THE BASICS of SFR

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Spot Free Rinse water must have less than 40 ppm of TDS. Our preferred is 25 ppm of TDS or less.

Average TDS range in the U.S. is 330–410 ppm.

Spotting is caused by mineral salts, TDS (total dissolved solids), which are left behind when water evaporates.

Softeners do not remove any TDS.

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TDS EXAMPLES

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FOR

Common TDS Levels

Less than .05 ppm Laboratory grade water

Less than 10 ppm Deionized water, distilled water – (batteries, irons)

Less than 40 ppm Typical spot free water – we prefer less than 25 ppm

Less than 150 ppm High quality bottled drinking water

Less than 225 ppm Acceptable quality tap water

333 – 410 ppm Average TDS in the United States

Greater than 500 ppm Not recommended for human consumption (USEPA)

Greater than 1,000 ppm Not fit for human consumption – potential health hazards

35,000 ppm Sea water

WHAT YOU SHOULD KNOW

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Total Dissolved Solids (TDS)

Hardness

About Your Water SupplyBefore Getting a Spot Free Rinse System

Iron

Is water chlorinated or non-chlorinated?

pH

Temperature Variation

TERMINOLGY

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FOR

Reverse Osmosis

FEEDWATER Water fed into the system that requires improvement in quality.

PERMEATE The product of the RO system.

CONCENTRATE The reject from the RO system.

PERCENT REJECTION (Feed TDS – Permeate TDS) ÷ Feed TDS

PERCENT RECOVERY (Gallons/Hour Permeate) ÷ (Gallons/Hour Feedwater)

OSMOTIC PRESSURE The pressure corresponding to the difference in liquid.

SEMI-PERMEABLE MEMBRANE A selective membrane that allows some materials to pass through it and other materials cannot.

INSTALLATION SCHEMATIC

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REVERSE OSMOSIS TREATMENT

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Softening to remove hardness minerals which can scale membrane(for over 25% RO recovery).

Pretreatment of the feedwater is generally required to eliminate damaging or fouling the RO membrane.

PRETREATMENT

Carbon adsorption for free chlorine removal to protect TFC membranes. Chloramines OK. Should be backwashing type to avoid biofouling and prolong effective life of carbon.

5 micron sediment removal.

Chemical feed of colloidal dispersants if silica, alum, silt, and/or polyelectrolytes are present in enough concentration.

Municipal water supplies are more than prone to fouling than ever before due to excessive use of Flocculants and anti-corrosion chemicals that raise ph. Colloidal fouling can occur very rapidly and results in loss of production without much decrease in rejection.

REVERSE OSMOSIS TREATMENT

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The percentage of feed water separated out as pure water.

Recovery: the efficiency of an RO system in terms of water use.

RECOVERY

Water chemistry dictates dictates how much you can recover.

With softened water and well designed system, you should be able to recover 50% and avoid fouling.

At 50%, the RO system operates very cost effectively with regard to water use, energy, salt, heat, etc.

In terms of recovery, reject to product ratios are:50% - 1:1 25% - 4:133% - 2:1 16.6% - 5:129% - 3:1

For 500 GPD systems and larger, anything less than 33% recovery is very wasteful and costly. With increasing frequency states are regulating water usage.

REVERSE OSMOSIS TREATMENT

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The recovery setting should be dictated by the water conditions.• temperature • pH • hardness• ion composition • TDS • silt density index

Facts About Setting the Percent Recovery

The key is to set the “percent recovery” so the impurities don’t permanently deposit on the membrane surface.

GENERAL RULES *(Temperature not to exceed 77° F.)

Very Hard Water

Up to 20 grains

Percent Recovery should not exceed 25%

(3:1 ratio)

Slight-Moderately Hard Water Supply

Up to 5 grains

Percent Recovery should not exceed 33%

(2:1 ratio)

Softened Water (pretreated)

Less than 1 grain

Percent Recovery should not exceed 50%

(1:1 ratio)* Understand that these are general rules that are not 100% correct in all cases

REVERSE OSMOSIS TREATMENT

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Facts About Setting the Percent Recovery

Understand that these are general rules that are not 100% correct in all cases

“GENERAL” RULES(Temperature not to exceed 77° F.)

Very Hard Water

Up to 20 grains

Percent Recovery should not exceed 25%

(3:1 ratio)

Slight-Moderately Hard Water Supply

Up to 5 grains

Percent Recovery should not exceed 33%

(2:1 ratio)

Softened Water (pretreated)

Less than 1 grain

Percent Recovery should not exceed 50%

(1:1 ratio)

OPERATING GUIDELINES

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Change prefilter cartridge every 90 days minimum Lubricate motors yearly

FOR

Reverse Osmosis Systems

Test for free chlorine weekly Test for soft water daily – Test Strips, Test Kit Monitor weekly (minimum):

• Flow rates • Operating pressure

• Feedwater temperature • TDS (total dissolved solids)

Check clock and settings on GAC filter