Low-carbon resourceful sewage treatment method and system

Abstract

This invention relates to the field of wastewater treatment and discloses a low-carbon resource-based wastewater treatment method and system. The method includes the following steps: (1) introducing the comprehensive wastewater from a pharmaceutical factory into a pretreatment tank for bioflocculation to obtain mixture I and bottom sludge; (2) introducing mixture I into an anaerobic tank, an anoxic tank, and an aerobic tank for anaerobic treatment, anoxic treatment, and aerobic treatment respectively to obtain mixture II; (3) introducing mixture II into an MBR unit for membrane separation to obtain concentrated liquid and treated water; (4) introducing a portion of the concentrated liquid into a sludge digestion tank for digestion treatment to obtain supernatant and sludge I; (5) introducing sludge I into a sludge dewatering unit for dewatering to obtain dry sludge and filtrate. The method provided by this invention has high treatment efficiency for comprehensive wastewater from pharmaceutical factories, does not require the addition of additional bioflocculators, and can achieve self-sufficiency in carbon sources for nitrogen and phosphorus removal, thus achieving both high treatment efficiency and energy conservation and emission reduction.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment, and specifically to a low-carbon, resource-efficient wastewater treatment method and system. Background Technology

[0002] Carbon emissions from my country's wastewater treatment industry account for approximately 1%-2% of total social emissions. Achieving low-carbon wastewater treatment is a significant contribution of the wastewater treatment industry to achieving the "dual carbon" goals. Carbon emissions from wastewater treatment mainly originate from direct emissions of CH4 and N2O during the treatment process, as well as indirect emissions of CO2 from energy and material consumption. Carbon dioxide generated from the degradation of water pollutants is considered biogenic carbon emissions. Methane primarily originates from the anaerobic stages of wastewater treatment, including pipe networks, anaerobic ponds, septic tanks, and sludge anaerobic digesters. Nitrous oxide mainly originates from the nitrification and denitrification stages of the wastewater treatment process. Material consumption refers to the use of chemical agents such as coagulants, flocculants, carbon sources, disinfectants, and cleaning agents during the operation of wastewater treatment plants; the use of these chemical agents indirectly generates carbon emissions.

[0003] Currently, the mainstream wastewater resource utilization process is "pretreatment + biological treatment + advanced treatment". Pretreatment mainly uses physicochemical methods, such as sedimentation, flotation, and pre-oxidation to improve biodegradability; biological treatment mainly involves the significant degradation of organic matter and nitrogen and phosphorus removal; advanced treatment, namely reclaimed water treatment technology, is mainly divided into physicochemical treatment technology and membrane treatment technology (including single membrane, dual membrane treatment technology and membrane bioreactor technology).

[0004] The AAO process, or Anaerobic-Anoxic-Aerobic Activated Sludge Process, refers to an activated sludge wastewater treatment method that removes organic pollutants, nitrogen, and phosphorus from water through various combinations of anaerobic, anoxic, and aerobic zones and different sludge return methods. However, the AAO process suffers from drawbacks such as low treatment efficiency and effluent quality that does not meet the requirements for resource utilization.

[0005] Membrane bioreactors (MBRs) are a common wastewater resource recovery process, producing effluent that meets or exceeds the Class A standard of the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002). The reclaimed water can be used for urban miscellaneous purposes, landscaping, and industrial applications. However, membrane separators can cause membrane fouling and clogging, and have high energy consumption.

[0006] Therefore, from an energy conversion perspective, traditional wastewater treatment methods use a large amount of electricity and chemicals to reduce water pollution, thus indirectly emitting a significant amount of carbon dioxide. Essentially, they exchange energy and material consumption for water quality. Based on this, providing a wastewater treatment method that can both strengthen pollution prevention and control and synergistically manage carbon emissions is of great significance for promoting wastewater resource utilization, energy conservation and consumption reduction in wastewater treatment plants, and optimization of process flows. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem that existing sewage treatment systems cannot simultaneously achieve high treatment efficiency and energy conservation and emission reduction.

