From the cursory studies and surveys conducted to date, some concern has been generated regarding dissolved oxygen, gross alpha radioactivity, fluorides and sulfides normally present in RO concentrates.
None of these were produced by the RO process itself and it would appear that post-treatment methods can be developed to eliminate any adverse effect on the environment. However, compliance with the radioactivity standards is a difficult problem not easily resolved.
Presently, there is a wide disparity in post-treatment methods being carried out at each facility. This is most probably due to the differences in permitting requirements (i.e., some plants are given potable water permits, some are given industrial waste permits).
Finally, there are apparent differences in the types of testing and reporting being carried out.
INTRODUCI'ION
On the most recent list available from the Florida Department of Environmental Regulation (FDER), there are 96 membrane plants in Florida treating water for potable consumption. Most of these plants are located in coastal areas and utilize brackish groundwater as their raw water source. Table I shows the location and size of each plant. Recently, questions have been raised as to the environmental impacts of these discharges to the surface waters; and, as