U.S. Environmental Protection Agency's (USEPA's) National Risk Management Research
Laboratory (NRMRL) in Cincinnati, Ohio is evaluating drinking water filtration systems
to determine their capability to meet the requirements of the Long-Term 2 Enhanced
Surface Water Treatment Rule (LT2ESWTR) for small communities with less than
10,000 people. This paper presents the preliminary results of tests conducted at the USEPA Test and Evaluation (T&E) Facility in Cincinnati, Ohio to evaluate and compare the
effectiveness of a radial flow fluidized filter (R3f) versus a conventional multimedia filter
(anthracite/sand/garnet/gravel). The R3f system uses either a fine glass bead or a garnet
media that can be fluidized and backwashed. Both systems were challenged with
different levels of turbidity and microbiological contaminants such as B. subtilis, E. coli
and polystyrene latex (PSL) beads (as a surrogate for Cryptosporidium). The results of
initial turbidity tests established that the use of fine garnet media (33 micron size) in the
lead and lag filtration units in the R3f system generated effluent with turbidity levels of
approximately 0.5 nephelometric turbidity unit (NTU) from influent feed water with
turbidity levels of 5 NTU and 10 NTU. The R3f system was operated at a flow rate of 5
gallons per minute (gpm) without using chemical coagulants. The R3f filtration system
performed significantly better than the conventional multimedia filtration system in
removing turbidity and microbiological contaminants and surrogates. Although the
frequency of backwashing is higher in the R3f system as compared to the multimedia
filtration system, the overall water throughput in the R3f system was more than that of
the multimedia filtration system. One challenge test was conducted on the R3f filtration
system using Cryptosporidium oocysts to verify PSL bead surrogate removal; the results
demonstrated equivalent removal. Includes 6 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 930 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 14 |
| Published : | 11/01/2008 |