[0008] To achieve the above objectives, the first aspect of the present invention provides a low-carbon resource-based wastewater treatment method, the method comprising:

[0009] (1) The wastewater from the pharmaceutical plant was introduced into the pretreatment tank for biological flocculation to obtain mixture I and bottom sludge;

[0010] (2) The mixture I was introduced into the anaerobic tank, the anoxic tank and the aerobic tank and subjected to anaerobic treatment, anoxic treatment and aerobic treatment respectively to obtain mixture II;

[0011] (3) The mixture II is introduced into the MBR unit for membrane separation to obtain concentrate and treated water;

[0012] (4) A portion of the concentrated liquid is introduced into a sludge digestion tank for digestion treatment to obtain supernatant and sludge I;

[0013] (5) The sludge I is introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate;

[0014] Specifically, concentrated solution I is returned to the pretreatment tank, concentrated solution II is returned to the anaerobic tank, concentrated solution III is returned to the anoxic tank, and concentrated solution IV is returned to the aerobic tank.

[0015] The supernatant is returned to the anaerobic tank and the anoxic tank;

[0016] At least a portion of the mixture II is returned to the anoxic tank.

[0017] A second aspect of the present invention provides a low-carbon resource-based wastewater treatment system, the system comprising a pretreatment tank, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR unit, a sludge digestion tank, and a sludge dewatering unit connected in sequence.

[0018] The pretreatment tank is used to bio-flocculate the wastewater from the pharmaceutical plant.

[0019] The anaerobic tank, the anoxic tank, and the aerobic tank are used in sequence to treat the mixture I from the pretreatment tank in anoxic, anoxic, and aerobic conditions, respectively.

[0020] The MBR unit is used to perform membrane separation on mixture II from the aerobic tank;

[0021] The sludge digestion tank is used to digest a portion of the concentrate from the MBR unit.

[0022] The sludge dewatering unit is used to dewater a portion of the sludge I from the sludge digester.

[0023] A reflux pipeline for the first concentrate I is provided between the MBR unit and the pretreatment tank;

[0024] A return pipeline for the first concentrate II is provided between the MBR unit and the anaerobic tank;

[0025] A return pipeline for the first concentrate III is provided between the MBR unit and the anoxic tank;

[0026] A return pipeline for the first concentrate IV is provided between the MBR unit and the aerobic tank;

[0027] Concentrate I, Concentrate II, Concentrate III, and Concentrate IV are all part of the concentrated solution;

[0028] The sludge digestion tank is connected to the anaerobic tank and the anoxic tank by a return pipeline for the sludge I.

[0029] Compared with existing technologies, the method and system provided by this invention not only have high processing efficiency, but also have at least the following advantages:

[0030] (1) The method provided by the present invention does not require the addition of chemical flocculants during the bioflocculation process, thereby reducing operating costs and carbon dioxide emissions. At the same time, it is environmentally friendly because no new substances are introduced.

[0031] (2) In the method provided by the present invention, nitrification-denitrification is a short process, which can save electricity and carbon source consumption, thereby reducing CO2 emissions;

[0032] (3) The carbon source for nitrogen and phosphorus removal in the method provided by the present invention can be self-sufficient, without the need for additional carbon source addition, which can reduce CO2 emissions;

[0033] (4) The method provided by the present invention produces a small amount of sludge, which can save energy and cost of sludge disposal. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the process flow of a preferred low-carbon resource-based wastewater treatment method provided by the present invention. Detailed Implementation

[0035] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0036] As mentioned above, this invention provides a low-carbon, resource-efficient wastewater treatment method, which includes:

[0037] (1) The wastewater from the pharmaceutical plant was introduced into the pretreatment tank for biological flocculation to obtain mixture I and bottom sludge;

[0038] (2) The mixture I was introduced into the anaerobic tank, the anoxic tank and the aerobic tank and subjected to anaerobic treatment, anoxic treatment and aerobic treatment respectively to obtain mixture II;

[0039] (3) The mixture II is introduced into the MBR unit for membrane separation to obtain concentrate and treated water;

[0040] (4) A portion of the concentrated liquid is introduced into a sludge digestion tank for digestion treatment to obtain supernatant and sludge I;

[0041] (5) The sludge I is introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate;

[0042] Specifically, concentrated solution I is returned to the pretreatment tank, concentrated solution II is returned to the anaerobic tank, concentrated solution III is returned to the anoxic tank, and concentrated solution IV is returned to the aerobic tank.

