CN113415955A - Method for treating sulfur-containing hot spring bath sewage - Google Patents

Method for treating sulfur-containing hot spring bath sewage Download PDF

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CN113415955A
CN113415955A CN202110848083.XA CN202110848083A CN113415955A CN 113415955 A CN113415955 A CN 113415955A CN 202110848083 A CN202110848083 A CN 202110848083A CN 113415955 A CN113415955 A CN 113415955A
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tank
sewage
mbr membrane
sludge
water
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袁锦宝
昝林涛
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Nanjing Sucheng Environmental Protection Technology Co ltd
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Nanjing Sucheng Environmental Protection Technology Co ltd
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    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/30—Treatment of water, waste water, or sewage by irradiation
    • C02F1/32—Treatment of water, waste water, or sewage by irradiation with ultraviolet light
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/442—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by nanofiltration
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
    • C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
    • C02F1/5245—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents using basic salts, e.g. of aluminium and iron
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/101—Sulfur compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/105—Phosphorus compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/42—Nature of the water, waste water, sewage or sludge to be treated from bathing facilities, e.g. swimming pools
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/30—Aerobic and anaerobic processes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F3/00—Biological treatment of water, waste water, or sewage
    • C02F3/34—Biological treatment of water, waste water, or sewage characterised by the microorganisms used

Abstract

The invention relates to a method for treating sulfur-containing hot spring bathing sewage, which comprises the following steps: firstly, a pretreatment procedure: step 1: introducing the bath sewage into a regulating tank for temporary storage; step 2: introducing the bath sewage in the regulating tank into a coagulating sedimentation tank, and adding a coagulant and a coagulant aid; II, biochemical treatment process: and step 3: anoxic tank-MBR composite biochemical treatment: the effluent of the coagulation sedimentation tank sequentially enters an anoxic tank and an MBR membrane tank, which are pre-fed with activated sludge, and the anoxic tank simultaneously receives return sludge from the MBR membrane tank; thirdly, advanced treatment process: and 4, step 4: the effluent of the MBR membrane tank firstly enters an intermediate water tank, enters a nanofiltration device after being pressurized, and is subjected to membrane separation under the driving of pressure on residual pollutants such as organic substances CODcr, total phosphorus, total nitrogen and the like in water through a nanofiltration membrane in the device. The TP content in the sulfur-containing hot spring bathing sewage treated by the method can be reduced to below 0.2mg/L, and the drainage index can reach the standard of surface three types of water.

Description

Method for treating sulfur-containing hot spring bath sewage
Technical Field
The invention relates to a method for treating sulfur-containing hot spring bathing sewage, belonging to the technical field of domestic sewage treatment.
Background
With the vigorous development of the economy of China, the problem of water pollution is increasingly highlighted, and with the intensive implementation of the environmental protection policies of 'water pollution prevention and control action plan' and 'pollution discharge permit', the state comprehensively controls the pollutant discharge, promotes the transformation and upgrade of the economic structure, makes efforts to save and protect water resources and fully ensures the safety of the water ecological environment. The 'ten items of water' particularly proposes that local water pollutant discharge standards strict with national standards can be established everywhere. The discharge standard of the first class A of the pollutant discharge standard of the municipal wastewater treatment plant can not meet the requirements of the current discharge policy, the effluent quality of the first class A standard is worse than that of the V class water of the environmental quality standard of surface water, which is equivalent to the bad V class water in the surface water, and the effluent has no water area use function and can not be directly discharged into natural water.
Table 1 shows the difference between the surface water quality standard and the discharge standard of the urban sewage treatment plant
Figure BDA0003181442660000011
The bath sewage belongs to a type of domestic sewage and has the characteristics of light pollution degree, simple pollutant components, relatively stable water quality, large periodical change of water quantity and the like. The main pollutant sources in the bath sewage are human skin secretion, grease, scurf, hair, dirt, synthetic detergent and perfume, bacteria, fungi, escherichia coli, viruses and the like, so that the pollutant indexes in the discharged bath sewage exceed standards, and the applicant shows the detailed test conclusion in table 2 after test analysis.
TABLE 2 Water quality index of bath waste water
Figure BDA0003181442660000012
Compared with the common bathing sewage, the sulfur-containing hot spring bathing sewage has more particularity, which is particularly shown in that:
the sulfur-containing hot spring bathing sewage contains a small amount of sulfide (hydrogen sulfide), the concentration range is 0.2-3.0 mg/L, the peculiar odor of the hydrogen sulfide is generated, the biological toxicity is obvious to the existing mainstream biochemical treatment process, the activity of microorganisms in activated sludge can be inhibited, and the quality of the effluent is poor and does not reach the standard.
The main flow process of the existing bath sewage treatment is a treatment process combining a physical and chemical method and a biochemical method. The physical and chemical method is usually used as a pretreatment measure of the biochemical method, and the process flow mainly comprises coagulating sedimentation-filtration, coagulating-air flotation, micro-flocculation fiber filtration-membrane filtration and the like. The biochemical method mainly comprises AO process and A2O process and the like. The water quality of the discharged bath sewage treated by the process can reach the first grade A standard of pollutant discharge Standard of urban wastewater treatment plant (GB 18918-2002). According to the requirements of the current discharge policy, the effluent treated by the mainstream treatment process of the bath sewage is first-grade A, which can not meet the requirements of III-class discharge standards of surface water environment quality standard (GB3838-2002), and can only be discharged into municipal sewage pipe network, but can not be directly discharged into a natural river channel!
