China revises water efficiency standard for water purifiers

On December 1, 2021, the State Administration for Market Regulation of the People’s Republic of China promulgated the revised GB 34914-2021 “Minimum allowable value of water efficiency and water efficiency grades for reverse osmosis drinking water treatment purifiers”. The national standard (hereinafter abbreviated as GB), which will serve as the replacement standard for GB 34914-2017, will come into effect on July 1, 2022. The main changes to the new GB are as follows:

Changes in scope of application

1. Water use efficiency testing and grading requirements for water purifiers with nanofiltration membranes as the main purification components have been added. Water purifiers have been classified into reverse osmosis membrane water purifiers, nanofiltration water purifiers, and other water purifiers depending on the main purification components.
2. It has been clarified that GB applies to small water purifiers used in homes or similar locations, and the definition of large and small water purifiers has also been clarified.
3. Water purifiers have been classified into continuous and non-continuous (one-time) types according to the characteristics of various products in the market. Detailed provisions for testing have been given a more specific classification of test requirements for two different modes of water purifiers.

Changes in water use efficiency grade

1. The water use efficiency grade has been changed from a 5-grade to a 3-grade system. In addition, the water use efficiency limit value (grade 3) has been increased to 45%, and the water use efficiency index value of the highest grade (grade 1) has been increased to 65%. The index for nanofiltration water purifiers has been set to be identical to that of reverse osmosis membranes.
2. In the new GB grading, the total water purification amount has also been added to the evaluation index. This total water purification amount is classified into grade 1 for 4000 L or more, grade 2 for 3000 L or more, or grade 3 for 2000 L or more.

Changes in technical requirements

1. For machine purification performance, the removal rate requirement for all dissolved solids has been changed to the removal rate of electrical conductivity.
2. Considering the specificity of nanofiltration membranes, in order to reflect the removal effect of nanofiltration membranes on bivalent ions, the condition that the removal rate of sulfate (SO₄² – equivalent) is ≥ 90% has also been added.
3. The former GB water saving evaluation value concept has been abolished.

Changes in test methods

1. Changes in test water

Since nanofiltration water purifiers have been added, in the revised version, MgSO₄ has been added to the formulation of test water to verify the removal rate of different valence ions by nanofiltration water purifiers. The water quality index requirement for test water has been changed from total dissolved solids content (500 ± 50) mg/L to conductivity (1000 ± 100) μs/cm.

2. Changes in performance tests

(1) A water purifier flow test method has been added.

(2) Classification based on the flow rate of the water purifier has been added.

(3) The formula for calculating the removal rate has been given.

(4) In the revised version, a more detailed explanation has been given of the effect of water treatment processes for different types of water purifiers on water purification production rates.

(5) A schematic diagram of the water use efficiency test equipment has been added to Annex B of the revised version.