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Nitrification
In the nitrification process (Fig. 9-1) MARPAK
MXF Series fixed film reactor provides an
effective means of oxidizing ammonia nitrogen of
secondary treated wastewater.
Nitrifying trickling filters require less mechanical
equipment, less operating power and less
attention than the activated sludge process
(Fig. 9-3). Nitrifying trickling filters are less
effected by cold temperature than the
activated sludge process (Fig. 9-4).
MARPAK nitrification fixed film reactor,
when preceded by clarified secondary
effluent with the BOD
5
below 35 mg/l, will
continue to reduce suspended solids and
BOD
5
to a level below 20 mg/l.
A performance curve for nitrification is
shown in Fig. 9-2.
MARPAK
Nitrification
Reactor
BOD-30
SS-20
NH
4
N-25
BOD<15
SS<15
NH
4
N<1
Effluent from
Secondary
Treatment
9-1
Nitrification
Media
Surface
Area
Required
sq ft/lb of
NH
4
-N
Oxidized
Per Day
12000
10000
8000
6000
4000
2000
0
9-2
1.0 2.0 3.0 4.0 5.0 6.0
Effluent Ammonia-N (mg/L)
12° To 19°C
7° To 11°C
Source: Process Design Manual For Nitrogen Control, U.S. EPA
+
9-3
Cost Comparison
Source: Water Engineering and Management
Activated Nitrifying
Cost Sludge Trickling Filter
Project
Energy (10 year)
Project - present worth
Energy - present worth
Total - present worth
$ 8,497,000
3,450,000
7,423,000
2,847,000
$10,270,000
$ 4,870,000
1,175,000
4,250,000
971,000
$ 5,221,000
Nitrification
Rate
(as % of rate
at 20°C)
100
80
60
40
20
0
9-4
10 12 14 16 18 20
Temperature °C
Effect of Temperature
Activated Sludge
Nitrifying Trickling Filter
Source: Water Engineering and Management