The Significance of Calibrating the Conductivity Meter in Saving Water Resources

1 The importance of conductivity Conductivity represents the conductivity of various ions in aqueous solution, can be used to represent the total amount of various ions, both accurate, simplified detection methods, but also online measurement, monitoring the work of the water treatment system at any time .

"China Pharmacopoeia" UPS24 stipulates that the use of pharmaceutical water for on-site production, the use of electrical conductivity measurement of alternative chloride, * salt, calcium salt, ammonia and carbon dioxide five detection, we can see the importance of conductivity testing. The newly installed on-line conductivity meter, because the host and the conductivity cell are all new, after installation and debugging at the factory site, it is estimated that the problem is not large, and its accuracy is relatively reliable. The raw water enters the reverse osmosis unit after it has been processed by a series of processes including source water storage tanks, source water pumps, medicine boxes, metering pumps, mechanical filters, activated carbon filters, softeners, fine filtration, and high-pressure pumps. The main part of the reverse osmosis system in the water system is the reverse osmosis membrane module. The residual reverse osmosis reference temperature is 25°C, and the water utilization rate should reach 70% to 75%. When the factory engineer is installing and debugging, it will set an on-line conductivity meter to measure the conductivity range and measurement point. After a series of preliminary treatment of water in the previous stage, the second conductivity measurement is performed in this step (the first time The original water conductivity test). When the on-line conductivity meter has been in operation for a long time, especially when the conductivity cell is immersed in water for a long time, it is prone to ageing. As a result, measurement errors occur, resulting in great water waste. Today, it is particularly important to promote water conservation throughout the world.

2 Conductivity Meter Verification Protocol Requirements for the Conductivity Meter From the verification procedures, it is sufficient for the on-line conductivity meter to detect the instrument reference error. The conductivity of the conductivity standard solution measured by an on-line conductivity meter conductivity cell, the instrument reference error should not be greater than ± 4.5% FS, otherwise the on-line conductivity should be adjusted to meet the measurement requirements.

3 On-line conductivity meter real-time dynamic detection scheme The conductivity measurement data of the original water tank, intermediate water tank and purified water tank are transmitted to the single-chip microcomputer control through wireless transmission, and dynamic measurement is realized. The on-line conductivity meter is calibrated every six months.

4 Trends in project development According to my long-term experience in physical and chemical testing, and consulting related data, I learned that the calibration of this project is the first in Guangxi. By then, all pharmaceutical factories in Guangxi Province will follow suit and have great potential for development.

5Pure water production process for pharmaceutical industry 5.1 The most popular new process technology: raw water (conductivity detection) → raw water pressurization pump → multi-media filter → activated carbon filter → softener → precision filter first → first stage Permeation (conductivity detection) → pH adjustment → Intermediate tank → Reverse osmosis of the second stage (positive charge on the reverse osmosis membrane) → Purified water tank → Pure water pump → Ultraviolet sterilizer → Microporous filter → Water point 5.2 Typical pharmaceutical system Design Examples Pharmaceutical Water Systems There are various system designs depending on the process water requirements and the specific water conditions. No matter which kind of system design form, all around the peculiar situation of the pharmaceutical water, carry on the comprehensive design to the process water preparation, the storage, the distribution transportation and the microorganism control and so on the request. The design of pharmaceutical water systems is a comprehensive design.

5.3 Design Principles of a Typical Purified Water System Process The purified water system can be designed for a single use purpose or as a pre-process for injection water. The design of the purified water system can have many options. These choices are related to the water quality of the source water, the technological requirements of the product and other actual conditions of the company. The most fundamental principle is to meet the requirements of GMP and produce purified water that meets the standards.

6 Design points of a typical purified water system configuration 6.1 Source water storage tanks General source water storage tanks should be provided with high and low water level electromagnetic induction level gauges to dynamically detect the tank liquid level. When the water level is not low, the conditions for starting the source pump and the metering pump are still available, and the tank material is often made of non-metal, such as polyethylene (PE).

6.2 The source water pump can be an ordinary centrifugal pump. The pump should be provided with a high-temperature overheat protector and a pressure controller to increase the life of the pump. In order to prevent failure, the pump should also be equipped with an automatic alarm system.

6.3 Medicine tanks and metering pumps If the turbidity of the source water is high, the automatic dosing pump is usually used for automatic dosing (the dosing amount is determined during commissioning). At the same time, according to the characteristics of the urban pipe network water supply and the source water quality report, A suitable amount of flocculant allows the algae, colloids, particles and some organic matter in the source water to be agglomerated into larger particles for removal by the subsequent sand filtration. The material of the addition kit is also mostly non-metallic material (such as PE). The dosing of the metering pump should be synchronized with the operation of the source pump.

