One of the challenging yet critical aspects of wastewater treatment is controlling the foul odors. Uncontrolled wastewater odors can lead to complaints, litigations, and objections from neighbors and employees alike.
Since odor control in wastewater treatment facilities is crucial, professionals have developed numerous ways to treat it with the help of high-quality wastewater treatment chemicals which significantly mitigate the smell; they have shown results in detoxifying fumes as well.
Several technologies have been developed over the years to control and eliminate wastewater odors. This brief will explore the features of these technologies to help inform you and your team, organization, or municipality on solutions that work best for you. To learn more about water treatment systems be sure to check out Cleanawater.
Table of Contents
What are Wastewater Odors?
Wastewater emits foul odors when it is collected and treated in the plants. Most of the odor emission occurs during the collection process; however, this can also occur when wastewater is stagnant or not actively moving in pipes or drainage systems. The odors form due to the absence of oxygen in the wastewater. In such anaerobic conditions, the sulfate production increases resulting in the release of hydrogen sulfide (H2S), which has a strong, rotten egg-like smell.
Apart from H2S, mercaptans and amines are two other components often detected in wastewater treatment plants. These compounds are mostly made of nitrogen or sulfur and can be detected by the human nose, even at small concentrations.
As stated earlier, there are several methods to remove this odor. These methods can be broadly categorized into liquid-phase and vapor-phase technologies. Let us explore these methods in detail to understand the features and characteristics of each.
Impact of Uncontrolled Wastewater Odors
While many of these smells stay within the plant premises, the more noxious and foul-smelling odors like H2S can spread into neighboring areas. The odors can enter residential areas, public parks, and commercial areas, causing discomfort and breathing problems to people. Understandably, people can complain and, in worst cases, sue the management for such a nuisance.
If not addressed promptly, odor complaints can severely hamper production and brand image.
Techniques for Odor Control in Wastewater Treatment Facilities
Vapor-Phase Technology:
As the name suggests, these techniques control and eliminate odor in the gas or air. These techniques are usually applied at point-source facilities like pump stations, also known as lift stations, and at wastewater treatment plants. Lift stations can be strategically placed in underground facilities that allow for wastewater to be moved along the pipeline system to the main treatment plants. Lift stations can be designed such that wastewater is not fully isolated to the atmosphere, which can allow for H2S to off-gas, which people tend to smell in the neighborhoods of a city or municipality.
Vapor-phase technologies target the sources from where the odor is released and use a ventilation system to create negative pressure in the area, preventing the smell from leaking through vents and other routes. It is an effective way to treat and control toxic fumes. Enviro-Scrub® Bio inhibits the formation of H2S by introducing a nutrient-based product designed to change the metabolism of Sulfur Reducing Bacteria (SRB) which prevents H2S formation. Ideal for lift stations and other wastewater treatment applications.
Wet Air Scrubbing:
It is the most commonly used odor removal method in most wastewater treatment plants. With this technology, you can treat a variety of contaminants that dissolve in water. This method absorbs the pollutants from their gaseous state into a liquid chemical solution.
The mechanism is entirely chemical and does not affect the biological treatment process. Furthermore, you can also use odor control chemicals explicitly designed for this process to target a wide range of foul gases at different stages in a multi-stage scrubber. Applying different wastewater treatment chemicals at varying levels of concentrations at different stages in the scrubber will help you successfully control the odors while optimizing the chemical spend. Consider using Q2 Technologies’ Enviro-Scrub® for effective removal of H2S.
Biofiltration:
An effective method that can be used to eliminate water-soluble adulterants and is often used to remove sulphuric odors from wastewater. In combination with filtration systems, Enviro-Scrub® Bio is ideally paired to increase the efficiency and effectiveness of filtration systems.
Liquid Redox Technology:
Compared to the other odor removal methods, the liquid redox technology is costly and not commonly used in treatment plants due to capital expense requirements and sizing.
Carbon Absorption:
The gases emitted from the wastewater are passed over layers of absorbent carbon to soak up the odor-causing compounds. It is the most straightforward method of odor control under vapor phase technologies. Carbon media beds must often be replaced by cleaning or disposing of properly.
Solid Scavengers:
Last but not least is solid scavengers. These solid compounds eliminate sulfur from liquid or gas. Solid scavengers are primarily used in biogas plants to remove low concentrations of H2S. These may be in the form of pellets that float or sink in the wastewater and dissolve over time, typically used at the main wastewater facilities as this tends to be a more manual operations process.
Liquid-Phase Technology:
This method treats a wastewater stream with odor control chemicals to control the gases released. The wastewater treatment chemicals are added to the wastewater to stop the odor formation or to limit the smell by reacting with the contaminating compounds.
This treatment is mainly carried out in the collection systems to prevent the emission of hydrogen sulfide from the liquid into the surrounding air. Besides odor control, liquid phase technologies also help control corrosion on pipe crowns and process structures.
Liquid phase odor control treatments are usually a multi-point application. It can be applied to air relief valves, re-pump stations, maintenance holes, and more. Applications of iron salts, oxidizers, anthraquinone, and the bioxide process are some of the examples of liquid phase techniques frequently used in wastewater treatment facilities. Liquid-Phase as well as in Vapor-Phase, Wet-Air Scrubbing, and Biofiltration – Enviro-Scrub® Bio and Enviro-Scrub® are ideal products for treating H2S in wastewater management.
To learn more about water treatment systems be sure to check out Cleanawater.
In Conclusion:
The above-mentioned techniques are the most popular and effective ways to control odor emissions during wastewater treatment. There are many high-quality odor control treatments available on the market. Choose the best process with Q2 Technologies that suits your requirement to improve wastewater odor control.
