodiment

[0074]

[0075]

[0076]

[0077] Table 1 shows the main equipment and specifications of the daily chemical wastewater treatment system in the embodiment. It can be seen from Table 1 that the treatment system used in the embodiment mainly includes an intermediate water tank 1, an intermediate water tank 2, a self-cleaning filter, an aerated biological filter, an intermediate water tank 3, a chemical dosing device, a bag filter, an activated carbon filter, an intermediate water tank 4 and a reverse osmosis system which are connected in sequence; wherein the self-cleaning filter and the aerated biological filter are respectively connected to the backwash water tank, and the backwash water of the aerated biological filter and the sewage of the self-cleaning filter flow into the backwash water tank by gravity; a discharge tank is provided between the intermediate water tank 4 and the physical disinfection device; the reverse osmosis system is connected to the cleaning water tank, and the cleaning water tank inputs cleaning liquid into the reverse osmosis system, and the reverse osmosis system includes a membrane assembly, a physical disinfection device, a security filter and a dosing device for adding a reducing agent and an antiscalant.

[0078] Table 2 is the daily chemical wastewater water quality index detection method and standard for reference in the embodiment.

[0079] Table 2 Testing methods and standards for water quality indicators of daily chemical wastewater

[0080]

[0081]

[0082]

[0083] Table 3 Water quality test results of raw water (sewage station effluent) treated in the embodiment

[0084] Water quality indicators Sewage station effluent Water quality indicators Sewage station outlet COD(mg / L) 174 Chloroform(mg / L) 0.00206 Ammonia nitrogen (mg / L) 0.252 Chroma(degrees) 5 Conductivity (μs / cm) 2120 Turbidity(NTU) 3.7 Chloride (mg / L) 1200 Smell and taste none Sulfate (mg / L) 124 Visible to the naked eye none Total dissolved solids (mg / L) 2360 pH 7.74 <![CDATA[Total hardness (calculated as CaCO3, mg / L)]]> 612 Aluminum (mg / L) 0.24 <![CDATA[Chemical Oxygen Demand (COD Mn method, calculated as O2, mg / L)]]> 3.5 Iron (mg / L) 0.0727 Total colony count (CFU / mL) 11000 Manganese (mg / L) 0.0084 Total coliform bacteria (CFU / 100mL) 12000 Total organic carbon (mg / L) 3.9 Fluoride (mg / L) 0.3 Total α radioactivity (Bq / L) 1.54 Nitrate (N, mg / L) 0.29 Total β radioactivity (Bq / L) 1.74 Nitrite (N, mg / L) 0.002 Anionic synthetic detergent Not detected Petroleum 0.06

[0085] Table 3 is the water quality test result of the raw water (sewage station effluent) treated in the embodiment. The daily chemical wastewater is mainly the production wastewater of daily chemical products such as laundry detergent, hand soap, and dishwashing liquid, which is discharged from the sedimentation tank after preliminary treatment at the sewage station. As shown in Table 3, after a series of preliminary treatments such as flotation tank, hydrolysis acidification tank, oxidation tank, and precipitation in the sewage station, typical pollutants such as COD, anionic synthetic detergents, ammonia nitrogen, and petroleum in the daily chemical wastewater have been efficiently removed, but the content of pollutants such as organic matter, chloride, and total dissolved solids in the water is still high, the total bacterial count and total coliform group exceed the standard, and the water body has a large hardness, high turbidity, and high conductivity.

[0086] Example 1

[0087] In this embodiment, the effluent from the daily chemical wastewater and sewage station with water quality parameters as shown in Table 3 is treated, and the treatment steps are as follows:

[0088] S1, the effluent from the daily chemical wastewater station flows into the intermediate water tank 1 by gravity, is pumped into the intermediate water tank 2, and then pumped into the self-cleaning filter (filtration accuracy 100μm, flow rate 10m 3 / h) to perform primary filtration to remove large particle impurities such as suspended matter to obtain pretreated wastewater;

[0089] S2, pre-treated wastewater flows into the aerated biological filter by gravity, and the aerated biological filter is filled with ceramsite (particle size is 3-5mm, specific surface area is 100-400m 2 / m 3 ), using blower aeration (air volume 1.82m 3 / min, wind pressure of 5.8m, 4kw), dissolved oxygen content in the pool of 4mg / L, hydraulic retention time of 3h; wastewater is biochemically treated in the pool to remove pollutants such as suspended solids, organic matter, ammonia nitrogen, etc., to obtain biochemically treated wastewater;

[0090] S3, after the biochemical treatment wastewater is pumped into the intermediate water tank 3, sodium hypochlorite is added to the effluent for disinfection by using a chemical dosing device to kill various types of microorganisms such as bacteria, spores, viruses, fungi, etc., to prevent the growth of microorganisms in subsequent filtration, and to clean and disinfect the entire process pipeline and the intermediate water tank. The amount of sodium hypochlorite added is 2 mg / L; the disinfected wastewater is pumped into a bag filter (filtration accuracy 50 μm) to further filter and remove suspended matter, particulate matter and other impurities in the wastewater; the effluent of the bag filter is pumped into an activated carbon filter (filter material is 800 mg / g iodine value fruit shell activated carbon) to remove the residual chlorine generated by the aforementioned disinfection device, as well as organic matter in the wastewater, to obtain intermediate filtered effluent;

