Sodium Hypochlorite Bleach Tanks

Sodium hypochlorite (NaClO) is commonly known as bleach.  It is manufactured using chlorine gas and sodium hydroxide and it is used in many industries. It is strongly alkaline with a pH greater than 11 in its concentrated form. This makes it highly corrosive and hazardous, so the correct storage tank is essential.

Pure anhydrous (without water) sodium hypochlorite is very unstable and subject to intense chemical, even explosive, reactions in the presence of heat, friction, or other chemicals. It is rarely used in this form. The solution of sodium hypochlorite is a clear, yellow to green liquid with an immediately recognizable odour.

Its molecular structure is formed by the sodium cation Na⁺ and the anionic compound hypochlorite, ClO^– which combine to form NaOCl.

What is sodium hypochlorite used for?

Sodium hypochlorite is used as a whitening agent, an oxidizer, and as a sanitizing disinfectant. Plant matter such as cotton and wood fibre/pulp are processed with NaOCl to brighten or render the end product white. These are some of the industries that use bleach:

• Textiles
• Paper
• Detergents
• Petrochemical refining
• Water/wastewater treatment
• Households use bleach for toilet cleaning and whitening.

What do Sodium Hypochlorite Bleach Tanks require?

What do these special tanks need?

1. Secondary containment

Sodium Hypochlorite is classed as a hazardous substance. Safety regulations require a form of secondary containment in case of a catastrophic leak. Therefore bunded tanks are used with double walls. The outer container has a capacity of at least 110% of the inner tank.

HDPE catchment basins are secondary containment measures applicable for smaller NaOCl storage tanks.

2. Tank venting

The oxygen gas formed from NaOCl decomposition presents a problem not only in the piping and use of sodium hypochlorite but also in the storing of the chemical. If O₂ gas production occurs under storage, the pressure can build-up and become a safety issue. Sodium Hypochlorite Bleach Tanks should have a venting system to allow the release of built-up oxygen gas and should receive regular maintenance/inspections to ensure that any accumulated pressure is released. A general recommendation for venting is to use vents of diameters at least double the inlet pipe diameter. The use of flexible joints in the pipework is recommended to accommodate for potential contraction.

3. Outlet valve

Sodium Hypochlorite Bleach Tanks should also have an outlet valve that allows for full draining of the sodium hypochlorite tank for maintenance and before refilling with fresh sodium hypochlorite.

Complete flushing will prevent the buildup of nickel, cobalt, copper, iron and other suspended solids that contribute to the decomposition of NaOCl. Without regular flushing, these metals can accumulate in the container and can contribute to the very rapid decomposition of a sodium hypochlorite solution and subsequently the generation of oxygen gas.

Enduramaxx Sodium Hypochlorite Bleach Tanks

You can see our selection of Sodium Hypochlorite Bleach Tanks. They conform to all the necessary regulations for safety.