Aquacros Ortho/Polyphosphate FAQs


Corrosion Control
To achieve the best Corrosion Control out of the Aquacros Ortho/Polyphosphates the following is recommended:
– PH range: 7.5 to 8.0
– Alkalinity of Finish Water: 20 ppm
– PO4: 1 – 4.5

Frequently Asked Questions:
What are Phosphates?
Phosphates are water treatment chemicals used to solve specific water quality problems resulting from inorganic contaminants (Iron, Manganese, Calcium, etc.) in ground water supplies and also to maintain water quality (inhibit corrosion, scale, biofilm, reduce lead and copper levels) in the distribution system. Ortho/polyphosphates and polyphosphate are two general types used in water treatment along with many different phosphate compounds that exist for use in the water treatment process. Ortho and polyphosphates work together, stabilizing water quality and minimizing color, scale, deposits, corrosion, and chlorine in drinking water systems.

What do the Phosphates help to solve?
Phosphates are used in municipal water systems to perform three broad functions: inhibit corrosion of water mains/plumbing (iron, steel, galvanized, asbestos/cement, lead, copper), sequester nuisance metals in the water supply (iron, manganese, calcium, magnesium). They can also improve the quality of water in the distribution system by removing scale deposits & tuberculation, discourage microbial film formation/regrowth and stabilizing free chlorine disinfectant residuals.

Are Phosphates commonly used in drinking water?
We estimate that over 15% of public & private water systems use some form of phosphate in the treatment of their drinking water. Aquacros Ortho/polyphosphate blends are used to inhibit corrosion in the distribution system, sequester iron, manganese, calcium and magnesium and to meet the EPA regulations on Lead and Copper.

How do phosphates work in a water system?
The Orthophosphate is the corrosion inhibitor, which will react with dissolved metals (e.g. Ca, Mg, Zn, etc.) in the water to form a very thin metal-phosphate coating or it reacts with metals on a pipe surface to form a microscopic film on the inner surface of the pipe that is exposed to the treated water.

The Polyphosphate is the sequestrant, which will react with soluble metals (iron, manganese, calcium, magnesium, etc.) by sequestering (binding up) the metals to maintain their solubility in water. The phosphate sequestering process minimizes the risk of discoloration, staining, scaling, taste/odor and other water quality complaints.

How effective are phosphates at controlling color?
Color in water system may be the result in the precipitation of soluble iron/manganese when they react with dissolved oxygen, chlorine disinfectant and other oxidizing agents during water treatment. Polyphosphates bind-up the Fe/Mn, keeping them in solution and preventing the color from initially forming. Another source of color is the natural release of soluble iron by-products that appear to be ‘bleeding’ from the scale deposits (tuberculation) inside water pipes. Polyphosphates bind with soluble iron before it turns color (precipitates), while orthophosphates react with the pipe surface to slow down pipe corrosion and the release of corrosion particulates. Blended mixtures of ortho/polyphosphates control both sources of potential color at the water supply and in the distribution system.

Do phosphates affect trihalomethane (THM) formation?
The primary cause of THMs is pre-oxidation, with chlorine, of raw water that contains organic precursors. The presence of biological regrowth (biofilm) inside water pipes is another source of organic precursors. After chlorine reacts with organic material, THMs may form. Alternative disinfectants or treatment adjustments will often reduce THM formation. However, phosphates also contribute to lowering system THMs. Phosphates inhibit corrosion effectively in a lower pH (7-7.5) range. THM formation potential is significantly reduced when water is chlorinated at a lower pH (<8.0). Phosphate inhibitors/sequestering agents minimize corrosion by-products scale formation inside the pipe, thereby keeping the pipes cleaner and free of the biofilm that may generate additional organic precursors if left uncontrolled.

What other benefits of phosphate treatment exist?
Phosphates easily adapt to any pre-existing water quality without changing the water chemistry. Referred to as inhibitors (ortho), sequestrants (poly), or blends (ortho/poly), phosphates have a selective function, yet wide range of performance. Primary treatment benefits include: corrosion control, lead/copper control, sequestration of iron/manganese, control of calcium carbonate scale, and water softening, etc.

Many secondary benefits develop, such as: reduced chlorine demand due to corrosion inhibition and sequestration of Fe/Mn, lower color and turbidity in the distribution system, less staining, removal of system scale deposits, control of biofilm regrowth, lower TOC, fewer system coliform violations, increased C-factors and hydraulic flow rates in system, reduced electrical demand, fewer main breaks, better valve operation, improved meter accuracy, increased revenue, reduced hydrant flushing frequency, less wasted water during flushing, less maintenance and service expenditures, fewer complaint calls, and overall improved consumer satisfaction.

Are Aquacros Ortho/Polyphosphates NSF Approved?
Yes all Aquacros ortho/polyphosphate blends are NSF/ANSI Standard 60 Drinking Water Treatment Chemicals are approved for use in potable drinking water. Product data sheets and Material Safety Data Sheets (MSDS) are available for all products.

What is the dosage required?
The most effective dosage rate is determined by running complete water analysis to determine the total demand of the finished water and the consumption rate of the distribution system.

How are Ortho/Polyphosphates fed?
Aquacros ortho/polyphosphate based corrosion inhibitors/sequestering agents are injected via a chemical metering pump at the well head prior to other chemical additives (chlorine, fluoride, caustic soda, etc.). Aquacros ortho/polyphosphate blends selectively react with Iron, Manganese, Calcium and Magnesium ions to maintain a colorless molecule that resists precipitation caused by aeration, disinfection, oxidation, storage and transmission of finished water.

How are phosphates dosages controlled?
Since phosphates do not change water chemistry, measuring phosphate in the raw finished water is necessary to monitor the dosage rate. Orthophosphate ion (PO4) is the most common species used to measure the initial and total quantity of phosphate n the water. Orthophosphates can be measured on a cold water sample, while the total phosphate requires a digestion step to break down all other forms of phosphate in the ortho form. Simple field test kits or laboratory analytical equipment can be used to monitor all forms. Subtracting the initial orthophosphate quantity from the total phosphate yields the quantity of polyphosphate present in the finished water (Total – Orhto = Poly).

What happens if phosphate is overfed?
An overdose of phosphate is difficult to detect immediately unless orthophosphate is being monitored in the finished water. Too much orthophosphate typically will not result in a water quality problem unless calcium hardness reacting with the phosphate begins to form a slight turbidity during the film formation process inside the system. Excessive polyphosphate dosage may result in an accelerated cleaning of scale and tuberculation from the pipe surface, resulting in colored water, turbidity or suspended solids.