What are general bacteria? Causes of exceeding standards in water quality testing [Basic Knowledge]

basic information

■Why is the standard "100"? The management of microorganisms in drinking water began with Koch's work in the late 19th century. It was observed that drinking water with a bacterial colony count of fewer than 100 per mL, achieved through sand filtration, did not lead to outbreaks of cholera or typhoid. This standard was introduced in Japan in 1904 and has been used in the operation management of slow sand filtration ponds. ■Are general bacteria pathogens themselves? Many general bacteria are so-called non-pathogenic bacteria and are not necessarily pathogens. However, since they are usually low in uncontaminated water, a high count serves as a warning signal for contamination. If detected in large quantities, contamination by pathogenic organisms is suspected. ■Difference from E. coli E. coli is a bacterium found in the intestines of humans and animals, and the standard is "not detected." While general bacteria serve as a general indicator of water cleanliness, E. coli is specifically an indicator of fecal contamination. ■Items judged by a single result! The presence of general bacteria and E. coli in drinking water directly indicates the potential for contamination by pathogenic microorganisms. Therefore, the results of each test are evaluated against the standard values.

Price range

Delivery Time

Applications/Examples of results

■Why exceed the standards? 1. Insufficient disinfection: General bacteria are used to confirm whether chlorine disinfection is being properly conducted. 2. Loss or stagnation of chlorine: If chlorine disappears or water stagnates during distribution, heterotrophic bacteria will increase. 3. Inspection points for wells: Check for damage to the well cover and any inflow of rainwater, and regularly clean the well and its surroundings. ■First, confirm with a re-examination If abnormalities are found in the test results, a re-examination will be conducted immediately for confirmation. Since this is an item evaluated based on a single result, it is important not to leave abnormal values until the next regular inspection. For well water, it is stipulated by national guidelines to contact the health department if the standards are exceeded and receive instructions. ■Confirmation of disinfection and residual chlorine General bacteria are typically killed by chlorine disinfection or boiling. When drinking well water, chlorine is injected for disinfection, and it is regularly checked whether the free residual chlorine in the tap water is 0.1 mg/L or higher. Torii handles sodium hypochlorite used for disinfecting well water and water in storage tanks, and also responds to requests for water quality testing in conjunction with storage tank cleaning. Please feel free to consult with us first.