Chapter 4
Nitrogen and Phosphorous Recovery
from Municipal Wastewater and Sludge
Abstract Advanced municipal wastewater management aims to remove the contaminants from wastewater and sewage sludge to protect water quality and recover
resources such as nutrients and energy. Wastewater is usually treated through preliminary, primary, secondary and tertiary treatments. It contains significant amounts of
nutrients such as nitrogen and phosphorous that can be recovered and reused as fertilizers. Nitrogen is present in wastewater in the forms of nitrates, ammonia, particulate
organic nitrogen and soluble organic nitrogen. Ammonia could be removed from
the wastewater through the ammonia stripping process. The particulate fraction of
the organic nitrogen can be removed through solids separation using filtration or
sedimentation. Nitrates can be removed from wastewater in a biological nutrient
removal method through nitrification–denitrification process. Phosphorous exists in
wastewater in the forms of soluble and particulate phosphate. Particulate phosphate
can be removed/recovered from wastewater by filtration and clarification, while the
soluble fraction of the phosphorous can be removed/recovered by chemical precipitation, physical–chemical methods, biological treatment or a combination of various
methods. Wastewater sludge, a by-product of wastewater treatment, also contains
nutrients such as nitrogen and phosphorous, and energy in the form of organic carbon
compounds that can be recovered. Phosphorous from sludge can be removed by
incineration, seeding processes, precipitation, wet oxidation, physical/chemical and
thermal processes. The technology for nitrogen recovery from sludge is known as
ARP, which is based on ammonia concentration and crystallization. The nutrient
recovery technologies and the details of each process are discussed in this chapter.
Numerous nutrient recovery technologies have been developed fast in recent years,
and many of them have been implemented at full scale in many wastewater treatment plants around the world. The low price for nitrogenous fertilizer production
is, however, a great barrier for the economic viability of the nitrogen recovery from
wastewater or sludge. Instead, phosphorous is mined from mineral reserves that
are relatively limited. Thus, there is a greater motivation for phosphorous recovery
compared to nitrogen. The environmental factors of various nutrient recovery technologies greatly depend on the technological principles of each recovery method.
Generally, the technologies that recover phosphorous from wastewater are able to
reduce the environmental impacts.
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_4
97
Nitrogen and Phosphorous Recovery
from Municipal Wastewater and Sludge
Abstract Advanced municipal wastewater management aims to remove the contaminants from wastewater and sewage sludge to protect water quality and recover
resources such as nutrients and energy. Wastewater is usually treated through preliminary, primary, secondary and tertiary treatments. It contains significant amounts of
nutrients such as nitrogen and phosphorous that can be recovered and reused as fertilizers. Nitrogen is present in wastewater in the forms of nitrates, ammonia, particulate
organic nitrogen and soluble organic nitrogen. Ammonia could be removed from
the wastewater through the ammonia stripping process. The particulate fraction of
the organic nitrogen can be removed through solids separation using filtration or
sedimentation. Nitrates can be removed from wastewater in a biological nutrient
removal method through nitrification–denitrification process. Phosphorous exists in
wastewater in the forms of soluble and particulate phosphate. Particulate phosphate
can be removed/recovered from wastewater by filtration and clarification, while the
soluble fraction of the phosphorous can be removed/recovered by chemical precipitation, physical–chemical methods, biological treatment or a combination of various
methods. Wastewater sludge, a by-product of wastewater treatment, also contains
nutrients such as nitrogen and phosphorous, and energy in the form of organic carbon
compounds that can be recovered. Phosphorous from sludge can be removed by
incineration, seeding processes, precipitation, wet oxidation, physical/chemical and
thermal processes. The technology for nitrogen recovery from sludge is known as
ARP, which is based on ammonia concentration and crystallization. The nutrient
recovery technologies and the details of each process are discussed in this chapter.
Numerous nutrient recovery technologies have been developed fast in recent years,
and many of them have been implemented at full scale in many wastewater treatment plants around the world. The low price for nitrogenous fertilizer production
is, however, a great barrier for the economic viability of the nitrogen recovery from
wastewater or sludge. Instead, phosphorous is mined from mineral reserves that
are relatively limited. Thus, there is a greater motivation for phosphorous recovery
compared to nitrogen. The environmental factors of various nutrient recovery technologies greatly depend on the technological principles of each recovery method.
Generally, the technologies that recover phosphorous from wastewater are able to
reduce the environmental impacts.
© Springer Nature Singapore Pte Ltd. 2021
L. Nazari et al., Advanced and Emerging Technologies for Resource Recovery
from Wastes, Green Chemistry and Sustainable Technology,
https://doi.org/10.1007/978-981-15-9267-6_4
97