The removal of phosphorus from sanitary effluents is one of the main focuses of innovation in the sanitation sector in Brazil and worldwide. The growing need to reduce the discharge of this nutrient into receiving bodies has driven the development of new technologies to reduce phosphorus in sanitary effluent, increasing the efficiency of treatment plants (STPs) and contributing to environmental sustainability.
Phosphorus, which is present mainly due to the decomposition of organic waste and the use of detergents, is one of the main factors responsible for the eutrophication process – a phenomenon that causes algae proliferation, oxygen depletion and damage to aquatic life. Therefore, investing in appropriate solutions is essential to protect ecosystems and meet regulatory standards.
What is phosphorus removal in sanitary effluent?
Phosphorus removal involves reducing the phosphate forms present in sewage, usually dissolved and/or particulate. Treatment can take place using biological or physical-chemical processes, or both, selected according to the characteristics of the effluent, legal requirements and operating conditions.
Why is reducing phosphorus in wastewater important?
The presence of excess phosphorus can have serious environmental and health impacts. Its main consequences include:
- Proliferation of algae and cyanobacteria;
- Eutrophication, reducing water quality;
- Loss of biodiversity;
- Change in the taste and smell of the water;
- Difficulties in the collection and treatment processes for supply.
Globally, several countries are setting increasingly strict limits for total phosphorus, such as the United States, the Netherlands and Sweden. In Brazil, state legislation has been adopting more restrictive criteria in sensitive regions, which is driving the modernization of WWTPs and the use of more advanced technologies.
Main technologies for reducing phosphorus in sanitary effluent
Below, we present the main solutions applied to phosphorus removal in sanitary effluents, from consolidated approaches to emerging technologies.
Biological Processes: MBBR and IFAS Reactors and Bio-removal
Phosphorus removal can be intensified with the adoption of technologies such as Phosphorus Accumulating Bacteria (PAOs) and the use of mobile or fixed media to intensify biological activity.
Physical-chemical processes:
Chemical Precipitation Struvite (MgNH₄PO₄-6H₂O)
Application of metallic salts (aluminum, iron or calcium) to form insoluble precipitates.
Coagulation and Flocculation
Removal of particulate phosphorus associated with suspended solids.
How to apply technologies to reduce phosphorus in sanitary effluent
The choice of technology depends on variables such as
- Initial phosphorus concentration;
- Existing structure of the WWTP;
- Launch targets;
- Operational and cost requirements.
General Steps:
Best practices and common mistakes
Good practices
- Monitor total phosphorus and orthophosphate regularly;
- Adjust chemical dosage to avoid under- or overdosing;
- Train operators in real-time adjustments.
Common mistakes
- Only consider soluble phosphorus and ignore particulates;
- Lack of evaluation of the sludge generated, increasing costs;
- Selecting technology without analyzing CAPEX and OPEX impacts;
- Disregard synergy with nitrogen removal processes.
Conclusion
Controlling phosphorus in sanitary effluents is essential to preserving the quality of water bodies and complying with environmental requirements. Globally, technologies to reduce phosphorus in sanitary effluent are evolving towards integrated, efficient solutions in line with the circular economy.
Contact our PDI team for an expert technical assessment.