Cristina Tuser is associate editor for Water & Wastes Digest. Tuser can be reached at [email protected].
Definition of Advanced Wastewater Treatment
The American Institute of Chemical Engineers defines advanced wastewater treatment as “any process that can reduce impurities in wastewater below [what is] attainable through conventional secondary or biological treatment.”
Why is Advanced Wastewater Treatment Technology Necessary?
These advanced treatment solutions have become an area of global interest as individuals, communities, and industries identify ways to keep essential resources available and suitable for use. Advanced wastewater treatment is necessary as society mitigates the impacts of increased population, urbanization, industrialization, and the depletion of potable water.
Wastewater treatment can not always treat wastewater efficiently, which can generate a number of concerns including odor issues and health problems. To keep up with these challenges, new techniques are implemented to treat wastewater.
With the application of these treatment technologies, it is possible to further improve the quality of wastewater beyond the limitations of conventional technologies to achieve the goal of resource recovery or resource conservation. Advanced wastewater treatment plant effluents may be recycled directly or indirectly to increase the available domestic water supply, as well.
According to The Food and Agriculture Organization of the United Nations, from a public health standpoint, “provisions adequate and reliable disinfection are the most essential features of the advanced wastewater treatment process.”
What Are the Processes of Advanced Wastewater Treatment?
Advanced wastewater treatment processes can be biological processes, physicochemical processes, or a combination of both.
Biological processes remove nutrient pollutants such as nitrogen and phosphorus.
Intermittently decanted extended aeration lagoon systems for nitrogen removal and biologically enhanced phosphorus removal systems are important tertiary treatment technologies. The extended aeration lagoon system biologically removes nitrogen from domestic wastewater.
Biological removal of nitrogen is a two-step process. The first step is the nitrification of ammonia nitrogen into nitrate-nitrogen by nitrifying bacteria and the second step is denitrification of nitrate nitrogen into nitrogen gas.
Physicochemical processes including deep-bed filtration, floating media filtration, and membrane filtration.
According to a sustainability assessment of advanced treatment technologies (Hoibye et al., 2008), other technologies include:
- Sand filtration;
- Ozone treatment;
- Ultraviolet (UV) exclusively for disinfection of pathogenic microorganisms;
- Membrane bioreactor (MBR);
- Advanced oxidation processes (AOP);
- UV in combination with advanced oxidation;
- Nanotechnology; and
- Automatic variable filtration.
New treatment technologies can remove a wide range of challenging contaminants from wastewater successfully. As the world grapples with shrinking water resources, advanced treatment will become critical to recovering water resources for both potable and non-potable uses.