Disclosure of Invention
The invention aims to solve the technical problem that the quality of the effluent of the sulfur-containing hot spring bathing sewage treated by the prior art can not reach the III-class water standard on the earth surface in the environmental quality Standard of surface Water (GB3838-2002) and can not be directly discharged into a natural river.
The applicant analyzes that the main pollutants in the sulfur-containing hot spring bath sewage are CODcr, SS and NH3N, TP and sulfides. Based on the above research, the applicant proposed the following method for treating sulfur-containing hot spring bath sewage, specifically comprising the following steps:
first, pretreatment process
The pretreatment mainly solves the problems of uneven water supply and larger solid carried in the hot spring bath sewage, and carries out chemical phosphorus removal.
Step 1: introducing the bath sewage into a regulating tank for temporary storage.
The purpose of setting up the equalizing basin is because the inhomogeneous emission of bathing sewage can lead to the fluctuation of water yield, consequently needs the equalizing basin to store it temporarily to make the sewage in the equalizing basin can flow with stable flow, avoid the drain pump in the equalizing basin to open frequently and stop.
Step 2: the bath sewage in the regulating tank is led into a coagulating sedimentation tank, and a coagulant aid are added.
The purpose of this step is to remove the relatively large solids entrained in the wastewater, while removing the contaminants in the wastewater: phosphorus.
In the step 2, a coagulant is added at the water inlet pipe of the coagulating sedimentation tank, and is mixed with the sewage introduced from the regulating tank in the water inlet pipe and then is subjected to the coagulating sedimentation tank; the coagulant aid is directly added into the reaction area of the coagulating sedimentation tank. Soluble phosphate and coagulant contained in the sewage are subjected to chemical reaction in a reaction zone of the coagulation tank to generate water-insoluble micro precipitates, and then the micro precipitates form larger flocculants under the actions of flocculation, adsorption bridging, surface adsorption, reinforcement and the like of the coagulant aid, and the larger flocculants and other settleable substances and/or floating substances carried in the sewage are settled in the settling zone of the coagulation tank to form sludge. The sewage formed at the upper part of the coagulation tank is introduced into an anoxic tank in the subsequent step, and the sludge at the lower part is periodically discharged into a sludge concentration tank.
The chemical reaction involved in step 2 is shown below:
Figure BDA0003181442660000031
the applicant has found that the use of an aluminum salt as a coagulant can effectively remove soluble phosphate in sewage, but this results in an increase in the amount of sludge. In order to effectively remove soluble phosphate in sewage and simultaneously reduce the sludge amount as much as possible, through a plurality of experiments, the applicant finds out the corresponding relation between the following coagulants and the phosphorus concentration in the sewage entering a coagulating sedimentation tank after repeatedly balancing the two purposes of reducing the sludge amount and reducing the phosphorus by measuring the concentrations of the phosphorus in the inlet water and the outlet water of the coagulating sedimentation tank for a plurality of times:
the addition amount of the coagulant is 1 to 2 times of the phosphorus content in the bath sewage, and 1.5 times is optimal.
The coagulant in the step 2 is aluminum salt, the aluminum salt is used as the coagulant, the phosphate in the bath sewage can be effectively removed, and the removal rate of phosphorus can reach more than 75%.
In step 2, the remaining small amount of phosphorus in the wastewater is treated by the subsequent MBR membrane tank unit.
The adjusting tank adopted in the pretreatment process is a common water tank, and the adopted coagulating sedimentation tank is the same as that adopted in the existing physicochemical method bath sewage treatment process, so the structure of the coagulating sedimentation tank is not described in detail.
Second, biochemical treatment process
The biochemical treatment process is to degrade and remove organic pollutants, ammonia nitrogen, total phosphorus and other pollutants in the hot spring bathing sewage by using the life activities of microorganisms contained in the activated sludge.
And step 3: anoxic tank-MBR composite biochemical treatment: and the effluent of the coagulation sedimentation tank sequentially enters an anoxic tank and an MBR membrane tank, which are pre-fed with activated sludge, and the anoxic tank simultaneously receives return sludge from the MBR membrane tank.
The activated sludge pre-thrown in the anoxic pond and the MBR membrane pond consists of aerobic microorganisms (including bacteria, protozoa, metazoan, fungi, algae and the like), metabolic products of the microorganisms, adsorbed organic matters, inorganic matters and the like. The activated sludge has strong adsorption and oxidative decomposition capacity on organic pollutants in sewage, and the activated sludge must contain three types of bacteria, namely denitrifying bacteria, nitrifying bacteria and phosphorus accumulating bacteria. The pre-dosed activated sludge may be derived from fresh sludge produced by any sewage treatment plant.
