Method for filtering styrene contaminants in water

Using granular activated carbon combined with aeration through the insert tower can help filter water contaminated with styrene.

Styrene is a colorless liquid organic substance, lighter than water, insoluble in water, volatile, and has a sweet taste, but gives off an unpleasant odor when concentrated. Styrene is widely used to make polystyrene and many other polymers, plastics, coatings and paints.

Styrene is on the list of harmful air pollutants, according to the US Environmental Protection Agency. This substance is active in the atmosphere and can contribute to haze formation as well as secondary pollutants.

Styrene soaked in water will quickly evaporate or break down due to bacterial activity. This substance does not adhere to the soil and can seep into groundwater. Styrene also rarely accumulates in aquatic animals.

With short-term exposure, styrene can cause many health problems such as effects on the nervous system, leading to depression, loss of concentration, fatigue, weakness and vomiting. In the long term, styrene can damage liver and nerve tissue, leading to cancer.

Method for filtering styrene contaminants in water
Granular activated carbon can filter styrene in water. (Image: Wikipedia).

The US Environmental Protection Agency (EPA) recommends the use of granular activated carbon (GAC) or compressed tower aeration to remove styrene from water sources.

Activated carbon is a versatile absorbent solid material thanks to its capillary structure of many sizes (small, medium, large). In particular, the small capillary of activated carbon well absorbs small molecules of volatile substances such as styrene. In the form of activated carbon, granular is widely used in water purification systems or home water treatment.

GAC is usually located between the filter stages of the water treatment system. From the water source to be filtered, water can be arranged to flow through the shower to create rain that sprays through the top layer of sand, helping to filter out dirt, organisms, and alum. Then, the water will seep through the activated carbon layer. Activated carbon will absorb styrene and many other toxic organic substances, dangerous microorganisms and neutralize minerals that are difficult to dissolve in water. Through the activated carbon layer, the water continues to penetrate through the second layer of sand, the small gravel layer and the largest gravel layer before going to the clean water tank.

However, activated carbon only works with a certain amount of water. After that, the coal will no longer be able to work because it is saturated.

Water treatment by aeration is very effective for volatile organics such as styrene or industrial solvents, metals such as iron and manganese, according to the Institute of Food and Agriculture. The insertion tower aeration system consists of a filter tower about 3 meters high that inserts multiple layers of material. The material used for inserting can be pieces of porcelain from 0.6 cm to 7.6 cm in size. The smaller the pieces of material, the higher the filtration efficiency, but the energy cost to pump the air also increases.

In this system, water flows from the top of the tower down under the influence of gravity while air is pumped up from the bottom in the opposite direction of the water flow. Volatile contaminants will follow the gas stream to the top of the tower and be led out.