CITY OF PASCAGOULA – REVERSE OSMOSIS WATER PLANT
Reverse Osmosis pressure vessels at Communy Street Water Plant in Pascagoula , Mississippi.
Improving Drinking Water to Meet 2002 Requirements.
In an effort to improve the quality of drinking water provided to its citizens, the City of Pascagoula initiated a Pilot Testing Program in 1998 to assess the effectiveness of Reverse Osmosis Water Treatment Systems. The results of the pilot tests proved conclusively that this technology would be effective in removing most of the dissolved and suspended solids from the raw water supply.
Additionally, ozone injection was successfully tested for the removal of the Hydrogen Sulfide and offensive color from the raw water.
Based on the results of the Pilot Testing Program provided by Osmonics, the City of Pascagoula chose Compton Engineering to design two Reverse Osmosis Water Treatment Plants. The plants include a 700 GPM & a 500 GPM system.
Currently, a third facility is being designed to provide quality water to all of Pascagoula .
Water Treatment System Overview
Reverse Osmosis (RO) is a method of removing ionic, organic, dissolved, and suspended impurities from water by means of a semi-permeable membrane.
The semi-permeable membrane has a high permeability to water, but a very low permeability to salts and other impurities. In other words, under sufficient pressure, the semi-permeable membrane allows passage of water while rejecting and concentrating dissolved and suspended solids.
As water passes through the semi-permeable membrane, it becomes purified. This purified water that is produced is called permeate. The permeate leaves the Reverse Osmosis Membrane Unit and is then injected with ozone to remove hydrogen sulfide from the water. The ozone will oxidize the hydrogen sulfide and remove the offensive odor. After injection with ozone, the PH of the permeate water is adjusted, if necessary. Final mixing of the ozone is achieved in a standpipe. The permeate water overflows the top nozzle on the standpipe into a ground storage tank.
As the permeate water is produced, a concentrated stream containing all of the impurities rejected by the membranes is also produced. This concentrate stream, which is sometimes referred to as brine or reject is discharged to the storm sewer.
Raw Water vs. Treated Water
Parameters |
Raw |
Treated |
Iron |
0.25 mg/l |
0.05 mg/L |
Potassium |
2.5 mg/L |
0.2 mg/L |
Calcuim |
2.6 mg/L |
1.0 mg/L |
Magnesium |
0.25 mg/L |
0.05 mg/L |
Manganese |
0.01 mg/L |
0.01 mg/L |
Sodium |
350 mg/L |
70 mg/L |
Alkalinity (CaCO3) |
320 mg/L |
30 mg/L |
Chloride |
350 mg/L |
30 mg/L |
Color |
68 pcv |
5 pcv |
Conductivity |
1380 numho |
250 numho |
Fluoride |
1 mg/L |
0.01 mg/L |
Hardness (CaCO3) |
8 mg/L |
3 mg/L |
Nitrate Nitrogen |
0.2 mg/L |
0.2 mg/L |
Nitrate Nitrogen |
0.1 mg/L |
0.1 mg/L |
Sulfate |
10 mg/L |
1 mg/L |
Turbidity |
3 Ntu |
1 Ntu |
pH |
8.5 |
7.5 |
Alkalinity, P (CaCO3) |
25 mg/L |
<1 mg/L |
Silica |
22mg/L |
3 mg/L |
Total Dissolved Solids (TDS) |
1000 mg/L |
150 mg/L |
The above information is the minimum design requirements that were specified to be met by the contractor and equipment designers and has been provided for comparisons only.
In the City of Pascagoula, we are receiving reading as low as the following...
Sodium |
20 mg/L |
Chloride |
18 mg/L |
TDS |
66 mg/L |
Color |
2 mg/L |
Reverse Osmosis and Ozonation equipment supplied by
Michael Lowry, Sales Engineer (888) 898-6766