Facility in Alexandria, VA, is
currently implementing a full-
scale sidestream anammox
system to help address Virginia's
state regulatory requirement to
remove 62 percent of 2005 levels
of effluent nitrogen by 2011.
AlexRenew selected anammox
technology because it can achieve
significant nitrogen removal with
reduced supplemental chemical
addition and energy. (Figure 2)
Methodology
Using CH2M's proprietar y
Pro2D
2
whole plant simulator
tool, sidestream treatment with
PAD, sidestream treatment with
anammox, and a baseline (no
sidestream treatment) at three
hypothetical wastewater treatment
facilities were compared to evaluate
the respective benefits and cost-
effectiveness of implementing
these two treatment technologies.
As shown in the process flow
diagrams for the three models
illustrated in Figures 3, 4, and
5, respectively, the PAD and
anammox technologies target
different sidestream flow streams;
PAD targets digester effluent,
while anammox targets the
filtrate or centrate produced from
dewatering.
Each model assumed a flow of
20 MGD, a greenfield site, and the
same raw influent characteristics
and effluent limitations, including
1 mg/L ammonia-nitrogen, 5.0
mg/L total nitrogen, and 1.0 mg/L
total phosphorus.
Results
• The baseline model could
not achieve the effluent
l i m i t a t i o n s w i t h o u t
supplemental carbon (1,715
pounds per day), but no
supplemental alkalinity
or carbon was needed for
either sidestream treatment
model to achieve these
limitations.
• Both sidestream treatment
technologies can remove
a significant amount of
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NUTRIENTREMOVAL
Figure 3. Process flow diagram for the baseline wastewater treatment facility (no sidestream treatment)
Figure 2. AlexRenew WRRF process flow diagram with sidestream anammox
Figure 4. Process flow diagram for sidestream treatment with PAD