The sewage after the coagulation sedimentation tank treatment that the oxygen deficiency pond accepts directly discharges into MBR membrane cisterna earlier to carry out following biochemical treatment in MBR membrane cisterna:
1) through the biological activity of microorganisms in the activated sludge in the MBR membrane tank, most of organic pollutants COD (chemical oxygen demand) in the sulfur-containing hot spring bathing sewage are efficiently removedCr；
2) Nitrifying bacteria in the activated sludge in the MBR membrane tank are used for treating ammonia Nitrogen (NH) dissolved in the bath sewage3and-N) carrying out nitrification to form nitrate nitrogen and nitrate phase nitrogen, filtering and carrying out solid-liquid separation on the sewage by an MBR membrane element arranged in an MBR membrane tank, leaving the separated sludge containing the nitrate nitrogen and nitrate phase nitrogen in the MBR membrane tank to flow back to an anoxic tank, and feeding the separated liquid into a nano-filter tank of a subsequent deepening treatment process.
3) Because the phosphorus accumulating bacteria in the activated sludge in the MBR membrane tank can excessively suck phosphorus in the sewage into the body in an aerobic state, the phosphorus content in the body is far higher than that of common bacteria by multiple times. And after the sludge in the MBR membrane tank is accumulated to a certain degree, the sludge is periodically discharged into a sludge concentration tank, so that the phosphorus in the sewage is removed.
4) Because the sulfur in the bath sewage mainly exists in the form of hydrogen sulfide, the MBR membrane tank is oxygenated in the biochemical treatment process, so that the water in the MBR membrane tank maintains higher oxygen concentration, and the oxygen and the hydrogen sulfide are subjected to the following displacement reaction in the water:
2H2S+O2＝2H2O+2S↓
the displacement reaction generates light yellow elemental sulfur which is discharged into a sludge concentration tank along with the sludge discharged regularly, thereby realizing the removal of the sulfur in the sewage.
Through the life activity of microorganism in the activated sludge in the MBR membrane tank, can effectively get rid of the pollutant in the bathing sewage: CODcr, NH3N, TP and hydrogen sulfide.
After the anoxic tank receives return sludge from the MBR membrane tank, denitrifying bacteria of active sludge pre-thrown in the anoxic tank are utilized, organic matters (CODcr) in sewage treated by a coagulation sedimentation tank and subsequently received are used as carbon sources, and nitrate nitrogen brought by the return sludge of the MBR membrane tank is reduced into N2And released to the atmosphere, and a small amount of CODcr in the sewage can be removed in the process.
The applicant finds that when the dissolved oxygen concentration of the anoxic pond is controlled to be 0.1-0.5mg/l, denitrifying bacteria in the anoxic pond are most active, and nitrate radical brought by sludge backflow of an MBR membrane pond is reduced into N2The effect of (2) is optimal.
In the step, the concentration of the dissolved oxygen in the anoxic pond is realized by controlling the return flow of the sludge according to the water inlet flow (unit m) of the anoxic pond3H) controlling the sludge reflux quantity (unit m) of the MBR membrane tank3H), realizing the control of the dissolved oxygen concentration range: the returned MBR membrane tank sludge (the dissolved oxygen concentration range is more than 2.0 mg/l) and the inlet water (the dissolved oxygen concentration is almost zero) of the anoxic tank are mixed, and the volume reflux ratio is generally controlled to be between 0.3 and 0.5 times.
In the step, in order to avoid the interference of trace sulfide in the sewage on the activated sludge, the MBR membrane tank needs to adopt the activated sludge with higher concentration and higher dissolved oxygen concentration when in operation. The sludge concentration is kept between 6000mg/L and 12000mg/L, which is more than 2 times higher than that of the traditional activated sludge method, and the concentration of dissolved oxygen is kept above 3mg/L, so that the interference of sulfide to the activated sludge can be well solved, and the sulfur content of the effluent treated by the biochemical treatment process is less than 0.01 mg/L.
As the hot spring bath sewage generally contains animal and vegetable oil with certain concentration, the MBR flat membrane element with better tolerance to the animal and vegetable oil is preferred in the invention.
In the biochemical treatment process, the principle of biochemical treatment by using denitrifying bacteria, nitrifying bacteria and phosphorus accumulating bacteria contained in the activated sludge is as follows:
1) denitrifying bacteria refer to a kind of bacteria that can reduce nitrate nitrogen (NO-3N) into gaseous nitrogen (N) under the condition of oxygen deficiency2) The bacterial group (2) of (1) is known to have a denitrification effect in 10 families and 50 or more genera. The most common denitrifying bacteria in nature are the genera Pseudomonas; secondly, the genus Alcaligenes. The denitrifying bacteria have wide distribution range, and exist in a large amount in sewage and soil, and also exist in activated sludge produced in a sewage treatment plant in the sewage treatment process.
In the anoxic tank, denitrifying bacteria in the sludge can reduce nitrate nitrogen in the sewage into gaseous nitrogen (N) in an anoxic state2)。
The overall denitrification process can be expressed by the following equation:
2NO3-+10e-+12H+→N2+6H2O,ΔG＝-333kJ/mol
the method comprises the following four reduction reactions:
nitrate (NO)3-) to Nitrite (NO)2-)：2NO3-+4H++4e-→2NO2-+2H2O
Nitrite (NO)2-) reduction to Nitric Oxide (NO): 2NO2-+4H++2e-→2NO+2H2O
Reduction of Nitric Oxide (NO) to dinitrogen monoxide (N)2O)：2NO+2H++2e-→N2O+H2O
Nitrous oxide (N)2O) reduction to nitrogen (N)2)：N2O+2H++2e-→N2+H2O
The above four reactions are exothermic reactions, so that the denitrifying bacteria can convert Nitrate (NO) under anaerobic or anoxic conditions3-) as the final electron acceptor (TEA) of the Electron Transport Chain (ETC) to accomplish the exchange of mass energy.
