Production of zeolite composite filters using waste paper pulp as slow release carbon source and performance investigation in a biological aerated filter

The filter medium plays an important role in modulating the performance of biological aerated filters (BAFs). In this study, a zeolite composite filter (ZCF) was fabricated using a mixture of natural zeolite powder as the main material, cement as the binder, and waste paper pulp as the pore-forming agent (slow-release carbon source). Scanning electron microscopy and porosimetry were then conducted to evaluate the properties of the ZCF. Results showed that the uniform and interconnected pores of the ZCF are suitable for microbial growth. ZCF and commercially available ceramsite (CAC) used in an upflow laboratory-scale BAF were investigated to determine their suitability for advanced wastewater treatment. The results indicated that the ZCF–BAF is superior to the CAC–BAF in terms of total organic carbon, total nitrogen, ammonia nitrogen, and phosphorus removal. The carbon source from the waste paper pulp was released slowly, which decisively influenced simultaneous nitrification and denitrification. Therefore, ZCF is suitable for use as a novel filter medium for the simultaneous removal of nitrogen and phosphorus in BAFs for advanced wastewater treatment.