Wastewater treatment

The rising global population and global warming are combining to put extreme demands on clean water supplies. Wastewater treatment plants are critical infrastructure assets in most parts of the world.

Severe odour issues are a common problem at most wastewater treatment plants. And as cities increase in size and the protection of green spaces becomes more important, these plants are increasingly being located closer to areas of high population density. The odours are more than just a simple nuisance for your plant and the surrounding communities: they can have a huge impact on the health and safety of plant personnel and your treatment system equipment.

Notorious and malodorous corrosive gases

Unlike previous constructions, some of which were in remote green locations, modern wastewater treatment plants are enclosed as much as possible and in some cases built partially or totally underground, often close to cities. 

Enclosure helps to contain odours – but it creates different problems. In particular, enclosure can lead to an accumulation of methane, an odourless yet explosive gas. So enclosed spaces must be ventilated to maintain the methane concentration at a safe level. When the ventilation air is exhausted to atmosphere, the gases responsible for the characteristic foul odour are also released. Odour control solutions are required in the exhaust air system.

A complex mixture of gases is responsible for the odour. The most notorious gases are hydrogen sulphide (the “rotten egg smell”, H2S) and mercaptans, but the foul air will also contain other organo-sulphur, ammonia (NH3) and organo-nitrogen gases.

The benefits of proper air filtration

In wastewater treatment facilities, the release of acidic gases also poses a problem. If these gases are not controlled in the supply air to control rooms, they will damage electrical gear used to regulate the complex array of process equipment such as pumps and penstocks.

Luckily, molecular filtration provides solutions for the problems associated with both contaminated exhaust and supply air experienced at treatment plants. Here are some of the benefits.

• Manage odour complaints and maintain positive community relations. Many foul odours have a low odour threshold, and people have different odour tolerances. Molecular filtration is an established method of reducing the odour signature of wastewater treatment plants.
• Protect against safety hazards. Exposure to elevated concentrations of certain gases can be fatal. For example, continued exposure to hydrogen sulphide can cause drowsiness and even death if a person cannot escape the exposure.
• Reduce equipment damage and maintenance downtime. Continued exposure of plant equipment to certain gases can cause severe corrosive damage and even the collapse of manholes and sewage lines.