Wednesday, June 12, 2013

How to Use Ultra-Filtration to Filter River Water

Question for you: We take water from the river to a cistern (2000 L). Then we use powdered activated carbon and ferric chloride to precipitate the color in the water.   Then we pump the water up to a high tank (1000 L) using a 3/4 HP pump. The water is still turbid. We use a heavy metal filter on the kitchen. We believe we need some kind of UF membrane, but we don't know which one to get.  We have two bathrooms, six persons in our home.

Baja California

sediment backwash turbidity filter
Sediment Backwash Filter
An ultrafiltration or “UF” system will filter all particles out of the water down to 0.015 microns and are self-cleaning.  These systems works particularly well after the water has been treated as you mention, with ferric chloride and PAC.

The best approach would be to install after your tank  a ¾ HP and pressure tank, then consider using a backwashing turbidity filter, followed by a dual grade 25/1 micron filter then the UF system.    An optional ultraviolet sterilizer can provide an additional barrier to bacteria after the system if desired. 


See this diagram which shows what a system like this looks like installed on a well head.

See this Antunes UF system,  which can produce 10-12 gallons per minute of filtered water, or about 40 Liters per minute.

Ultra-Filtration System 440
Ultra-Filtration System 440