[0043] The supernatant is returned to the anaerobic tank and the anoxic tank;

[0044] At least a portion of the mixture II is returned to the anoxic tank.

[0045] In a preferred embodiment, 10-30 wt% of the supernatant is returned to the anaerobic tank, and 70-90 wt% of the supernatant is returned to the anoxic tank.

[0046] Preferably, the water quality parameters of the pharmaceutical plant's wastewater are: COD Cr The concentrations are 1000-3000 mg / L, BOD5 is 300-1000 mg / L, SS is 200-500 mg / L, NH3-N is 30-60 mg / L, TN is 60-95 mg / L, TP is 5-10 mg / L, and pH is 7-9.

[0047] Preferably, each of the following concentrates—concentrate I, concentrate II, concentrate III, and concentrate IV—is a portion of the concentrate, and their respective weights are 2-10 wt%, 5-10 wt%, 2-10 wt%, 10-15 wt%, and 40-65 wt% of the total concentrate weight, respectively. The inventors have found that this preferred configuration can improve COD. Cr The removal effect of NH3-N.

[0048] In a preferred embodiment, the method of the present invention further includes, in step (1), introducing the wastewater into an equalization tank for equalization treatment before bioflocculation; and

[0049] The concentrate V is returned to the equalization tank. Concentrate V is a portion of the concentrated solution and its weight is 1-5 wt% of the weight of the concentrated solution. The inventors have found that, in this preferred configuration, COD can be increased. Cr The removal effect of NH3-N.

[0050] Preferably, in step (1), the bottom sludge is introduced into the sludge digestion tank.

[0051] Preferably, in step (2), the sludge discharged from the anaerobic tank and the anoxic tank is introduced into the sludge dewatering unit for dewatering.

[0052] Preferably, in step (3), the MBR unit uses an external membrane with an average diameter of 0.01-0.6 μm.

[0053] More preferably, the external membrane uses membranes of three specifications: large pore size, medium pore size, and small pore size. One or more of these three membrane specifications are selected for membrane separation based on the real-time sludge concentration, pressure difference, and reclaimed water quality requirements of the mixture II, to prevent membrane clogging and fouling.

[0054] The average diameter of the large pores is 0.4-0.6 μm, the average diameter of the medium pores is 0.1-0.3 μm, and the average diameter of the small pores is 0.01-0.05 μm. The inventors have found that this preferred configuration is more conducive to preventing membrane fouling and clogging.

[0055] In a preferred embodiment, a portion of the mixture II is recycled back to the anoxic tank, and the weight of the portion of the mixture II is 100-400 wt% of the influent volume of the pharmaceutical plant's comprehensive wastewater.

[0056] Preferably, in step (5), the filtrate is introduced into the conditioning tank.

[0057] According to a preferred embodiment, the conditions for bioflocculation are at least: dissolved oxygen concentration of 0.7-1.2 mg / L, pH of 6.5-8.5, and aeration rate of 1.5-3 m³ / L. 3 / m 2 ·h.

[0058] Preferably, the anaerobic treatment conditions at least meet the following requirements: dissolved oxygen concentration not greater than 0.2 mg / L, and stirring power of 5-8 W / m³. 3 Pool capacity.

[0059] Preferably, the conditions for the anoxic treatment at least satisfy the following: dissolved oxygen concentration of 0.2-0.5 mg / L and stirring power of 6-10 W / m. 3 Pool capacity.

[0060] According to a preferred embodiment, the conditions for the aerobic treatment shall at least satisfy: dissolved oxygen concentration of 2-5 mg / L and sludge concentration of 10-40 g / L.

[0061] Preferably, the dissolved oxygen concentration in the aerobic tank is achieved through precise aeration.

[0062] It should be noted that the present invention does not have special requirements for the digestion treatment conditions, and the parameters of conventional sludge digestion treatment in this industry can be selected.

[0063] The following combination Figure 1 A preferred embodiment is provided, comprising:

[0064] (1) The integrated wastewater (influent) of the pharmaceutical plant is introduced into the equalization tank for equalization treatment, and then introduced into the pretreatment tank for biological flocculation to obtain mixture I and bottom sludge. The bottom sludge is then introduced into the sludge digestion tank.

