Accessories and Parts

Concrete Washwater Washout Tanks

Concrete Washwater Washout Tanks, Enduramaxx holding tanks, settlement tanks and chemical dosing tanks are designed to work with a range of systems to deal with high pH concrete wash water.  These tanks can be used on your existing Concrete Wash Out Area or to establish new dedicated processes/zones for above ground, below ground and for holding the chemicals required for dosing.

Why the control and treatment of concrete wash water are essential?

The chemical processes or chemical reactions that cause concrete to slowly harden and set are complex. These processes give a by-product calcium hydroxide which is a highly alkaline chemical that has a pH in excess of 12 – (in comparison to drinking water which is 6.5 to 7) and a strong acid a pH of circa 2 to 3. Typical discharge permits stipulate pH limits of between 6 and 9 for discharges into the aquatic environment as the release of untreated highly alkaline concrete wash water into the aquatic environment through surface water or groundwater can have devastating effects.

High pH (alkaline) water can look clean after the solids have been removed thr9ugh settlement or clarification, yet this water is corrosive and can cause damage to vegetation and ecosystems, killing fish and other aquatic life.  A misconception is that dilution can be used as a method of treating the high pH as large amounts of water are needed to make a small change.

Sources of alkaline water on construction sites

  • Washing down of machinery used with fresh concrete – chutes, drums, pumps
  • Cutting or coring of concrete structures
  • Hydrodemolition (high-pressure water cutting)
  • Surface water runoff from concreted areas
  • Crushed demolition materials

Why Dilution isn’t the solution?

The pH scale is a logarithmic scale, for example, to dilute 1 litre of pH 12 concrete wastewater, would need approximately 100,000 litres of tap water.  Traditionally a high pH would be treated with mineral acid (sulphuric or hydrochloric) or citric acid reagents but these chemicals need careful handling and specialist training, and are difficult to dose correctly, with overdosing to form acidic water a strong possibility.

Managing Concrete Washwater

Active concrete washout area serves two functions. These are:

  • Containment of slurry and solids created
  • Containment of liquids through washing down of chutes, mixers, hoppers and concrete pumps & which has come into contact with fresh concrete.

The use of a correct design installed and operated washout facility not only assists in preventing pollution but is also a matter of good housekeeping on site.

Enduramaxx manufactures Concrete Washwater Washout Tanks for above and below ground storage of wastewater, and mixers for Coagulation and Flocculation in Water and Wastewater Treatment mixing applications, for more details, please get in touch.

View Our Concrete Washwater Washout Tank Range

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