Efficient nitrogen removal from wastewater

Nitrogen compounds such as nitrate and ammonium need to be removed from wastewater to prevent eutrophication causing algae bloom. High concentrations of ammonium in wastewater depletes oxygen in water bodies and can poison fish. In light of more stringent legislation and tighter discharge limits enhanced nitrogen removal becomes paramount.

ANAMMOX® (ANaerobic AMMonium OXidation) is considered one of the best methods for nitrogen removal and ammonium removal in wastewater. The unique Paques granular sludge based ANAMMOX® process is converting ammonium into climate neutral nitrogen gas (N₂) without the need for any carbon source (e.g. methanol). The ANAMMOX® process is an energy efficient way saving up to 60% of energy consumption as compared to conventional biological processes.

The biological processes in ANAMMOX® also produce significantly less sludge and have a smaller carbon footprint compared to conventional nitrification/denitrification in wastewater treatment. ANAMMOX® applied in the sidedestreams of municipal wastewater treatment plants will boost the overall nitrogen removal performance so that expensive extension of the sewage works can become obsolete. ANAMMOX® is also applied for nitrogen removal from anaerobically treated industrial effluent. Due to the use of highly active dense granular sludge Paques ANAMMOX® reactors are compact and highly energy efficient (< 1 kWh/kgN).

Effluent from anaerobic reactors might still contain residual levels of BOD and possibly ammonia. The CIRCOX^® bioreactor is a very efficient aerobic system for the post-treatment of anaerobically treated effluents (BIOPAQ). The CIRCOX® is a continuous aerobic reactor system for simultaneous BOD removal and nitrogen removal from wastewater. The CIRCOX^® reactors are compact due to the use of granular sludge and require only a small footprint.