Deeper brackish ferrous and manganous water intrusion in freshwater aquifers is a frequent
problem that can affect the quality of water resources.
In San Lorenzo, a city of 30,000 inhabitants in Argentina, historical problems of water quality,
provided by downtown wells, concerned water utilities from its origin in the 50s: high
sulfates, chloride, sodium, ferric and manganese contents. Obstructions and occurrence of
black water were common problems in the distribution system.
Hydrogeological studies determined that brackish reduced aquifer underlies the freshwater
aquifer used by the production wells. As a result of pumping, the hydraulic potential
equilibrium of the aquifer was disturbed, causing saline, manganous and ferrous water intrusion to
degrade the well water.
A project was initiated consisting of restoring the hydraulics equilibrium of the aquifer by an
extraction of brackish water by means of "a correction well" near the production well. This
solution was firstly studied by modeling and, after a comparative analysis with other
alternatives, implemented on site.
The project has been ongoing since the beginning of 2000. At the source point and in the water
network total dissolved solids (TDS) diminished from 2.5 to 1.2 g/L. Fe and Mn total contents
passed from 0.9 and 0.7 mg/L respectively to <0.05 and <0.03 mg/L. A drastic reduction of
taste and color customer claims and maintenance intervention over the network were
registered in San Lorenzo city.
Regarding investments, groundwater management was 8% less expensive than the classical
treatment solution of reverse osmosis (RO). The operation cost was estimated to be more than 50% less expensive for this case in comparison to the RO solution. Includes 4 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 450 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 7 |
| Published : | 11/02/2003 |
