Removal of NOM, Nutrients, and Micropollutants in BAC Filtration - Activated Carbon for Water and Wastewater Treatment - page 279

Amsterdam Water Supply Location Weesperkarspel (WPK)

Amsterdam-Rhine
canal

Bethunepolder

Pretreatment by
Coagulation,
Flocculation,
Sedimentation,
Storage in Reservoir,
Rapid Sand Filtration

Pilot-Scale Study

Nonozonated Water

Ozonation-WPK 1

Ozonation
WPK 5

Ozonation
WPK 6

Ozonation
WPK 7

Pellet Softening

BAC-WPK 5 BAC-WPK 6 BAC-WPK 7 BAC-WPK 8 BAC-WPK 1

Figure 9.7 Flow scheme of the pilot-scale plant at Weesperkarspel/Netherlands (drawn
based on [34]).

processes taking place inside BAC filters effectively reduce AOC, as shown in
Table 9.5. For example, Chien and co-workers showed that preozonation increased
the total AOC concentration, which, however, was reduced in biofiltration at pilot-
scale [16, 44]. In one river water, the fraction of NOM with MW o 1 kDa corre-
sponded to 53-67% of DOC. The AOC constituted only 2.7-5.9% of DOC. Most of
the AOC had a MW o 1 kDa (Table 9.5). The ozonation/BAC process removed a
large part of DOC, but did not necessarily result in a great reduction in AOC [45].
Another study showed that a large part of DOC had a molecular weight less than 1
kDa [46]. In another case, in combination with post-ozonation, BAC filtration
could eliminate a large part of DOC in the o 1 kDa MW fraction [47]. Further,
enhanced biodegradation of TOC was observed for NOM sources with a lower
SUVA 254 value, indicating that low aromaticity of organic matter favored effective
removal [48].
Figure 9.7 shows the flow scheme of a pilot-scale study at the Weesperkarspel
Plant in Amsterdam. The characteristics of waters fed to each BAC filter are
presented in Table 9.5. The NOM in the source raw water consisted of large humic
acid molecules. Preozonated water was fed to the filters denoted as BAC-WPK5,
BAC-WPK6, and BAC-WPK7. In all filters, the EBCT was 40 min, while the HLR
was about 3.15-3.18 m h 1 . Preozonation resulted in the formation of AOC,
whereas without preozonation the AOC concentration in the influent of filter
BAC-WPK8 was very small [34]. BAC filters receiving preozonated water removed