BNR 101: Pilot Study
clarifier) was added before the ANITA Mox stage to ensure
influent with a low biodegradable COD concentration
coming to the ANITA Mox stage. Both C-stage and ANITA
Mox reactors were started with 100-percent-seeded carriers
(AnoxKaldnes K5 plastic media carriers), which were
obtained from the ANITA Mox pilot plant in Denver. Figure
2 on the next page shows the actual system layout in the
plant. The C-stage reactor was located on the shelf, and the
ANITA Mox reactors were located on
the table.
Table 1 on the next page sum-
marizes the reactor volumes, media
volumes, and media surface areas in
the bench-scale reactor system. The
feed was the old leachate that was
delivered from the Rumpke Sanitary
Landfill on a weekly basis. Table 2
on the next page summarizes the
feed characteristics during the testing
period. The characteristics indicate a
variation of a factor of 10 between the
maximum and minimum values on
COD, total suspended solids (TSS),
and ammonia with a pH range from
7.6 to 10.6. For both the MBBR and
IFAS phases, the influent flow rate
was adjusted to achieve relatively
stable performance. Nitrogen
components (ammonia, nitrate, and
nitrite), COD, TSS, and alkalinity
were measured daily in each reac-
tor for influent and effluent. The
operating conditions (e.g., dissolved
oxygen [DO], temperature, pH, and
intermittent aeration cycles) were
monitored by online probes, and DO
was controlled manually with adjustment of airflow.
Results And Discussion
Figure 3 on page 28 presents the COD removal
performance for both the MBBR and IFAS phases.
During the MBBR phase, the C-stage was capable of
removing a majority of the influent COD, and not
much COD was left to the ANITA Mox stage. On
25
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Water Online The Magazine
Process control (DO,
pH, temperature,
and free ammonia)
is
key to
maintaining the
right microbial
population
and structure
to
maximize
performance
.