[0065] (2) The mixture I was introduced into the anaerobic tank, the anoxic tank and the aerobic tank and subjected to anaerobic treatment, anoxic treatment and aerobic treatment respectively to obtain mixture II;

[0066] (3) A portion of the mixture II is returned to the anoxic tank, and another portion of the mixture II is introduced into the MBR unit for membrane separation to obtain concentrated liquid and treated water. The treated water is then introduced into the product water tank for further resource utilization.

[0067] (4) A portion of the concentrated liquid is introduced into the sludge digestion tank for digestion treatment to obtain supernatant and sludge I. The supernatant is then returned to the anaerobic tank and the anoxic tank.

[0068] (5) The sludge discharged from the anaerobic tank and the anoxic tank, and the sludge I are introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate. The filtrate is then introduced into the equalization tank.

[0069] Specifically, concentrated solution I is returned to the pretreatment tank, concentrated solution II is returned to the anaerobic tank, concentrated solution III is returned to the anoxic tank, concentrated solution IV is returned to the aerobic tank, and concentrated solution V is returned to the equalization tank.

[0070] The dissolved oxygen concentration in the aerobic tank is adjusted using precise aeration.

[0071] As mentioned above, a second aspect of the present invention provides a low-carbon resource-based wastewater treatment system, which includes a pretreatment tank, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR unit, a sludge digestion tank, and a sludge dewatering unit connected in sequence.

[0072] The pretreatment tank is used to bio-flocculate the wastewater from the pharmaceutical plant.

[0073] The anaerobic tank, the anoxic tank, and the aerobic tank are used in sequence to treat the mixture I from the pretreatment tank in anoxic, anoxic, and aerobic conditions, respectively.

[0074] The MBR unit is used to perform membrane separation on mixture II from the aerobic tank;

[0075] The sludge digestion tank is used to digest a portion of the concentrate from the MBR unit.

[0076] The sludge dewatering unit is used to dewater a portion of the sludge I from the sludge digester.

[0077] A return pipeline for the first concentrate I is provided between the MBR unit and the pretreatment tank;

[0078] A return pipeline for the first concentrate II is provided between the MBR unit and the anaerobic tank;

[0079] A return pipeline for the first concentrate III is provided between the MBR unit and the anoxic tank;

[0080] A return pipeline for the first concentrate IV is provided between the MBR unit and the aerobic tank;

[0081] Concentrate I, Concentrate II, Concentrate III, and Concentrate IV are all part of the concentrated solution;

[0082] The sludge digestion tank is connected to the anaerobic tank and the anoxic tank by a return pipeline for the sludge I.

[0083] In a preferred embodiment, the sludge dewatering unit is also used to dewater the sludge discharged from the anaerobic tank and / or the anoxic tank.

[0084] In a preferred embodiment, according to the logistics direction, the system of the present invention further includes an equalization tank located upstream of the pretreatment tank for equalizing and treating the combined wastewater from the pharmaceutical plant.

[0085] The present invention will be described in detail below through examples. Unless otherwise specified, the raw materials used are all commercially available products.

[0086] Please see Table 1 for the comprehensive wastewater quality parameters of the pharmaceutical plant;

[0087] Unless otherwise specified, the following examples use Figure 1 The process shown is carried out, and the influent volume of the pharmaceutical plant's overall wastewater is 2m³. 3 / h.

[0088] Example 1

[0089] This embodiment illustrates the low-carbon resource-based wastewater treatment method provided by the present invention, which is performed according to the following steps and with reference to the parameters in Table 2:

[0090] (1) The integrated wastewater (influent) of the pharmaceutical plant is introduced into the equalization tank for equalization treatment, and then introduced into the pretreatment tank for biological flocculation to obtain mixture I and bottom sludge. The bottom sludge is then introduced into the sludge digestion tank.

[0091] (2) The mixture I was introduced into the anaerobic tank, the anoxic tank and the aerobic tank and subjected to anaerobic treatment, anoxic treatment and aerobic treatment respectively to obtain mixture II;

[0092] The dissolved oxygen concentration in the aerobic tank is adjusted using precise aeration.

[0093] (3) A portion of the mixture II is returned to the anoxic tank (200 wt% of the influent of the pharmaceutical plant's comprehensive wastewater), and another portion of the mixture II is introduced into the MBR unit for membrane separation to obtain concentrated liquid and treated water (denoted as P1). The treated water is then introduced into the product water tank for further resource utilization.