[0091] S4, the intermediate filtered water flows into the intermediate water tank 4 by gravity, and then is pumped into the physical disinfection device of the reverse osmosis system, where it is sterilized by ultraviolet irradiation to kill bacteria, viruses and other microorganisms, while avoiding the formation of microbial membranes and protecting the rear-end reverse osmosis membranes; after sterilization, the wastewater enters the security filter (filtration accuracy 5μm) for deep filtration to remove particulate matter and suspended matter, and the effluent is subjected to membrane separation deep treatment using Dow BW3FR-400 / 34 reverse osmosis membranes. The operating pressure of the reverse osmosis system is 4MPa, the temperature is 28℃, and the flow rate is 10m 3 / h, the effective membrane area of ​​the reverse osmosis membrane is 37m 2 , water production is 42m 3 / d, the desalination rate is 99.5%. During operation, acid and alkali cleaning liquids are input from the cleaning water tank to avoid membrane pollution and blockage, and then reducing agents and scale inhibitors are added from the dosing device to obtain fresh water (6.5m 3 / h) and concentrated water (3.5m 3 / h), and the fresh water production rate is 65%.

[0092] Example 2

[0093] In this embodiment, the effluent from the daily chemical wastewater and sewage station with water quality parameters as shown in Table 3 is treated, and the treatment steps are as follows:

[0094] S1, the effluent from the daily chemical wastewater station flows into the intermediate water tank 1 by gravity, is pumped into the intermediate water tank 2, and then pumped into the self-cleaning filter (filtration accuracy 100μm, flow rate 10m 3 / h) to perform primary filtration to remove large particle impurities such as suspended matter to obtain pretreated wastewater;

[0095] S2, pre-treated wastewater flows into the aerated biological filter by gravity, and the aerated biological filter is filled with ceramsite (particle size is 3-5mm, specific surface area is 100-400m 2 / m 3 ), using blower aeration (air volume 1.82m 3 / min, wind pressure of 5.8m, 4kw), dissolved oxygen content in the pool of 4mg / L, hydraulic retention time of 3h; wastewater is biochemically treated in the pool to remove pollutants such as suspended solids, organic matter, ammonia nitrogen, etc., to obtain biochemically treated wastewater;

[0096] S3, after the biochemical treatment wastewater is pumped into the intermediate water tank 3, sodium hypochlorite is added to the effluent for disinfection by using a chemical dosing device to kill various types of microorganisms such as bacteria, spores, viruses, fungi, etc., to prevent the growth of microorganisms in subsequent filtration, and to clean and disinfect the entire process pipeline and the intermediate water tank. The amount of sodium hypochlorite added is 2 mg / L; the disinfected wastewater is pumped into a bag filter (filtration accuracy 50 μm) to further filter and remove suspended matter, particulate matter and other impurities in the wastewater; the effluent of the bag filter is pumped into an activated carbon filter (filter material is 800 mg / g iodine value fruit shell activated carbon) to remove the residual chlorine generated by the aforementioned disinfection device, as well as organic matter in the wastewater, to obtain intermediate filtered effluent;

[0097] S4, the intermediate filtered water flows into the intermediate water tank 4 by gravity, and then is pumped into the physical disinfection device of the reverse osmosis system, where it is sterilized by ultraviolet irradiation to kill bacteria, viruses and other microorganisms, while avoiding the formation of microbial membranes and protecting the rear-end reverse osmosis membranes; after sterilization, the wastewater enters the security filter (filtration accuracy 5μm) for deep filtration to remove particulate matter and suspended matter, and the effluent is subjected to membrane separation deep treatment using Dow BW3FR-400 / 34 reverse osmosis membranes. The operating pressure of the reverse osmosis system is 4MPa, the temperature is 28℃, and the flow rate is 10m 3 / h, the effective membrane area of ​​the reverse osmosis membrane is 37m 2 , water production is 42m 3 / d, the desalination rate is 99.5%. During operation, acid and alkali cleaning liquids are input from the cleaning water tank to avoid membrane pollution and blockage, and then reducing agents and scale inhibitors are added from the dosing device to obtain fresh water (6.5m 3 / h) and concentrated water (3.5m 3 / h), and the fresh water production rate is 65%.

[0098] The fresh water obtained by the treatment in Examples 1 and 2 was tested for water quality. The test methods and standards are shown in Table 2. The test results are shown in Table 4. At the same time, the index requirements of "Suzhou Drinking Water Quality Index Limits (2021)", "GB / T 19923 Urban Wastewater Recycling Industrial Water Quality" for "washing water" and "process and product water" are met. The BOD / COD index requirements for Class I surface water in "GB3838-2002 Surface Water Environmental Quality Standards", and the water quality index of the recycled water with a conductivity of <100μs / cm are shown in Table 5.

