Biological nutrient removal

• Energy-effective treatment of sludge digestion effluent
• Highly efficient post-treatment of anaerobic effluent
• Compact effluent polishing in wastewater treatment plants

Typically, 15-25% of the total nitrogen load of a municipal wastewater treatment plant derives from the reject water. If the final effluent exceeds nitrogen limits, plant managers can effectively increase the nitrogen removal capacity of the overall treatment by treating the sidestream dewatering reject water that comes from sludge digestion. The Paques ANAMMOX® technology removes ammoniacal nitrogen (NH4) without the use of an external carbon source such as methanol, and requires 60% less energy than conventional systems using biological nitrification-denitrification in wastewater treatment.

Combining ANAMMOX with the PHOSPAQ technology allows for additional removal and recovery of phosphate by producing a slow-release struvite fertilizer. Application of ANAMMOX after BIOPAQ anaerobic treatment will maximize the production of renewable energy (production of biogas) as all COD can be anaeobicaly converted and no bypass is required for conventional denitrification.

Effluent from anaerobic reactors still contains residual levels of BOD and possibly ammonia and phosphate. The CIRCOX® bioreactor is a very efficient aerobic system for the treatment of anaerobic effluents. It uses aerobic granular sludge in an airlift bioreactor for COD and biological nutrient removal. This compact CIRCOX system is an aerobic system with outstanding purification performance, as the purified effluent can be further polished to be discharged to surface water. Combining BIOPAQ anaerobic treatment with CIRCOX aerobic polishing allows for highly efficient purification, producing renewable energy (biogas) at the smallest footprint.

Find out if CIRCOX® is the most cost-effective solution for your facility

To raise the effluent quality of industrial or municipal wastewater treatment plants, a treatment stage can be added for enhanced biological nutrient removal. The ASTRASAND® continuous sand filtration technology can combine the removal of TSS and nutrients in one single filter. Through chemical precipitation, nitrification or denitrification of wastewater it can reduce concentrations of nitrogen, BOD, phosphate and TSS. ASTRASAND® removes total nitrogen to levels below 2 mg/l and total phosphate to 0.15 mg/l. The ASTRASAND filter operates under a constant backwash mode, continuously cleaning the filter bed. This self-cleaning, continuous process allows for consistently high filtrate quality.