Safety of human drinking water sparks renewed debate: Secondary pollution of tap water draws attention

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　　What is secondary pollution? As the name implies, secondary pollution refers to the contamination that occurs during the transportation of water from water treatment plants to households, after it has been purified there. It mainly consists of impurities such as rust, sediment, bacteria, viruses, etc., resulting from the aging of water pipes, as well as by-products of chlorine treatment used in water treatment plants. 　　The main sources of secondary pollution are tap water pipes, community secondary water supply systems, and faucets. 　　First, pollution of water supply pipes. The metal pipes used by municipalities to deliver tap water contain heavy metals such as lead, and the vast majority of them are in poor condition due to lack of maintenance over time. Rust and dirt clog the pipes. During the transportation of tap water, these impurities are carried along with it to various households. Some water pipes even run parallel to the sewage pipes, and leaks in these water and sewage pipes often occur, leading to contamination of the tap water, an unpleasant odor, bad smells, and even the intrusion of microorganisms and pathogens. 　　Second, the contamination of the secondary water supply system in residential areas. Residential areas generally use water storage devices such as rooftop water towers or underground water tanks for storing and supplying water. Water towers or tanks are often not cleaned in a timely manner, resulting in the accumulation of dust and other impurities. Some water storage devices even become severely aged, overgrown with moss, and become a breeding ground for numerous bacteria. In severe cases, there have been situations where residents of apartments in Shijiazhuang fell ill collectively. 　　Third, faucets with excessive lead content are also sources of secondary pollution. Due to the lack of **standard regulations, faucets available on the market consist of both lead-free and lead-containing products mixed together. Even if these faucets cause the tap water passing through them to have an excessive lead content, they can still be sold on the market. 　　The health hazards caused by secondary pollutants in tap water cannot be underestimated. It is understood that when tap water is boiled, the residual chlorine, when heated, produces a carcinogenic substance called trichloromethane. This substance can cause prostate cancer and bladder cancer. The heavy metal lead damages the reproductive, sexual, renal functions and the nervous system in the human body, can cause dementia in children, and is also a major cause of cancers such as stomach cancer and esophageal cancer. Bacteria and viruses can lead to infectious diseases and acute inflammations. Silt and rust can cause stone diseases in the body, such as gallstones and kidney stones. At present, there are no effective measures to prevent secondary pollution. The best way to ensure the safety of drinking water at home is to use a water purifier to filter it. “Water purifiers produced by reputable manufacturers can effectively remove harmful substances such as viruses, bacteria, and impurities from tap water, allowing it to be drunk straight away without the need to boil it. 　　If tap water poses a risk of secondary pollution, what preventive measures are available? This is a question that people are very concerned about. Currently, there are many household water purifiers available on the market; installing one at home can help ensure the safety of drinking water, while tap water can be used for daily household purposes. Home water purifiers can effectively remove pollutants in water that may be harmful to health, and they also kill common disease-causing bacteria and viruses in water. 　　Many residents use bottled water for drinking at home, but it has some disadvantages compared to water purifiers. The advantage of using a water purifier is that water is prepared on demand, ensuring its freshness ； Made for personal use, safe and reliable. 　　When choosing a home water purifier, one should not act blindly; it is recommended to follow these principles: First, consider your needs. To remove ions from water, it is necessary to use a system with both ultrafiltration and reverse osmosis functions ； To remove chlorine odor and microorganisms, activated carbon combined with ultrafiltration functionality is required. Secondly, consider the brand: do not purchase products from unknown brands or those without any quality certifications, no matter how cheap they are; it is recommended to choose products that have NSF certification. Once again, looking at the technology aspect: some existing water purifiers take into account the source of the wastewater; they allow the wastewater generated by ultrafiltration or reverse osmosis to be returned to the tap water supply for use in household purposes. Moreover, when the tap water is turned on, it can also be used to flush the ultrafiltration or reverse osmosis membranes – which is a quite sophisticated technical solution. Fourth, look at the price; it should be appropriate. 　　In addition, it is hoped that netizens will acquire some basic knowledge about drinking water safety. 1. It is best to prepare drinking water just before use, as this ensures that the water quality remains fresh. Old water is prone to having excessive levels of microorganisms and nitrite nitrogen, making it unsuitable as drinking water ； 2. Bucket water dispensers are inexpensive, but the levels of microorganisms and nitrite nitrogen in the water they produce can easily exceed acceptable limits ； 3. The high-level water tanks in the south are exposed to sunlight, resulting in high water temperatures; microbial levels often exceed safe limits, so it is essential to drink water from a water purifier. That’s all for what I’d like to share with you today. This article is from water treatment equipment: http://www.aoliyuan.cn