Adsorption/precipitation prototype agent for simultaneous removal of phosphorus and organic micropollutants from wastewater

Abstract

In this study, the effectiveness of a novel adsorbent/precipitant containing powdered activated carbon (PAC) and poly aluminum chloride (PACl) was evaluated for the simultaneous removal of organic micropollutants (OMP) and phosphorus. Results showed better performance with the prototype suspension at similar PAC/DOC doses, possibly due to changes in surface chemistry caused by PAC's suspension in the acid precipitant. Further lab tests with wastewater treatment plant (WWTP) effluent samples confirmed the prototype's effectiveness for different matrices. They highlighted the need for optimizing PAC content based on the total phosphorus and DOC content of the wastewater to use both PAC and PACl most efficiently. Full-scale testing at a specific PAC/DOC ratio of 2 over one month demonstrated the prototype's suitability for simultaneous phosphorus and OMP removal under real WWTP conditions. OMP removal increased by > 90 % for carbamazepine, > 50 % for diclofenac and metoprolol, and 30 % for benzotriazole; overall, > 80 % elimination was achieved for all investigated proxy substances. The full-scale experience confirmed that the prototype is easier to store and to apply. It can be immediately used in existing P-dosing systems without additional investment costs, making it advantageous over other OMP removal technologies.