TREATMENT PROCESS*
*per http://www.hollywoodfl.org/pub-util/Water/memb-sft.htm
Pre-Treatment
Treating the Biscayne and Floridan waters using membrane technology is essentially the same despite the fact the waters differ substantially in quality The process steps include pre-treatment, a pressure increase for the membrane treatment units, removal of hydrogen sulfide (present in the raw water), and post-treatment. All of the processes utilize a state-of-the-art computer control system.
During pre-treatment the raw water is dosed with acid and anti-scalant and then filtered. The acid and anti-scalant reduce the pH of the water and prevent minerals from clogging the membranes. The minerals are captured by the membranes and are rejected to the waste stream. In addition to the chemical treatment, the raw water is also passed through large cartridge filters to remove any particulate matter larger than 5 microns prior to reaching the reverse osmosis units.
Degassification
The raw water from the Biscayne and Floridan aquifers contain gases, i.e.: hydrogen sulfide (H2S) and carbon dioxide (CO2) which pass through the membranes. H2S must be captured and treated since it can cause odors in and around the plant. After the water is treated using the membrane units it is sent to large tanks in which the water is sprayed through an air stream. This air stream removes about 99% of the H2S and CO2, The off gas from this process is further treated in an air scrubber to prevent any escape of the H2S to the atmosphere. This prevents any undesirable odors in the area.
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