6.4 Mechanical Filters If well water is used as the source water, the well water often contains fine particles of dust, humus, starch, cellulose, bacteria, and algae. The colloidal particles in which these impurities and water form a sol state exhibit sedimentation stability and polymerization stability due to Brownian motion and electrostatic repulsive force. Usually, they cannot be removed by natural sedimentation but they should be treated by source water, ie, by adding flocculation. The agent destroys the stability of the sol and causes the fine colloidal particles to flocculate into larger particles which are removed by pre-filtration through sand filtration and charcoal filtration. The filter media used in sand filtration mostly uses large-grained quartz sand to remove the floccular impurities (mainly organic humus and clay inorganic compounds) in the source water, and the effluent turbidity is less than 0.5 FTU after being treated by a mechanical filter. Because of the oxidation of the chloride ion in the source water to the metal, and for a long time, the surface of the metal will undergo intergranular corrosion. Therefore, the mechanical filter tank can be made of non-metallic glass liner lined with PE bile, or stainless steel lined with rubber tank.

6.5 Activated carbon filter In this example, the reverse osmosis treatment process was used in the water system. In addition to the reverse osmosis water influent, the sediment density index SDI ≤ 5 was required, and there was another influent index, namely residual chlorine <0.1 mg. /L, an active filtration device is configured for this purpose. In the system, the activated carbon filter mainly has two processing functions: (1) It adsorbs part of the organics in the water, and the adsorption rate is about 60%; (2) The residual residual oxygen ions in the water are difficult to remove through the mechanical filter. In order to further purify the source water, so that it meets the requirements of the influent index of the reverse osmosis membrane, a grade 1 activated carbon filter is usually designed in the process flow. Activated carbon can be used to adsorb substances with a particle size of about 0.1 to 0.9 nm due to the presence of a large number of pores and gaps in the structure with an average pore size of 2 to 5 nm. This structure characteristic of activated carbon makes its adsorption surface area reach 500-2000 m2/g. Since the molecular diameter of general organic materials is slightly more than 2-5 nm, the adsorption of organics by activated carbon is most effective. In addition, activated carbon also has a strong dechlorination capacity. There is no problem of saturated adsorption of activated carbon, but only a small amount of carbon is lost, so dechlorination of activated carbon can be operated for a long time. In addition to dechlorination and adsorption of organics, activated carbon can also remove odors, chromaticity, and residual turbidity in water. The integrated treatment in the water system is extremely strong. However, it should be noted that after a certain period of use, activated carbon still weakens its adsorption capacity and requires regeneration.

After the above secondary treatment, the purity of the source water is greatly improved. The residual chlorine content in the treated water is less than 0.01mg/L. Because of the oxidation of the residual chlorine ions in the source water to the metal, and after prolonged use, intergranular corrosion occurs at the surface of the metal. Therefore, the tank of the activated carbon filter can be made of non-metallic glass liner lined with PE, or stainless steel lined with rubber tank.

6.7 The softener used in the softener water system uses exchangeable Na in the sodium ion resin to exchange Ca and Mg in the water and soften the source water to demineralized water. This is of great significance in preventing fouling of the reverse osmosis membrane surface and improving the working life and treatment efficiency of the reverse osmosis membrane. Since the CL- in the regeneration liquid can cause corrosion of the metal, the softener tank body should be made of a non-metallic material, for example, a FRP shell lined with PE bile, or a stainless steel lined rubber tank. The softener filter uses sodium cation resin.

6.8 Fine filtration Fine filtration is also referred to as security filtration in each system of water. It is usually achieved by melt-blown polypropylene (PP) membranes with a pore size of 5 μm. Fine filtration is the last process before the source water enters the reverse osmosis membrane. Its role is to prevent possible leaks in the previous filtration process. Otherwise, some solid particles will infiltrate the reverse osmosis membrane, blocking the reverse osmosis membrane.

6.9 High-pressure pump As the power source of the reverse osmosis system, the high-pressure pump should be equipped with high and low voltage protection and overheat protection to prevent damage to the pump. The performance of the high pressure pump is stable and reliable to protect the operation of the water system. The secondary pump is generally made of 316L stainless steel.

