The study found that biofiltration was effective in reducing the concentrations of VOCs and odor in the petrochemical wastewater emissions. The removal efficiencies of the biofilters varied depending on the VOCs, with higher removal rates observed for aliphatic and aromatic hydrocarbons compared to halogenated hydrocarbons. The authors concluded that biofiltration could be a promising method for the treatment of odorous emissions from petrochemical wastewater and that further research is needed to optimize the biofilter design and operation parameters for enhanced performance.
Activated carbon filters
A third technology that is commonly used is activated carbon filters. These systems work by adsorbing the VOCs on the surface of the activated carbon, effectively removing them from the wastewater. Activated carbon filters can be made from a variety of materials, including coconut shells, coal and wood. Activated carbon is a porous material that has a large surface area, which allows it to adsorb large amounts of VOCs. Activated carbon filters are effective at controlling odors, but they can be expensive to operate and the carbon may need to be replaced frequently.
Photo-bioreactors
Another promising technology is the use of photo-bioreactors in wastewater treatment plants. These systems use a combination of algae and bacteria to naturally remove odor-causing compounds from the wastewater. This technology is based on the synergism between the two organisms, where the algae remove the organic matter while the bacteria consume the remaining nutrients, thus reducing the odor emissions. Photobioreactors can be used to treat both liquid and gaseous streams and can be integrated into existing treatment systems
The algae in the photobioreactor consume the organic matter in the wastewater and convert it into oxygen, which can then be used by the bacteria to consume the remaining nutrients. This process can effectively reduce the levels of VOCs and other pollutants in the wastewater.
3.5: UV-C lights
For the management of airborne bacteria, UV-C light is a commonly used technology. UV-C light is effective in killing bacteria, viruses and other microorganisms. By installing UV-C lights in the plant, it is possible to reduce the number of airborne bacteria and thus reducing the odors.
The team of Kaixiong Yang [2] investigate the emission characteristics and sources of airborne bacteria in a large-scale wastewater treatment plant and assessed the associated health risks to workers and nearby residents. The authors found that the concentration and diversity of airborne bacteria in the treatment plant varied greatly among different units and operational conditions, with higher levels of bacteria in areas with greater organic matter content, water depth and wastewater flow rate. The study also identified potential emission sources of airborne bacteria, including aeration tanks, sedimentation tanks and sludge treatment facilities.
The health risk assessment indicated that exposure to airborne bacteria in the wastewater treatment plant could pose a risk to the respiratory system of workers and neighboring residents, especially those with pre-existing respiratory conditions. The authors suggested that improving the ventilation systems, wearing protective equipment and minimizing the exposure time for workers could help to reduce the risk of health effects associated with airborne bacteria in the wastewater treatment plant.