NITROGEN REDUCTION FACILITY
(NRF).
SPEC Industries Inc. developed
the NRF for Nitrogen reduction as a pretreatment phase before
AIRR unit to ensure the total nitrogen reduction is less
than 10 mg/l, in order to meet the EPA requirements. The
SPEC NRF is a Sequential Anaerobic-Aerobic-Anoxic System,
which accomplishes different cycles in three internal chambers
in the Nitrification – Denitrification process. The
relation of this process to the internal chambers is as
follow:
1. Chamber No.1. Receives
the effluent from the septic tank. The sequence begins with
the aeration cycle performed by a media and aeration device.
In this sequence the ammonia nitrogen and the organic nitrogen
oxidation are being converted to nitrite by Nitrosomonas
bacteria, followed by nitrite being oxidized to nitrate
by Nitrobacter bacteria. The Nitrification processes depend
on temperature, dissolved oxygen concentrations, PH and
solids retention time (SRT). The Biomass created in this
chamber is facultative with emphasis on the Nitrobacteria
colony, assuring the appropriate C: N ratio.
2. Chamber No.2. From Chamber
No.1 the nitrified effluent travels through an Anaerobic
– Anoxic stage where the DO level decreases below
1 mg/L. In this cycle the nitrate NOx - N is being taken
as an oxygen source for the Anaerobic Denitrifying bacteria
colony with a minimum C: N ratio 3:1. Hence the NRF will
supply oxygen requirements to nitrification – denitrification
processes with a consequence BOD5 reduction (domestic wastewater
natural carbon source).
3. Chamber No.3. The last
chamber ensure an appropriate SRT and Nitrogen release,
The facultative bacterial colony will grow; nitrobacteria
colonies take place for the nitrification process. The Dosing
Tank in the AIRR system will receive a total Ammonia conversion
and between 50 -70 % NOx – N reduction.