2) Nitrifying bacteria, which belong to autotrophic bacteria, prokaryotes, include two completely different metabolic groups: nitrosomonas and Nitrobacter, which include species of bacilli, cocci and spirochetes that vary in morphology, are widely present in activated sludge.
The nitrite bacteria include bacteria of the genera nitrosomonas, nitrosococcus, nitrosospira and nitrosophyllum. The nitrobacteria include Nitrobacter,
Bacteria of the genera Nitrococcus and Nitrosystus. Both types of bacteria are obligate aerobic bacteria, and oxygen is used as a final electron acceptor in the oxidation process.
Nitrite bacteria (also called ammonia oxidizing bacteria) oxidize ammonia to nitrite. The reaction formula is as follows:
2NH3+3O2→2HNO2+2H2O+158kcal(660kJ)。
nitrate bacteria (also known as nitrite oxidizing bacteria) oxidize nitrite to nitric acid. The reaction formula is as follows:
HNO2+1/2O2＝HNO3-⊿G＝18kcal。
the two types of bacteria can respectively obtain energy required by growth from the oxidation process.
3) The phosphorus accumulating bacteria, also called phosphorus uptake bacteria and phosphorus removing bacteria, such as acinetobacter, aeromonas, corynebacterium, microfilaria and the like, can excessively absorb phosphorus in an aerobic stage and store phosphorus, and have the characteristic of aerobic (or anoxic) excessive phosphorus absorption. Phosphorus accumulating bacteria widely exist in activated sludge generated by sewage treatment plants, and are often used for biological phosphorus removal.
Under aerobic conditions, the PHB stored in the cells is oxidized by phosphorus accumulating bacteria by taking free oxygen as an electron acceptor, phosphate is excessively taken from sewage by utilizing energy generated by the reaction, high-energy substances ATP and phosphorus accumulation are synthesized, and the phosphorus accumulation is stored in the cells as a storage substance. And the residual sludge (rich in phosphorus accumulating bacteria which excessively absorb phosphorus) in the MBR membrane tank is discharged to a sludge concentration tank, so that the high-efficiency phosphorus removal of the sewage can be realized.
The effluent quality of the sewage treated by the biochemical treatment process is superior to the first-class A discharge standard of the national pollutant discharge Standard of municipal wastewater treatment plant (GB18918-2002), can reach the standard of quasi-IV class surface water, but can not reach the standard of surface III class water, so that further advanced treatment is required subsequently.
The anoxic tank and the MBR membrane tank adopted in the biochemical treatment process are both in the prior art, so the structures of the anoxic tank and the MBR membrane tank are not described in detail.
Compared with the traditional secondary sedimentation tank, the MBR flat sheet membrane adopted in the biochemical treatment process has the advantages of good and stable effluent quality, strong impact resistance of the effluent quality, low residual sludge yield, high concentration (6000 plus 12000mg/L) and nearly zero effluent suspended matter and turbidity, and meanwhile, the high-efficiency interception of the MBR membrane can ensure that the high-concentration activated sludge is kept in the MBR membrane tank, thereby reducing the floor area of a sewage treatment facility.
Third, advanced treatment process
And 4, step 4: the effluent of the MBR membrane tank firstly enters an intermediate water tank, and enters a nanofiltration device after being pressurized, and the residual pollutants such as organic substances CODcr, total phosphorus, total nitrogen and the like in the water are subjected to membrane separation under the driving of pressure through a nanofiltration membrane in the device.
The purpose of setting the middle water tank is used for adjusting and balancing the water quantity entering the middle water tank, and the frequent starting and stopping of the water pump are avoided; when the water level of the middle water tank reaches a high liquid level, the water level is pressurized by a water pump and then enters the nanofiltration device.
Step 4, separating organic pollutants CODcr, total phosphorus and ammonia nitrogen remained in the effluent of the MBR membrane tank by using a plurality of groups of nanofiltration membranes in the device, pressing small molecular substances such as sodium chloride and the like and water molecules in the water through the nanofiltration membranes under the pressurization action of a water pump to form fresh water, wherein the water quality meets the discharge requirements of the three types of water standards on the surface, and the fresh water can be discharged into a natural river channel after being collected; residual organic pollutants CODcr, total phosphorus, total nitrogen, divalent calcium magnesium ions and the like in water cannot pass through a nanofiltration membrane due to large particle diameter to form concentrated water, and the concentrated water is not directly discharged after being collected, but flows back to the regulating tank, is mixed with hot spring bathing sewage entering the regulating tank and then enters the circular treatment.
