Combined sterilization technical method

Abstract

The invention relates to a combined sterilization technical method, which can perform technical adjustment in time according to factors such as on-site actual conditions, incoming water quality and seasonal variation, adopts an efficient combined sterilization technical method to improve the sterilization effect, and effectively solves the technical problem that a water treatment system is puzzled by microbial pollution and blockage. Meanwhile, the influence of biological drug resistance on the sterilization effect can be avoided and eliminated, and the service life of water treatment equipment is greatly prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water treatment, in particular to a combined sterilization technology method. BACKGROUND

[0002] The composition of steel industry wastewater is complex, including various microorganisms, and the water temperature of industrial wastewater is maintained at 20-32 DEG C throughout the year, 28-32 DEG C in summer, and even above 20 DEG C in winter, which is very suitable for the growth of bacteria and microorganisms. Especially in the two seasons of April and May and September and October, the microorganisms grow explosively, and the pressure difference of all reverse osmosis units increases and the output greatly reduces within one or two days. In the water system, water is in a variety of closed containers in the whole process, such as filters, ultrafiltration membrane elements, security filters, reverse osmosis membrane elements and various water tanks, which are very suitable for the growth of microorganisms. Once the total amount of microorganisms exceeds the control range, it will cause serious pollution of ultrafiltration, security filter, reverse osmosis and other devices, rapid reduction of water quantity, increase of pressure difference and great reduction of system output. Moreover, due to the long process of the process system, it is difficult and costly to treat the water source contaminated by microorganisms for a long period of time, so the pollution caused by microorganisms is the primary problem of water treatment system.

[0003] The bactericides generally have strong oxidizing properties, such as sodium hypochlorite, chlorine, chlorine dioxide and ozone, which are conventional bactericides for water treatment and have strong oxidizing properties. However, the desalination layer on the reverse osmosis membrane element is an oxidizing substance, which will cause irreversible damage after contacting with the oxidizing bactericide, reduce the desalination rate and cannot be restored, so it is necessary to add a reducing agent before entering the reverse osmosis unit to ensure that all oxidizing substances are reduced to avoid damage to the surface of the membrane element.

[0004] The addition of bactericides to eliminate microbial contamination and the non-contact of reverse osmosis with strong oxidizing substances become contradictory, and the use of a single bactericide has great limitations, which is difficult to completely kill the bacteria in the water, and it is urgent to find a solution to the problem.

[0005] The purpose of the present application is to provide a scientific and effective combined sterilization technology method with strong operability, which can effectively kill the bacteria in the water through the combined sterilization technology method of full-flow multi-point, multi-species and variable frequency sterilization, control the reasonable range and ensure the stable operation of the system. SUMMARY

[0006] The purpose of the present application is to provide a combined sterilization technology method.

[0007] The object of the present application is achieved by a combined sterilization technology method, comprising: (1) full-process, multi-point sterilization: firstly adding sodium hypochlorite solution in the aeration tank, the flow rate being 25 L / h, the concentration being 80-100 ppm, and the sodium hypochlorite solution being stirred uniformly before entering the sedimentation tank, the first sterilization being performed within 3-4 hours of residence in the sedimentation tank, and the sodium hypochlorite solution being secondarily added in the sedimentation tank water production tank, the flow rate being 25 L / h, the concentration being 20-30 ppm, and the residual chlorine of the ultrafiltration product water being controlled to be between 0.5 ppm and 0.8 ppm; (2) multi-variety, variable-frequency sterilization: DBNPA and isothiazolinone non-oxidizing sterilizing agents are alternately used for sterilization in the aeration tank and the sedimentation tank water production tank, the sterilization cycle being 1 time of DBNPA sterilization, 2 times of isothiazolinone sterilization, and the scientific process adjustment being made according to seasons, the alternate sterilization being performed once every 2-3 days in summer and once every 3-5 days in winter.

[0008] (2) In mid-summer, solid chlorine cake is added at the inlet of the sedimentation tank, and the amount of the solid chlorine cake is 3-5 grams per cubic meter.

[0009] The present application has the beneficial effect that after the present application is used, the system microbial contamination is effectively controlled, the membrane pressure difference in summer can be controlled to be below 0.30 Mpa, the cleaning cycle is increased from 15-20 days to 24-30 days, the pressure of microbial contamination on the membrane system operation is relieved, the microbial contamination is controlled and relieved after the strengthened microbial control technology scheme is used, the pressure difference is controlled to be below 0.30 Mpa, and the water treatment system tends to be stable operation. DETAILED DESCRIPTION

[0010] Full-process, multi-point sterilization: firstly adding sodium hypochlorite solution in the aeration tank, the concentration being 80-100 ppm, the stirring being performed by the lifting pump to stir the medicament and water uniformly before entering the sedimentation tank, the first sterilization being performed within 3-4 hours of residence in the sedimentation tank to kill most of the microorganisms, and a small amount of microorganisms entering the sedimentation tank water production tank, and in order to avoid the growth of the filter in the next process, the sodium hypochlorite solution is secondarily added in the sedimentation tank water production tank, the concentration being 20-30 ppm, and the number of microorganisms being further reduced. The concentration of the two times of sodium hypochlorite addition is standardized by detecting the residual chlorine of the ultrafiltration product water, the residual chlorine of the ultrafiltration product water being controlled to be between 0.5 ppm and 0.8 ppm, the sodium hypochlorite solution being increased in the front-end sterilizing agent when the residual chlorine is found to be reduced, and the sodium hypochlorite solution being reduced in the front-end sterilizing agent when the residual chlorine is found to be too large to cause the sodium hypochlorite to combine with the hardness in water to form calcium scale.