[0094] The MBR unit employs an external membrane. Based on the real-time sludge concentration, pressure difference, and reclaimed water quality requirements of mixture II, one of three membrane specifications—large pore size, medium pore size, or small pore size—is selected for membrane separation to prevent membrane clogging and fouling.

[0095] The average diameter of the large pore is 0.5 μm, the average diameter of the medium pore is 0.2 μm, and the average diameter of the small pore is 0.03 μm.

[0096] (4) A portion of the concentrated liquid (10wt% concentrated liquid) is introduced into the sludge digestion tank for digestion treatment to obtain supernatant (carbon source) and sludge I. The supernatant is returned to the anaerobic tank and the anoxic tank, wherein 20wt% of the supernatant is returned to the anaerobic tank and 80wt% of the supernatant is returned to the anoxic tank.

[0097] (5) The sludge discharged from the anaerobic tank and the anoxic tank, and the sludge I are introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate. The filtrate is then introduced into the equalization tank.

[0098] Specifically, concentrate I (10 wt% concentrate) is returned to the pretreatment tank, concentrate II (5 wt% concentrate) is returned to the anaerobic tank, concentrate III (15 wt% concentrate) is returned to the anoxic tank, concentrate IV (55 wt% concentrate) is returned to the aerobic tank, and concentrate V (5 wt% concentrate) is returned to the equalization tank.

[0099] Example 2

[0100] This embodiment illustrates the low-carbon resource-based wastewater treatment method provided by the present invention, which is performed according to the following steps and with reference to the parameters in Table 2:

[0101] (1) The integrated wastewater (influent) of the pharmaceutical plant is introduced into the equalization tank for equalization treatment, and then introduced into the pretreatment tank for biological flocculation to obtain mixture I and bottom sludge. The bottom sludge is then introduced into the sludge digestion tank.

[0102] (2) The mixture I was introduced into the anaerobic tank, the anoxic tank and the aerobic tank and subjected to anaerobic treatment, anoxic treatment and aerobic treatment respectively to obtain mixture II;

[0103] The dissolved oxygen concentration in the aerobic tank is adjusted using precise aeration.

[0104] (3) A portion of the mixture II is returned to the anoxic tank (100wt% of the influent of the pharmaceutical plant's comprehensive wastewater), and another portion of the mixture II is introduced into the MBR unit for membrane separation to obtain concentrated liquid and treated water (denoted as P2). The treated water is then introduced into the product water tank for further resource utilization.

[0105] The MBR unit employs an external membrane. Based on the real-time sludge concentration, pressure difference, and reclaimed water quality requirements of mixture II, one of three membrane specifications—large pore size, medium pore size, or small pore size—is selected for membrane separation to prevent membrane clogging and fouling.

[0106] The average diameter of the large pore is 0.6 μm, the average diameter of the medium pore is 0.1 μm, and the average diameter of the small pore is 0.04 μm.

[0107] (4) A portion of the concentrate (5 wt% concentrate) is introduced into the sludge digestion tank for digestion treatment to obtain supernatant (carbon source) and sludge I. The supernatant is returned to the anaerobic tank and the anoxic tank, wherein 25 wt% of the supernatant is returned to the anaerobic tank and 75 wt% of the supernatant is returned to the anoxic tank.

[0108] (5) The sludge discharged from the anaerobic tank and the anoxic tank, and the sludge I are introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate. The filtrate is then introduced into the equalization tank.

[0109] Specifically, concentrate I (8 wt% concentrate) is returned to the pretreatment tank, concentrate II (8 wt% concentrate) is returned to the anaerobic tank, concentrate III (12 wt% concentrate) is returned to the anoxic tank, concentrate IV (65 wt% concentrate) is returned to the aerobic tank, and concentrate V (2 wt% concentrate) is returned to the equalization tank.

[0110] Example 3

[0111] This embodiment uses a method similar to that of Embodiment 1, except that the weights of the concentrate, concentrate I, concentrate II, concentrate III, concentrate IV, and concentrate V are 1wt%, 15wt%, 15wt%, 30wt%, 35wt%, and 4wt% of the total weight of the concentrate, respectively, ultimately yielding treated water (denoted as P3).