The nanofiltration membrane adopted in the step 4 is the prior art, the aperture is generally 1-2nm, and the nanofiltration membrane is a functional semipermeable membrane which allows solvent molecules or certain low molecular weight solutes or low valence ions to permeate, and is named because the size of the substance to be intercepted is about nanometer. Nanofiltration membranes have been widely used to remove organic substances and color in surface water, to remove hardness of groundwater, to partially remove soluble salts, to concentrate fruit juices, to separate useful substances from drugs, and the like.
In the step 4, the recovery rate of the nanofiltration device is controlled to be 70-75%, the nanofiltration membrane with the recovery rate of over 75% is easy to scale, and the nanofiltration membrane with the recovery rate of less than 70% is uneconomical. Note: recovery rate is 100% fresh water flow/influent water flow.
In order to effectively inhibit the calcium and magnesium in water from scaling in a nanofiltration membrane element, a scale inhibitor is added into nanofiltration inlet water, and the scale inhibitor has the functions of dispersing insoluble inorganic salt in water and preventing or interfering the precipitation and scaling of the insoluble inorganic salt on the surface of the nanofiltration membrane. The scale inhibitor which can be applied to the reverse osmosis process can be used in the invention.
In order to kill virus and bacteria which cannot be eliminated in the biochemical treatment process, the effluent of the MBR membrane tank is irradiated and disinfected by ultraviolet light of an ultraviolet sterilizer (the ultraviolet light of 254um can effectively kill virus and bacteria in water), and then enters the nanofiltration unit.
For the excess sludge formed after the long-term operation of the coagulation sedimentation tank and the MBR membrane tank, the invention is additionally provided with a sludge concentration tank which is used for receiving the sludge discharged from the coagulation sedimentation tank and the MBR membrane tank, concentrating and storing the sludge and periodically outsourcing treatment.
The invention has the following advantages:
1. compared with the common biochemical treatment processes (SBR, A/O, A/A/O, oxidation ditch, biological filter, biological contact oxidation pond and the like), the biochemical treatment process has the advantages of short process flow, small occupied area, high removal efficiency of organic pollutants and phosphorus, strong nitration capability, small amount of generated sludge, no secondary sewage, no priority of malodorous gas discharge, and the like, and simultaneously avoids the interference of sulfide contained in the hot spring bathing sewage on the activated sludge.
2. Compared with the common advanced treatment process (ozone and active carbon combined process, single active carbon process and reverse osmosis process), the advanced treatment process of the invention adopts a nanofiltration mode and has the following advantages:
1) compared with ozone and active carbon, the nano-filtration saves energy and occupies small area.
2) Compared with reverse osmosis, the nano-filtration does not need a calcium and magnesium ion removal pre-process of reverse osmosis, and the process is simple; meanwhile, the operating pressure of nanofiltration is lower than that of reverse osmosis, and energy is saved (the operating pressure of nanofiltration is about 0.7MPa, and the operating pressure of reverse osmosis is generally more than 1.0 MPa).
3) Compared with the single use of the activated carbon, the activated carbon needs to be completely used every year, the workload is large, and meanwhile, the waste activated carbon belongs to dangerous waste; the nanofiltration membrane can stably run for more than 5 years without replacement.
The TP content in the sulfur-containing hot spring bathing sewage treated by the method can be reduced to be below 0.2mg/L, the drainage index can reach the standard of surface three types of water, and the sulfur-containing hot spring bathing sewage can be used as a water supply source of a natural river channel and a landscape water body and can be recycled. The main water quality indexes of the treated effluent are shown in the following table:
Figure BDA0003181442660000081
meets the discharge requirements of the three types of water standards of the ground.
Drawings
FIG. 1 is a process flow diagram of the present invention
Detailed Description
The invention will be further described in detail with reference to FIG. 1, which shows an example of treating sulfur-containing hot spring bath wastewater with a treatment capacity of 300 t/d.
Detection data of inlet water pollutants of sulfur-containing hot spring bath sewage:
Figure BDA0003181442660000082
step 1: introducing the bath sewage into a regulating tank for temporary storage
Adjusting the overall dimension of the tank: l multiplied by W multiplied by H is 9m multiplied by 2.8m multiplied by 3m, and the hydraulic retention time is more than or equal to 5H.
The main corollary equipment:
lift pump, quantity: 2 sets of the sewage treatment device are provided, wherein the flow rate is 15M3/h, the lift is 10M, 1 set of the sewage treatment device is provided with 1 set of equipment, and the equipment is installed in a self-coupling mode and is used for pumping the bath sewage into a regulating tank;
submersible mixer, quantity: 2, the diameter of the blade is 260mm, the blade is made of stainless steel 304, and the blade is used for stirring the bath sewage in the regulating reservoir;
liquid level controllers, number: and the input type static pressure liquid level meter is used for measuring the liquid level in the regulating reservoir and is used as the starting and stopping conditions of the lifting water pump.
The process is as follows:
1) the regulating pool receives hot spring bath sewage, and the hot spring bath sewage is temporarily stored to buffer flow impact;
2) the submersible mixer is started, and sewage in the adjusting tank is uniformly stirred, so that muddy water layering is avoided.
