Model DF-775

DF-775 is an aqueous solution of inorganic cationic coagulant. It is effective for increasing the particle size of precipitated of metal compounds typically produced in industrial waste water treatment.

DF-775 is recommended as a treatment chemical for effluents, where the metals have been precipitated by hydroxide, sulfide, dithiocarbamates (DF-610, DF-640, and DF- 650), ferrous sulfate, or sodium borohydride.

The product can be used in combination with an anionic polymer to further enhance settling rates. It is excellent for use in continuous flowing processes which use gravity clarification or membrane microfiltration as well as to enhance settling and filtration in batch treatment of concentrates.

Applications

Depending on the specific application, the optimum concentration of DF-775 to achieve rapid settling and superb liquid clarity, is determined by jar testing. The concentration of the various wastewater contaminants, such as, suspended solids, total dissolved solids, COD, BOD, and oil and grease, all have an impact on the optimum DF-775 dosage. DF-775 is effective over a wide pH range (4.0 to 11.0).

Addition of DF-775 is controlled by volumetric feed, proportional to the wastewater feed rate. DF-775 can be added prior to, during, or after the metal precipitation step. The optimum addition location is a function of the waste composition and the equipment available to perform the precipitation.

When used in a gravity settling system, DF-775 is usually used in combination with a high molecular weight anionic polymer, which is added in a later reaction tank after the DF-775.

Laboratory evaluation is recommended to determine the optimum conditions for use of the DF-775. Duraflow LLC will provide onsite technical support to assist with the treatability study.

DF-775 Case Studies

Case Study #1

A printed circuit board manufactured in Nashua, New Hampshire was having difficulty with its clarifier due to the rapid accumulation of suspended solids beyond the circuit maker's ability to press them off. The company considered the installation of a bigger press or a separate sludge storage tank.

By converting to DF-775 from an aluminum based coagulant, the company was able to achieve superior effluent clarity while reducing their solids generation by almost 50%. Reducing the generation of solids:

• Improved the performance of the clarifier
• Reduced the amount of hazardous waste shipped, and
• Increased the concentration of copper in the sludge and thus its recycle value

Case Study #2

A second circuit board manufacturer, also located in Nashua, New Hampshire, has a crossflow microfiltration system for wastewater treatment. Removal of solids is critical to maintaining the throughput of the filter.

The throughput in gallons per minute per square foot of membrane is referred to "flux". When the system starts to back up solids, this flux will decrease, reducing the operator's ability to keep up with the wastewater generated.

By converting to DF-775 from an aluminum-based coagulant, the circuit board manufacturer reduced the the number of solids pressings required from one press load per day to one press load every three days. In the process, the company reduced its hazardous waste generation, increased the concentration of copper in the waste for recycling, and improved the operation of their system.