This paper presents results from the final phase of an on-going study exploring
chemical treatment of high-pressure membrane concentrate, specifically the removal of
arsenic by adsorption to iron solids followed by solid-liquid separation. Concentrate
received from two brackish water reverse osmosis plants located in California and
Florida, respectively, were spiked with arsenate to approximately 500 ppb as As. Arsenic
removal was determined experimentally using small volume jar test procedures. After
iron addition (as ferric chloride), the test solutions were rapidly mixed for a short time
followed by a longer period of mixing at a slower rate. After mixing, solids formed
during treatment were separated from solution using a 0.22 mm pore size filter.
Levels of arsenic, natural organic matter (as dissolved organic carbon), UV254
absorbance, and iron in the raw and treated waters are reported as a function of iron dose
and final pH. The effect of pH on arsenic removal by adsorption to in situ precipitated
iron hydroxide is discussed. Arsenic removal from the full-scale residuals is also
compared with removal from simpler model concentrates made in the laboratory. Includes 2 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.3 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 15 |
| Published : | 11/01/2008 |
