Blue NITE™ Denitrification Solution
Excessive nutrients in wastewater discharge can lead to degradation of water quality by algal growth and dissolved oxygen depletion. Traditionally the Clean Water Act required wastewater plants to remove ammonia by converting it to nitrate / nitrite. Regulators are now issuing permits to address total nitrogen (TN) that require the removal of the nitrate / nitrite species.
To address these permit changes, nitrate / nitrite needs to be transformed into nitrogen gas by a process called denitrification. Blue NITE™ allows municipalities to meet permit levels for discharge of wastewater by lowering nitrate to less than 1 mg/L.
Blue NITE™ is currently installed at several locations world wide, lowering nitrate to less than 0.3 mg/L as N. Results from a combined denitrification and phosphorus removal installation are shown in the data sheet, achieving total nutrient reduction in the same vessel.
Blue NITE™ may also be used in series with a second Blue PRO® pass for total phosphorus concentrations <0.020 mg/L P>.
In projects using alternatives to methanol as the carbon source, Blue NITE™ has been shown to work with Micro-C™ and UniCarb™. This allows plants more choices for operation.
Blue NITE™ is able to accommodate high or fluctuating influent nitrate levels. The process applies to wastewater or groundwater applications. Hydraulic loading rates to Blue NITE™ filters are dependent on influent levels, dissolved oxygen (DO) levels, and temperature.
Blue Water’s Centra-flo™ Filter line is a well-established continuous backwashing, sand filtration system with more than 250 installations worldwide. The Blue NITE™ denitrification process is accomplished in a Centra-flo™ continuous backwash, upflow sand filter with a carbon source added to the influent water.
In the filter, fixed-film, heterotrophic, denitrifying bacteria convert nitrate to atmospheric nitrogen (N2). A portion of the bacteria laden sand is continuously lifted and passes through a built in sand washer. The washer separates solids and excess biomass, which are directed to a reject line. The clean sand then falls by gravity back to the media bed.
Nitrogen gas is produced during operation and becomes entrapped by the filter media. This gas is carried down with the sand and is released in the sand washer.
Some of the advantages of this method of gas removal include; no false readings of headloss, no backwashing is required, filters will not “burp” and upset if a significant nitrogen bubble accumulates, as typical in static bed filters.