Water quality standards related to TOC analysis

TOC total organic carbon analyzers have been increasingly used in the environment, drinking water, pharmaceuticals, electronics, power plants and other industries. Related TOC testing standards have also been introduced one after another. Today, let’s take a look at the TOC testing standards with the editor. How did it come into our sight step by step?

In 2003, the four national ministries and commissions officially included TOC in the water pollutant pollution equivalent value table as an important indicator for environmental monitoring in the newly promulgated "Standard Management Measures for the Collection of Pollution Fees".

Pollution equivalent value of type II water pollutants

At present, my country's sewage standards mainly implement GB8978-1996 "Comprehensive Wastewater Discharge Standard" and GB18918-2002 "Urban Wastewater Treatment Plant Pollutant Discharge Standard". In GB8978-1996, the maximum allowable emission concentration of TOC (i.e., the primary standard) is 20 mg/L. GB18918-2002 has not yet introduced TOC into the standard.

In the GB3097-1997 "Sea Water Quality Standard", the first-class requirements for chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) are 2 mg/L and 1 mg/L respectively, and TOC has not been introduced. GB5084 - 2021 "Farmland Irrigation Water Quality Standard" currently only has relevant restrictions on BOD5 and COD, and there is no value requirement for TOC.

In the drinking water industry, the current implementation is GB5749-2006 "Hygienic Standards for Drinking Water" issued by the Ministry of Health in 2006. The TOC testing item was added to the appendix in 2006, and the TOC limit is 5mg/L.

In the pharmaceutical industry, the United States Pharmacopoeia officially adopted the TOC test method in 1998, requiring that all water for injection and purified water must be tested for TOC, and the TOC value of purified water and water for injection must be ≦0.5 mg/L. The European Pharmacopoeia only Water for injection is required to be tested for TOC, with a limit of 0.5 mg/L. Purified water TOC testing and easy oxidation testing can be optional. In 1991, the "Japanese Pharmacopoeia" stipulated that water for injection produced by ultrafiltration method The TOC value must be determined. The "Japanese Pharmacopoeia" recommends lower TOC detection limits for TOC detection in purified water and water for injection: the limit value for online TOC measurement is 300 ppb, and the limit value for offline TOC measurement is 400 ppb. The TOC released by packaging materials, especially plastic packaging bags, is also considered to contaminate pharmaceutical water. My country's current 2020 version of the "Chinese Pharmacopoeia" requires all pharmaceutical companies to detect the TOC content in water for injection. For purified water, you can choose one of the easy oxidation and TOC items. The qualification limit of water for injection and purified water is 500 μg/L and the quality control experimental water used for TOC testing requires a TOC limit of 100 μg/L.

Other industrial standards, such as GB/T 1616-2014 "Industrial Hydrogen Peroxide" issued in 2014, stipulates that industrial hydrogen peroxide with a total carbon content (calculated as C) ≦0.030% is considered a superior product. GB/T 12145 -2016 "Water Vapor Quality of Thermal Power Generators and Steam Power Equipment" stipulates the quality of boiler feed water and boiler make-up water. The total organic carbon ions (TOCi) of the boiler feed water once-through furnace must not exceed 200 μg/L, and the boiler make-up water must also meet at least TOCi does not exceed 400 μg/L. The Ministry of Machinery Industry issued JB/T 7621-1994 "High Purity Water for Power Semiconductor Device Processes", which stipulates that the TOC limits of special-grade electronic grade high-purity water EH-T and first-class electronic grade high-purity water EH-I are 50 μg/L and 100 μg respectively. /L. In GB/T 11446-1997 "Electronic Grade Water", EW-I grade water requires a TOC limit of 20 μg/L.

In short, with the application and development of total organic carbon analysis technology, the TOC detection limit standards will gradually be updated and improved. Optosky has taken up this banner and has a long way to go.