As we all know, each indicator has its corresponding standard in wastewater monitoring. Compliance with this standard means the discharge is qualified; failure to meet it means the discharge is unqualified and requires further treatment. Coliform bacteria are a key indicator in medical wastewater monitoring. So what are the standards for coliform bacteria? This article will clarify this issue.
let’s look at Several Precautions for Testing Coliform Bacteria in Wastewater:
1.When placing inoculated samples in a constant-temperature water bath or water-jacketed incubator, ensure the equipment has reached and stabilized at the specified temperature before loading the samples.
2.When preparing MFC medium, the purity and quality of aniline blue affect colony color. It is recommended to mix imported and domestic aniline blue in an appropriate ratio based on test results to obtain typical colony colors of coliform bacteria.
3.Among colonies grown on the membrane filter, in addition to dark blue colonies, light blue colonies and those with a dark blue center should also be picked for identification.
4.For domestic drinking water, residual chlorine from chlorination may damage or inhibit coliform bacteria. Sodium thiosulfate should be added during sampling to neutralize chlorine, allowing injured bacteria to recover and avoiding false test results.
5.Proper preservation of water samples after collection is essential. Improper storage may cause coliform bacteria to die or reproduce under certain conditions, reducing the accuracy of test results.
Having Covered these Points, What is the Regulatory Standard for Coliform Bacteria in Wastewater?
According to China’s wastewater discharge standards:
– The coliform index is specified as 1000 per liter.
– For fecal coliform:
– First-class discharge standard: ≤ 10³ CFU/L
– Second-class discharge standard: ≤ 10⁴ CFU/L
– No limit is specified for third-class discharge.
To accurately measure the concentration of coliform bacteria in wastewater, the WECT-900 Online Coliform Analyzer manufactured by Hangzhou Modi can be used for real-time monitoring.