[0112] Example 4

[0113] This embodiment uses a method similar to that of Embodiment 1, except that the weights of the concentrate, concentrate I, concentrate II, concentrate III, concentrate IV, and concentrate V are 5wt%, 6wt%, 6wt%, 12wt%, 56wt%, and 15wt% of the total weight of the concentrate, respectively, ultimately yielding treated water (denoted as P4).

[0114] Example 5

[0115] This embodiment uses a method similar to that of Embodiment 1. The difference is that in the membrane separation, the external membrane uses only one type of membrane with a pore size of 0.2 μm, and the final treated water (denoted as P5) is obtained.

[0116] Comparative Example 1

[0117] This comparative example was carried out using a method similar to that of Example 1. The difference was that the concentrate was not returned to the pretreatment tank, anaerobic tank, sludge digestion tank and aerobic tank. Instead, all the concentrate was introduced into the anoxic tank to obtain sludge I.

[0118] The final product is treated water (denoted as DP1).

[0119] Comparative Example 2

[0120] This comparative example uses a method similar to that of Example 1, except that the supernatant is not returned to the anaerobic tank and the anoxic tank, but all of the supernatant is introduced into the sludge dewatering unit.

[0121] The final product is treated water (denoted as DP2).

[0122] Comparative Example 3

[0123] This comparative example was conducted using a method similar to that of Example 1, except that mixture II was not returned to the anoxic tank, but instead all of mixture II was introduced into the MBR unit for membrane separation to obtain concentrate and treated water (denoted as DP3).

[0124] Test Example 1

[0125] Table 3 shows the power consumption per ton of pharmaceutical wastewater treated in the examples and comparative examples, as well as the water quality measurements of the treated water.

[0126] Table 1

[0127] project numerical values <![CDATA[COD Cr (mg / L)]]> 2000 <![CDATA[BOD5(mg / L)]]> 600 SS (mg / L) 350 <![CDATA[NH3-N(mg / L)]]> 54 TN (mg / L) 80 TP (mg / L) 8 pH 8.2

[0128] Table 2

[0129] project Example 1 Example 2 Bioflocculation pH 7.2 7.5 <![CDATA[Biological flocculation aeration volume (m 3 / m 2 ·h)]]> 2 2.5 Dissolved oxygen concentration (mg / L) in bioflocculants 1.0 0.8 Dissolved oxygen concentration (mg / L) during anaerobic treatment 0.1 0.1 <![CDATA[Stirring power of anaerobic treatment (W / m 3 pond volume)]]> 6 7 Dissolved oxygen concentration (mg / L) under hypoxic treatment 0.3 0.4 <![CDATA[Stirring power (W / m 3 pond volume) under hypoxia treatment]]> 8 7 Dissolved oxygen concentration (mg / L) during aerobic treatment 2.8 2.6 Sludge concentration in aerobic treatment (g / L) 20 19

[0130] Table 3

[0131]

[0132]

[0133] Table 3 (continued)

[0134] project DP1 DP2 DP3 <![CDATA[COD Cr (mg / L)]]> 51 53 57 <![CDATA[NH3-N(mg / L)]]> 6.5 8.4 7.9 TN (mg / L) 16.4 16.6 17.1 <![CDATA[Power consumption (kw·h / m 3 )]]> 2.8 3.0 3.0

[0135] The results above show that the method provided by this invention has high treatment efficiency for pharmaceutical wastewater, and does not require the addition of additional biological flocculants. The carbon source for nitrogen and phosphorus removal can be self-sufficient, eliminating the need for additional carbon source addition, thus reducing CO2 emissions. It combines the advantages of high treatment efficiency and energy saving and emission reduction.

