Oxygen for water purification

Both households as well as the industry ensure each year massive quantities of waste water. Before this can be discharged back in canals or rivers, is it first purified in waste water treatment plants.

Application scope

The waste water is usually purified in a traditional sewage treatment plant (WWTP) until it has again a quality that allows the discharge of the water further in the surface water rivers.

A typical water treatment process consists of four phases:

• primary purification by which larger particles are filtered out of the effluent;
• secondary treatment whereby organic substances are removed through biological purification and also involve the oxygen (O₂) to be added;
• tertiary purification, in this phase nutrients are removed from the waste water stream;
• quaternary purification, involving the removal of specific substances which are characteristic of the waste water flow.

At the secondary water purification, as has been said, one makes use of aeration systems to add oxygen to this process. It needs be known that there is only 21% oxygen present in air. This can due to overload of the WWTP lead to a less good water purification.

The administration of higher concentrations of oxygen can help to assist in the functioning of the water treatment plant at higher demand or at higher temperatures.

Requirements

A basic setup consists of a cryogenic tank for liquid oxygen. This oxygen is then brought in gaseous phase with an atmospheric evaporator and subsequently via a nozzle or ejector into a liquid flow of a dirt carrier.

IJsfabriek Strombeek possesses besides the necessary oxygen the different techniques that can be used to inject this in the waste water in a waste water treatment plant.

The injection can be done by injecting directly in the water or by making use of injection systems that injects the oxygen in a circulating water flow. Depending on the shape and the type of installation the right choice of injection system is made.

Our team of engineers can advise you with all their experience and expertise to choose the appropriate method and continue to lead your project in the right direction.

Advantages

• increase the ROI of the WWTP
• increase the braking up of organic substances
• increase the operation of the active sludge
• reduce foaming
• reduce Volatile Organic Compounds (VOC) responsible for odour nuisance
• postponement of heavy investments to increase the capacity of the WWTP

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