[0011] Multi-variety, variable frequency sterilization: To avoid the development of drug resistance in the water and the accumulation of microorganisms on the system walls, DBNPA and isothiazolinone non-oxidizing bactericides are used alternately in the aeration tank and sedimentation tank. This avoids the impact of biological resistance on the sterilization effect. A cyclical sterilization method of one DBNPA sterilization and two isothiazolinone sterilizations is adopted. Scientific process adjustments are made according to the season. In summer, bactericide is added once every 2-3 days, and in winter, bactericide is added once every 3-5 days.

[0012] In summer, to enhance the sterilization effect and avoid insufficient addition of sterilizing agents to the aeration tank, solid chlorine cake is added to the inlet of the sedimentation tank. The chlorine cake can slowly release sterilizing components and work synergistically with sodium hypochlorite.

[0013] (I) Multi-point sterilization throughout the entire process: 1. The sodium hypochlorite dosing and delivery system consists of two 5m³ sodium hypochlorite storage tanks, one with a concentration of 80-100ppm and the other with a concentration of 20-30ppm. Each sodium hypochlorite tank is equipped with two unloading pumps and two mechanical metering pumps. During operation, one metering pump is in use and the other is on standby. The metering tank is equipped with high and low level alarms to promptly remind operators to prepare the dosing solution. A Y-type filter is installed at the inlet of the metering pump, and the dosing pipeline is equipped with a check valve and a manual ball valve.

[0014]

[0015] (II) Multi-variety, frequency conversion sterilization: 1. Two metering boxes are respectively filled with liquid non-oxidizing bactericides DBNPA (2,2-dibromo-3-nitropropionamide) and isothiazolinone (5-chloro-2-methyl-4-isothiazolin-3-one / 2-methyl-4-isothiazolin-3-one).

[0016] 2. Specific sterilization method: 2.1 Use DBNPA and isothiazolinone non-oxidizing bactericides alternately to avoid the impact of biological resistance on the sterilization effect. Use a cycle of one DBNPA sterilization and two isothiazolinone sterilizations. In summer, add bactericide once every 2-3 days and in winter, add bactericide once every 3-5 days.

[0017] 2.2 Use DBNPA for sterilization, with an effective concentration of 200~500mg / l and a duration of 2-4 hours.

[0018] 2.3 Use isothiazolinone, with an effective concentration of 150~300 mg / L, for a duration of 1-2 hours.

[0019] Example 1

[0020] The membrane system of the Energy and Power Plant adopts this combined sterilization technology, which effectively controls and alleviates microbial contamination of the system. In particular, the membrane pressure difference in summer can be controlled below 0.30 MPa, compared to the previous 3-4.5-30 MPa. The cleaning cycle has been increased from 7-15 days to 15-20 days, which alleviates the pressure of microbial contamination on the operation of the membrane system and extends the service life of reverse osmosis membrane elements to more than 3 years.

[0021] After adopting this technology, the No. 2 membrane at the Energy and Power Plant effectively controlled microbial fouling in the reverse osmosis system. In summer, the membrane pressure differential could be kept below 0.30 MPa, and the cleaning cycle was increased from 15-20 days to 24-30 days, alleviating the pressure of microbial fouling on the membrane system's operation. In particular, at the end of September 2011, the No. 1 membrane system suffered from severe microbial fouling, resulting in a rapid increase in the reverse osmosis pressure differential, rising from 0.1 MPa to 0.4 MPa in a short period. Membrane fouling was severe, making it difficult to maintain the demineralized water supply. After adopting the enhanced microbial control technology, microbial fouling was controlled and alleviated, the pressure differential was kept below 0.30 MPa, and the reverse osmosis system stabilized.

[0022] The above description is only a specific embodiment of the present invention, but the structural features protected by the present invention are not limited thereto. Any changes or modifications made by those skilled in the art within the scope of the present invention are covered by the patent scope of the present invention.

Claims

1. A combined sterilization technology method, characterized in that: include: (1) Full-process, multi-point sterilization: First, add sodium hypochlorite solution to the aeration tank for 2-4 hours each time, with a flow rate of 25L / h and a concentration of 80-100ppm. Stir the sodium hypochlorite solution and water evenly before entering the sedimentation tank. Perform the first sterilization within 3-4 hours of residence in the sedimentation tank. Add sodium hypochlorite solution to the product water tank of the sedimentation tank for 1-2 hours each time, with a flow rate of 25L / h and a concentration of 20-30ppm. Control the residual chlorine of the ultrafiltration product water to be between 0.5ppm and 0.8ppm. (2) Multi-variety, variable frequency sterilization: DBNPA and isothiazolinone non-oxidizing bactericides are used alternately in the aeration tank and sedimentation tank. The sterilization method is to use DBNPA once and isothiazolinone twice in a cycle. Scientific process adjustments are made according to the season. In summer, the alternating sterilization is carried out once every 2-3 days, and in winter, the alternating sterilization is carried out once every 3-5 days.

2. The combined sterilization technology method according to claim 1, characterized in that: (2) In summer, add solid chlorine cake at the inlet of the sedimentation tank. The amount of solid chlorine cake is 3-5 grams per cubic meter.

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