The growing interest in reverse osmosis includes not only coastal areas for desalination
of seawater but also inland areas where reverse osmosis is proposed for desalination of brackish
groundwater, particularly in arid climates where freshwater is extremely scarce. Most existing
reverse osmosis facilities are in coastal areas, and the most common concentrate disposal
methods are discharge to surface water, discharge to a municipal sewer system, and deep well
injection. In inland areas, these disposal options may not be available, and the remaining options
may be expensive and difficult to implement. Furthermore, in inland areas, the concentrate
represents not only a significant management problem, but also a waste of a precious resource,
the water. This paper discusses
Several issues in regard to concentrate in inland areas. First, the
concentrate must be isolated from the surrounding freshwater resources so that the existing
resources are not contaminated. Evaporation ponds and deep wells (if suitable injection zones
can be identified) can be constructed to fit these criteria. The second issue, however, is to
recover as much of the freshwater from the concentrate as possible, to minimize wasting of the
natural resource. Technologies to increase recovery or convert the concentrate into solid
salts (zero liquid discharge) using mechanical evaporators or distillation systems are discussed. Identification of appropriate methods of concentrate management is necessary for
determining the feasibility of a reverse osmosis project.
An attractive solution to the concentrate disposal issue is to convert this disposal problem
into a natural resource. The paper discusses possible beneficial uses of concentrate that include:
land application or irrigation of salt tolerant crops; saline aquaculture, farming of brine
shrimp or other saltwater species; restoration of brackish waterways or development of
saltwater marshes, wetlands or habitats; energy generation using solar gradient ponds;
industrial uses as feedstock or process stream; and, production of marketable salts or mineral
commodities. The selection of a concentrate disposal option depends on site-specific conditions
of the treatment plant. The variables that may affect the selection include economics, quality and quantity of concentrate, regulatory concerns, availability of the receiving site, public acceptance,
and the climatic and geographical considerations.
Includes 25 references, tables, figure.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 440 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 16 |
| Published : | 03/01/2005 |