3) Setting the high liquid level of the regulating tank to be 2.7m and the low liquid level to be 0.5m, controlling the lifting water pump to start and stop through the liquid level controller, lifting hot spring bathing wastewater and sewage into the coagulating sedimentation tank through the lifting water pump, wherein the sewage flow is 15m3/h
Step 2, introducing the bath sewage in the regulating tank into a coagulating sedimentation tank, and adding a coagulant PAC and a coagulant aid PAM
The overall dimension of the coagulating sedimentation tank is as follows: l × W × H is 2.8 × 3 × 3m, and the surface load is less than or equal to 0.9m3/m2H, the hydraulic retention time is more than or equal to 1.5 h.
The main corollary equipment:
coagulant dosing device: 2 metering pumps are used for one time, wherein Q is 20L/h, and the metering pumps are used for adding a coagulant into a water inlet pipe of a coagulation sedimentation tank;
coagulant aid charge device: 2 metering pumps are used for one time, Q is 50L/h, and the metering pumps are used for adding coagulant aids into a reaction area of a coagulation sedimentation tank;
1 sludge pump, Q is 5.0m3The head is 10M, and the sludge is discharged into a sludge concentration tank;
1 mixer, model JBJ-350, rotation speed 85 r/min. The coagulant aid is used for stirring in a reaction area of a coagulation tank, and the added coagulant aid is uniformly mixed;
the process is as follows:
1) adding a coagulant aid PAM into a water inlet pipe of the coagulating sedimentation tank, mixing the coagulant aid PAM with the sewage introduced from the regulating tank in the water inlet pipe, and then performing the coagulation sedimentation tank; the coagulant aid PAC is directly added into the reaction zone of the coagulating sedimentation tank. Soluble phosphate and coagulant contained in the sewage are subjected to chemical reaction in a reaction zone of the coagulation tank to generate water-insoluble micro precipitates, and then the micro precipitates form larger flocculants under the actions of flocculation, adsorption bridging, surface adsorption, reinforcement and the like of the coagulant aid, and the larger flocculants and other settleable substances and/or floating substances carried in the sewage are settled in the settling zone of the coagulation tank to form sludge.
2) The sewage formed at the upper part of the coagulating sedimentation tank automatically flows into the anoxic tank, the sewage flow is 15m3/h, the sludge at the lower part is periodically discharged into the sludge concentration tank, and the sludge is periodically discharged into the sludge concentration tank.
3) Determining the dosage of a coagulant PAC to be 5-10PPM according to the content of Total Phosphorus (TP) in the bath sewage detected before treatment; the dosage of the coagulant aid PAM is 1-2 PPM.
4) Sludge discharge control: the principle is to arrange the mud twice a day for 5 minutes each time with less work.
Step 3, anoxic pond-MBR composite biochemical treatment
The shape and size of the anoxic pond are as follows: l multiplied by W multiplied by H is 4m multiplied by 2.8m multiplied by 3m, and the retention time is more than or equal to 2.0H.
The main corollary equipment:
the water inlet and distribution pipe of the anoxic tank: DN100 and DN50, chemical grade UPVC, quantity: 1, 1 set of;
an anoxic tank sludge return pipe; DN100 and DN50, chemical grade UPVC, quantity: 1, 1 set of;
the process is as follows:
the anoxic tank receives the incoming water of the coagulation sedimentation tank and the return sludge of the MBR membrane tank in the rear-end procedure, denitrifying bacteria in the anoxic tank perform denitrification activity under an anoxic environment to remove nitrate nitrogen brought by the return sludge, and a small amount of CODcr can be removed at the same time. The effluent of the anoxic tank automatically flows into an MBR membrane tank, and the sewage flow is 15m 3/h.
The process control parameters are as follows:
1) sewage inflow rate of 15m in anoxic pond3H, controlling the amount of the returned sludge in the MBR membrane tank to be 3-5m3Is between/h.
2) The dissolved oxygen concentration of the anoxic tank is kept between 0.1 and 0.5 mg/l.
MBR membrane pool: 1 seat, the external dimension L multiplied by W multiplied by H is 5.5m multiplied by 2.8m multiplied by 3m, and the hydraulic retention time is more than or equal to 3.0 hours.
MBR membrane element that MBR membrane cisterna is built-in: flat membrane with membrane flux less than or equal to 0.4m3/m2D, flat sheet membrane module 7 groups, total membrane area 770m2PVDF as membrane material, 304 stainless steel as membrane frame material,
the main corollary equipment:
2 self-priming pumps are provided, Q is 16-18m3/h, the head is 8-10m, and 1 is used; the water discharging device is used for discharging water in the MBR membrane tank into the intermediate water tank;
2 sludge reflux pumps with Q equal to 5m3H, the lift is 8-10m, and 1 is used as 1; the sludge backflow device is used for discharging sludge in the MBR membrane tank into the anoxic tank;
2 excess sludge pumps, 5-8m Q3The delivery lift is 8-11m, 1 is 1 device, and the device is installed in a self-coupling mode; the sludge concentration tank is used for discharging the residual sludge in the MBR membrane tank into the sludge concentration tank;
2 blowers, Q being 12m3Min, wind pressure of 30kpa, 1 is prepared with 1; used for aerating and oxygenating the MBR membrane tank;
the process is as follows:
1) remove most organic pollutants (COD) in the sulfur-containing hot spring bath sewageCr) Removing large amount of sewagePart of NH3And (N) removing residual phosphorus in the sewage.
