Emerging wastewater treatment strategy for efficient nitrogen removal and compact footprint by coupling mainstream nitrogen separation with chemical coagulation and biological aerated filter

In this study, an ammonia nitrogen (NH4+-N) ion exchange (IE) and regeneration (AIR) was constructed, and the chemical enhanced primary treatment (CEPT), AIR and biological aerated filter (BAF) were coupled in series to construct a novel CEPT-AIR-BAF process for efficient pollutants removal. At total hydraulic retention time of 4.6 h, the pilot-scale CEPT-AIR-BAF system obtained effluent with chemical oxygen demand of 17.9 +/- 6.0 mg/L, NH4+-N of 0.5 +/- 0.3 mg/L, total nitrogen of 2.4 +/- 1.0 mg/L and total phosphorus of 0.08 +/- 0.05 mg/L. AIR module achieved outstanding NH4+-N IE performance with NaClO-NaCl regeneration, and long-term regeneration increased surface area and mesopore of zeolites. Faster-growing heterotrophic bacteria, such as Pseudomonas and Comamonas, were enriched in BAF. The CEPT-AIR-BAF system saved at least 60% of land occupation and upfront investment, and the treatment cost ($ 0.155/m(3)) should be further reduced by investigations on the regeneration of loaded zeolite.