Low-temperature alkali-modified fly ash as an effective adsorbent for removal of ammonia nitrogen, phosphorus and COD from the wastewater

Abstract

In this study, low-temperature alkali-modified fly ash and polymeric aluminum chloride(PAC) for the removal of total phosphorus, COD and ammonia nitrogen, from wastewater was systematacially investigated. The removal rate of ammonia nitrogen was 81.10%, and the removal rates of phosphorus and COD were 90.21% and 55.48%, respectively., when a dosage of the alkali-modified fly ash was 5g/L, the amount of PAC was 50mg/L, and the mixing time was 39min. In comparison with raw fly ash, the removal rate of ammonia nitrogen is 80.16% higher than that of the original fly ash, and the removal rate of total phosphorus is 35.48% higher. Fly ash with improved surface can be used as an alternative adsorbent to flocculate and precipitate in cooperation with polymeric aluminum chloride, which can be applied to the treatment of total phosphorus, COD and ammonia nitrogen in the sewage. This study provides a theoretical basis for the coagulation adsorption method and realizes the utilization of fly ash.