2) Receiving the incoming water from the anoxic tank, and aerating and supplying oxygen to the MBR membrane tank by using an air blower, wherein the dissolved oxygen concentration is kept between 3 and 5 mg/l.
3) The activated sludge concentration was kept between 8000-12000 mg/l. If the sludge concentration exceeds the range, an excess sludge pump is used for delivering excess sludge to the sludge concentration tank every 30 minutes.
4) The sludge is returned to the anoxic tank by a sludge pump, and the flow is controlled to be 3-5m3Is between/h.
5) MBR membrane cisterna goes out water, uses the self priming pump to aspirate from MBR membrane element, through the filtering action of MBR membrane, aspirates clear water from the membrane cisterna, and flow 16-18m3/h, self priming pump effluent flow in middle pond.
6) An ultraviolet sterilizer is arranged in the middle of the water outlet pipe of the self-priming pump, and bacteria and viruses in the water are sterilized under the irradiation of ultraviolet light of 254 um.
And 4, step 4: effluent of the MBR membrane tank firstly enters an intermediate water tank for temporary storage, enters a nanofiltration device after being pressurized by a water pump, is subjected to membrane separation under the driving of pressure by nanofiltration membranes in the device on residual pollutants such as organic substances CODcr, total phosphorus, total nitrogen and the like in water, and pollutants which cannot pass through form concentrated water, are discharged into an adjusting tank for retreatment, can pass through to form fresh water, and are discharged into a clean water tank.
A middle water tank: 1, overall dimension: l × W × H is 3m × 2.8m × 3 m. The water pump is used for adjusting the water quantity and avoiding the frequent start and stop of the water pump;
and (3) nanofiltration device: 1 set, external dimension: l × W × H is 5.5 × 1.5 × 2.5 m. And the effluent water used for the MBR membrane tank is subjected to membrane separation under the driving of the pressure of a water pump.
The main corollary equipment (the following equipment are all installed on a stainless steel shelf):
cartridge filter (containing filter element), DN400, filtration precision 5 μm, SS 304; the device is arranged in front of the nanofiltration device and used for filtering solid particles with the particle size larger than 5 mu m in water and protecting the nanofiltration membrane;
high-pressure pumps, number: 1, Q is 20m3H, the lift is 120m, and N is 15 kW; the water supply and pressurization device is used for supplying water and pressurizing to the intermediate water tank;
nanofiltration membrane shell, 4 cores, quantity: 6 branches; is used for containing the nanofiltration membrane element;
nanofiltration membrane, combined VNF1-8040, quantity: 24 sets of the medicine bag; effluent for filtering MBR membrane tank
Membrane frame, 5000 × 1000 × 2600mm, material: stainless steel 304, amount: 1 set. Used for fixing the equipment in the nanofiltration device;
glass float flowmeter, range: 0-40m3H, amount: 1, 1 set of; for measuring fresh water flow;
glass float flowmeter, range: 0-20m3/h, number: 1, 1 set of; for measuring concentrate flow;
scale inhibitor charge device, V200L, 1 platform of supporting measuring pump, Q5L/h, quantity: 1 set. Used for adding a scale inhibitor into nanofiltration inlet water.
The process is as follows:
1) and receiving the water coming from the MBR membrane tank, and deeply purifying residual CODCr, total phosphorus and total nitrogen in the effluent of the MBR membrane tank through the separation of the nanofiltration membrane to ensure that the effluent reaches the III-class water on the earth surface.
2) Inflow rate of 20m3H, fresh water flow 15m3H, concentrate flow 5m3/h。
3) The operation pressure is controlled between 0.7 and 0.8 MPa.
4) The scale inhibitor is PWT200, and the dosage is controlled to be 1-3 PPM.
5) And the fresh water is discharged to a nearby landscape river channel after being detected to reach the standard and is used as a supplementary water source. And (5) refluxing the concentrated water to the regulating tank for treatment again.
The corollary equipment: sludge thickening tank
Sludge thickening tank
The external dimension is as follows: l × W × H is 3m × 2.8m × 3 m.
The process is as follows: and (4) concentrating and storing the sludge discharged from the coagulation sedimentation tank and the MBR membrane tank, and periodically outsourcing treatment.
The main indexes of the sulfur-containing hot spring bathing sewage treated by the process can stably reach the standard of surface standard three types of water, and the method comprises the following steps:
Figure BDA0003181442660000121

Claims (10)

1. a method for treating sulfur-containing hot spring bathing sewage is characterized by comprising the following steps:
first, pretreatment process
The pretreatment mainly solves the problems of uneven water supply and large solid carried in the hot spring bath sewage, and chemical phosphorus removal is carried out;
step 1: introducing the bath sewage into a regulating tank for temporary storage;
step 2: introducing the bath sewage in the regulating tank into a coagulating sedimentation tank, and adding a coagulant and a coagulant aid;
second, biochemical treatment process
The biochemical treatment process is to degrade and remove organic pollutants, ammonia nitrogen, total phosphorus and other pollutants in the hot spring bathing sewage by using the life activities of microorganisms contained in the activated sludge;
and step 3: anoxic tank-MBR composite biochemical treatment: the effluent of the coagulation sedimentation tank sequentially enters an anoxic tank and an MBR membrane tank, which are pre-fed with activated sludge, and the anoxic tank simultaneously receives return sludge from the MBR membrane tank;
third, advanced treatment process
And 4, step 4: the effluent of the MBR membrane tank firstly enters an intermediate water tank, enters a nanofiltration device after being pressurized, and is subjected to membrane separation under the driving of pressure on residual pollutants such as organic substances CODcr, total phosphorus, total nitrogen and the like in water through a nanofiltration membrane in the device.
