Reverse osmosis system

Claim 2

A water purification process for removing dissolved solids of the type that are normally present in a municipal water supply or the like, which comprises the steps of: providing a first reverse osmosis unit having an inlet, a product outlet and a brine outlet; providing a second reverse osmosis unit having an inlet, a product outlet and a brine outlet; locating said second reverse osmosis unit downstream of said first reverse osmosis unit with the product outlet of said first reverse osmosis unit being coupled to the inlet of said second reverse osmosis unit; providing water to be purified to the inlet of said first reverse osmosis unit; treating the product from said reverse osmosis unit at a location upstream of said second reverse osmosis unit with a chemical treatment agent comprising a solution having a pH that exceeds 7 to reduce carbon dioxide concentration of the product by chemical conversion and to ionize certain otherwise difficult to remove chemicals; and directing the product from said second reverse osmosis unit toward a point of use or storage for purified water.

Claim 3

A process as described in claim 1, including the step of conditioning the water to be purified upstream of said first reverse osmosis unit.

Claim 4

A process as described in claim 1, in which said treating step comprises introducing a solution from the group consisting of sodium hydroxide, sodium bicarbonate, sodium carbonate, disodium phosphate, trisodium phosphate, ammonium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide.

Claim 5

A process as described in claim 1, including the step of recirculating the brine from the brine outlet of said second reverse osmosis unit back to the water flow line upstream of said first reverse osmosis unit.

Claim 6

A process as described in claim 1, including the step of bleeding the product downstream of said treatment but upstream of said second reverse osmosis unit.

Claim 7

A process as described in claim 1, including the step of treating the water to be purified upstream of said reverse osmosis unit to adjust its pH to below about 5.

Claim 8

A process as described in claim 1, including said treating step comprising the step of adjusting the pH of the product water from said first reverse osmosis unit to above about 9.

Claim 9

A water purification process for removing dissolved solids of the type that are normally present in a municipal water supply or the like, which comprises the steps of: providing a first reverse osmosis unit having an inlet, a product outlet and a brine outlet; providing a second reverse osmosis unit having an inlet, a product outlet and a brine outlet; locating said second reverse osmosis unit downstream of said first reverse osmosis unit with the product outlet of said first reverse osmosis unit being coupled to the inlet of said second reverse osmosis unit; pumping water to be purified to the inlet of said first reverse osmosis unit; treating the water to be purified upstream of said first reverse osmosis unit to adjust the pH to below about 5; introducing a chemical treatment agent into the product from said reverse osmosis unit to adjust its pH to below about 5; introducing a chemical treatment agent into the product from said first reverse osmosis unit at a location upstream of said second reverse osmosis unit to adjust the pH of the product water from said first reverse osmosis unit to above about 9 to reduce carbon dioxide concentration of the product by chemical conversion and to ionize certain otherwise difficult to remove chemicals; and directing the product from said second reverse osmosis unit toward a point of use or storage for purified water.

Claim 10

A water purification process for removing dissolved solids of the type that are normally present in a municipal water supply or the like, which comprises the steps of: providing a first reverse osmosis unit having an inlet, a product outlet and a brine outlet; providing a second reverse osmosis unit having an inlet, a product outlet and a brine outlet; locating said second reverse osmosis unit downstream of said first reverse osmosis unit with the product outlet of said first reverse osmosis unit being coupled to the inlet of said second reverse osmosis unit; pumping water to be purified to the inlet of said first reverse osmosis unit; treating the water to be purified upstream of said first reverse osmosis unit to adjust the pH to below about 5; introducing a chemical treatment agent into the product from said reverse osmosis unit to adjust its pH to below about 5; introducing a chemical treatment agent into the product from said first reverse osmosis unit at a location upstream of said second reverse osmosis unit to adjust the pH of the product water from said first reverse osmosis unit to above about 9 to reduce carbon dioxide concentration of the product by chemical conversion and to ionize certain otherwise difficult to remove chemicals; and directing the product from said second reverse osmosis unit toward a point of use or storage for purified water.

Claim 11

A process as described in claim 8, including the steps of: recirculating the brine from the brine outlet of said second reverse osmosis unit back to the water flow line upstream of said first reverse osmosis unit; and bleeding the product downstream of the chemical treatment agent introduction but upstream of said second reverse osmosis unit.

Claim 12

A water purification process for removing dissolved solids of the type that are normally present in a municipal water supply or the like, which comprises the steps of: providing a first reverse osmosis unit having an inlet, a product outlet and a brine outlet; providing a second reverse osmosis unit having an inlet, a product outlet and a brine outlet; locating said second reverse osmosis unit downstream of said first reverse osmosis unit with the product outlet of said first reverse osmosis unit being coupled to the inlet of said second reverse osmosis unit; providing water to be purified to the inlet of said first reverse osmosis unit; treating the product from said first osmosis unit at a location upstream of said second reverse osmosis unit with a chemical treatment agent comprising a solution having a pH that exceeds 7 to reduce carbon dioxide concentration of the product by chemical conversion and to ionize certain otherwise difficult to remove chemicals; said second reverse osmosis unit inlet receiving product water from said first reverse osmosis unit product outlet at substantially the same flow rate and pressure as the flow rate and pressure of the product water from said reverse osmosis unit product outlet; and directing the product from said second reverse osmosis unit toward a point of use or storage for purified water.

Claim 13

A water purification process for removing dissolved solids of the type that are normally present in a municipal water supply or the like, which comprises the steps of: providing a first reverse osmosis unit having an inlet, a product outlet and a brine outlet; providing a second reverse osmosis unit having an inlet, a product outlet and a brine outlet; locating said second reverse osmosis unit downstream of said first reverse osmosis unit with the product outlet of said first reverse osmosis unit being coupled to the inlet of said second reverse osmosis unit; providing water to be purified to the inlet of said first reverse osmosis unit; treating the product from said first osmosis unit at a location upstream of said second reverse osmosis unit with a chemical treatment agent comprising a solution having a pH that exceeds 7 to reduce carbon dioxide concentration of the product by chemical conversion and to ionize certain otherwise difficult to remove chemicals; said second reverse osmosis unit inlet receiving product water from said first reverse osmosis unit product outlet at substantially the same flow rate and pressure as the flow rate and pressure of the product water from said reverse osmosis unit product outlet; and directing the product from said second reverse osmosis unit toward a point of use or storage for purified water.