What is reverse osmosis?

Reverse osmosis is a process that filters most impurities from water. The reverse osmosis unit passes water through a membrane that keeps the minerals, including uranium, behind.

Who can use reverse osmosis?

The RO unit works for small central systems, institutions, and individual households.

Can I use the reverse osmosis unit to treat my entire water supply?

You can use the RO unit for your entire water supply in small central systems. It is generally only economical to use it for drinking water supplies in institutions and households.

Is the reverse osmosis unit reliable?

Yes, the RO unit is reliable.

How effective is the reverse osmosis unit?

Tests show that the RO unit generally removes 90 per cent of the uranium. The efficiency of the unit depends on the manufacturer and the type of membrane in the unit.

Is the reverse osmosis unit affected by raw water quality?

An RO unit may be affected by raw water that is muddy or cloudy, hard, or high in chlorine. You may need to upgrade the quality of your raw water before you use reverse osmosis.

How practical or difficult is the reverse osmosis unit to operate and maintain?

The RO unit is simple to operate and to maintain. It is practical for institutions and households. It can be practical for small central systems that use high-quality units.

How much does the reverse osmosis unit cost?

A unit that is large enough to treat household drinking water costs between $300 - $1000 (2004 prices). Central system- and institutional-size units are more expensive.

About how long does the reverse osmosis unit last?

The RO unit has a long life.

How much does it cost operate and maintain the reverse osmosis unit?

RO units work off pump pressure so operating costs are low. The membrane should last up to five years, depending on the quality of your raw water. A new one costs about $100 (2004 prices). The filter should be changed every year, which costs about $45 .

What happens to the substances that are taken from the water?

They are flushed through the drainage system.

How much waste water is created by the reverse osmosis unit and how is it disposed of?

Half of the water drawn from a well and processed through an RO unit will be waste water, which is flushed out the drainage system. Waste water can be recycled in some systems.

Does the reverse osmosis unit remove other contaminants from water supplies?

The RO unit can remove a wide range of contaminants including arsenic, chloride, and nitrates. It removes nearly all particles and most ions you might expect to find in drinking water.

Does reverse osmosis have any side effects?

Water treated by the RO unit can be corrosive because so much of the mineral has been removed. In general this is no problem in households and institutions. Central systems, though, might also require a neutralizing system to protect against corrosion.

Where can I get the reverse osmosis unit?

The unit is available from water treatment companies in Nova Scotia. For more information check the Yellow Pages of your telephone book under the heading Water Treatment for a list of water treatment dealers.

You asked about... is a series of fact sheets produced by Nova Scotia Environment. For additional copies, contact the regional or head office nearest you.

Bedford: 902 424-7773
Halifax: 902 424-3600
Kentville: 902 679-6086
Sydney: 902 563-2100
Truro: 902 893-5880

Labs that test for uranium in drinking water:

QEII Health Sciences Centre
Environmental Chemistry Laboratory, Halifax
902-473-8466

Maxxam Analytics Inc., Bedford
(902) 420-0203

Maxxam Analytics Inc., Sydney
(902) 567-1255