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What is the relationship between influent TDS and conductivity?

Author: Site Editor     Publish Time: 2023-02-07      Origin: Site


What is the relationship between influent TDS and conductivity?

When a feed water conductivity value is obtained, it must be converted to a TDS value so that it can be entered in the software design. For most water sources, the conductivity/TDS ratio is between 1.2 and 1.7. For ROSA design, a ratio of 1.4 for seawater and 1.3 for brackish water is used for conversion, which usually gives a good approximation of the conversion rate.

How do I know if a membrane has been contaminated?

The following are common symptoms of contamination.

Decrease in water production at standard pressure

The operating pressure must be increased to achieve the standard water yield

Increase in pressure drop between influent and concentrated water

Increase in weight of the membrane element

Significant change (increase or decrease) in membrane removal rate

When the element is removed from the pressure vessel, water is poured on the inlet side of the vertical membrane element, water cannot flow through the membrane element and only overflows from the end face (indicating that the inlet water channel is completely blocked)

water treatment

How to prevent the growth of microorganisms in the original packaging of the membrane element?

When the protective fluid is cloudy, it is likely to be due to microbial growth. Membrane elements protected with sodium bisulphite should be checked once every three months.

When the protective solution becomes cloudy, the element should be removed from the storage seal and re-soaked in a fresh protective solution of 1% (by weight) food grade sodium bisulphite (not cobalt activated) for approximately 1 hour and re-sealed and sealed, and the element should be drained before repackaging.

What are the incoming water requirements for the RO membrane element and IX ion exchange resin?

Theoretically, the incoming RO and IX systems should be free from impurities such as

Suspended matter


Calcium sulphate



Oxidising agents, e.g. residual chlorine

Oil or lipid substances (must be below the lower detection limit of the instrument)

Organic substances and iron-organic complexes

Metal oxides such as iron, copper and aluminium corrosion products

The water quality of the incoming water will have a huge impact on the life and performance of the RO element and IX resin.

What impurities can be removed by the RO membrane?

RO membranes can remove ions and organics very well, and RO membranes have a higher removal rate than nanofiltration membranes. RO can usually remove 99% of the salts in the feed water and ≥99% of the organics in the feed water.

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