Packaged Dissolved Nitrogen Flotation (DNF) Systems

DNF systems are utilized mainly in applications where there may be a risk of detonation such as refining, oil and gas processing, or in applications where oxygen is not the preferred or most efficient method of flotation. Xylem’s DNF systems are vapor-tight, providing compliance with the U.S. Environmental Protection Agency’s (EPA) NESHAP requirements.

Dissolved nitrogen flotation (DNF) is a proven and effective physical/chemical technology for treating a variety of industrial and municipal process and wastewater streams using nitrogen or other inert gasses instead of oxygen as part of the process. DGF systems are commonly used where there may be a risk of detonation such as refining, oil and gas processing, or in applications where oxygen is not the preferred or most efficient method of flotation. Dissolved nitrogen flotation (DNF) or other dissolved gas flotation (DGF) systems can be used as secondary clarification in cases where air/oxygen cannot be used such as when used as part of an anaerobic system. 
DNF systems can help customers meet a variety of treatment goals including:

• Product recovery and reuse
• Pretreatment to meet sewer discharge limits
• Pretreatment to reduce loading on downstream biological treatment systems

One of the most common DNF applications is for the pretreatment of wastewater to remove suspended solids and oils and greases prior to discharge to a municipal sewer or a biological treatment system. For example:

A pretreatment DNF can be used by an industrial discharger to meet specific limits for oil and grease and/or suspended solids set by a municipality (e.g., to meet a discharge limit of 100 mg/L O&G, etc.).

An industry may need to use a pretreatment DNF to remove contaminants (e.g., product solids, oils and greases, heavy metals, etc.) that would negatively impact a biological wastewater treatment system downstream.

In most cases, the wastewater contaminants must be chemically flocculated in order for the floatation system to remove them. Pretreatment DNF systems are used in about every industry class. DNF has proven to be very effective for the removal of biological solids from wastewater streams. Some of the advantages over traditional, gravity clarification include:

• Smaller footprint and more rapid implementation
• Higher sludge solids content (4%TS vs. 1%TS) resulting in a much lower sludge volume
• Ability to handle bulking solids that tend to float
• More reliable effluent quality

We can meet your need for an entire temporary treatment system, combined with ancillary equipment. We can provide DNF or other DGF systems as well as mixer tanks, pumps, catwalks, and other wastewater treatment equipment and solutions.