Waste Water Treatment, Using Fenton’s Reagent for Chemical Oxidation

The Fenton reagent is produced when a solution of hydrogen peroxide is mixed with dissolved ferrous iron. The ferrous iron acts as a catalyst to produce a hydroxyl radical. The hydroxyl radical generated in the Fenton Process is a strong oxidizer that is second only to Fluorine in its oxidizing strength. It has approximately twice the oxidizing strength of hydrogen peroxide alone. Fenton’s reagent is used to oxidize organic contaminates found in industrial waste waters. Fenton’s reagent is most commonly used to destroy organic compounds that are resistant to other wastewater treatment techniques such as biological treatment or carbon adsorption. ... » Read More

Waste Water Treatment, Design and Build vs. Standard Vendor Unit

Waste water treatment technology is not new. The individual components that make up a complete system are readily available. Standard Vendor Unit As a rule of thumb vendor units are usually designed for flow rates up to 30 gallons per minute (GPM). Vendors state the flow rate as 0 to 30 for a 30 gpm system. It is stated this way because as filters are used they become blocked and the flow will continuously drop off. High contaminate concentrations will also reduce the amount of waste water that the system is able to treat. Design and Build For high contaminate ... » Read More

dewatering box caking

Solving Sludge De-Watering Box Problems – Cake removal

De-watering Box Cake Removal One problem that can occur when using a de-watering box with a dense sludge is that after drying, the dried material or cake, can stick inside the de-watering box. Filter Cloth is a Simple Solution A simple solution to this is to line the de-watering box with a filter cloth. When you dump the hopper, just throw the filter cloth away along with the cake and start over. An inexpensive Poly Ethylene or Rayon filter cloth works well for this situation. Filter cloth can be purchased in rolls up to six feet in width. A typical ... » Read More

Sludge Conditioning to Aid Sludge De-Watering

Most sludge de-watering applications will benefit from sludge conditioning ahead of the thickening or de-watering device. Coagulants and flocculants, polymers, are widely used in many industries to remove water from wet solids (sludge). Note that flocculants alone are often all that is required to improve sludge de-watering. This process is known as sludge conditioning. Water release from sludge is affected by electrostatic forces of attraction and repulsion that control floc formation and size. Floc size and uniformity controls the flow of water through the sludge under gravity (de-watering boxes), or under pressure (belt presses and plate and frame filter presses). ... » Read More

dewatering screen

Waste Water Treatment – Gravity Sludge De-Watering

Gravity de-watering is accomplished in a de-watering box. This can be a roll off type box or a self-dumping hopper. The box or hopper will have a perforated bottom plate. Typically, a 100-mesh stainless steel wire screen is over the perforated plate. A 20 mesh wire screen is also typical when a filter paper is to be used on top of the screen.  Other sizes of wire mesh screen are readily available. The wire screen is typically held in a metal frame making it easy to remove for cleaning or replacement. The wire screen may be enough by itself, if ... » Read More

Waste Water Treatment – COD vs BOD as a Measure of Waste Water Strength

BOD, Biochemical Oxygen Demand, is the standard measurement for determining the strength of waste water.    It is also a common regulatory tool used around the world to measure the strength of industrial waste water.   Most municipalities will charge a fee per 1,000 gallons of waste water when the BOD is considered to be high.    High BOD is generally anything over 1,000 mg/l where household BOD is around 350 mg/l.   Industrial waste water is often well above this threshold resulting in high fees from the sewer authority.   The sewer authority charges theses fees to cover increased cost associated with the high ... » Read More

Waste Water Treatment Coagulation and Flocculation – Importance of Mixing Energy

We were recently involved in an industrial waste water project for the removal of Molybdenum. We conducted jar testing with pH adjustment, addition of coagulant and a flocculent along with a body feed of bentonite clay. We were successful at clarifying the waste water and removing the molybdenum in the jar testing. The jar testing went so easily, that we were surprised when it failed on a pilot scale. The pilot plant was a continuous flow treatment system with three 36 gallon CSTRs (continuously stirred tank reactors) followed by simple filtration. Chemicals were added to the first tank, a rapid ... » Read More

Bentonite Clay

Waste Water Treatment Coagulation and Flocculation, Using a Bentonite Clay – Body Feed

It seems counter-intuitive, but the cleaner the waste water the harder it is to treat. When a coagulant is added to nearly clear waste water it will often form a very tiny floc known as a Pin Floc. In waste water treatment Pin Floc is to be avoided. Pin Floc tends to not settle and can cause filter problems. To produce a more robust floc that will settle and can be separated and filtered out, a Body Feed is often added. A common Body Feed for industrial waste water treatment is Bentonite Clay. Bentonite Clay is inexpensive and can be ... » Read More

Waste Water Treatment Coagulation and Flocculation – Static Mixers vs Dynamic Mixers

In waste water treatment, the term Dynamic Mixer means any mixer with a moving part, such as an impeller. This is usually a square tank with a center mounted mixer motor, shaft and impeller. Where Static Mixers are usually several sections of pipe with a convoluted insert that causes the water to change direction over and over again to achieve mixing. The mixing energy comes from the flow rate through the pipe. When adding coagulants and flocculants for waste water treatment, dynamic mixers work well for both chemicals. However static mixers work best for coagulants, but not for flocculants. Flocculants ... » Read More

Choosing the Right De-watering Box Filter Media

There are many choices for the filter media in your de-watering box. Cloth filters come on a roll that can be any width and are usually 50 yards, 100 yards or 250 yards in length. The filter cloth is typically cut by hand and laid on top of the wire screen in the bottom of the box.  The wire screen can be any mesh size but is usually in the range of is 20 to 100 mesh stainless steel. The wire screen wire can be used by itself or used to support the filter cloth. The most popular filter cloths ... » Read More