[0136] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A low-carbon, resource-efficient wastewater treatment method, characterized in that, The method includes: (1) The wastewater from the pharmaceutical factory is introduced into the pretreatment tank for bioflocculation to obtain mixture I and bottom sludge; wherein, before the bioflocculation, the wastewater from the pharmaceutical factory is first introduced into the equalization tank for equalization treatment, and no additional chemical flocculant is required during the bioflocculation process. (2) The mixture I is introduced into the anaerobic tank, the anoxic tank and the aerobic tank for anaerobic treatment, anoxic treatment and aerobic treatment respectively, to obtain mixture II; (3) The mixture II is introduced into the MBR unit for membrane separation to obtain concentrate and treated water; (4) A portion of the concentrated liquid is introduced into a sludge digestion tank for digestion treatment to obtain supernatant and sludge I; (5) The sludge I is introduced into the sludge dewatering unit for dewatering to obtain dry sludge and filtrate; This method requires no additional carbon source. In step (3), concentrate I is returned to the pretreatment tank, concentrate II is returned to the anaerobic tank, concentrate III is returned to the anoxic tank, concentrate IV is returned to the aerobic tank, and concentrate V is returned to the conditioning tank. The aforementioned concentrates, concentrate I, concentrate II, concentrate III, concentrate IV, and concentrate V are all part of the concentrate, and their respective weights are 2-10 wt%, 5-10 wt%, 2-10 wt%, 10-15 wt%, 40-65 wt%, and 1-5 wt% of the total concentrate weight, respectively. The supernatant is returned to the anaerobic tank and the anoxic tank; At least a portion of the mixture II is returned to the anoxic tank.

2. The method according to claim 1, wherein, The water quality parameters of the pharmaceutical plant's wastewater are: COD Cr The concentrations are 1000-3000 mg / L, BOD5 is 300-1000 mg / L, SS is 200-500 mg / L, NH3-N is 30-60 mg / L, TN is 60-95 mg / L, TP is 5-10 mg / L, and pH is 7-9.

3. The method according to claim 1 or 2, wherein, In step (3), the MBR unit uses an external membrane with an average diameter of 0.01-0.6 μm.

4. The method according to claim 1 or 2, wherein, A portion of the mixture II is returned to the anoxic tank, and the weight of the portion of the mixture II is 100-400 wt% of the influent volume of the pharmaceutical plant's comprehensive wastewater.

5. The method according to claim 1 or 2, wherein, In step (5), the filtrate is introduced into the conditioning tank.

6. The method according to claim 1 or 2, wherein, The conditions for bioflocculation must at least meet the following: dissolved oxygen concentration of 0.7-1.2 mg / L, pH of 6.5-8.5, and aeration rate of 1.5-3 m³ / L. 3 / m 2 ·h; and / or The anaerobic treatment conditions must at least meet the following: dissolved oxygen concentration not exceeding 0.2 mg / L, and stirring power of 5-8 W / m³. 3 Pool capacity; and / or The conditions for the anoxic treatment must at least meet the following requirements: dissolved oxygen concentration of 0.2-0.5 mg / L, and stirring power of 6-10 W / m. 3 Pool capacity; and / or The aerobic treatment conditions must at least meet the following requirements: dissolved oxygen concentration of 2-5 mg / L and sludge concentration of 10-40 g / L.

7. A low-carbon, resource-efficient wastewater treatment system, characterized in that, The system includes a pretreatment tank, an anaerobic tank, an anoxic tank, an aerobic tank, an MBR unit, a sludge digestion tank, and a sludge dewatering unit connected in sequence. The pretreatment tank is used to bio-flocculate the wastewater from the pharmaceutical plant. The anaerobic tank, the anoxic tank, and the aerobic tank are used in sequence to treat the mixture I from the pretreatment tank in anoxic, anoxic, and aerobic conditions, respectively. The MBR unit is used to perform membrane separation on mixture II from the aerobic tank; The sludge digestion tank is used to digest a portion of the concentrate from the MBR unit. The sludge dewatering unit is used to dewater a portion of the sludge I from the sludge digester. A reflux pipeline for the first concentrate I is provided between the MBR unit and the pretreatment tank; A return pipeline for the first concentrate II is provided between the MBR unit and the anaerobic tank; A return pipeline for the first concentrate III is provided between the MBR unit and the anoxic tank; A return pipeline for the first concentrate IV is provided between the MBR unit and the aerobic tank; Concentrate I, Concentrate II, Concentrate III, and Concentrate IV are all part of the concentrated solution; The sludge digestion tank is connected to the anaerobic tank and the anoxic tank by a return pipeline for the sludge I.

8. The system according to claim 7, wherein, According to the logistics direction, the system also includes an equalization tank set up upstream of the pretreatment tank for equalizing and treating the comprehensive wastewater from the pharmaceutical plant.

Images