Sewage Plant Odour Control

Odour Control within Sewage Treatment Works

Sewage treatment plants are one of the most effective means to remove wastewater from a building, homes or other commercial sites.

Foul-smelling odours are common from sewage treatment plants, and although they are generally not harmful, they interrupt and deteriorate everyday life.

Air emissions and nuisance odours can be treated with odour control to ensure compliance with environmental regulations and better the lives of those living nearby.

Why does a sewage treatment plant smell?

Sewage treatment plants give off odours for a variety of reasons, , but the main reason for odours is the build-up of hydrogen sulphide (H2S) over time which causes an offensive odour (also known as “sewer gas”). Other types of odours include amines which possess an ammonia smell and mercaptans which give off the stench of rotting food. The plants release the wastewater leaving the sludge behind.

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Why do sewage treatment plant odours need to be controlled and what is its impact?

Odours from sewage treatment plants can be deeply unpleasant for anyone who lives or works in the surrounding area. Sewage treatment plants contain various bacteria which release different gases. This includes ammonia, methane and hydrogen sulfide, all of which can impact your overall health. Some of the symptoms of exposure to sewage gases include coughing, nausea, headaches and even memory issues and dizziness.

Persistent problems with odour from sewage treatment plants can lead residents to complain and can even result in legal action. Odour discharge limits need to be met and residents can enforce changes in this limit if there are continued problems with unpleasant odours.

How can you stop odours from sewage treatment plants?

Keeping your sewage treatment plant well-maintained and regularly emptied is your first line of defence against odours. Regular maintenance should check that the air vents are clear and operating properly and that there are no objects such as food waste in the plant that cannot be broken down.

Wastewater Odour Control

Wastewater is water that has been used in any domestic, commercial, or industrial setting. This means that the composition of wastewater will differ depending on where the water was used. As well as water, it may also include microorganisms and inorganic compounds. This might include protein fat, vegetable and other materials, detergents, and industrial and chemical components. While the actual constituents of wastewater can differ, whatever its makeup, wastewater always has the potential to create odours. Odour removal from wastewater is therefore a vital aspect of any wastewater plant.

What causes wastewater odours?

Odours occur in wastewater plants for a variety of reasons. Firstly, the components of the wastewater itself will be a determining factor whether or not it creates odour and the degree of the problem. Other reasons include:

Rising temperatures

Rising temperatures generate more odours. During the summer months, the temperature of the wastewater increases allowing aerobic bacteria to become more active. They will then begin digesting nutrients in the wastewater at a faster rate. The warmer the water, the more active they become and the greater the odour.

Anoxic Zones

Anoxic zones are created at the bottom of wastewater aeration basins by low dissolved oxygen and rising temperatures. Anaerobic digestion then releases sulphur dioxide along with other noxious gases leading to wastewater odour.

If either of these are left untreated the odour can soon become problematic for people who work at the plant as well as for those who live or work nearby. Wastewater odour can become an environmental hazard leading to complaints. Wastewater odour control should be a key consideration for anyone operating a wastewater plant.

How do you tackle wastewater odour problems?

There are a number of techniques used to tackle wastewater odour problems. Odour control technologies chemically, physically, or biologically suppress unpleasant odours from treatment plants. A wastewater odour control biofilter is a good example of this. These are fixed bed reactors filled with a carrier material for microorganisms that break down odours and pollutants. This tackles the conditions that allow odours to generate.

Similarly, so too does increasing the oxygen content in wastewater by using a diffuser aeration system.

Wet air scrubbing is a widely used technique for tackling wastewater odour problems. These systems draw large amounts of process-air from the fume source into the scrubber unit. This air is drawn under negative pressure helping to ensure that any contaminants are not released prior to reaching the scrubber itself. Once these unpleasant fumes are safely transported, the wet scrubber system then converts the vaporous odour pollutants into a liquid/condensate solution.

Odour and Emission Control Systems from Exeon

If odours persist or are at an unacceptable level, then an odour and emission control system may be appropriate. These reduce the amount of air pollution including odours via different types of site-specific filtration systems. They can tackle even the most persistent problems and provide a strong defence against odour problems at your sewage treatment plant.

Contact us to find out more about how Exeon can help you tackle unpleasant odours at your sewage treatment plant.