Leading the biotech revolution
in wastewater and biogas


Discover phosphate filter PHOSPAQ™: the most cost-effective way to meet discharge requirements ánd produce valuable, EU-approved fertilizer.

Phosphate filter for removal and recovery

Phosphorus needs to be removed before industrial facilities can discharge wastewater or recycle it. Public water facilities also need a phosphate filter to transform sewage into drinking water. That’s because effluent from anaerobic reactors can still contain low levels of phosphate, BOD and ammonia. The PHOSPAQ™ post-treatment process removes biologically degradable COD, phosphate (PO43-) and ammonium (NH4+) from wastewater. It takes place in an aerated reactor, which provides optimal conditions for biological conversion of COD and quality struvite formation.

As phosphate becomes scarce, phosphorus recovery becomes more commercially interesting. PHOSPAQ™ allows facilities to harvest commercial phosphate. Struvite is an excellent slow-release, EU-approved fertilizer. Compared to e.g. dosing of iron salts, PHOSPAQ™ is a more cost-effective technology for phosphorus recovery.

How PHOSPAQ™ works

The PHOSPAQ™ process takes place in an aerated reactor. Aeration provides the oxygen for the biological conversion of COD and provides optimal conditions for struvite formation. Stripping of carbon dioxide raises the pH and stimulates struvite precipitation.

Magnesium oxide is added to remove phosphate that is recovered by precipitation as struvite at a pH of 8.2 to 8.3. The PHOSPAQ™ reactor is equipped with separators that retain the struvite.

The struvite is harvested from the bottom of the reactor by means of a hydrocyclone, followed by a screw press and transferred into a container. The dry weight of the harvested struvite is around 50% and the crystals have an average size of around 0,7 mm.


At Paques, we believe in a cleaner, more sustainable world where innovation in biotechnology plays a crucial role in managing our planet's resources wisely.

If you have any questions or wish to explore what Paques technologies can do for your operations, we encourage you to connect with our team of experts. Our knowledgeable professionals are ready to assist you, offering insights and guidance tailored to your specific needs.

Leading the biotech revolution in wastewater and biogas

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Thank you for reaching out to Paques

Your inquiry is important to us, and we are eager to assist you in exploring our innovative solutions for biological wastewater and gas treatment.

A member of our expert team will be in touch shortly to discuss your specific needs and how Paques can help you achieve your environmental and operational goals.

We look forward to collaborating with you and hope to build a cleaner, more sustainable world together.

Warm regards,
The Paques Team