[0099] Table 4 Water quality test results of fresh water obtained by treatment in the embodiment

[0100]

[0101]

[0102] Table 5 Water quality standards for recycled water used in production workshops

[0103]

[0104]

[0105] It can be seen from Tables 3-5 that after the effluent from the daily chemical wastewater treatment plant is deeply treated by the method and system provided by the present invention, the removal rate of COD, chloride, and total dissolved solids in the obtained water body can reach more than 85%, and the organic matter removal effect is good; the content of microorganisms such as bacteria in the wastewater is greatly reduced, and the total coliform group in the effluent is not detected; the hardness and conductivity of the treated effluent are reduced, and the water quality indicators meet the "Suzhou Drinking Water Quality Index Limits (2021)" index requirements, "GB / T19923-2005 Urban Wastewater Recycling Industrial Water Quality" for "washing water" and "process and product water" index requirements, "GB3838-2002 Surface Water Environmental Quality Standard" Class I surface water BOD / COD index requirements, and conductivity <100μs / cm reuse water index requirements, can be directly reused to the production workshop for pre-cleaning of production workshop equipment and pipelines.

[0106] The deep treatment method of daily chemical wastewater provided by the present invention is used for deep treatment of effluent from a daily chemical wastewater sewage treatment plant. The steps are simple, and the treatment effect on pollutants such as organic matter and microorganisms is good. It can reduce the hardness, conductivity and turbidity of the water body, and expand the reuse scenarios of daily chemical wastewater.

Claims

1. A method for deep treatment of daily chemical wastewater, characterized in that: The following steps are involved: S1. The daily chemical wastewater treated by the sewage station is filtered through a self-cleaning filter to obtain pre-treated wastewater; S2, the pretreated wastewater enters an aerated biological filter for biochemical treatment to obtain biochemically treated wastewater; S3, after chemical disinfection, the biochemical treatment wastewater is sequentially filtered through a trapping filter and an adsorption filter; S4. The wastewater after the intermediate filtration enters the reverse osmosis system, and after physical disinfection, enters the security filter for deep filtration, and then undergoes deep treatment by membrane separation to obtain treated water.

2. The deep processing method according to claim 1, characterized in that: The water quality parameters of the daily chemical wastewater treated by the sewage treatment plant include at least one of the following: COD content of 150-200 mg / L; NH3-N content of 0.2-0.5 mg / L; chloride content of 1000-1500 mg / L; sulfate content of 100-150 mg / L; total dissolved solid content of 2000-2500 mg / L; total bacterial colony count of 1.0×10 4 -1.5×10 4 CFU / mL; total coliform bacteria: 1.0×10 4 -1.5×10 4 CFU / 100mL; total hardness (calculated as CaCO3) is 600-630mg / L; conductivity is 1700-2400μs / cm; pH is 6-9; turbidity is 3-5NTU.

3. The deep processing method according to claim 1, characterized in that: In the step S1, the filtering accuracy of the self-cleaning filter is 80-100 μm; And / or, the flow rate of the self-cleaning filter is 8-12m 3 / h.

4. The deep processing method according to claim 1, characterized in that: In step S2, the aerated biological filter is filled with fillers; the particle size of the fillers is 3-5 mm; the specific surface area is 100-400 m 2 / m 3 ; and / or, the dissolved oxygen content in the aerated biological filter is 2-8 mg / L; And / or, the hydraulic retention time of the aerated biological filter is 2-5h.

5. The deep processing method according to claim 1, characterized in that: In step S3, the chemical disinfection includes adding a disinfectant; the disinfectant includes at least one of sodium hypochlorite and chlorine dioxide; And / or, the dosage of the disinfectant is ≤2 mg / L.

6. The deep processing method according to claim 1, characterized in that: In step S3, the filtration accuracy of the interception filter is 30-50 μm; And / or, the filter material of the adsorption filter includes activated carbon; the iodine value of the activated carbon is 800-1300 mg / g.

7. The deep processing method according to claim 1, characterized in that: In step S4, the physical disinfection includes ultraviolet irradiation; And / or, the time of the physical disinfection is 10-15s; And / or, the filtration accuracy of the security filter is 1-5 μm.

8. The deep processing method according to claim 1, characterized in that: In step S4, the pressure of the reverse osmosis system is ≤4.1MPa; and / or, the reverse osmosis system operates at a temperature of 20-45°C; And / or, the effective membrane area of ​​the reverse osmosis system membrane element is 35-40m 2 ; And / or, the water production of the reverse osmosis system membrane element is 40-45m 3 / d; And / or, the desalination rate of the reverse osmosis system membrane element is ≥99.35%.

9. Use of the treated water obtained by the deep treatment method for daily chemical wastewater according to any one of claims 1 to 8 in pre-cleaning of equipment or pipelines in a production workshop.

10. A treatment system for the deep treatment method of daily chemical wastewater according to any one of claims 1 to 8, characterized in that: Along the water flow direction, the treatment system includes a self-cleaning filter, an aerated biological filter, a chemical dosing device, a bag filter, an activated carbon filter and a reverse osmosis system.

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