Soluble aluminum (Al3+) reacts with both ambient silica and antiscalant components to form
colloidal foulants during reverse osmosis (RO) treatment. Aluminum sulfate (alum) and
polyaluminum chloride (PACl) were evaluated at various coagulant dose and influent water pH
conditions to lower the total aluminum to below 50 ug/L, a level previously observed to cause
RO membrane fouling. Results from pilot-scale testing demonstrated that PACl consistently met
the 50 ug/L aluminum goal regardless of pH (pH 6.0-8.3), whereas alum could only meet the
goal for soluble aluminum below pH 6.5. For total aluminum, alum coagulation at pH 6.0-8.3
failed to meet the 50 ug/L goal, which may result in colloidal fouling of any downstream
membrane. Further testing using RO fed with optimized alum or PACl coagulated water are
needed to confirm that reduced membrane fouling may result by controlling the conventional
treatment plant residual aluminum concentration.
Includes 24 references, table, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 620 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 10 |
| Published : | 11/01/2002 |