6.10 Reverse osmosis The main part of the reverse osmosis system of the host water system is the reverse osmosis membrane module. Since the effluent of the reverse osmosis is acidic, the metal membrane shell will be gradually corroded. Therefore, the selection of the membrane shell should protect the host from salt removal for a long time. Stable and reliable to meet the design requirements. The reverse osmosis mainframe is designed, the residual reverse osmosis reference temperature is 25°C, the water utilization rate should reach 70% to 75%, and the total desalination rate of the reverse osmosis system should be greater than 97%. The reverse osmosis control system can be controlled by microcomputers to achieve automatic control of reverse osmosis membrane modules such as smooth washing, water making, full tank filling, medicine washing, high and low pressure protection of the high pressure pump, and overheat protection. There is a random display of conductivity.

6.11 Primary Purification Tank (Intermediate Water Tank)

The material of the equipment can be S304 stainless steel, and the capacity of the container is based on design requirements.

6.12 grade purified water pump (middle booster pump)

The primary purification pump of the water system shall be provided with a high-temperature overheat protector, a pressure controller and a water monitor to increase the life of the pump. In the event of a fault, the pump should have an automatic alarm system.

6.13 Acid-base Regeneration Tank and Hydraulic Jet Pump To ensure the regeneration of the anion resin and cation resin in the mixed bed, the system is equipped with two acid-base regeneration tanks with appropriate capacity and a jet pump. The material of the regeneration tank should be made of corrosion-resistant non-metallic materials.

6.14 mixed bed ion exchange device in order to make the quality of the water after reverse osmosis host treatment to resistivity ≥ 2MΩ.m requirements, but also to ensure that the resin regeneration after the failure of the ion exchanger does not affect the production, usually in the design of two sets of mixed The bed, one set is used, and one set is used for regeneration. The entire process of use and regeneration can be automatically switched by the control system and manually regenerated. An ion-exchanged deep desalination device is generally provided behind the reverse osmosis system in the water system. Filters used in ion exchangers should use high quality resins.

6.15 Micropore Filtration The micropore filter composed of 0.25μm pore size polyvinyl fluoride filter rods is used to remove fine particles remaining in the purified water and the broken resin leaked from the ion exchange device after the above treatment to make the water outflow. Ultimately meet all requirements for using water quality in the conditions.

6.16 The secondary purified water tank is purified water product water tank. The container is made of 316L stainless steel. In order to completely drain the water in the container and facilitate on-line cleaning, the container should adopt a dome-shaped vertical structure.

6.17 Secondary purification pumps should use sanitary pumps.

The pump shall be in the form of a non-volumetric air gap and a drain valve shall be installed at the lowest point of the pump to drain the water. The pump should be equipped with a high thermal protector, pressure controller, and water monitor to increase pump life. In the event of a fault, the pump is equipped with an automatic alarm system. The power used by the pump should be large enough to make the water flow rate in the system >2m/s.

6.18 Ultraviolet sterilizer Although the entire purified water system was treated through the above processes, the water quality was met the water quality requirements, but in order to prevent the stagnant water on the pipeline and the bacteria on the inner wall of the container pipeline from affecting the quality of the water supply, the reverse osmosis treatment unit was A high-power ultraviolet sterilizer should be installed at the end of the outlet water supply pipeline to protect the reverse osmosis treatment unit from possible microbial contamination of the water system, and to prevent or delay the growth of microbial cells in the pipeline system.

6.19 Pasteurization There are two places in the entire water system that require special control of microorganisms. One is an activated carbon filter and a softener. This is because the main function of the activated carbon filter is to remove organic matter. The upstream side of the activated carbon filter must accumulate a large amount of organic matter with the use of time. In order for the treatment unit to have a defined ability to treat microorganisms, it will not cause pollution on the downstream side due to excessive accumulation of microorganisms, and it is necessary to perform regular disinfection thereof. The other is the regular disinfection of the product purified water circulation system. In this example, a Pasteur sterilizer was used to accomplish the above-mentioned required periodic sterilization.

Each Pasteur sterilizer is equipped with 2 temperature-controlled probes, one in the equipment storage tank and the other at the outlet of the heat exchanger. The return temperature of the Pasteur sterilizer is not lower than 80°C. The temperature is above 83°C. Normally, it is sterilized and sterilized once a week. The entire disinfection process lasts 1 to 2 hours.

Pasteurization is a commonly used disinfection procedure: the tank is about 15% water, heated to 80°C within a certain period of time, then kept warm for 1 to 2 hours, then cooled, and purified water is added and cooled to 25°C. The pasteurization sterilization cycle depends on the level of microbial contamination, for example when microorganisms exceed 50 CFU/ml.