2. The method for treating sulfur-containing spa bath sewage as claimed in claim 1 wherein in step 2, a coagulant is added to the inlet pipe of the coagulation sedimentation tank and mixed with the sewage introduced from the conditioning tank at the inlet pipe to be conducted to the coagulation sedimentation tank; the coagulant aid is directly added into the reaction area of the coagulating sedimentation tank.
3. The method as claimed in claim 1, wherein the amount of coagulant added in step 2 is 1-2 times, preferably 1.5 times, the phosphorus content of the bath wastewater.
4. The method for treating sulfur-containing hot spring bath sewage as claimed in claim 1, wherein in step 3, the activated sludge pre-fed into the anoxic tank and the MBR membrane tank is composed of aerobic microorganisms, metabolic products of microorganisms, and adsorbed organic and inorganic substances; the aerobic microorganism comprises bacteria, protozoa, metazoan, fungi and algae; the activated sludge contains at least three types of bacteria, namely denitrifying bacteria, nitrifying bacteria and phosphorus accumulating bacteria.
5. The method for treating sulfur-containing hot spring bath sewage as claimed in claim 1, wherein in step 3), the sewage treated by the coagulation sedimentation tank and received by the anoxic tank is firstly directly discharged into the MBR membrane tank, and the following biochemical treatment is carried out in the MBR membrane tank:
the sewage after the coagulating sedimentation tank is treated is directly discharged into the MBR membrane tank at the initial stage, and the following biochemical treatment is carried out in the MBR membrane tank:
1) through the biological activity of microorganisms in the activated sludge in the MBR membrane tank, most of organic pollutants (COD) in the sulfur-containing hot spring bath sewage are efficiently removedCr)；
2) Nitrifying bacteria in the activated sludge in the MBR membrane tank are used for treating ammonia Nitrogen (NH) dissolved in the bath sewage3N) nitrifying to form nitrate nitrogen, filtering and carrying out solid-liquid separation on the sewage by using an MBR membrane element arranged in an MBR membrane tank, leaving the separated sludge containing the nitrate nitrogen in the MBR membrane tank to flow back to an anoxic tank, and allowing the separated liquid to enter a nanofiltration tank of a subsequent deepening treatment process;
3) phosphorus in sewage is excessively absorbed into the body by phosphorus accumulating bacteria in activated sludge in an MBR membrane tank in an aerobic state, so that the phosphorus in the sewage is removed;
4) the MBR membrane tank is oxygenated in the biochemical treatment process, so that water in the MBR membrane tank maintains higher oxygen concentration, oxygen and hydrogen sulfide are subjected to displacement reaction in the water to generate light yellow elemental sulfur, and the light yellow elemental sulfur is discharged into a sludge concentration tank along with sludge discharged periodically, so that the sulfur in the sewage is removed.
6. The method as claimed in claim 1, wherein in step 3), after the anoxic tank receives the return sludge from the MBR membrane tank, the denitrification bacteria of active sludge pre-thrown in the anoxic tank are used to reduce the nitrate nitrogen brought by the return sludge in the MBR membrane tank to N by taking the organic CODcr in the sewage treated by the coagulation sedimentation tank as a carbon source2And released to the atmosphere while removing a small amount of CODcr from the wastewater.
7. The method as claimed in claim 1, wherein the concentration of dissolved oxygen in the anoxic tank in step 3) is controlled to be between 0.1 and 0.5 mg/l.
8. The method for treating sulfur-containing spa bath sewage according to claim 1 wherein in step 3), the reflux ratio of the volume of the influent water to the sludge in the MBR membrane tank to the volume of the influent water to the anoxic tank is between 0.3 and 0.5.
9. The method for treating sulfur-containing spa bath sewage according to claim 1 wherein in step 3), the sludge concentration during the operation of the MBR membrane basin is maintained between 6000mg/L and 12000mg/L, and the dissolved oxygen concentration is maintained above 3 mg/L.
10. The method of claim 1, wherein the effluent from the MBR membrane tank is sterilized by UV irradiation using a UV sterilizer and then enters the intermediate tank.
CN202110848083.XA 2021-07-27 2021-07-27 Method for treating sulfur-containing hot spring bath sewage Pending CN113415955A (en)

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CN205115214U (en) * 2015-07-24 2016-03-30 上海市环境科学研究院 Distributed rural domestic sewage integrated process device of modularization MBR
CN109607965A (en) * 2019-01-09 2019-04-12 湖北君集水处理有限公司 A kind of system and method for sewage treatment plant tail water advanced nitrogen dephosphorization
CN110028209A (en) * 2019-05-30 2019-07-19 安徽欣创节能环保科技股份有限公司 A kind of application of MBR technique in sanitary sewage disposal

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