Laboratory Water Purification System: Working Principle and Troubleshooting

The laboratory water purification system is an indispensable piece of equipment in the laboratory. These systems remove impurities and contaminants from tap water through physical and chemical processes to produce pure, sterile, high-quality water. In today's laboratories, the water environment as the most basic environment of the vast majority of laboratories occupies a very important position in the experiment, water quality often determines the authenticity and reproducibility of many experimental results, because any trace substances that may contaminate or interfere with the experimental results may lead to erroneous experimental results. In this blog, ATO will share with you some information and experiences about laboratory water purification systems. 

The laboratory water purification system is one of the common equipment in laboratories, its role is to remove impurities and pollutants in tap water to obtain high-purity water quality to meet the needs of various applications in laboratories. Laboratory ultrapure water is a kind of water with extremely high purity, which refers to the water that almost completely removes the conductive medium in the water, and at the same time removes non-dissociated gases, colloids, and organic matter (including bacteria) to a shallow level. Its conductivity is generally 0.1~0.055uS/cm, resistivity (25°C) > 10x106Ω/cm, and salt content < 0.1mg/L. The ideal pure water (theoretically) is 0.055 uS/cm, and the resistivity (25°C) is 18.3x106Ω/cm. 

Working principle of laboratory water purification system

Laboratory water purification systems generally use advanced reverse osmosis technology to produce pure water. The working principle of a laboratory pure water system can be divided into several steps, including water pretreatment, ion exchange, activated carbon filtration, ultraviolet(UV) disinfection, and reverse osmosis.

1. The first is water pretreatment. Tap water may contain sediment and impurities that can affect the experiment, so pretreatment is required. This step generally filters out large particles of impurities through sedimentation tanks and screens. 
2. The second is ion exchange. Ion exchange is the core process of a laboratory pure water system, which can effectively remove ions and impurities in water. In ion exchange, water passes through a layer of resin beds, and the ion exchange resin adsorbs the ions in the water and then releases an equal number of hydrogen ions or hydroxide ions. Ion exchange resins usually use anion or cation exchange resins, which are used to remove anions or cations from water respectively.
3. Next is activated carbon filtration. Activated carbon filtration can effectively remove chlorine and organic substances from water. In this step, the water passes through a layer of activated carbon, which removes chlorine and organic matter from the water through adsorption and catalytic oxidation.
4. Then comes ultraviolet(UV) disinfection. UV disinfection is an important step used to kill bacteria and viruses in water. In UV disinfection, water passes through a layer of UV sterilizer, which disinfects water by killing bacteria and viruses.
5. Lastly is reverse osmosis. Reverse osmosis membrane can effectively remove macromolecular organic matter, heavy metals, and ions in water. In this step, water is pushed against a reverse osmosis membrane, which only allows water molecules to pass through while filtering out impurities such as macromolecular organics, heavy metals, and ions.

The workflow of the whole laboratory pure water system is relatively complicated, and different systems may adopt different technological processes, but the general principle is similar. Through these steps, the laboratory water purification system is able to remove impurities and contaminants from the water, producing high-quality, sterile, high-purity water that provides a reliable source of water for research in the laboratory. 

Advantages of laboratory water purification system

1. High purity: The laboratory water purification system can remove impurities, microorganisms, organic matter, etc. in the water to obtain high-purity water quality, thereby ensuring the accuracy of experimental results.
2. Economical and practical: Compared with purchasing bottled pure water, the laboratory water purification system has a lower cost of use, and does not need to store or treat wastewater, reducing the cost of waste treatment and environmental pollution. 
3. Convenient and practical: the laboratory water purification system adopts automatic control, which can automatically detect water quality, clean and disinfect equipment, and has a variety of alarm and protection functions, which is convenient and safe to use.

Troubleshooting

The optimal working temperature of laboratory pure water equipment is 25°C, and the available working temperature is around 5°C-45°C. If the temperature is lower or higher than this range, the machine should be turned off in time or the temperature should be adjusted before use. 

In the cold winter, if the water machine runs at a low temperature for a long time, the water outlet may be blocked, and the internal consumables may be cracked and deformed by the frozen ice, which may cause equipment malfunction.

Common equipment malfunctions in winter

When a water machine is used in winter, the water production of the water machine usually decreases, and in some cases, it may only be 50% of the summer water production, because the reverse osmosis membrane has a low water temperature in winter. When the water temperature of the osmotic membrane is 25°C, the water production rate is rated. Every time the water temperature drops by 1°C, the water production rate of the reverse osmosis membrane will drop by 3%. When the water temperature is lower than 5°C, the reverse osmosis membrane will stop producing water.

In addition, due to the decrease in water production, the flow rate of wastewater will increase accordingly, the wastewater ratio will increase, and after the temperature rises, the wastewater will be reduced and the amount of water produced will increase.

Common maintenance measures for water machines in winter

1. Decreased or stopped water production: If the water output of the water machine in winter cannot meet the water demand, the ambient temperature of the water machine can be improved as much as possible, such as by raising the room temperature or wrapping the body with thermal insulation materials. 

Outdoor unit: When the ambient temperature is lower than 5 °C, please turn off the pure water machine in time, and move the pure water machine to a place where the temperature is suitable before use; When the ambient temperature is lower than 0 °C, please do not use the pure water machine to avoid the expansion of the water during the solidification process. If the ultrapure water machine is used forcibly in the event of freezing, it may cause the pipeline and filter element of the ultrapure water machine to rupture, resulting in water leakage.

Indoor unit: When the ambient temperature is lower than 5°C, please turn on the indoor heating system such as heating or air conditioning in time, adjust the ambient temperature, and take antifreeze measures related to the ultrapure water machine.

2. Leakage of the water machine: If there is water leakage in the water machine, carefully check the water leakage place to see if the accessories are frozen, cracked, and deformed, and replace the corresponding accessories in time.

3. Icing occurs in the pure water machine: Place the pure water machine in an environment with a room temperature above 10 °C, and only after 48 hours of natural thawing can the machine be turned on for normal use, and after starting, fully check whether the pure water machine has water leakage, as well as the change of water quality and quantity.

4. Freezing and cracking of tap water supply pipes: At this time, the use of the water purifier needs to be suspended. After the temperature rises, first, turn on the tap water faucet to drain the sediment accumulated in the water supply pipeline to avoid too many impurities entering the water purifier, and then open the water inlet ball valve to activate the equipment.

5. Storage conditions of the water machine in winter: Cut off all water and power sources of the ultrapure water machine. Discharge all the existing ultra-pure water tanks and running water inside the machine. Store the machine in an environment where the temperature is not lower than 5°C. If the temperature is too low, please use foam cotton and other materials to pack and insulate the outside of the water purifier.

In short, the laboratory pure water system is indispensable equipment for scientific research, and its quality and performance are crucial for the laboratory's research work. When selecting and using a pure water system, it is necessary to consider factors such as filtration efficiency, sterilization capacity, service life, maintenance cost, etc. At the same time, attention should be paid to the details of installation and use to ensure the efficiency of the laboratory and the quality of research results. ATO offers a variety of types of laboratory water purification systems, welcome to purchase.