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Optimise plant nutrient management and struvite mitigation


Sidestreams such as digester supernatants, centrates and filtrates, are extremely high in phosphorus, which can lead to permit violations, heavy maintenance and costly shutdowns due to struvite buildup. PHOSPAQ is a cutting-edge system for phosphorus removal and recovery in high concentration streams, such as municipal sidestreams and industrial effluents.

The flexible and compact PHOSPAQ process helps manage complex streams with controlled struvite precipitation, and optional recovery, permitting optimised phosphorus management and operating and maintenance at the plant with minimal chemical handling requirements.

PHOSPAQ is a compact and highly efficient system that helps optimise phosphate management across the plant while also offering the flexibility of phosphorus recovery. The process also acts as an excellent pretreatment step ahead of deammonification, ensuring the overall process train optimisation with minimal operating and maintenance (O&M) requirements.

PHOSPAQ has numerous features and benefits, such as:

  • Flexibility of design for phosphorus removal or recovery
  • Low O&M Costs
  • Simple operation with compact construction
  • Enhanced struvite precipitation with free BOD and sulphide removal
  • Longest experience with large reference base

The PHOSPAQ is a continuous and completely mixed process in which the nitrogen and phosphorus present in the concentrated sidestream is reacted with magnesium oxide or magnesium hydroxide to form magnesium ammonium phosphate (MAP), otherwise known as struvite. The continuous aeration not only helps to mix the tank but also aids in stripping out the carbon dioxide, increasing the pH and thereby aiding formation of MAP, while also providing free BOD and sulphide removal.

The produced struvite can either just be dewatered, mixed with biosolids and disposed of, or additional unit processes can be added to clean and further increase the dry matter content of the struvite, enabling recovery as a fertiliser product.




PHOSPAQ™ is a registered trademark of Paques BV